Hyperbranched polymers and multiarm star polymers are a type of dendritic polymers which have attracted substantial interest during the last 30 years because of their unique properties. They can be used to modify epoxy thermosets to... more
Hyperbranched polymers and multiarm star polymers are a type of dendritic polymers which have attracted substantial interest during the last 30 years because of their unique properties. They can be used to modify epoxy thermosets to increase their toughness and flexibility but without adversely affecting other properties such as reactivity or thermal properties. In addition, the final properties of materials can be tailored by modifying the structure, molecular weight, or type of functional end-groups of the hyperbranched and multiarm star polymers. In this review, we focus on the modification of epoxy-based thermosets with hyperbranched and multiarm star polymers in terms of the effect on the curing process of epoxy formulations, thermal, mechanical, and rheological properties, and their advantages in fire retardancy on the final thermosets.
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In this work, a new family of poly(thiourethane) shape memory thermosetting actuators was developed and characterized. These materials can be easily prepared from mixtures of two different aliphatic diisocyanates and a trithiol in the... more
In this work, a new family of poly(thiourethane) shape memory thermosetting actuators was developed and characterized. These materials can be easily prepared from mixtures of two different aliphatic diisocyanates and a trithiol in the presence of a latent catalyst, allowing an easy manipulation of the formulation. Rheological studies of the curing process confirm the latent character of the formulations. The glass transition temperatures and the mechanical properties can be modified by varying the proportion of diisocyanates (hexamethylene diisocyanate, HDI, and isophorone diisocyanate, IPDI) with stoichiometric amounts of trimethylolpropane tris(3-mercaptopropionate). The shape-memory behavior was deeply investigated under three different conditions: unconstrained, partially constrained, and fully constrained. Tests were performed in single cantilever bending mode to simulate conditions closer to real complex mechanics of thermomechanical actuators under flexural performances. The ...
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Click chemistry has emerged as an effective polymerization method to obtain thermosets with enhanced properties for advanced applications. In this article, commonly used click reactions have been reviewed, highlighting their advantages in... more
Click chemistry has emerged as an effective polymerization method to obtain thermosets with enhanced properties for advanced applications. In this article, commonly used click reactions have been reviewed, highlighting their advantages in obtaining homogeneous polymer networks. The basic concepts necessary to understand network formation via click reactions, together with their main characteristics, are explained comprehensively. Some of the advanced applications of thermosets obtained by this methodology are also reviewed.
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Epoxy resins are commonly used as thermosetting materials due to their excellent mechanical properties, high adhesion to many substrates and good heat and chemical resistances. This type of thermosets is intensively used in a wide range... more
Epoxy resins are commonly used as thermosetting materials due to their excellent mechanical properties, high adhesion to many substrates and good heat and chemical resistances. This type of thermosets is intensively used in a wide range of fields, where they act as fiber-reinforced materials, general-purpose adhesives, high-performance coatings and encapsulating materials. These materials are formed by the chemical reaction of multifunctional epoxy monomers forming a polymer network produced through an irreversible way. In this article the improvement of the characteristics of epoxy thermosets using different hyperbranched poly(ethyleneimine) (PEI) derivatives will be explained.
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Novel composite coatings prepared from 3,4-epoxy cyclohexylmethyl 3,4-epoxycyclohexane carboxylate (ECC) and different ceramic fillers have been prepared to improve the thermal dissipation of electronic devices. As latent cationic... more
Novel composite coatings prepared from 3,4-epoxy cyclohexylmethyl 3,4-epoxycyclohexane carboxylate (ECC) and different ceramic fillers have been prepared to improve the thermal dissipation of electronic devices. As latent cationic initiator, a benzylanilinium salt with triethanolamine has been used, which leads to a polyether matrix. Different proportions of Al2O3, AlN and SiC as fillers were added to the reactive formulation. The effect of the fillers selected and their proportions on the evolution of the curing was studied by calorimetry and rheometry. The thermal conductivity, thermal stability, thermal expansion coefficient and thermomechanical and mechanical properties of the composites were evaluated. An improvement of 820% in thermal conductivity in reference to the neat material was reached with a 75 wt % of AlN, whereas glass transition temperatures higher than 200 °C were determined in all the composites.
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Research Interests: Materials Engineering, Chemical Engineering, Materials Science, Analytical Chemistry, Polymer Chemistry, and 14 moreCatalysis, Polymer, Differential scanning calorimetry, Cationic polymerization, Epoxy, Epoxy Resins, Glass Transition, Thermal Analysis, Thermal Stability, Thermogravimetric Analysis, Eugenol, Squalene, Click, and Thermosets
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Photoinitiated thiol-yne reaction was combined with thermal thiol-epoxy to get thermosets by dual curing from propargyl decorated poly(ethyleneimine) and DGEBA.
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A new dual curing procedure based in the combination of UV-induced thiol-ene and thermal thiol-epoxy reactions has been established by the use of a latent amine precursor that can catalyze the thermal process.
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Mixtures of DGEBA with γ-valerolactone (γ-VL) or α-methyl-γ-butyrolactone (γ-MBL) 2:1 (mol/mol) were cationically copolymerized in the presence of scandium, ytterbium, or lanthanum triflates as initiators. The evolution of the different... more
Mixtures of DGEBA with γ-valerolactone (γ-VL) or α-methyl-γ-butyrolactone (γ-MBL) 2:1 (mol/mol) were cationically copolymerized in the presence of scandium, ytterbium, or lanthanum triflates as initiators. The evolution of the different reactive groups was followed by means of FTIR/ATR spectroscopy. From these experiments, we could detect the coexistence of two unexpected processes: a reversion of the intermediate spiroorthoester formed to the initial products and a depolymerization process, which only takes place in samples with γ-VL, when scandium triflate was used as initiator or when the proportion of ytterbium triflate was increased from 1 to 3 phr. When γ-MBL was used as comonomer no depolymerization occurs which supports the proposed mechanism. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2129–2141, 2007
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Research Interests: Engineering, Materials Science, Polymer Chemistry, Kinetics, FTIR, and 14 moreDifferential scanning calorimetry, bisphenol A, Applied, Cationic polymerization, Crosslinking, Epoxy, CHEMICAL SCIENCES, Thermal Stability, Thermogravimetric Analysis, Ether, Shrinkage, Reaction Mechanism, Journal of Applied Polymer Science, and Thermosets
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Cellulose nanocrystals (CNCs) are attractive materials due to their renewable nature, high surface-to-volume ratio, crystallinity, biodegradability, anisotropic performance, or available hydroxyl groups. However, their source and... more
Cellulose nanocrystals (CNCs) are attractive materials due to their renewable nature, high surface-to-volume ratio, crystallinity, biodegradability, anisotropic performance, or available hydroxyl groups. However, their source and obtaining pathway determine their subsequent performance. This work evaluates cellulose nanocrystals (CNCs) obtained from four different eucalyptus species by acid hydrolysis, i.e., E. benthamii, E. globulus, E. smithii, and the hybrid En × Eg. During preparation, CNCs incorporated sulphate groups to their structures, which highlighted dissimilar reactivities, as given by the calculated sulphate index (0.21, 0.97, 0.73 and 0.85, respectively). Although the impact of the incorporation of sulphate groups on the crystalline structure was committed, changes in the hydrophilicity and water retention ability or thermal stability were observed. These effects were also corroborated by the apparent activation energy during thermal decomposition obtained through kine...
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Dual-curing thermosetting systems are recently being developed as an alternative to conventional curing systems due to their processing flexibility and the possibility of enhancing the properties of cured parts in single- or multi-stage... more
Dual-curing thermosetting systems are recently being developed as an alternative to conventional curing systems due to their processing flexibility and the possibility of enhancing the properties of cured parts in single- or multi-stage processing scenarios. Most dual-curing systems currently employed in three-dimensional (3D) printing technologies are aimed at improving the quality and properties of the printed parts. However, further benefit can be obtained from control in the curing sequence, making it possible to obtain partially reacted 3D-printed parts with tailored structure and properties, and to complete the reaction by activation of a second polymerization reaction in a subsequent processing stage. This paves the way for a range of novel applications based on the controlled reactivity and functionality of this intermediate material and the final consolidation of the 3D-printed part after this second processing stage. In this review, different strategies and the latest deve...
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A new type of tetraphenylborate salts derived from highly basic and nucleophilic amines, namely 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU) and triazabicyclodecene (TBD), was applied to the preparation... more
A new type of tetraphenylborate salts derived from highly basic and nucleophilic amines, namely 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU) and triazabicyclodecene (TBD), was applied to the preparation of networked poly(thiourethane)s (PTUs), which showed a vitrimer-like behavior, with higher stress-relaxation rates than PTUs prepared by using dibutyl thin dilaurate (DBTDL) as the catalyst. The use of these salts, which release the amines when heated, instead of the pure amines, allows the formulation to be easily manipulated to prepare any type of samples. The materials prepared from stoichiometric mixtures of hexamethylene diisocyanate (HDI), trithiol (S3) and with a 10% of molar excess of isocyanate or thiol were characterized by FTIR, thermomechanical analysis, thermogravimetry, stress-relaxation tests and tensile tests, thus obtaining a complete thermal and mechanical characterization of the materials. The recycled materials obtained by grin...
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A series of bio-based epoxy shape-memory thermosetting polymers were synthesized starting from a triglycidyl phloroglucinol (3EPOPh) and trimethylolpropane triglycidyl ether (TPTE) as epoxy monomers and a polyetheramine (JEF) as... more
A series of bio-based epoxy shape-memory thermosetting polymers were synthesized starting from a triglycidyl phloroglucinol (3EPOPh) and trimethylolpropane triglycidyl ether (TPTE) as epoxy monomers and a polyetheramine (JEF) as crosslinking agent. The evolution of the curing process was studied by differential scanning calorimetry (DSC) and the materials obtained were characterized by means of DSC, thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), stress-strain tests, and microindentation. Shape-memory properties were evaluated under free and totally constrained conditions. All results were compared with an industrial epoxy thermoset prepared from standard diglycidyl ether of Bisphenol A (DGEBA). Results revealed that materials prepared from 3EPOPh were more reactive and showed a tighter network with higher crosslinking density and glass transition temperatures than the prepared from DGEBA. The partial substitution of 3EPOPh by TPTE as epoxy comonomer caused an i...
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The pure trifunctional glycidyl monomer from phloroglucinol (3EPO-Ph) was synthesized and used as feedstock in the preparation of novel bio-based thermosets by thiol-epoxy curing. The monomer was crosslinked with different commercially... more
The pure trifunctional glycidyl monomer from phloroglucinol (3EPO-Ph) was synthesized and used as feedstock in the preparation of novel bio-based thermosets by thiol-epoxy curing. The monomer was crosslinked with different commercially available thiols: tetrafunctional thiol (PETMP), trifunctional thiol (TTMP) and an aromatic dithiol (TBBT) as curing agents in the presence of a base. As catalyst, two different commercial catalysts: LC-80 and 4-(N,N-dimethylamino) pyridine (DMAP) and a synthetic catalyst, imidazolium tetraphenylborate (base generator, BG) were employed. The curing of the reactive mixtures was studied by using DSC and the obtained materials by means of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and dynamic mechanical thermal analysis (DMTA). The results revealed that only the formulations catalyzed by BG showed a latent character. Already prepared thermosetting materials showed excellent thermal, thermomechanical and mechanical propertie...
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New thermosets from a triglycidyl eugenol derivative (3EPOEU) as a renewable epoxy monomer were obtained by an epoxy-amine curing process. A commercially-available Jeffamine® and isophorone diamine, both obtained from renewable resources,... more
New thermosets from a triglycidyl eugenol derivative (3EPOEU) as a renewable epoxy monomer were obtained by an epoxy-amine curing process. A commercially-available Jeffamine® and isophorone diamine, both obtained from renewable resources, were used as crosslinking agents, and the materials obtained were compared with those obtained from a standard diglycidylether of bisphenol A (DGEBA). The evolution of the curing process was studied by differential scanning calorimetry and the materials obtained were characterized by means of calorimetry, thermogravimetry, thermodynamomechanical analysis, stress–strain tests and microindentation. 3EPOEU formulations were slightly less reactive, and the thermosets obtained showed higher Tgs than those prepared from DGEBA, since they had higher crosslinking density than formulations with DGEBA because of the more compact structure and higher functionality of the eugenol derivative. 3EPOEU thermosets showed good thermal stability and mechanical proper...
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ABSTRACT Hybrid thiol-ene system based on a hyperbranched polyester with different degrees of 10-undecenoyl modification are prepared via a dual UV-thermal process. The pristine thiol-ene formulation shows a high reactivity towards UV... more
ABSTRACT Hybrid thiol-ene system based on a hyperbranched polyester with different degrees of 10-undecenoyl modification are prepared via a dual UV-thermal process. The pristine thiol-ene formulation shows a high reactivity towards UV curing and the addition of the inorganic precursor to the photocurable formulation does not affect the UV-curing process. The crosslinked systems show an increase of Tg by increasing the vinyl functionality content in the HBP and a Tg increase is also evidenced in the hybrid system as a function of inorganic precursor content. Morphological investigations show that the inorganic domains generated in situ are homogeneously distributed throughout the polymeric matrix. By varying the 10-undecenoyl modification in the terminal groups of the HBP, the size of the inorganic domains is tunable and it is possible to decrease the dimension of the silica domains by using the HBP with a higher modification degree.
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Diglycidylether of bisphenol A (DGEBA) was cured with different proportions of 1,6-dioxaspiro[4.4]nonane-2,7-dione (s(γ-BL)) with ytterbium triflate as initiator. The curing was studied with differential scanning calorimetry (DSC) and... more
Diglycidylether of bisphenol A (DGEBA) was cured with different proportions of 1,6-dioxaspiro[4.4]nonane-2,7-dione (s(γ-BL)) with ytterbium triflate as initiator. The curing was studied with differential scanning calorimetry (DSC) and Fourier transform infrared in the attenuated total reflection mode (FTIR/ATR). FTIR/ATR was used to monitor the competitive reactive processes and to quantify the conversion of the epoxide, lactone and intermediate spiroorthoester (SOE)
Research Interests: Engineering, Kinetics, Polymer, Differential scanning calorimetry, bisphenol A, and 8 moreCHEMICAL SCIENCES, Glass Transition Temperature, Fourier transform infrared spectroscopy, Dynamic Mechanical Thermal Analysis (DMTA), Shrinkage, Fourier transform infrared, Mechanical Property, and Thermal Degradation
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Research Interests: Engineering, Materials Engineering, Chemical Engineering, Kinetics, FTIR, and 15 morePolymer, Applied, DSC, Epoxy, CHEMICAL SCIENCES, Polymer Degradation, Epoxy Resin, Reaction Rate, Reaction Mechanism, Journal of Applied Polymer Science, Hydrolysis, Chemical Stability, Anionic Polymerization, Ring Opening Polymerization, and kinetic analysis
... Correspondence: Marina Galià, Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili, Plaça Imperial Tarraco 1, 43005 Tarragona, Spain. Publication History. ... 7 Galante, MJ; Williams, RJJ J Appl Polym Sci... more
... Correspondence: Marina Galià, Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili, Plaça Imperial Tarraco 1, 43005 Tarragona, Spain. Publication History. ... 7 Galante, MJ; Williams, RJJ J Appl Polym Sci 1995, 55, 89. ...
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ABSTRACT A new hyperbranched poly(ethyleneimine) with ethoxysilyl groups at the chain ends has been synthesized and characterized and then used in epoxy formulations to generate new organic/inorganic hybrid materials. Formulations of... more
ABSTRACT A new hyperbranched poly(ethyleneimine) with ethoxysilyl groups at the chain ends has been synthesized and characterized and then used in epoxy formulations to generate new organic/inorganic hybrid materials. Formulations of different proportions of diglycidylether of bisphenol A and the prepared ethoxysilylated hyperbranched poly(ethyleneimine) were maintained in a thermostatized controlled humidity chamber to form the inorganic silica network by a sol-gel process and then the epoxy resin was cured at higher temperature using 1-methylimidazole as anionic initiator.
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ABSTRACT Hyperstar polymers (HSPs) with hyperbranched aromatic polyester core and arms consisting of block copolymers of poly(methyl methacrylate) and poly(hydroxyethyl methacrylate) have been used as polymeric modifiers in cycloaliphatic... more
ABSTRACT Hyperstar polymers (HSPs) with hyperbranched aromatic polyester core and arms consisting of block copolymers of poly(methyl methacrylate) and poly(hydroxyethyl methacrylate) have been used as polymeric modifiers in cycloaliphatic epoxy-anhydride formulations catalyzed with tertiary amines, with the purpose of enhancing the impact strength of the resulting materials without compromising other thermal and mechanical properties.> In this work, the effect of these polymeric modifiers on the curing kinetics, processing, thermal-mechanical properties and thermal stability has been studied using thermal analysis techniques such as DSC, TMA, DMA, and TGA. The morphology of the cured materials has been analyzed with SEM. The curing kinetics has been analyzed by isoconversional procedures and phenomenological kinetic models taking into account the vitrification during curing, and the degradation kinetics has been analyzed by means of isoconversional procedures, summarizing the results in a time-temperature-transformation (TTT) diagram. The results show that HSPs participate in the crosslinking process due to the presence of reactive groups, without compromising significantly their thermal-mechanical properties. The modified materials show a potential toughness enhancement produced by the formation of a nano-grained morphology. The TTT diagram is shown to be a useful tool for the optimization of the curing schedule in terms of curing completion and safe processing window, as well as for defining storage stability conditions. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014
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... Roser Cervellera a , Xavier Ramis b , Josep Maria Salla b , Angels Serra a and Ana Mantecón a , Corresponding Author Contact Information , E-mail The ... Various kinetic models have been studied: diffusion (D 1 , D 2 , D 3 and D 4 ),... more
... Roser Cervellera a , Xavier Ramis b , Josep Maria Salla b , Angels Serra a and Ana Mantecón a , Corresponding Author Contact Information , E-mail The ... Various kinetic models have been studied: diffusion (D 1 , D 2 , D 3 and D 4 ), AvramiErofeev (A 2 , A 3 and A 4 ), power ...
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Rare earth metal triflates, BF3· MEA and N, N-dimethylaminopyridine (DMAP) were used as cationic and anionic initiators to cure mixtures of diglycidylether of bisphenol A (DGEBA) and Meldrum acid (2, 2-dimethyl-4, 6-dioxo-1, 3-dioxane)... more
Rare earth metal triflates, BF3· MEA and N, N-dimethylaminopyridine (DMAP) were used as cationic and anionic initiators to cure mixtures of diglycidylether of bisphenol A (DGEBA) and Meldrum acid (2, 2-dimethyl-4, 6-dioxo-1, 3-dioxane) derivatives in several proportions. ...
Research Interests: Materials Engineering, Mechanical Engineering, Collagen Cross-linking, bisphenol A, Epoxy Resins, and 10 moreRare Earth, Fourier transform infrared spectroscopy, Service Life, Three Dimensional, Epoxy Resin, Copolymerization, Chemical Structure, Fourier transform infrared, Thermal Degradation, and Thermosets
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ABSTRACT The curing reaction of formulations of diglycidyl ether of bisphenol A (DGEBA) and tetrahydrophthalic anhydride (THPA) catalyzed with a tertiary amine and containing sepiolite and/or hyperbranched poly(ester) has been studied by... more
ABSTRACT The curing reaction of formulations of diglycidyl ether of bisphenol A (DGEBA) and tetrahydrophthalic anhydride (THPA) catalyzed with a tertiary amine and containing sepiolite and/or hyperbranched poly(ester) has been studied by means of DSC, and the effect of each additive has been evaluated. The resulting coatings have been characterized by DMTA, TGA and also the shrinkage during the curing process has been determined. The influence of the additives in the toughness of the resulting coatings has been determined by performing standardized impact tests and observing the fracture surfaces by SEM. The values of impact strength have been correlated to the morphology of the samples by means of TEM. Also microhardness of the cured materials has been measured.
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ABSTRACT The synthesis and characterization of two novel amphiphilic multiarm star polymers with linear polyethylene glycol (PEG) and poly(ε-caprolactone) (PCL) arms and their use as toughening modifiers of epoxy anhydride thermosets are... more
ABSTRACT The synthesis and characterization of two novel amphiphilic multiarm star polymers with linear polyethylene glycol (PEG) and poly(ε-caprolactone) (PCL) arms and their use as toughening modifiers of epoxy anhydride thermosets are reported. The new star polymers were obtained by partial pegylation of a hyperbranched polyester and subsequent growth of PCL arms. The curing process was studied by calorimetry and thermomechanical analysis, demonstrating the accelerating effect and the influence on gelation of the hydroxyl terminal groups. The curing kinetics was analyzed by model-free and model-fitting methods. The final properties of the resulting materials were determined by thermal and mechanical tests. The addition of the star-like modifiers led only to notable improvement on impact strength in the material containing a 10% of the star with PCL and PEG arms, without compromising glass transition temperature and thermal stability. The morphology of the resulting materials depended on the structure of the toughness modifier used, as demonstrated by electron microscopy, but all modified thermosets obtained showed phase-separated morphologies with nanosized particles.
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ABSTRACT Multiarm star with poly(ethyleneimine) core and poly(e-caprolactone) arms as modifiers of diglycidylether of bisphenol A thermosets cured by 1-methylimidazole a b s t r a c t Well-defined multiarm star copolymers, with... more
ABSTRACT Multiarm star with poly(ethyleneimine) core and poly(e-caprolactone) arms as modifiers of diglycidylether of bisphenol A thermosets cured by 1-methylimidazole a b s t r a c t Well-defined multiarm star copolymers, with hyperbranched poly(ethyleneimine) (PEI) as the core and poly(e-caprolactone) (PCL) arms with different degree of polymerization were synthesized by cationic ring-opening polymerization of e-caprolactone from a hyperbranched poly(ethyleneimine) core and used to modify diglycidylether of bisphenol A formulations cured with 1-methylimidazole as anionic initiator. The curing process was studied by dynamic scanning calorimetry (DSC) and FTIR. By rheometry the com-plex viscosity of the multiarm stars synthesized and the influence of their addition to the reactive mix-ture was analyzed in detail. The resulting materials were characterized by thermal and mechanical tests. The addition of the multiarm star to the formulation led to homogeneous materials with a slightly tough-ened fracture in comparison to neat DGEBA thermosets without compromising thermal characteristics.
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A series of methyl ω-[p-(2,3-epoxypropoxy)phenyl] alkanoate esters of different lengths is prepared using a multistep synthetic method. These compounds which have 0, 1, 2, 5, 8 and 11 methylene groups are homopolymerized and copolymerized... more
A series of methyl ω-[p-(2,3-epoxypropoxy)phenyl] alkanoate esters of different lengths is prepared using a multistep synthetic method. These compounds which have 0, 1, 2, 5, 8 and 11 methylene groups are homopolymerized and copolymerized with non-functionalized phenylglycidylether (PGE) using the ionic coordinative initiator described by Teyssié. Other ionic-coordinative initiators were found to be less effective. All homo- and copolymers are characterized by NMR spectroscopy and their tacticity is determined. Their thermal characteristics were also studied by DSC.
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New epoxy resins have been synthesized by the reaction of diimide-diacids trimellitimide derivatives containing different aliphatic and aromatic fragments in N-methyl pyrrolidone (NMP) with their corresponding diglycidylesters, using... more
New epoxy resins have been synthesized by the reaction of diimide-diacids trimellitimide derivatives containing different aliphatic and aromatic fragments in N-methyl pyrrolidone (NMP) with their corresponding diglycidylesters, using several molar ratios. ...
ABSTRACT Multiarm star polymers have been synthesized by cationic ring-opening polymerization of epsilon-caprolactone from a hyperbranched poly(ethyleneimine) core and end-capped with acetic anhydride. These star polymers have been used... more
ABSTRACT Multiarm star polymers have been synthesized by cationic ring-opening polymerization of epsilon-caprolactone from a hyperbranched poly(ethyleneimine) core and end-capped with acetic anhydride. These star polymers have been used as modifiers in diglycidylether of bisphenol A/methyl tetrahydrophthalic anhydride/benzyl dimethylamine formulations. The curing process is studied by dynamic scanning calorimetry and rheometry and the resulting thermosets are characterized by dynamic mechanical thermal analysis and thermogravimetry. Internal stresses generated during curing are measured and interpreted in terms of the thermal mechanical properties of the cured materials. The influence of the modifier in the toughness improvement of the cured thermosets is determined by standardized impact tests and the microstructure of the material observed by scanning electron microscopy.
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ABSTRACT A hyperbranched aromatic polyester (HBPOH) has been synthesized, and poly(ε-caprolactone) arms have been grown on some of its end hydroxyl groups (HBPCL). These modifiers have been used in cationic diglycidyl ether of bisphenol A... more
ABSTRACT A hyperbranched aromatic polyester (HBPOH) has been synthesized, and poly(ε-caprolactone) arms have been grown on some of its end hydroxyl groups (HBPCL). These modifiers have been used in cationic diglycidyl ether of bisphenol A formulations cured with ytterbium triflate as cationic initiator. The effect of HBPOH and HBPCL on the curing kinetics has been studied using differential scanning calorimetry (DSC). The obtained materials have been characterized by dynamomechanical analysis, DSC, thermogravimetric analysis and mechanical tests. The modifiers are incorporated into the thermosetting network because of the participation of the end hydroxyl groups in the cationic curing of epoxides by the activated monomer mechanism. Homogeneous thermosets have been obtained with a remarkable increase in impact strength without sacrificing elastic modulus or hardness. A compromise between the rigid structure of the aromatic hyperbranched core and the flexibilizing effect of the poly(ε-caprolactone) arms is believed to be responsible for the overall thermal and mechanical properties of the materials. The use of these polymeric modifiers increases the thermal stability of the resulting materials because of the low degradability of the aromatic ester groups in the hyperbranched core and the incorporation of the modifier into the network structure. However, the presence of such ester groups makes them reworkable by hydrolysis or alcoholysis in an alkaline medium, thus opening a way for recovery of valuable substrates. Copyright © 2013 John Wiley & Sons, Ltd.
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ABSTRACT Hyperbranched polyesters modified with long aliphatic chains with vinyl or epoxy groups as chain ends were synthesized and added as modifiers to diglycidyl ether of bisphenol A/toluene-2,4-diisocyanate mixtures in the presence of... more
ABSTRACT Hyperbranched polyesters modified with long aliphatic chains with vinyl or epoxy groups as chain ends were synthesized and added as modifiers to diglycidyl ether of bisphenol A/toluene-2,4-diisocyanate mixtures in the presence of benzyldimethylamine as catalyst. The influ-ence of the addition of these modifiers on the curing was investigated by thermal analysis and infrared spectroscopy. The materials obtained were investi-gated by electron microscopy and some mechanical characteristics were determined by nanoindentation tests. Epoxy terminated hyperbranched led to homoge-neous materials with high crosslinking densities, whereas vinyl terminated hyperbranched produced phase separated morphologies. The materials showing phase separation presented a tough fracture, whereas the homogeneous materials obtained with epoxidated hyperbranched showed increased brittleness on increasing the proportion of modifier. On increasing the proportion of vinyl terminated hyperbranched in the thermosets, Young's modulus and hardness decreased but the addition of epoxy terminated hyperbranched did not influence these parameters. The addition of vinylic hyperbranched to the formulations produced a decrease in the curing shrinkage, whereas the epoxidic hyperbranched did not.
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ABSTRACT New epoxy thermosets have been prepared via cationic UV-photopolymerization introducing two different multiarm star-like polymers. Both stars have a poly(glycidol) core but one has poly(methylmetacrylate) arms and the other... more
ABSTRACT New epoxy thermosets have been prepared via cationic UV-photopolymerization introducing two different multiarm star-like polymers. Both stars have a poly(glycidol) core but one has poly(methylmetacrylate) arms and the other poly(ε−caprolactone) ones. The characterization of the curing process has been performed by Real-Time FTIR and photo-DSC, observing a slight reduction in the curing rate on increasing the proportion of star. The thermosets prepared were characterized by gel content determination, DMTA and TGA, and finally the morphology observed by FE-SEM, demonstrating the formation of nanophases in the case of the star with poly(ε−caprolactone) arms. POLYM. ENG. SCI., 54:17–23, 2014. © 2013 Society of Plastics Engineers
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ABSTRACT Abstracts The chemical reworkability of epoxy thermosets in alkaline solutions has been increased by adding a hyperbranched polyester (HBPE) as a reactive modifier to the diglycidyl ether of bisphenol A (DGEBA) cured by... more
ABSTRACT Abstracts The chemical reworkability of epoxy thermosets in alkaline solutions has been increased by adding a hyperbranched polyester (HBPE) as a reactive modifier to the diglycidyl ether of bisphenol A (DGEBA) cured by lanthanide triflates as cationic initiators. The presence of hydroxyl chain-ends in the HBPE allows the modifier to be linked covalently to the epoxy matrix through the monomer activated propagation mechanism, which occurs in cationic polymerizations. Yb(OTf)3 leads to quicker curing than the lanthanum salt and to materials with the highest glass transition temperature (Tg). The addition of HBPE does not affect adversely the thermal stability and leads to a slight reduction of the global shrinkage. The Tg of the materials, the relaxed modulus and the linear thermal expansion coefficients are practically maintained by the addition of HBPE.
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Research Interests: Materials Engineering, Chemical Engineering, Kinetics, Mass Spectrometry, POlymer degradation and stability, and 11 moreInfrared spectroscopy, bisphenol A, Degradation, Thermogravimetry, Epoxy Resins, Thermal Stability, Polymer Degradation, Epoxy Resin, Reaction Mechanism, Thermal Degradation, and Thermosets
ABSTRACT Epoxy/anhydride networks were modified, in the presence of benzyldimethylamine as catalyst, with two polyhedral oligomeric silsesquioxanes (POSS), whose inorganic framework had a compact and stable Si-O core and an organic... more
ABSTRACT Epoxy/anhydride networks were modified, in the presence of benzyldimethylamine as catalyst, with two polyhedral oligomeric silsesquioxanes (POSS), whose inorganic framework had a compact and stable Si-O core and an organic substituent shell. The influence of the content and type of POSS during curing and on the properties of the thermosets was investigated by thermal analysis and infrared spectroscopy. The curing kinetics was analyzed by means of an integral isoconversional nonisothermal procedure. When the POSS modifier was added, the storage modulus in the rubbery plateau increased and the glass transition temperature decreased because of the presence of the flexible organic moieties and the influence in the crosslinking density. The presence of these POSS structures hardly affected the thermodegradation behavior of cured materials. The dispersion of the POSS structures in the epoxy/anhydride matrix was good, but some submicron-sized POSS agglomerates could be observed by transmission electron microscopy. POLYM. COMPOS., 2013. © 2012 Society of Plastics Engineers
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Diglycidylether of bisphenol A (DGEBA) was cured with different proportions of 1,6-dioxaspiro[4.4]nonane-2,7-dione (s(γ-BL)) with ytterbium triflate as initiator. The curing was studied with differential scanning calorimetry (DSC) and... more
Diglycidylether of bisphenol A (DGEBA) was cured with different proportions of 1,6-dioxaspiro[4.4]nonane-2,7-dione (s(γ-BL)) with ytterbium triflate as initiator. The curing was studied with differential scanning calorimetry (DSC) and Fourier transform infrared in the attenuated total reflection mode (FTIR/ATR). FTIR/ATR was used to monitor the competitive reactive processes and to quantify the conversion of the epoxide, lactone and intermediate spiroorthoester (SOE)
Research Interests: Engineering, Kinetics, Polymer, Differential scanning calorimetry, bisphenol A, and 8 moreCHEMICAL SCIENCES, Glass Transition Temperature, Fourier transform infrared spectroscopy, Dynamic Mechanical Thermal Analysis (DMTA), Shrinkage, Fourier transform infrared, Mechanical Property, and Thermal Degradation
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Poly(epichlorohydrin) [poly(oxy-1-chloro-methylethylene)] (PECH) has been modified chemically by basic nucleophiles, such as phenolate, producing dehydrochlorination as side reaction. The comonomer composition of the resulting... more
Poly(epichlorohydrin) [poly(oxy-1-chloro-methylethylene)] (PECH) has been modified chemically by basic nucleophiles, such as phenolate, producing dehydrochlorination as side reaction. The comonomer composition of the resulting poly(oxy-1-chloromethylethylene-co-oxy-1-phenoxymethyl-ethylene-co-oxy-1-methyleneethylene) can be determined by quantitative 13C nuclear magnetic resonance (n.m.r.) spectroscopy. Some polymeric models were synthesized in order to make accurate assignments, since most of the signals were not completely resolved. The various 13C n.m.r. signals were assigned to comonomer sequences in the main chain, which were fitted to a Bernouillian statistical model.
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Research Interests: Engineering, Kinetics, Comparative Study, Polymer, Differential scanning calorimetry, and 12 morebisphenol A, DSC, CHEMICAL SCIENCES, Thermal Stability, Fourier transform infrared spectroscopy, Functional Group, Epoxy Resin, Reaction Mechanism, Anionic Polymerization, Fourier transform infrared, Thermal Degradation, and Thermosets
Research Interests: Engineering, Kinetics, Polymer, Differential scanning calorimetry, bisphenol A, and 12 moreCrosslinking, Water Absorption, CHEMICAL SCIENCES, Glass Transition Temperature, Thermal Stability, Fourier transform infrared spectroscopy, Epoxy Resin, Shrinkage, Reaction Mechanism, Linear Coefficient of Thermal Expansion, Water uptake, and Thermal Degradation
... If both types of ring + + + o+ opening occur in the propagation step, head-to-tail, ooo IIIIIIhead-to-head, tail-to-head and tail-to-tail linkages appear Ph Ph Ph Ph Ph Ph in the polymer chainT,t3,~4. 2-001 6-01 I In addition to this... more
... If both types of ring + + + o+ opening occur in the propagation step, head-to-tail, ooo IIIIIIhead-to-head, tail-to-head and tail-to-tail linkages appear Ph Ph Ph Ph Ph Ph in the polymer chainT,t3,~4. 2-001 6-01 I In addition to this different regiostructural arrange--r--a~.a--~oa-.-- ...
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To prepare a family of functionalized polymers, we investigated the nucleophilic substitution reaction of poly(epichlorohydrin) (PECH) and its 1:1 copolymer with ethylene oxide (PECH–PEO) with a series of substituted phenolates with... more
To prepare a family of functionalized polymers, we investigated the nucleophilic substitution reaction of poly(epichlorohydrin) (PECH) and its 1:1 copolymer with ethylene oxide (PECH–PEO) with a series of substituted phenolates with electron-withdrawing and electron-donating groups. The basic character of the phenolates involves an undesired dehydrochlorination side-reaction and the subsequent chain scission process. Depending on the characteristics of the substituent directly
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ABSTRACT The synthesis and characterization of a new type of hyperbranched polyester with a flexible ethoxylated Bisphenol-A structure and terminal hydroxyl groups is reported. The influence of the hyperbranched polyester on the curing... more
ABSTRACT The synthesis and characterization of a new type of hyperbranched polyester with a flexible ethoxylated Bisphenol-A structure and terminal hydroxyl groups is reported. The influence of the hyperbranched polyester on the curing and thermomechanical properties of both unfilled and silica filled epoxy-novolac systems was studied. The curing behavior was investigated by differential scanning calorimetry (DSC) and rheolometry. The addition of the hyperbranched polyester to the formulation reduced the contraction on curing of both unfilled and filled systems, while Tg of the cured samples dropped down with the increase of polyester content due to the flexible backbone structure of the modifier. SEM microscopy on the fractured surface of cured samples revealed a homogeneous morphology and a possible effect of polyester as a toughness enhancer.
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ABSTRACT Liquid crystalline thermosets (LCTs) were prepared by curing difunctional LC dimeric epoxy monomers with imine moieties in the mesogenic core and central spacers of different length. Primary diamines or tertiary amines were used... more
ABSTRACT Liquid crystalline thermosets (LCTs) were prepared by curing difunctional LC dimeric epoxy monomers with imine moieties in the mesogenic core and central spacers of different length. Primary diamines or tertiary amines were used as curing agents obtaining materials with different characteristics. The results obtained were related to the mesogen structure, since dipolar moments in the mesogenic cores affect the ability to form ordered networks.
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ABSTRACT Hybrid thiol-ene system based on a hyperbranched polyester with different degrees of 10-undecenoyl modification are prepared via a dual UV-thermal process. The pristine thiol-ene formulation shows a high reactivity towards UV... more
ABSTRACT Hybrid thiol-ene system based on a hyperbranched polyester with different degrees of 10-undecenoyl modification are prepared via a dual UV-thermal process. The pristine thiol-ene formulation shows a high reactivity towards UV curing and the addition of the inorganic precursor to the photocurable formulation does not affect the UV-curing process. The crosslinked systems show an increase of Tg by increasing the vinyl functionality content in the HBP and a Tg increase is also evidenced in the hybrid system as a function of inorganic precursor content. Morphological investigations show that the inorganic domains generated in situ are homogeneously distributed throughout the polymeric matrix. By varying the 10-undecenoyl modification in the terminal groups of the HBP, the size of the inorganic domains is tunable and it is possible to decrease the dimension of the silica domains by using the HBP with a higher modification degree.
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... Jose Antonio Reina, Angels Serra, Virginia Ckdiz* ... SUMMARY Poly(epich1orohydrin) was modified in a high extent with several vinyl-terminated aro-matic potassium carboxylates (4-(2-propenyloxy)benzoate, 4-(5-hexenyloxy)benzoate,... more
... Jose Antonio Reina, Angels Serra, Virginia Ckdiz* ... SUMMARY Poly(epich1orohydrin) was modified in a high extent with several vinyl-terminated aro-matic potassium carboxylates (4-(2-propenyloxy)benzoate, 4-(5-hexenyloxy)benzoate, 3-(2-propenyloxy)-2-naphthoate, 3-( ...
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... Roser Cervellera 1 ,; Xavier Ramis 2 ,; Josep Maria Salla 2 ,; Angels Serra 1 ,; Ana Mantecón 1,*. ... described elsewhere, to assign a reaction model to the systems studied.23 Different kinetic models have been studied: diffusion (D... more
... Roser Cervellera 1 ,; Xavier Ramis 2 ,; Josep Maria Salla 2 ,; Angels Serra 1 ,; Ana Mantecón 1,*. ... described elsewhere, to assign a reaction model to the systems studied.23 Different kinetic models have been studied: diffusion (D 1 , D 2 , D 3 , and D 4 ), Avrami-Erofeev (A 2 , A 3 ...
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Research Interests: Materials Engineering, Analytical Chemistry, Kinetics, Polymer, Differential scanning calorimetry, and 14 moreDSC, Activation Energy, Epoxy Resins, Data Association, Thermal Analysis, Fourier transform infrared spectroscopy, Epoxy Resin, Shrinkage, Infrared Spectrometry, Experimental Data, Kinetic Parameter, Fourier Transformation, Thermosets, and Kinetic model
ABSTRACT Ytterbium and lanthanum triflates were used as initiators to cure mixtures of diglycidyl ether of bisphenol A and 6,6-dimethyl-(4,8-dioxaspiro[2.5]octane-5,7-dione) in several proportions. The evolution of the epoxy and... more
ABSTRACT Ytterbium and lanthanum triflates were used as initiators to cure mixtures of diglycidyl ether of bisphenol A and 6,6-dimethyl-(4,8-dioxaspiro[2.5]octane-5,7-dione) in several proportions. The evolution of the epoxy and 6,6-dimethyl-(4,8-dioxaspiro[2.5]octane-5,7-dione) bands during curing and the linear ester groups in the final materials were evaluated with Fourier transform infrared in the attenuated-total-reflection mode. The use of a conventional cationic initiator, boron trifluoride monoethylamine, was also studied to test the advantages of lanthanide triflates. The shrinkage after curing and the thermal degradability of the materials with variations in the comonomer ratio and the initiator were evaluated and related to the chemical structure of the final network. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6869–6879, 2006
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ABSTRACT We used readily available commercial reagents and well-known procedures to synthesize a series of aromatic imine mesogenic diglycidylester compounds with dimeric architectures. The compounds obtained were characterized by... more
ABSTRACT We used readily available commercial reagents and well-known procedures to synthesize a series of aromatic imine mesogenic diglycidylester compounds with dimeric architectures. The compounds obtained were characterized by spectroscopic techniques. Their liquid-crystalline behavior was examined by differential scanning calorimetry, hot-stage polarized optical microscopy (POM), and wide-angle X-ray scattering (WAXS) and related to the different structures that varied in the length of the central spacer. All the compounds exhibited nematic mesophases with the exception of the dimer with a three-methylene central spacer that did not reveal liquid-crystalline character. We investigated the crosslinking of the synthesized compounds and obtained liquid-crystalline thermosets (LCTs) with several primary aromatic diamines in stoichiometric ratios or a tertiary amine as a catalyst. The curing processes were measured by calorimetry, and the thermal stability of the LCTs was evaluated by thermogravimetry. The ordered character of the LCTs was confirmed by POM and WAXS. Finally, the mechanical characterization of the LCTs obtained was examined by dynamic mechanical thermal analysis. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4344–4356, 2002
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ABSTRACT The curing kinetics and network buildup during cur- ing of epoxy–anhydride formulations using tertiary amines as initiators are reviewed in this work. A mechanism-based kinetic and structural model has been defined, showing... more
ABSTRACT The curing kinetics and network buildup during cur- ing of epoxy–anhydride formulations using tertiary amines as initiators are reviewed in this work. A mechanism-based kinetic and structural model has been defined, showing better predic- tion capabilities than previous living polymerization and simple regeneration models. The curing kinetics have been analyzed using differential scanning calorimetry (DSC), and the gelation during curing has been determined by combined thermome- chanical analysis and DSC. The effect of initiator content and epoxy equivalent weight are taken into account. The network buildup has been modeled using a stochastic network buildup model based on the random combination of primary chains generated by the kinetic model
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ABSTRACT We examine some of the structural aspects that influence the mesomorphic behavior of liquid-crystalline dimeric epoxy resins with imine groups in the mesogens. We synthesized two new series of monomers and compared them with... more
ABSTRACT We examine some of the structural aspects that influence the mesomorphic behavior of liquid-crystalline dimeric epoxy resins with imine groups in the mesogens. We synthesized two new series of monomers and compared them with previously synthesized monomers. Compared with previously studied series, the imine group in the new monomers is oriented differently with respect to the ether and ester groups linked to the end of the mesogenic unit. Our results confirmed the importance of polarization of the mesogenic groups and the presence of an ester group in the inner position in the formation of smectic mesophases. By curing with primary and tertiary amines, we demonstrate that these two requirements are necessary if liquid-crystalline thermosets are to be obtained with different degrees of order. These studies were carried out with differential scanning calorimetry, polarized optical microscopy, and X-ray diffraction. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1465–1477, 2003
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ABSTRACT We reacted various dimeric, liquid-crystalline epoxy–imine monomers, differing in the length of the central aliphatic spacer or the dipolar moments, with heptanedioic acid. The resulting systems showed a liquid-crystalline phase... more
ABSTRACT We reacted various dimeric, liquid-crystalline epoxy–imine monomers, differing in the length of the central aliphatic spacer or the dipolar moments, with heptanedioic acid. The resulting systems showed a liquid-crystalline phase in some cases, depending on the dimer and on the reaction conditions. The systems were characterized with respect to their mesomorphic properties and then were submitted to dynamic mechanical thermal analysis in both fixed-frequency and frequency-sweep modes in the shear sandwich configuration. The arrangement in the liquid-crystalline phase seemed to be mainly affected both by the polarization of the mesogen and by the reaction temperature, which favored the liquid-crystalline arrangement when it was lying in the range of stability of the dimer mesophase. In agreement with other recent literature data, dynamic mechanical thermal analysis results suggested that the presence of the mesogen directly incorporated into the main chain increased the lifetimes of the elastic modes both in the isotropic phase and in the liquid-crystalline phase with respect to side-chain liquid-crystalline elastomers and that the time–temperature superposition principle did not hold through the liquid-crystalline-to-isotropic transition. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44:6270–6286, 2006
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... Roser Cervellera 1 ,; Xavier Ramis 2 ,; Josep Maria Salla 2 ,; Ana Mantecón 1 ,; Angels Serra 1,*. ... described elsewhere, to assign a reaction model to the systems studied.17 Different kinetic models have been studied: diffusion (D... more
... Roser Cervellera 1 ,; Xavier Ramis 2 ,; Josep Maria Salla 2 ,; Ana Mantecón 1 ,; Angels Serra 1,*. ... described elsewhere, to assign a reaction model to the systems studied.17 Different kinetic models have been studied: diffusion (D 1 , D 2 , D 3 , and D 4 ), AvramiErofeev (A 2 , A 3 ...
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... Cristina Mas 1 ,; Xavier Ramis 2 ,; Josep Maria Salla 2 ,; Ana Mantecón 1 ,; Angels Serra 1 ... procedure,8 described elsewhere, to assign a reaction model to the systems studied.9 Various kinetic models have been studied: diffusion... more
... Cristina Mas 1 ,; Xavier Ramis 2 ,; Josep Maria Salla 2 ,; Ana Mantecón 1 ,; Angels Serra 1 ... procedure,8 described elsewhere, to assign a reaction model to the systems studied.9 Various kinetic models have been studied: diffusion (D 1 , D 2 , D 3 , and D 4 ), Avrami-Erofeev (A 2 , A ...
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ABSTRACT An epoxy–anhydride formulation used for the coating electrical devices was modified with a commercially available hyperbranched poly(ester amide), Hybrane S2200, to improve the thermal degradability of the resulting thermoset... more
ABSTRACT An epoxy–anhydride formulation used for the coating electrical devices was modified with a commercially available hyperbranched poly(ester amide), Hybrane S2200, to improve the thermal degradability of the resulting thermoset and, thus, facilitate the recovery of substrate materials after the service life of the component. The thermomechanical, mechanical, and dielectric properties and thermal degradability were studied and interpreted in terms of the composition and network structure of the cured thermosets. Although the crosslinking density was significantly reduced with the incorporation of S2200, the glass transition temperature of the fully cured material (Tg ∞) of the modified thermoset was hardly affected because of the enhancement of H‐bonding interactions in the presence of S2200. Despite the different network structures, the combined dielectric and dynamic mechanical analysis revealed that the relaxation dynamics of both networks were very similar. In terms of application, improvements in the dielectric and mechanical properties were observed. The incorporation of S2200 accelerated the thermal decomposition of the material and, thus, facilitated the recovery of the valuable parts from the substrate at the end of the service life of the apparatus. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
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Research Interests: Engineering, Materials Engineering, Chemical Engineering, Kinetics, FTIR, and 15 morePolymer, Applied, DSC, Epoxy, CHEMICAL SCIENCES, Polymer Degradation, Epoxy Resin, Reaction Rate, Reaction Mechanism, Journal of Applied Polymer Science, Hydrolysis, Chemical Stability, Anionic Polymerization, Ring Opening Polymerization, and kinetic analysis
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ABSTRACT Multiam star polyesters were synthesized by growing poly(ε-caprolactone) (PCL) arms from hyperbranched polyesters cores of different molecular weight and used as polymeric modifiers in UV-curable cationic formulations based on a... more
ABSTRACT Multiam star polyesters were synthesized by growing poly(ε-caprolactone) (PCL) arms from hyperbranched polyesters cores of different molecular weight and used as polymeric modifiers in UV-curable cationic formulations based on a biscycloaliphatic epoxy resin. The effect of the multiarm stars on the curing kinetics has been investigated by real-time FTIR. The thermal-mechanical properties of the photocured thermosets have been studied with calorimetry and dynamomechanical and thermogravimetric analysis. Impact strength tests have been performed to assess their effect on the toughness of the cured materials. An accelerative effect of these modifiers has been observed as a consequence of the participation of the hydroxyl groups of the modifiers in the cationic curing of the epoxy resin. A modest increase in toughness accompanied by a decrease in the glass transition are observed, as a consequence of the incorporation of the modifiers into the network structure, leading to homogeneous, in situ reinforced materials. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014, 131, 40005.
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... Correspondence: Marina Galià, Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili, Plaça Imperial Tarraco 1, 43005 Tarragona, Spain. Publication History. ... 7 Galante, MJ; Williams, RJJ J Appl Polym Sci... more
... Correspondence: Marina Galià, Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili, Plaça Imperial Tarraco 1, 43005 Tarragona, Spain. Publication History. ... 7 Galante, MJ; Williams, RJJ J Appl Polym Sci 1995, 55, 89. ...
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ABSTRACT Abstract Multiarm stars containing a hyperbranched poly(ethyleneimine) core of different molecular weight and poly(lactide) arms were synthesized by cationic ring-opening polymerization of lactide from a hyperbranched... more
ABSTRACT Abstract Multiarm stars containing a hyperbranched poly(ethyleneimine) core of different molecular weight and poly(lactide) arms were synthesized by cationic ring-opening polymerization of lactide from a hyperbranched poly(ethyleneimine) core. After characterization by rheometry, calorimetry, thermogravimetry and nuclear magnetic resonance, these polymers were used as chemically modifiers in the anionic curing of diglycidylether of bisphenol A epoxy resin. The curing process was studied by dynamic scanning calorimetry, demonstrating the influence of the mobility of the reactive species and the hydroxyl content on the curing kinetics. The resulting materials were characterized by thermal and mechanical tests. The addition of the multiarm stars led to homogeneous materials with a slight improvement on the impact strength in comparison with the neat material, without compromising the glass transition temperature. The reworkable nature of the materials was demonstrated by monitoring the changes in their glass transition under thermal rework conditions.
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ABSTRACT A hyperbranched poly(glycidol) has been synthesized and modified by acylation with 10-undecenoyl chloride to obtain hyperbranched polymers (HBPs) with different degree of modification. These HBPs have been used as reactive... more
ABSTRACT A hyperbranched poly(glycidol) has been synthesized and modified by acylation with 10-undecenoyl chloride to obtain hyperbranched polymers (HBPs) with different degree of modification. These HBPs have been used as reactive modifiers in a proportion of 3%, 5%, and 10% with respect to a biscicloaliphatic diepoxide cured using ytterbium triflate as thermal cationic initiator. The materials obtained have been characterized and their mechanical properties evaluated. Phase separated materials have been obtained, with a 2-fold increase in impact resistance without sacrificing thermomechanical properties, thermal stability or processability. This good combination of properties can be explained by the achievement of a regular microphase separation with a good interfacial interaction between the microparticles and the epoxy matrix. The compatibility between the HBP and the matrix can be tuned by changing the degree of modification, which leads to a variable amount of available hydroxyl groups of the HBP that can react with the epoxy groups. This chemical bonding occurs through the activated monomer mechanism (AM) which is typical of the cationic homopolymerization of epoxides.
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... thermosets obtained. Mercé Arasa a , Xavier Ramis b , Josep Maria Salla b , Francesc Ferrando c , Angels Serra a and Ana Mantecón a , Corresponding Author Contact Information , E-mail The Corresponding Author. a Departament ...
Research Interests: Materials Engineering, Chemical Engineering, Comparative Study, Differential scanning calorimetry, bisphenol A, and 11 moreCationic polymerization, Crosslinking, Activation Energy, Epoxy Resins, Optimal Reactive Power System, Rare Earth, Epoxy Resin, Calorimetry, Reaction Mechanism, Linear Coefficient of Thermal Expansion, and Thermosets
Research Interests: Materials Engineering, Chemical Engineering, Kinetics, Morphology, Differential scanning calorimetry, and 12 morebisphenol A, Water Absorption, Glass Transition Temperature, Thermal Stability, Fourier transform infrared spectroscopy, Epoxy Resin, Molecular weight, Shrinkage, Reaction Mechanism, Linear Coefficient of Thermal Expansion, Water uptake, and Thermal Degradation
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Ytterbium and lanthanum triflates were used as cationic initiators to cure mixtures of diglycidylether of bisphenol A (DGEBA) and Meldrum acid (MA) in several proportions of comonomers and initiators. The evolution of epoxy and lactone... more
Ytterbium and lanthanum triflates were used as cationic initiators to cure mixtures of diglycidylether of bisphenol A (DGEBA) and Meldrum acid (MA) in several proportions of comonomers and initiators. The evolution of epoxy and lactone groups during curing, and ...
Research Interests: Materials Engineering, Chemical Engineering, Collagen Cross-linking, bisphenol A, Cationic polymerization, and 10 moreActivation Energy, Epoxy Resins, Thermal Stability, Fourier transform infrared spectroscopy, Epoxy Resin, Shrinkage, Reaction Mechanism, Fourier transform infrared, Thermal Degradation, and Thermosets
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Two-dimensional (2D) covariance analyses applied to spectroscopy data obtained while monitoring chemical processes allow exploring the chemical reactions involved. Some slices of the sample–sample covariance map are an approach to the... more
Two-dimensional (2D) covariance analyses applied to spectroscopy data obtained while monitoring chemical processes allow exploring the chemical reactions involved. Some slices of the sample–sample covariance map are an approach to the concentration profiles of the reactive species and we present a novel methodology to identify them. The method overcomes problems habitually referenced in the application of this technique and it is based on the selection of spectral zones with similar standard deviation of the variables and row centering the spectra data in each zone. The slices are identified according to the correlation coefficient value. The method is illustrated using simulated spectra data set representatives of two model reactions A → B and A → I → B. It has been applied to analyze the effect of rare earth metal triflate initiators in the cationic curing process of diglycidyl ether of bisphenol A with γ-valerolactone. The number of significant slices found is equal to the number...
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... Antoni Roig, Angels Serra*, Virginia Cadiz, Ana Mantecon (Received 24 October 1991) ... Chem. 29 (1991) 619 FW Wehrli, AP Marchand, S. Wehrli, Interpretation of Carbon-13 NMR Spectra, Wiley, New York 1988, p. 52 M. Galia, A. Mantech,... more
... Antoni Roig, Angels Serra*, Virginia Cadiz, Ana Mantecon (Received 24 October 1991) ... Chem. 29 (1991) 619 FW Wehrli, AP Marchand, S. Wehrli, Interpretation of Carbon-13 NMR Spectra, Wiley, New York 1988, p. 52 M. Galia, A. Mantech, V. Cadiz, A. Serra, Makromol. Chem. ...
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... Chem. 181,19007-1914 (1986) 1907 Some spectral and thermal contributions to the curing of new epoxy compounds with aromatic diamines Angels Serra, Virginia Cddiz*, Pedro-Albert0 Martinez, Ana Mantecdn ... 1912 a N A. Serra, V. CBdiz,... more
... Chem. 181,19007-1914 (1986) 1907 Some spectral and thermal contributions to the curing of new epoxy compounds with aromatic diamines Angels Serra, Virginia Cddiz*, Pedro-Albert0 Martinez, Ana Mantecdn ... 1912 a N A. Serra, V. CBdiz, P.-A. Martinez, A. Mantech u N I I I I ...
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... Preparation of prepolymers from diglycidylether of Bisphenol A containing imide groups Virginia Cadiz*, Ana Mantecon, Angels Serra, Christophe Thepaut (Received 25 March 1991) ... Page 2. V. Cadiz, A. Mantech, A. Serra, C. Thepaut ...
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Makromol. Chem. 191, 1111-1118 (1990) 1111 13C NMR study of the reaction of unsymmetrical diacids with Marina Galici, Ana Mantecdn, Virginia Ccidiz: Angels Serra ... 0025-1 16X/90/$03.00 Page 2. 1112 M. GaliB, A. Mantech, V. CAdiz, A.... more
Makromol. Chem. 191, 1111-1118 (1990) 1111 13C NMR study of the reaction of unsymmetrical diacids with Marina Galici, Ana Mantecdn, Virginia Ccidiz: Angels Serra ... 0025-1 16X/90/$03.00 Page 2. 1112 M. GaliB, A. Mantech, V. CAdiz, A. Serra Acid index 56,l N(A - B) W ...
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... Imperial Tarraco s/n, Tarragona, Spain. Curing of New Trimellitimide Glycidyl Ester Derivatives with Aromatic Diamines Pedro-Albert0 Martinez, Virginia CBdiz*, Angels Serra, and Ana Mantech (Received 13 May 1985) SUMMARY ...
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... Tarraco n0 1, Tarragona, Spain A Modification of Diglycidylether of Bisphenol A with Diimide-Diacids Angels Serra, Virginia Chdiz*, and Ana Mantech (Received 25 February 1987) SUMMARY: A conventional epoxy resin derived ...
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SUMMARY: New diglycidyl esters coming from the corresponding diacids and epichlorohydrin were synthetized using a quaternary ammonium salt as a catalyst. The new asym-metric compounds were characterized by spectroscopic methods and... more
SUMMARY: New diglycidyl esters coming from the corresponding diacids and epichlorohydrin were synthetized using a quaternary ammonium salt as a catalyst. The new asym-metric compounds were characterized by spectroscopic methods and employed as starting monomers in a ...
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Departamento de Quimica Orghnica, Facultad de Quimicas de Tarragona, Universidad de Barcelona, P1. Imperial Tarraco s/n, Tarragona, Spain ... Preparation and Reactivity of New 3,3 ' ,4,4 '-Tetracarboxybenzop henone Dianhydride... more
Departamento de Quimica Orghnica, Facultad de Quimicas de Tarragona, Universidad de Barcelona, P1. Imperial Tarraco s/n, Tarragona, Spain ... Preparation and Reactivity of New 3,3 ' ,4,4 '-Tetracarboxybenzop henone Dianhydride Glycidyl Ester Derivatives
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SUMMARY: Spectroscopic data of epoxy resins, derivatives of pyromellitimide, have shown two types of attack on the two carbons of the oxirane group, giving rise to normal and abnormal opening of the ring. Thus, primary and secondary... more
SUMMARY: Spectroscopic data of epoxy resins, derivatives of pyromellitimide, have shown two types of attack on the two carbons of the oxirane group, giving rise to normal and abnormal opening of the ring. Thus, primary and secondary hydroxy groups were obtained. The physical ...
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ABSTRACT Novel epoxy-terminated monomers based on imine groups were synthesized and their mesogenic properties studied. Aliphatic spacers of different lengths were introduced between the rigid unit and the glycidylic group, and their... more
ABSTRACT Novel epoxy-terminated monomers based on imine groups were synthesized and their mesogenic properties studied. Aliphatic spacers of different lengths were introduced between the rigid unit and the glycidylic group, and their liquid-crystalline behavior was examined. They were reacted with primary aromatic diamines inside a magnetic field so that the formation of anisotropic networks could be investigated. The influence of curing conditions and the structure of monomers and amines on the formation of liquid-crystal thermosets were investigated. Thermosets with locked nematic textures were obtained in all cases. The influence of a 7.1 T magnetic field on the macroscopic orientation of these materials was studied, and mechanical properties of the resulting networks were evaluated by dynamic mechanical analysis. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1–12, 2003
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In this work, starch-based composites reinforced with jute strands were obtained by injection moulding procedure. The influence of the degree of adhesion at fibre–matrix interface to the mechanical properties of the composites was... more
In this work, starch-based composites reinforced with jute strands were obtained by injection moulding procedure. The influence of the degree of adhesion at fibre–matrix interface to the mechanical properties of the composites was evaluated. For this purpose, partial delignification of jute strands by means of NaOH treatment was carried out and the mechanical properties of the corresponding composites determined. The alkali treatment resulted in an increase of the strength and stiffness of the jute strand/starch composites. The enhancement was analysed in terms of compatibility and extension of the adhesion at fibre–matrix interface. The application of a blocking reaction to the surface hydroxyl groups of jute strands corroborated the influence of the mechanical properties to the extension of the interfacial adhesion. Thus, higher extension of the hydrogen bonds at fibre–matrix interface gave higher strength and stiffness of the jute strand/starch-based composites.