Alginate dialdehyde and l-lysine-functionalized alginate dialdehyde were prepared to provide acti... more Alginate dialdehyde and l-lysine-functionalized alginate dialdehyde were prepared to provide active aldehyde and l-lysine sites along the alginate backbone, respectively. Different concentrations of substrates and the reduction agent were added, and their influence on the degree of l-lysine substitution was evaluated. An amination reduction reaction (with l-lysine) was conducted on alginate dialdehyde with a 31% degree of oxidation. The NMR confirmed the presence of l-lysine functionality with the degree of substitution of 20%. The structural change of the polymer was observed via FTIR spectroscopy, confirming the formation of Schiff base covalent linkage after the crosslinking. The additional l-lysine sites on functionalized alginate dialdehyde provide more crosslinking sites on the hydrogel, which leads to a higher modulus storage rate than in the original alginate dialdehyde. This results in dynamic covalent bonds, which are attributed to the alginate derivative–gelatin hydrogels...
In this work, two novel routes to synthesis cross-linked polypropylene (PP) are introduced by usi... more In this work, two novel routes to synthesis cross-linked polypropylene (PP) are introduced by using two different precursors (2-thiophenemethyl amine (TMA) and 1-(3 aminopropyl) imidazole (API)), both cross-linked with 1,1′-(methylenedi-4,1-phenylene) bismaleimide (BM) at two different annealing temperature values (T = 50 °C and T = 150 °C). Both Diels–Alder (DA) and Michael addition reactions were successfully performed with TMA and API, respectively, albeit with different reactivity. Imidazole clearly shows a higher reactivity compared to thiophene. In addition, an increase in annealing temperature leads to a higher degree of cross-linking. The highest degree of cross-linking was obtained by the imidazole product after annealing at 150 °C (IMG1A150) as evident from the highest complex viscosity (|η*|) value of IMG1A150. A difference in rheology and thermal properties between the imidazole and thiophene cross-linked products was also observed. However, both products have superior m...
In this work, the possibility of preparing cross-linked polypropylene (PP) via Diels–Alder (DA) c... more In this work, the possibility of preparing cross-linked polypropylene (PP) via Diels–Alder (DA) chemistry is explored. The overall strategy involves reaction of maleated polypropylene (the starting material), furfuryl amine (FFA), and bismaleimide (BM) as the cross-linking agent. The occurrence of reversible cross-linking was studied by checking the presence of relevant peaks in FTIR spectra, i.e., CH out-of-plane bending vibrations of the furan ring’s peak (γCH) at an absorption band of 730–734 cm−1, CH=CH of the BM aromatic ring’s stretching vibrations (υCH=CH) at an absorption band of 1510 cm−1, and the DA adduct (C-O-C, δDAring) at an absorption band of 1186 cm−1. In agreement with the spectroscopic characterization, the presence of a cross-linked network is also confirmed by rheology, namely the higher storage modulus (G′) compared with loss modulus (G″) value (G′ >> G″), as obtained via temperature sweep. Both the maleic anhydride (MA) content as well as the annealing te...
In the present work, a series of highly branched random copolymers of acrylamide (AM), sodium 2-a... more In the present work, a series of highly branched random copolymers of acrylamide (AM), sodium 2-acrylamido-2-methyl-1-propanesulfonate (SAMPS), and N-isopropylacrylamide (NIPAM) were prepared by us...
Industrial & Engineering Chemistry Research, 2013
ABSTRACT The oil recovery from core material and a specifically designed flow cell using novel br... more ABSTRACT The oil recovery from core material and a specifically designed flow cell using novel branched (comblike) polyacrylamides (PAM) has been investigated. The injectivity characteristics of the different branched PAMs were evaluated by filtration tests and core-flow experiments. The number of arms of the branched PAM has little to no effect on the filterability and permeation through a porous medium. The 13-arm branched PAM displayed a higher residual resistance factor (RRF) in Berea sandstone than its linear analogue and a commercial HPAM. In addition, the thickness of the layer adsorbed at the rock surface is higher for the branched PAM. Oil trapped in dead-end pores is simulated using a 2D flow cell and the effect of the number of arms on the recovery of residual oil is evaluated. In brine solutions, the branched PAMs perform equal or better than their linear analogues in terms of the solution viscosity. The oil recovery of a branched PAM with a similar molecular weight is 3 times as high as that for the commercial polymer. The recovery efficiency, evaluated using low permeable Berea as the porous medium, is significantly improved by using branched PAM instead of linear ones (5.0 compared to 1.5% of the OOIP). An improvement is also observed when high permeable Bentheim cores are used as the porous medium (9.4% compared to 6.0% of the OOIP). The higher oil recovery in the 2D flow cell might explain the improved performance of the branched PAMs. The high thickening capability and the low molecular weight of the branched PAMs makes them suitable for application in enhanced oil recovery (EOR, especially for low permeable reservoirs).
In this work, we investigated the functionalization of polyketone 30 (PK30) with glycyl-glycine (... more In this work, we investigated the functionalization of polyketone 30 (PK30) with glycyl-glycine (Gly-Gly) via the Paal–Knorr reaction with the aim of homogenously dispersing two types of reduced graphene oxide (rGO, i.e., lrGO and hrGO, the former characterized by a lower degree of reduction in comparison to the latter) by non-covalent interactions. The functional PK30-Gly-Gly polymer was effective in preparing composites with homogeneously distributed rGO characterized by an effective percolation threshold at 5 wt. %. All the composites showed a typical semiconductive behavior and stable electrical response after several heating/cooling cycles from 30 to 115 °C. Composites made by hrGO displayed the same resistive behaviour even if flanked by a considerable improvement on conductivity, in agreement with the more reduced rGO content. Interestingly, no permanent percolative network was shown by the composite with 4 wt. % of lrGO at temperatures higher than 45 °C. This material can be...
Alginates are natural anionic polyelectrolytes investigated in various biomedical applications, s... more Alginates are natural anionic polyelectrolytes investigated in various biomedical applications, such as drug delivery, tissue engineering, and 3D bioprinting. Functionalization of alginates is one possible way to provide a broad range of requirements for those applications. A range of techniques, including esterification, amidation, acetylation, phosphorylation, sulfation, graft copolymerization, and oxidation and reduction, have been implemented for this purpose. The rationale behind these investigations is often the combination of such modified alginates with different molecules. Particularly promising are lectin conjugate macromolecules for lectin-mediated drug delivery, which enhance the bioavailability of active ingredients on a specific site. Most interesting for such application are alginate derivatives, because these macromolecules are more resistant to acidic and enzymatic degradation. This review will report recent progress in alginate modification and conjugation, focusin...
Hydrogels have gained a lot of attention with their widespread use in different industrial applic... more Hydrogels have gained a lot of attention with their widespread use in different industrial applications. The versatility in the synthesis and the nature of the precursor reactants allow for a varying range of hydrogels with different mechanical and rheological properties. Understanding of the rheological behavior and the relationship between the chemical structure and the resulting properties is crucial, and is the focus of this review. Specifically, we include detailed discussion on the correlation between the rheological characteristics of hydrogels and their possible applications. Different rheological tests such as time, temperature and frequency sweep, among others, are described and the results of those tests are reported. The most prevalent applications of hydrogels are also discussed.
Chemical Enhanced Oil Recovery (EOR) is currently and mainly based on the use of partially hydrol... more Chemical Enhanced Oil Recovery (EOR) is currently and mainly based on the use of partially hydrolyzed polyacrylamide as water-soluble polymer for mobility control. This choice is predominantly related to technological (thickening efficiency) as well as economic considerations. However, the presence of salt in the underground water significantly reduces the effect of such polymer on the solution rheology. This becomes even less when the polymer is used in combination with alkali. Therefore, the amount of polymer required is significantly higher than expected on the basis of simple rheological models, which in turn has a clear negative effect on the economics of the process. Against this backdrop, the search for alternative water-soluble polymers has been gaining a predominant attention at both academic and industrial level. In this work, we report on the latest development about the synthesis and application of novel polymeric products for EOR. Biography Francesco Picchioni has compl...
Low cross-link density thermally reversible networks were successfully synthesized from jatropha ... more Low cross-link density thermally reversible networks were successfully synthesized from jatropha and sunflower oils. The oils were epoxidized and subsequently reacted with furfurylamine to attach furan groups onto the triglycerides, preferably at the epoxide sites rather than at the ester ones. Under the same reaction conditions, the modified jatropha oil retained the triglyceride structure more efficiently than its sunflower-based counterpart, i.e., the ester aminolysis reaction was less relevant for the jatropha oil. These furan-modified oils were then reacted with mixtures of aliphatic and aromatic bismaleimides, viz. 1,12-bismaleimido dodecane and 1,1′-(methylenedi-4,1-phenylene)bismaleimide, resulting in a series of polymers with Tg ranging between 3.6 and 19.8 °C. Changes in the chemical structure and mechanical properties during recurrent thermal cycles suggested that the Diels–Alder and retro-Diels–Alder reactions occurred. However, the reversibility was reduced over the the...
Among smart materials, self-healing is one of the most studied properties. A self-healing polymer... more Among smart materials, self-healing is one of the most studied properties. A self-healing polymer can repair the cracks that occurred in the structure of the material. Polyketones, which are high-performance thermoplastic polymers, are a suitable material for a self-healing mechanism: a furanic pendant moiety can be introduced into the backbone and used as a diene for a temperature reversible Diels-Alder reaction with bismaleimide. The Diels-Alder adduct is formed at around 50 °C and broken at about 120 °C, giving an intrinsic, stimuli-responsive self-healing material triggered by temperature variations. Also, reduced graphene oxide (rGO) is added to the polymer matrix (1.6–7 wt%), giving a reversible OFF-ON electrically conductive polymer network. Remarkably, the electrical conductivity is activated when reaching temperatures higher than 100 °C, thus suggesting applications as electronic switches based on self-healing soft devices.
Polymers crosslinked via furan/maleimide thermo-reversible chemistry have been extensively explor... more Polymers crosslinked via furan/maleimide thermo-reversible chemistry have been extensively explored as reprocessable and self-healing thermosets and elastomers. For such applications, it is important that the thermo-reversible features are reproducible after many reprocessing and healing cycles. Therefore, side reactions are undesirable. However, we have noticed irreversible changes in the mechanical properties of such materials when exposing them to temperatures around 150 °C. In this work, we study whether these changes are due to the self-reaction of maleimide moieties that may take place at this rather low temperature. In order to do so, we prepared a furan-grafted polyketone crosslinked with the commonly used aromatic bismaleimide (1,1′-(methylenedi-4,1-phenylene)bismaleimide), and exposed it to isothermal treatments at 150 °C. The changes in the chemistry and thermo-mechanical properties were mainly studied by infrared spectroscopy, 1H-NMR, and rheology. Our results indicate t...
Alginate dialdehyde and l-lysine-functionalized alginate dialdehyde were prepared to provide acti... more Alginate dialdehyde and l-lysine-functionalized alginate dialdehyde were prepared to provide active aldehyde and l-lysine sites along the alginate backbone, respectively. Different concentrations of substrates and the reduction agent were added, and their influence on the degree of l-lysine substitution was evaluated. An amination reduction reaction (with l-lysine) was conducted on alginate dialdehyde with a 31% degree of oxidation. The NMR confirmed the presence of l-lysine functionality with the degree of substitution of 20%. The structural change of the polymer was observed via FTIR spectroscopy, confirming the formation of Schiff base covalent linkage after the crosslinking. The additional l-lysine sites on functionalized alginate dialdehyde provide more crosslinking sites on the hydrogel, which leads to a higher modulus storage rate than in the original alginate dialdehyde. This results in dynamic covalent bonds, which are attributed to the alginate derivative–gelatin hydrogels...
In this work, two novel routes to synthesis cross-linked polypropylene (PP) are introduced by usi... more In this work, two novel routes to synthesis cross-linked polypropylene (PP) are introduced by using two different precursors (2-thiophenemethyl amine (TMA) and 1-(3 aminopropyl) imidazole (API)), both cross-linked with 1,1′-(methylenedi-4,1-phenylene) bismaleimide (BM) at two different annealing temperature values (T = 50 °C and T = 150 °C). Both Diels–Alder (DA) and Michael addition reactions were successfully performed with TMA and API, respectively, albeit with different reactivity. Imidazole clearly shows a higher reactivity compared to thiophene. In addition, an increase in annealing temperature leads to a higher degree of cross-linking. The highest degree of cross-linking was obtained by the imidazole product after annealing at 150 °C (IMG1A150) as evident from the highest complex viscosity (|η*|) value of IMG1A150. A difference in rheology and thermal properties between the imidazole and thiophene cross-linked products was also observed. However, both products have superior m...
In this work, the possibility of preparing cross-linked polypropylene (PP) via Diels–Alder (DA) c... more In this work, the possibility of preparing cross-linked polypropylene (PP) via Diels–Alder (DA) chemistry is explored. The overall strategy involves reaction of maleated polypropylene (the starting material), furfuryl amine (FFA), and bismaleimide (BM) as the cross-linking agent. The occurrence of reversible cross-linking was studied by checking the presence of relevant peaks in FTIR spectra, i.e., CH out-of-plane bending vibrations of the furan ring’s peak (γCH) at an absorption band of 730–734 cm−1, CH=CH of the BM aromatic ring’s stretching vibrations (υCH=CH) at an absorption band of 1510 cm−1, and the DA adduct (C-O-C, δDAring) at an absorption band of 1186 cm−1. In agreement with the spectroscopic characterization, the presence of a cross-linked network is also confirmed by rheology, namely the higher storage modulus (G′) compared with loss modulus (G″) value (G′ >> G″), as obtained via temperature sweep. Both the maleic anhydride (MA) content as well as the annealing te...
In the present work, a series of highly branched random copolymers of acrylamide (AM), sodium 2-a... more In the present work, a series of highly branched random copolymers of acrylamide (AM), sodium 2-acrylamido-2-methyl-1-propanesulfonate (SAMPS), and N-isopropylacrylamide (NIPAM) were prepared by us...
Industrial & Engineering Chemistry Research, 2013
ABSTRACT The oil recovery from core material and a specifically designed flow cell using novel br... more ABSTRACT The oil recovery from core material and a specifically designed flow cell using novel branched (comblike) polyacrylamides (PAM) has been investigated. The injectivity characteristics of the different branched PAMs were evaluated by filtration tests and core-flow experiments. The number of arms of the branched PAM has little to no effect on the filterability and permeation through a porous medium. The 13-arm branched PAM displayed a higher residual resistance factor (RRF) in Berea sandstone than its linear analogue and a commercial HPAM. In addition, the thickness of the layer adsorbed at the rock surface is higher for the branched PAM. Oil trapped in dead-end pores is simulated using a 2D flow cell and the effect of the number of arms on the recovery of residual oil is evaluated. In brine solutions, the branched PAMs perform equal or better than their linear analogues in terms of the solution viscosity. The oil recovery of a branched PAM with a similar molecular weight is 3 times as high as that for the commercial polymer. The recovery efficiency, evaluated using low permeable Berea as the porous medium, is significantly improved by using branched PAM instead of linear ones (5.0 compared to 1.5% of the OOIP). An improvement is also observed when high permeable Bentheim cores are used as the porous medium (9.4% compared to 6.0% of the OOIP). The higher oil recovery in the 2D flow cell might explain the improved performance of the branched PAMs. The high thickening capability and the low molecular weight of the branched PAMs makes them suitable for application in enhanced oil recovery (EOR, especially for low permeable reservoirs).
In this work, we investigated the functionalization of polyketone 30 (PK30) with glycyl-glycine (... more In this work, we investigated the functionalization of polyketone 30 (PK30) with glycyl-glycine (Gly-Gly) via the Paal–Knorr reaction with the aim of homogenously dispersing two types of reduced graphene oxide (rGO, i.e., lrGO and hrGO, the former characterized by a lower degree of reduction in comparison to the latter) by non-covalent interactions. The functional PK30-Gly-Gly polymer was effective in preparing composites with homogeneously distributed rGO characterized by an effective percolation threshold at 5 wt. %. All the composites showed a typical semiconductive behavior and stable electrical response after several heating/cooling cycles from 30 to 115 °C. Composites made by hrGO displayed the same resistive behaviour even if flanked by a considerable improvement on conductivity, in agreement with the more reduced rGO content. Interestingly, no permanent percolative network was shown by the composite with 4 wt. % of lrGO at temperatures higher than 45 °C. This material can be...
Alginates are natural anionic polyelectrolytes investigated in various biomedical applications, s... more Alginates are natural anionic polyelectrolytes investigated in various biomedical applications, such as drug delivery, tissue engineering, and 3D bioprinting. Functionalization of alginates is one possible way to provide a broad range of requirements for those applications. A range of techniques, including esterification, amidation, acetylation, phosphorylation, sulfation, graft copolymerization, and oxidation and reduction, have been implemented for this purpose. The rationale behind these investigations is often the combination of such modified alginates with different molecules. Particularly promising are lectin conjugate macromolecules for lectin-mediated drug delivery, which enhance the bioavailability of active ingredients on a specific site. Most interesting for such application are alginate derivatives, because these macromolecules are more resistant to acidic and enzymatic degradation. This review will report recent progress in alginate modification and conjugation, focusin...
Hydrogels have gained a lot of attention with their widespread use in different industrial applic... more Hydrogels have gained a lot of attention with their widespread use in different industrial applications. The versatility in the synthesis and the nature of the precursor reactants allow for a varying range of hydrogels with different mechanical and rheological properties. Understanding of the rheological behavior and the relationship between the chemical structure and the resulting properties is crucial, and is the focus of this review. Specifically, we include detailed discussion on the correlation between the rheological characteristics of hydrogels and their possible applications. Different rheological tests such as time, temperature and frequency sweep, among others, are described and the results of those tests are reported. The most prevalent applications of hydrogels are also discussed.
Chemical Enhanced Oil Recovery (EOR) is currently and mainly based on the use of partially hydrol... more Chemical Enhanced Oil Recovery (EOR) is currently and mainly based on the use of partially hydrolyzed polyacrylamide as water-soluble polymer for mobility control. This choice is predominantly related to technological (thickening efficiency) as well as economic considerations. However, the presence of salt in the underground water significantly reduces the effect of such polymer on the solution rheology. This becomes even less when the polymer is used in combination with alkali. Therefore, the amount of polymer required is significantly higher than expected on the basis of simple rheological models, which in turn has a clear negative effect on the economics of the process. Against this backdrop, the search for alternative water-soluble polymers has been gaining a predominant attention at both academic and industrial level. In this work, we report on the latest development about the synthesis and application of novel polymeric products for EOR. Biography Francesco Picchioni has compl...
Low cross-link density thermally reversible networks were successfully synthesized from jatropha ... more Low cross-link density thermally reversible networks were successfully synthesized from jatropha and sunflower oils. The oils were epoxidized and subsequently reacted with furfurylamine to attach furan groups onto the triglycerides, preferably at the epoxide sites rather than at the ester ones. Under the same reaction conditions, the modified jatropha oil retained the triglyceride structure more efficiently than its sunflower-based counterpart, i.e., the ester aminolysis reaction was less relevant for the jatropha oil. These furan-modified oils were then reacted with mixtures of aliphatic and aromatic bismaleimides, viz. 1,12-bismaleimido dodecane and 1,1′-(methylenedi-4,1-phenylene)bismaleimide, resulting in a series of polymers with Tg ranging between 3.6 and 19.8 °C. Changes in the chemical structure and mechanical properties during recurrent thermal cycles suggested that the Diels–Alder and retro-Diels–Alder reactions occurred. However, the reversibility was reduced over the the...
Among smart materials, self-healing is one of the most studied properties. A self-healing polymer... more Among smart materials, self-healing is one of the most studied properties. A self-healing polymer can repair the cracks that occurred in the structure of the material. Polyketones, which are high-performance thermoplastic polymers, are a suitable material for a self-healing mechanism: a furanic pendant moiety can be introduced into the backbone and used as a diene for a temperature reversible Diels-Alder reaction with bismaleimide. The Diels-Alder adduct is formed at around 50 °C and broken at about 120 °C, giving an intrinsic, stimuli-responsive self-healing material triggered by temperature variations. Also, reduced graphene oxide (rGO) is added to the polymer matrix (1.6–7 wt%), giving a reversible OFF-ON electrically conductive polymer network. Remarkably, the electrical conductivity is activated when reaching temperatures higher than 100 °C, thus suggesting applications as electronic switches based on self-healing soft devices.
Polymers crosslinked via furan/maleimide thermo-reversible chemistry have been extensively explor... more Polymers crosslinked via furan/maleimide thermo-reversible chemistry have been extensively explored as reprocessable and self-healing thermosets and elastomers. For such applications, it is important that the thermo-reversible features are reproducible after many reprocessing and healing cycles. Therefore, side reactions are undesirable. However, we have noticed irreversible changes in the mechanical properties of such materials when exposing them to temperatures around 150 °C. In this work, we study whether these changes are due to the self-reaction of maleimide moieties that may take place at this rather low temperature. In order to do so, we prepared a furan-grafted polyketone crosslinked with the commonly used aromatic bismaleimide (1,1′-(methylenedi-4,1-phenylene)bismaleimide), and exposed it to isothermal treatments at 150 °C. The changes in the chemistry and thermo-mechanical properties were mainly studied by infrared spectroscopy, 1H-NMR, and rheology. Our results indicate t...
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