Maleic Anhydride

The use of sustainable and environmentally friendly materials in today’s society is becoming increasingly important due to mankind’s increasing pressure on the carrying capacity of the planet. Natural fibre reinforced composites (biocomposites) can be used for this purpose as high-performance engineering materials. These biocomposites contain good specific properties and can therefore be used as an alternative to materials such as metals. Among natural fibres, flax has attracted high interest because it is among the highest performing natural fibres. However, these fibres have a hydrophilic character which makes them sensitive to humid environments. In this thesis, the extent to which water absorption takes place in these composites is investigated, as well as the impact this has on their mechanical properties.Several composites were produced for this research. There are three commercial types of flax fabrics that are combined with four matrices. These flax fabrics are FlaxTapeTM an...

The behavior of stone groundwood / polypropylene injection-molded composites was evaluated with and without coupling agent. Stone groundwood (SGW) is a fibrous material commonly prepared in a high yield process and mainly used for papermaking applications. In this work, the use of SGW fibers was explored as a reinforcing element of polypropylene (PP) composites. The surface charge density of the composite components was evaluated, as well as the fiber’s length and diameter inside the composite material. Two mixing extrusion processes were evaluated, and the use of a kinetic mixer, instead of an internal mixer, resulted in longer mean fiber lengths of the reinforcing fibers. On the other hand, the accessibility of surface hydroxyl groups of stone groundwood fibers was improved by treating the fibers with 5% of sodium hydroxide, resulting in a noticeable increase of the tensile strength of the composites, for a similar percentage of coupling agent. A new parameter called Fiber Tensile...

The wood plastic composites studied in this work are composed of high-density polyethylene matrix and Pinus pinaster wood fibers. Despite some interesting intrinsic properties, this wood plastic composite has limited mechanical properties because of the incompatibility between the polar hydrophilic fibers and the non-polar hydrophobic matrix. In this study, the effects of maleic anhydride-modified polyethylene additive, of carbon chains grafted by acetylation and of wood fiber contents on the tensile mechanical properties of the wood plastic composite were studied. Tensile tests were carried out using digital image correlation as an intrusiveness and robust method for strain measurements. Results showed first that the addition of wood fibers made the wood plastic composite stiffer but less flexible. Acetylation improved the interfacial adhesion properties: the Young modulus was increased and a lower strain at failure was reported. The coupling agent also increased the compatibility ...

New magnesium complexes were used as catalysts for the ring opening polymerization of cyclic esters to produce degradable polymers. In the ROP of macrolactones, good activity and control were achieved at room temperature, conditions generally prohibitive for macrolactones.

The rate constants of the Diels-Alder reaction of 9,10-dimethylanthracene with tetracyanoethylene, 4-phenyl-1,2,4-triazoline-3,5-dione, maleic anhydride, and N-phenylmaleimide in solution have been determined. It was found that tetracyanoethylene and 4-phenyl-1,2,4-triazoline-3,5-dione can react instantly with 9,10-dimethylanthracene, which is a representative of toxic polycyclic aromatic hydrocarbons. The kinetics of the reactions of 9,10-dimethylanthracene with tetracyanoethylene and N-phenylmaleimide in the solid phase without solvent has been studied. The rate of these reactions in the solid phase appeared to be significantly lower than that of the same reactions in the solution, since the rate of reactions in the solid phase strongly depends on the rate of renewal of contacts between the reagent molecules. The data obtained can be useful for the purification of water bodies and soil from polycyclic aromatic hydrocarbons.

The potential energy surface of four stereoselective Diels-Alder reactions was studied, namely: cyclopentadiene-maleic anhydride, furan-maleic anhydride, the dimerization of cyclopentadiene, and cyclopentadiene-cyclopropene. For completeness, we also studied the reaction between ethylene and 2-hydroxy-6-methyl-1,4-benzoquinone, a [5+2] cycloaddition reaction. For all cases at least a stationary state of supramolecular nature a van der Waals complex, was determined. These stationary states are complexes formed by the interaction between the reagents, minima located in the paths between the non-interacting molecules and the transition states. The existence of these complexes makes it necessary to reconsider the role of Secondary Orbital Interactions in the selectivity of these reactions. As it is the case with other complexes, the stability of these supramolecular intermediates depends on electrostatic phenomena such as dispersion forces. The observation of [5+2] intramolecular comple...

Synthesis and characterization of a novel toughener–compatibilizer for polypropylene (PP)–montmorillonite (MMT) nanocomposites were conducted to provide enhanced mechanical and thermal properties. Poly(ethylene oxide) (PEO) blocks were synthetically grafted onto maleic anhydride‐grafted polystyrene‐block‐poly(ethylene/butylene)‐block‐polystyrene (SEBS‐g‐MA). Special attention was paid to emphasize the effect of PEO‐grafted SEBS (SEBS‐g‐PEO) against SEBS‐g‐MA on morphology, static/dynamic mechanical properties and surface hydrophilicity of the resultant blends and nanocomposites. It was found that the silicate layers of neat MMT are well separated by PEO chains chemically bonded to nonpolar SEBS polymer without needing any organophilic modification of the clay as confirmed by X‐ray diffraction and transmission electron microscopy analyses. From scanning electron microscopy analyses, elastomeric domains interacting with MMT layers via PEO sites were found to be distributed in the PP m...

Melt blending of linear low density polyethylene (LLDPE) and poly(l-lactic acid) (PLLA) was performed in an extrusion mixer with post extrusion blown film attachment with and without a compatibilizer-maleic anhydride grafted low density polyethylene. The blend compositions were optimized for tensile properties as per ASTM D 882-91. Based on this, LLDPE 80 (80 wt% LLDPE and 20 wt% PLLA) and M-g-L 80/4 (80 wt% LLDPE, 20 wt% PLLA and 4 parts compatibilizer/100 parts of resin were found to be an optimum composition. The thermal gravimetric profile and thermal endurance of these blends were characterized as per ASTM E1641-07 and E1877-05. The effect of physical aging on mechanical and thermal properties of these blends was evaluated. The PLLA showed the highest Arrhenius activation energy, relative thermal index and strongest thermal endurance of all samples followed by M-g-L 80/4 and LLDPE 80. The thermo-oxidation coefficient improved with addition of compatibilizer in the blends. With ...

Glycerides obtained from the glycerolysis of soybean oil with crude glycerol were acylated with maleic anhydride at 80–100 °C. Both uncatalyzed and catalyzed reactions with 2‐methylimidazole (2‐MI) were evaluated. Formation of maleated glycerides was confirmed by 1H‐NMR and FTIR analyses. Consumption of maleic anhydride as a function of time was followed by acid value titration. High conversion (ca. 95 %) of hydroxyl groups was obtained at 90 °C in 60 min without catalyst. Under these conditions, a product with 1.9 maleate moieties per glyceride molecule was obtained. Catalyzed reactions afforded lower conversions of hydroxyl groups and lower maleate yields compared to uncatalyzed reactions.

ABSTRACTIn-situ filling through hydrolysis and condensation of silicon alkoxides dissolved into polymers has been utilized to generate nanocomposites in which the filler phase can be intimately associated with the polymer on relatively small length scales. One problem of the method has been achieving useful fill volumes without bulk phase separation of the growing inorganic component from the polymer. In this paper, we describe the preparation of a new class of nanocomposite materials in which the inorganic filler phase is pre-assembled before copolymerization with an organic monomer. Maleimide monomers, prepared from alkoxysilylpropyl amines and maleic anhydride, were protected against side reactions by forming the oxonorbornene Diels-Alder adduct with furan. The monomers were then reacted under solgel conditions to form oligomers or polymers making up the filler phase. The material was activated by thermal deprotection of the maleimide and reacted with organic monomers or polymers...