Properties of soy protein isolate/poly(ethylene‐co‐ethyl acrylate‐co‐maleic anhydride) blends

Abstract

Blends of soy protein isolate (SPI) with 10, 20, 30, 40, and 50% poly(ethylene-co-ethyl acrylate-co-maleic anhydride) (PEEAMA), with or without addition of 2.0 wt % methylene diphenyl diisocyanate (MDI), were prepared by mixing with an intensive mixer at 150°C for 5 min, and then milling through a 1-mm sieve. Blends were then compression-molded into a tensile bar at 140°C. Thermal and mechanical properties and water absorption of the blends were studied by differential scanning calorimetry (DSC), dynamical mechanic analysis (DMA), a test of modulus and tensile strength (with an Instron tensile tester), a water absorption test, and scanning electron microscopy (SEM). The blends showed two composition-dependent glass transition temperatures. Furthermore, as the SPI content increased, the melting temperature of PEEAMA remained constant but the heat of fusion decreased. These results indicate that SPI and PEEAMA were partially miscible. Morphology observations support these results. Increasing the PEEAMA content resulted in decreases in the modulus and tensile strengths and increases in the elongation and toughness of the blends. Water absorption of the blends also decreased with increased PEEAMA content. Incorporating MDI further decreased the water absorption of the blends. The mechanism of water sorption of SPI was relaxation controlled, and that of the blends was diffusion controlled.

Morphological and thermal evaluation of soy protein concentrate on graft copolymerization with ethylmethacrylate

“…Soy proteins have been modified using alkali, 13 urea, 14 and guanidine hydrochloride-sodium dodecylsulphate. 15 Crosslinking, 16 acylation, 17 blending with other polymers, 18 and enzymatic modifications 19 are the other methods to modify the soy proteins. Modification of natural polymers like proteins by graft copolymerization is an important method to alter the properties.…”

Development of Novel Soy Protein-Based Polymer Blends

“…These polymers include poly (butylenes succinate-co-adipate) (14), polycaprolactone (3,15), poly (hydroxyl ester ether) (16) and poly (butylenes adipate-co-terephthalate) (17). Blending SP with non-biodegradable polymers including poly(ethylene-co-ethyl acrylate-co-maleic anhydride) (18), polyurethane (19) and styrene-butadiene latex (20) have also been studied. SP is a pressure-sensitive thermoset polymer; it will unfold/melt (paste-like) and cure under both elevated temperature and pressure.…”

RSM optimized soy protein fibre as a sorbent material for treatment of water contaminated with petroleum products

“…The presence of reactive functional groups provide site for the chemical modifications which improve the functional properties of proteins. Acylation, crosslinking, oxidation, blending with other polymers and copolymerization are some techniques to modify the structure of proteins to enhance or modify the functional and physiochemical properties [20][21][22]. Graft copolymerization is one of the promising techniques to improve the physical and chemical properties of biopolymers.…”