Plasticization of corn starch by polyol mixtures

Polyol mixtures including mixture of conventional plasticizer glycerol and higher molecular weight polyol (HP) such as xylitol, sorbitol and maltitol were used to plasticize corn starch by melt-blending method, and effect of the polyol mixture on the pocessibility, microstructures, thermal stability and mechanical properties of these starch composites (SC) were investigated. The introduction of HP providing greater processing torque can dramatically reduce the strong molecular chain interaction in starch without obvious residual starch granules in the starch composites. The increasing of the molecular weight and content of HP in polyol mixture is beneficial for the significant enhancement of the thermal stability and mechanical strength of the starch composite. Meanwhile, the addition of HP besides conventional glycerol increases the modulus and phase transition temperature of the starch composite too.