Rheological properties of thermoplastic starch and starch/poly(ethylene-co-vinyl alcohol) blends☆

摘要: Abstract Blends consisting of a systematic compositional series starch/poly(ethylene-co-vinyl alcohol) were studied by using capillary viscometry. Three different types starches used: waxy maize, starch containing essentially 100% amylopectin; native corn, possessing approximately 70% amylopectin and 30% amylose; treated, high-amylose starch, amylose. Poly(ethylene-co-vinyl with 44 mol% ethylene was blended in varying proportions the starches, glycerine water added as plasticizers. The viscosity blends measured over shear-rate range 1–1000 s−1. Samples unconditioned (as stored) well conditioned at 65% relative humidity 23°C temperatures between 140 170°C. All results fall power-law regime, there is no indication approach to zero-shear-rate any blend systems. As starch-based food materials, has an Arrhenius dependence on temperature, exponential moisture content shear rate. exponents from are less than unity, indicating that melts thinning. Results indicate decreases decreasing amylose or increasing poly(ethylene-co-vinyl content. increases increase blends.