WATER ADSORPTION CHARACTERISTICS AND ABRASION RESISTANCE OF STARCH-BASED FOAMS

摘要

Degradable polymers including Eastar Bio Copolyester 14766 (EBC), Mater-Bi® ZF03U (MBI) and polylactic acid (PLA) blended in various ratios (10, 25, and 40%) with regular (25% amylose) and waxy corn starches were extruded into loose-fill packaging foams using a co-rotating twin screw extruder. No significant differences existed in the water adsorption characteristics of the foams made from regular and waxy corn starches. MBI-starch foams had higher water adsorption capabilities than did the EBC-starch and PLA-starch foams. Equilibrium moisture contents of foams decreased linearly as the polymer contents increased, and increased significantly as the relative humidity increased. Models developed for different polymer-starch blends fit the data well with small standard errors and uniformly scattered residual plots. The testing procedure for abrasion resistance provided an objective measure of foam abrasion resistance. EBC-starch and PLA-starch foams had excellent abrasion resistance (> 99%).