Water proof and strength retention properties of thermoplastic starch based biocomposites modified with glutaraldehyde.

Abstract Water proof and strength retention properties of thermoplastic starch (TPS) resins were successfully improved by reacting glutaraldehyde (GA) with starch molecules during their gelatinization processes. Tensile strength ( σ f ) values of initial and aged TPS 100 BC 0.02 GA x and (TPS 100 BC 0.02 GA x ) 75 PLA 25 specimens improved significantly to a maximal value as GA contents approached an optimal value, while their moisture content and elongation at break values reduced to a minimal value, respectively, as GA contents approached the optimal value. The σ f retention values of (TPS 100 BC 0.02 GA 0.5 ) 75 PLA 25 specimen aged for 56 days are more than 50 times higher than those of correspoding aged TPS and TPS 100 BC 0.02 specimens, respectively. New melting endotherms and diffraction peaks of V H -type starch crystals were found on DSC thermograms and WAXD patterns of aged TPS or TPS 100 BC 0.02 specimens, respectively, while negligible retrogradation effect was found for most aged TPS 100 BC 0.02 GA x and/or (TPS 100 BC 0.02 GA x ) 75 PLA 25 specimens.