Moisture‐resistant and strength retention properties of supercritical CO2‐processed thermoplastic starch modified by polyvinyl alcohol with varying degrees of polymerization

다국어 초록 (Multilingual Abstract)

The ease of melt‐processing, moisture‐resistance, and tensile retention properties of scCO2 and polyvinyl alcohol (PVA)–modified thermoplastic starch (scCO2TPSxPVAay) materials were explored in this investigation. These characteristics were considerably improved by PVA modification particularly with decreasing PVA degree of polymerization (DP). The intensities of O―H stretching bands of scCO2TPSxPVAay were considerably larger, and peak location of O―H stretching bands were significantly smaller than those of the corresponding TPSxPVAay and reduced gradually with the decrease in PVA's DP. The ΔH of melting and diffraction peaks of Vh‐type crystals for conditioned TPSxPVAay and scCO2TPSxPVAay were considerably smaller than those of corresponding TPS and TPSxPVAay aged for the same time period and gradually reduced in intensity with decreasing PVA's DP. Possible reasons accounting for the considerably improved melt processing, moisture resistance, tensile retention, and retrogradation of scCO2TPSxPVAay with decreasing PVA's DP are proposed.