Effect of dialdehyde starch on cassava starch/poly(vinyl alcohol) blends fabricated by melt mixing method with glycerol plasticized

Abstract

Starch is considered an ideal alternative to petroleum‐based plastics. However, the application of thermoplastic starch (TPS), which produced from cassava starch plasticized with glycerol, is limited by its hydrophilic, poor mechanical properties, and inadequate processability. In this study, dialdehyde starch (DAS) is used as crosslinker to modify TPS/poly(vinyl alcohol) (PVA), and DAS crosslinked cassava starch/PVA blends are fabricated by melt mixing method. Studies on the molecular structure of DAS crosslinked cassava starch/PVA blend indicate that the addition of DAS enhances the intermolecular interactions between cassava starch and PVA, resulting in the formation of a dense internal structure. The plasticizing torque and equilibrium torque of crosslinked cassava starch/PVA blends are increased and the tensile strength reaches 3.60 MPa, an improvement of 186% compared with TPS. Additionally, the water contact angle increases from 87.8° to 119.6° after modification. Compared with other crosslinkers, DAS has obvious advantages, making the DAS crosslinked cassava starch/PVA blend a biodegradable material with excellent properties and promising application prospects.