Covalent incorporation of starch derivative into waterborne polyurethane for biodegradability

We introduced vinyltrimethoxysilane (VTMS) modified starch into the waterborne polyurethane (WPU) by covalent bond (hereafter called hybrids or chemical hybrids) to enhance the biodegradability of WPU. Effects of starch content on the biodegradation of the chemical hybrids in α-amylase solution and buffer solution were evaluated in terms of weight loss and tensile property change with incubation time, contact angle, Shore A hardness, and scanning electron microscopy morphology. The VTMS modified starch provided the chemical hybrids with multifunctional crosslinks and significantly enhanced tensile modulus and strength of the hybrids. When the hybrids were incubated in α-amylase solution, maximum weight loss of 15% and tensile strength decrease of 60% were noted in 10 days with 10% starch incorporation. Notably, these property changes were much smaller with physical blend of WPU and unmodified starch than those of chemical hybrids.