Improved stress relaxation resistance of composites films assisted by soy protein polymer

Abstract Stress relaxation is an important parameter factor to determine the applicability of materials under the condition of dynamic loading. Here, we found that soy protein polymer (SPP), a natural polymer, can improve stress relaxation resistance of polyvinyl alcohol (PVOH) films. Such improvement in stress relaxation resistance was accompanied with the improved thermal stability. The mechanism of the improved stress relaxation resistance was proposed and attributed to constructive interactions between SPP and PVOH, which restricted motions and rearrangements of polymeric chains. Such hypothesis was supported by differential scanning calorimetry (DSC) and modeling results in which decreased crystallizability and increased relaxation time for the composites systems were observed.