Effect of chain extender on the morphology, thermal, viscoelastic, and dielectric behavior of soybean polyurethane

The objective of this work was to determine the influence of different chain extenders (CEs) on the morphology, thermal, viscoelastic, and dielectric properties of soybean polyurethane (PU). The PU with ethane-1.2-diol showed a more organized structure, which was attributed to the smaller amount of methylene groups (-CH2-) and the shorter distance between the hydrogen bonds. While, PUs with dipropylene glycol, the free volume increased due to the less effective interactions formed between the hard and soft domains. The alpha, beta, and gamma transitions dipolar by conductive process, are probably associated with (a) local motions of the main chain, (b) the smaller groups rotation motions in the fatty acid chains in the soft phase, and (c) the -CH2- group rotation motion in the amorphous region. The phase-separated morphology is most evident at high temperatures due to the Maxwell-Wagner-Sillars interfacial polarization process.

Automated summary

This research aimed to investigate the effect of different chain extenders on the properties of soybean polyurethane, including morphology, thermal behavior, viscoelasticity, and dielectric properties. It was found that the choice of chain extender influenced the organization of PU structure and the interaction between hard and soft domains, resulting in different molecular motions and transitions. Additionally, the phase-separated morphology at high temperatures was attributed to the Maxwell-Wagner-Sillars interfacial polarization process.