Dielectric polarization and relaxation of soy protein-based biomaterial and its nanocomposites

Abstract

Plant protein-based biomaterials and biocomposites have gained great interest in non-biological and non-medical applications such as adhesives, foams, and plastics to substitute petroleum-based polymer products, because of their cost-effectiveness and eco-friendliness, etc. Despite the widely recognized potential of plant proteins in functional materials applications, the understanding of protein structures and properties in resulting functional materials is still immature, and previous studies mostly focused on protein solutions and hydrated proteins intended for food and biomedical applications. Meanwhile, soy protein, extracted from soybeans, is one of the most abundant plant protein sources in nature, receiving great attention in protein-based functional materials. The United States of America, as the leading country in growing soybeans, contributes to more than 30% of global soybean production every year. Therefore, successful transformation of soy protein to functional materials will not only meet the increasing demand for environmentally-benign materials, but also increase the add-on values of the agriculture products, benefiting agricultural economy including soybean farmers and related industry sectors. This study targeted exploration of new knowledge of protein structures and properties for functional materials applications via studying dielectric polarization and relaxation behaviors of soy protein-based biomaterials and nanocomposites over broad temperature and frequency ranges. The effects of compression molding, moisture absorption and boron nitride nanomaterials on the dielectric relaxation and polarization behaviors were investigated.