Depolymerization of proanthocyanidins and application exploration in the field of preparation of flexible materials

Abstract

Intelligent materials have become an important objective in the development of polymer materials. Here, we depolymerized polymeric proanthocyanidins extracted from larch bark, using a stable composite catalyst, Pd/SO₄²⁻/ZrO₂, to obtain oligomeric proanthocyanidins (OPC), which retained the structural proanthocyanidin units and were observed to have excellent antioxidant properties. The OPC were hydrogen bonded with acrylonitrile-butadiene rubber (NBR) to produce a thermally induced flexible shape memory material, L-NBR. The polyphenolic structure of the OPC improved the characteristic transition temperature, shape recovery rate and shape fixation rate of NBR, leading to improved tensile properties, thermal stability and resistance to aging. L-NBR has potential for use in fields such as stretchable electrodes, simulated robotic electronic skins and intelligent electronic components, and also provides a new use for renewable biomass resources.