Accelerated Aging Effects on Polymers Based on Fatty Acids and Soybean Oil Derivatives

Abstract

Aging of polymers is a complex process influenced by their chemical structure and external factors such as UV radiation, humidity, temperature, and shelf life. These factors often shorten service life through mechanisms including chain relaxation and release of low molecular weight components. Therefore, understanding the degradation pathways, or at least being able to predict long-term behavior is essential in fields ranging from materials design to environmental monitoring, and is particularly relevant for new bio-based polymers.This study investigates the evolution of several properties in polymers derived from modified fatty acids (methacrylated oleic acid, MOA, and methacrylated maleated ricinoleic acid, MMRA) and vegetable oils (acrylated epoxidized soybean oil, AESO) subjected to both natural (i.e. laboratory conditions) and accelerated aging. As expected, the obtained results confirm that accelerated aging affects more severely the performance of bio-based polymers than natural aging due to the simultaneous acting of moisture, UV radiation and relatively high temperatures. Aging led to the formation of carbonyl and hydroperoxide groups, low molecular weight products from chain scission, and additional crosslinking of macromolecular chains. These opposing effects generally result in increased superficial hydrophilicity and glass transition temperatures, as well as a broadening of the damping region. This work is the result of a rigorous and systematically planned experimental design conducted over more than four years. The resulting findings, though limited in availability, are highly significant for advancing the development of novel materials, particularly those derived from biomass.