Pure Hydrolysis of Polyamides: A Comparative Study

Nylon, also known as polyamides (PAs), undergoes local environmental degradation, leading to a decline in its mechanical properties over time. The degradation process is strongly influenced by the surrounding environment in which the polymer is utilized. PAs can experience various forms of degradation, such as thermal degradation, oxidation, hydrothermal oxidation, UV oxidation, and hydrolysis. It is crucial to understand each of these degradation mechanisms individually to better comprehend the degradation process of nylon. Although extensive research has been conducted on hydrolysis over the past few decades, there is currently no comprehensive review that consolidates the latest findings. This review analyzes the available characterization data and evaluates the changes in molecular weight, crystallinity, chemical structure, and mechanical properties of PAs that have aged in oxygen-free water at high temperatures. The primary objective is to gain a comprehensive understanding of the aging process of PAs in water without oxygen. Additionally, secondary information is provided, including the influence of fibers and additives in the polymer, hydrolysis susceptibility among PAs with longer aliphatic chains, correlation between different parameters, impact of acids, and important factors for determining the point at which PAs become brittle when subjected solely to hydrolysis.