Predictive Modeling of Mechanical Strength Degradation in Polycarbonate via Hydrolysis Under Temperature, Humidity, and Time-Dependent Conditions

A variety of engineering plastics are widely used in electrical industrial products. Compared to metals, these plastics generally have shorter product lifetimes and lower mechanical strength, making it important to predict their functional lifetime. Resins such as Polycarbonate (PC) or Polybutylene Terephthalate (PBT), which contain ester bonds in their polymer main chain, are prone to hydrolysis caused by water vapor, resulting in strength degradation. In this study, four types of hydrolyzable resins—including polycarbonate and polybutylene terephthalate—were selected, and their time-dependent mechanical strength were measured following exposure to high-temperature and high-humidity conditions. Based on the results, a new prediction formula for strength degradation was derived using vapor pressure and temperature as independent parameters.