Influence of Environmental Stress Cracking and Hydrothermal Aging on the Mechanical Properties of Polycarbonate

ABSTRACT In this study, the effect of environmental stress cracking (ESC) and hydrothermal aging on the mechanical properties of polycarbonate (PC) was investigated by solvent immersion at different strains and high temperature and humidity accelerated aging. Compared with isopropanol, toluene is a higher ESC risk medium for PC, and the easier dissolution and plasticization of PC in toluene lead to faster propagation of cracks and a more significant decrease in mechanical properties, especially toughness. The generation and propagation of cracks and the loss of mechanical properties increase with the increase in loading strain and exposure time. The strong polarity allows PC to interact with water molecules, and the degradation of PC occurs due to hydrolysis and induced oxidation during hydrothermal aging. Under the action of both temperature and the absorbed water, the created microcavities or cracks make PC unable to yield locally and change from ductile to brittle material with the increase of aging time, temperature and humidity.