Hydrophilic modification of polycarbonate using p-phenylenediamine

Polycarbonate is a commonly used plastic, particularly for making glasses lenses. Polycarbonate is prone to fogging, making hydrophilic modification desirable. In this work, polycarbonate is treated with p-phenylenediamine (PPD) to improve its hydrophilicity. The influence of treating conditions, such as solvent, PPD concentration, heating temperature, and heating time, are studied to reveal their impacts on the water contact angle of polycarbonate. For example, the water contact angle of polycarbonate is reduced to 33° from 83° after treated in water with 0.1 wt% PPD at 80°C for 120 minutes. The improvement of the hydrophilicity of polycarbonate by PPD is explained based on the introduction of polar groups by PPD or poly-PPD (p-PPD), in terms of polyurethane, benzyl hydroxyl, or amine centers, which can interact with water to have a better affinity to spread water on the surface due to the like-like principle. The possible mechanisms are supported with infrared spectroscopy measurements.