Study of transparent plastics for use on aircraft

Abstract

The purpose of this study was to determine the suitability of transparent plastics for use as flexible windshields on aircraft. The plastics included cellulose acetate, cellulose acetobutyrate, cellulose nitrate, ethyl cellulose, acrylate resin, vinyl chloride-acetate resin, vinyl acetal resin, and glyceryl-phthalate resin. The properties studied included light transmission, haziness, distortion of vision, resistance to weathering, scratch resistance, indentation hardness, impact strength, resistance to water, etc. Among these, the plastics made from some cellulose acetates and from acrylic resins showed the best weather resistance. Sheets of cellulose acetobutyrate remained unchanged in clarity after 12 months' exposure. The highest values for initial light transmission were obtained with samples of acrylate resins, the percentage transmission varying between 93.6 and 94.2 for these materials. The transmission value was little affected by 12 months' exposure, although the surface of the acrylate plastics had a slight tendency to craze. The acrylate and vinyl resins and cellulose acetobutyrate were found to be quite resistant to water absorption on immersion, but the cellulose acetate plastics absorbed a fair amount. Rutherford J. Gettens