Light transmission of composites made from the biaxially drawn ultrahigh molecular weight polyethylene (UHMWPE) film and polyether polyurethane

Optically transparent composite membranes have been made from two immiscibl e polymers, the biaxially drawn UHMWPE (the fiber, 80-400 mum in diameter) and the polyether polyurethane. The as-made composites have a volume fracti on up to 24% and a light transparency up to 70%. The light transmission of all the composites tested is linearly dependent on the wavelength of the vi sible incident light. The slope (K) and the constant (C) derived from the l inear relation were correlated with a mathematical model. The K-value chang ed with the changed of the residual voids in the composite. The C-value cha nged with the change of the refractive indices. The light transmission of t he composite membranes can be optimized through the control of both K and C , preferably controlling the K-values. The highest light transparency was f ound in Toyobo TM5 composite heat compacted at 115 degreesC. (C) 2001 Elsev ier Science Ltd. All rights reserved.