Diffusion of miscible polymers in multilayer films

Abstract

Abstract Thermal and optical properties of multilayer films of miscible polyethyloxazoline (PEOx) and poly(styrene‐co‐acrylonitrile) have been studied as a function of time and temperature. Differential scanning calorimetry showed that the distinct, characteristic T g 's of the component polymers of the original films disappear after only short heating periods above T g , and a single transition appears. The new transition region is broad at first, but narrows on subsequent heating. The measurement of light transmittance as a function of wavelength through the heat‐treated films also confirms the diffusion of the miscible polymers and gives results which are comparable to the thermal measurements. Films from immiscible polymers of polystyrene and PEOx retain their properties after various heat treatments. A qualitative discussion of the diffusion process as examined by the thermal measurements is presented.