Modulated differential scanning calorimetry .8. Interface development between films of polyepichlorohydrin and poly(vinylacetate)

A thermal method with the potential to determine the weight fraction and the interfacial thickness in multiphase polymer materials is described. The extent of interdiffusion, and hence the development of an interface between two miscible polymers, polyepichlorohydrin and poly(vinyl acetate), with time at 100 degrees C has been studied by means of modulated-temperature differential scanning calorimetry. This polymer pair is known to be miscible. By measurement of the change of increment of heat capacity in the glass transition region, the total interface content can be determined. With increasing time, the interfacial thickness increases. The average interfacial thickness is about O.1mm after a diffusion time of 4180 min. The interfacial thickness grows at t(1/2), where t is the diffusion time, and the interdiffusion coefficient is about 6.25 x 10(-11) cm(2)s(-1), assuming that the diffusion rates of the two polymers are equal. (C) 1997 Elsevier Science Ltd.