Infrared studies of crystallinity in poly(vinyl chloride)

The infrared spectrum of a solvent-cast film of commercial poly(vinyl chloride) (PVC) can be very sensitively compared to a rapidly quenched film of the same material by using a compensation technique. When this is done, crystalline bands, as seen in urea canal complex PVC, can be detected and measured in the solvent-cast film. The melting and recrystallization behavior as well as the broad melting range from 120° to 210°C indicate the presence of crystallites of widely different degrees of perfection. Crystallization kinetics from the quenched glassy state indicate that time-temperature superposition applies with an activation energy of 90 kcal/mole. Molecular mobility is indicated as the rate-controlling mechanism.