Chemical Modification of Pvc

The degradation of PVC at a processing temperature is mostly caused by its abnormal and unsta— ble molecular structures. It has been pointed out that its allyl chloride structures play a significant role as the abnormal and unstable structures. Inasmuch as the allyl chloride struc— tures are markedly more chemically active than the normal structure, the selective chemical treatments are applicable to the allyl chloride structures. The thermal stability of PVC can be remarkably improved by treating PVC with certain organo—aluminiuin compounds or protic solvents. Concretely, the results of analyzing the reaction mechanism with the low molecular model compounds of PVC or the tracer show that the selective stabilizing reaction on the allyl chloride structure takes place. On the other hand, the improvement of the mechanical properties of PVC, such as softening temperature, rigidity, anti—creep property, impact strength and tensile strength, is important for practical applications of PVC.