Thermo-mechanical degradation-induced grafting of poly(styrene-acrylonitrile) to chlorinated polyethylene

The thermo-mechanical degradation of acrylonitrile-chlorinated polyethylene-styrene (ACS) terpolymer was investigated by means of high temperature shearing in a Haake Rheomixer. The results showed that the chain scission takes place in the poly(styrene-acrylonitrile) (SAN) component while the residual rate of the ACS resin after extraction of SAN increases gradually with increasing the shearing time. FTIR and DSC analysis confirmed that the increase in the residual rate is due to the thermo-mechanical degradation-induced grafting of SAN to the CPE chain. SEM and TEM observation revealed a remarkable reduction in the CPE domain size and formation of a salami-like structure in which many CPE-g-SAN micelles are embedded in the fine CPE domain. These changes result in a significant improvement in the impact strength of the ACS resin. The mechanism of the thermo-mechanical degradation-induced grafting and the morphology change were discussed.