engleski

Dynamic and isothermal thermogravimetric degradation of poly(vinyl chloride)/chlorinated polyethylene blends

The thermal degradation of poly(vinyl chloride)/chlorinated polyethylene (PVC/CPE) blends of different compositions was investigated by means of dynamic and isothermal thermogravimetric analysis in flowing atmosphere of nitrogen. The effect of CPE modifier on thermal stability of PVC was also investigated. Increasing the ratio of CPE in the blend the onset temperature of degradation rises, while the mass loss at the end of the first degradtion step and the maximal rate of dehydrochlorination of PVC lower. In the range of conversions of 3-30% the kinetic parameters of the process(the apparent activation energy E and preexponential factor Z) were calculated after Flynn-Wall-Ozawa method for the dynamic degradation of PVC/CPE blends and for the isothermal degradation after Flynn method. There is the compensation dependence between the values E and logZ. The main, and the most rapid degradation reaction in the investigated range of conversions is dehydrochlorination; changing the blend composition only the rate of dehydrochlorination is changed.

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