Kinetic Analysis of the Theral Degradation of PP-Epdm Blends

摘要

The thermal degradation of polypropylene (PP)Iethylene-propylene—diene rubber (EPDM) and their blends is presented. In order to evaluate the effect of the components on the thermal stability, the degradation kinetics of blends of dilTerent composition is analyzed by rhermogravimerry in isothermal and constant heating rate conditions in pure nitrogen. The Flynn and Wall method is used to obtain the acti’~ation energies from the dynamic tests, while isothermal test results areus~d to dotso~dne the pseudo order of reaction and the shttpe of the f(~) function which is similar to an autocatalytic type equation. Model parameters such as activation energies and pseudo order of reaction arc calculated using a non-tine~r regression anaIy:~is. Although PP-EPDM blends are not compatible, the degradation process was not clearly characterized by two tndependent reactions, suggesting that both components are interacting during degradation. Moreover, the kinetic study showed that the activation energy of the whole degradation process changes linearly with the reiative amount of the components;on the other hand,small differences were observed in the reaction orders.