POLYSILOXANEIMIDE MEMBRANES .1. PHYSICAL-PROPERTIES

Polysiloxaneimide (PSI) membranes with siloxane moieties in the main chain were prepared by polycondensation of pyromellitic dianhydride (PMDA), 4,4'-oxydianiline (ODA) and amine-terminated poly(dimethyl siloxane) (PDMS). The effect of the PDMS content on the crystallinity, mechanical properties and thermal stability of the PSI membrane were investigated. Thermal degradation of PSI membrane was studied under nitrogen atmosphere at various heating rates. The Ozawa's method was applied for calculating kinetic parameters, such as the activation energy, the pre-exponential factor and the reaction order. The thermal stability of PSI membrane was found not to be appreciably affected by introducing PDMS, especially at a lower PDMS content. The kinetic order of degradation was determined to be unity in the nitrogen atmosphere.