Optimization of the Thermomechanical Behavior of a Poly(Chromium III Trisphosphinate).

A two-component reactive system consisting of a poly(chromium 3 bisphosphinate) and dioctyl phosphinic acid reacts to form a poly(chromium 3 trisphosphinate). Extensive thermomechanical hysteresis is displayed by the system throughout the temperature range -180C to >300C. Thermal pretreatment to about 400C (the limit of thermal stability) eliminated these instabilities. These results correlate with the reported brittle and tough character of films of the poly(chromium 3 bisphosphinate) and poly(chromium 3 trisphosphinate) respectively. Regardless of thermal history (between 200C and 400C), the polymer system displayed three major transition regions: one the glass transition centered at about 0C, another centered at about 230C, and a third at about -200C. (Author)