Acid Aging Behavior of Polycarbonates for Flame Retardant Plastic Containers for Central Office and UPS Lead-Acid Batteries

In these studies, the degradation of polycarbonates in battery acid was assessed by monitoring changes in impact resistance and melt flow rate. The effects of stress were investigated. Rates of hydrolysis were obtained from the rates of change in melt viscosity and allow estimation of service life at room conditions. These studies have shown that hydrolytic degradation of polycarbonates in battery acid results in severe reductions in strength and impact properties. These results provide a mechanistic explanation of premature stress crack failures observed in covers of polycarbonate battery containers in telephone central office reserve power usage. Potential implications of these results on the design, life and reliability of polycarbonate jars and covers for UPS* and central office stationary reserve batteries are discussed.