Polycarbonate copolymers physical aging

MOLECULAR ORIGINS OF DEFORMATION BEHAVIOR AND PHYSICAL AGING IN POLYCARBONATE COPOLYMERS... 

Polycarbonate is widely used in a nnmber of thermoplastic applications due to transparency and toughness. Copolymers of polycarbonate (PQ with polydimethyl siloxane (PDMS) fiirlher expand the property space to include extreme eonditions such as impact retention up to -60°C. It is known that hydrolysis of a carbonate linkage may lead to severance of polymer chains and may lead to deterioration of mechanical properties of polycarbonates under some conditions. Similarly for a molded part, physical aging at elevated temperatmes can also lead to deterioration of notched Izod impact of an amorphous polymer like polycarbonate . So, when a molded polycarbonate part is exposed to heat and humidity a combination of hydrolysis and physical aging may accelerate the property loss. Numerous approaches have been published in the past that leverage the use of various stabilizers to incrementally improve the performance. In this paper, we present the data for copolymers of polysiloxane with polycarbonate and their substantially improved heat aging and hydrolytic aging characteristics. 

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