EFFECT OF LIMITING CHAIN MOBILITY ON THE YIELDING AND CRAZING BEHAVIOR OF BISPHENOL-A POLYCARBONATE DERIVATIVES

The sub-T-g relaxations of Bisphenol-A polycarbonate (BPA-PC) can be s electively altered by appropriate chemical modification. It is establi shed that these secondary relaxations are responsible for the in-chain cooperative motions of BPA-PC and have profound effects on the deform ation behavior of the bulk material. Through investigations of the mic rodeformation behavior of BPA-PC and alternating block copolymers base d on BPA-PC, it is found that the extent of cooperative motion is also influential in activating the disentanglement crazing mechanism at el evated temperatures.