Kinetics of yielding

Kinetics of Yielding. Tensile yield stresses were measured at several Instron rates for block polymer B. These results and those of Bauwens-Crowet et ah (9) for BPA polycarbonate were analyzed in the framework of the Rhee-Eyring stress bias activation theory for comparison purposes. Yield stress of the block polymer is roughly half that of the homopolymer at a given temperature. The apparent activation volume for the block polymer is double that of the homopolymer at each temperature. Activation energies at zero stress are essentially the same (60 kcal/mole for the block polymer vs. 70 kcal/mole for BPA polycarbonate above —50°C). 

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