The effects of temperature and specimen size on the plastic deformation by crazing were investigated under constant rate tension at different temperatures in kerosene using poly (vinyl chloride) plates with different thickness. An increase in temperature facilitated the initiation and growth of crazes, and as a result reduced the craze yield point. As the specimen thickness increased, the craze yield point rose and the shape of deformation curve became similar to that of shear yielding. The temperature dependence of craze yielding was favourably explained by the theory which was previously developed on the conception that the plastic strain produced by crazes is given by the total volume of crazes per unit volume of the polymer. In order to account for the size effect on craze yielding, a simple model consisting of two crazed surface layers and non-crazed interior was proposed. By applying the above theory on craze yielding to describe the deformation of the surface layers, the calculated results accorded with the experimental results mentioned above.
