Study of stress-yielding mechanism of aged atactic polystyrene

The stess yielding mechanism of aged atactic polystyrene(alpha -PS) was stu died by use of mechanical tension, differential scanning calorimetry(DSC) a nd solvent-swelling. The viewpoint of cohensional entaglement(CE) was empol yed to interpret the experimental results, which indicated that the stress yielding of aged alpha -PS was the destruction of the CE formed during agin g. CE was a kind of ordered structure, which was formed by local parallel a lignment of several segments of several nearest neighboring chains, its int eraction energy was so low that heating beyond the T-g region, mechanical d rawing over the yield point and solvent swelling all could destroy it compl etely.