高聚物声发射的一些观察

对高聚物的声发射做了进一步的实验观察。玻璃态高聚物在拉伸屈服以前的声发射有Kaiser效应,但在高弹态则不然。非晶态高聚物从玻璃态到高弹态的转变,玻璃态拉伸时在屈服附近出现声发射,高弹态时声发射要少而弱得多,只在高弹拉伸的断裂前出现声发射。非晶态、晶态高聚物或共混高聚物在突然升温到100℃时有声发射,但在突然降温到-60℃时却不出现声发射,这可能也说明声发射与高聚物试样内形成空洞有关。一种聚丙烯树脂在不同注射成形工艺条件下所得试件,在拉伸时的声发射行为可反映加工成形的好坏,成形好的声发射少得多。

SOME OBSERVATIONS ON THE ACOUSTIC EMISSION OF POLYMERS

Experimental observations of acoustic emission (AE) of polymers have been extended in the following aspects: 1. Kaiser effect of AE during stretching of a polymer specimen before yielding has been observed for an amorphous polymer in its glassy state. 2. During stretching of an amorphous polymer in its glassy state AE appear-ed in the vicinity of yielding, while in rubbery state AE events were much fewer and weaker and appeared only before break. 3. In a temperature jump from room temperature to 100℃ both amorphous and semi-crystalline polymers and polymer blends showed AE while not in the sudden cooling to - 60℃. 4. A polypropylene sample injection molded under different conditions showed that AE during stretching could reflect the quality of molding.