摘要
本文研究了聚碳酸酯(PC)和聚碳酸酯/聚乙烯(PC/PE)合金材料在不同温度下老化后产生裂缝的规律,研究表明:PC在100℃和85℃热水中老化后会产生裂缝,裂缝的数量及尺寸与老化时的热水温度及老化时间有关。结合PC在热水老化过程中分子量降解规律及吸水规律,本文提出了PC热水老化后产生裂缝的原因是首先在应力集中较严重的位置产生应力诱导水解,从而导致PC分子量迅速下降,形成微缺陷,这些微缺陷在试样冷却过程中由于收缩产生的静张应力及过饱和水聚积时的相分离静张应力双重作用下,进一步发展为裂缝。这个假设能较全面地解释所观察到的许多现象。PC/PE合金材料由于不易水解,在热水老化过程中形成的微缺陷很少,因此在冷却时,产生的裂缝也很少,表现出优良的耐热水老化性能。
In this paper the law of crack emergence in the sample of PC and PC / PE alloy was studied. It was found that cracks emerged in the PC samples under 100℃ and 85℃ hot water. Quantities and sizes of cracks increased with increasing of temperature of hot water and time of ageing. In this paper we indicated that PC macromolecules were degraded because of stresses inducing hydrolysis. Then the microflaws were formed. There were two stresses in the samples of PC and PC / PE alloy after hot water ageing. One was cold shrinking stress. Another was phase separate stress which formed when supersaturated water concentrated in the microflaws. Under the action of these stresses the microflaws were developed into the cracks. Because hydrolysis of PC macromolecules in the sample of PC / PE alloy was much smaller than that of PC, and the microflaws in the sample of PC / PE alloy were much less than those of PC, we were very difficult to see the cracks in the samples of PC / PE alloy after hot water ageing.
出处
《塑料》
CAS
CSCD
1989年第6期25-29,共5页
Plastics
