硬聚氯乙烯在硝酸和硫酸中的老化

THE AGEING OF RIGID POLYVINYL CHLORIDE AGGRAVATED BY NITRIC AND SULFURIC ACIDS

用红外与紫外光谱法、热分析和分子量测定研究了硬聚氯乙烯在硝酸和硫酸中的老化。发现这是一个复杂的物理-化学过程。渗透到塑料内的介质使添加剂及聚合物的不稳定化学键发生转化反应,不单改变材料的化学组成与结构,还会改变其物理形态。后者对硬聚氯乙烯制品在化学介质中的使用耐久性的影响很大。

The ageing of rigid polyvinyl chloride (R-PVC) aggravated by nitric and sulfuric acids was studied by IR, UV Spectroscopy, thermo-analysis and molecular weight determination. It was found that a number of groups, such as -NO2, -ONO2, -ONO were incorporated into the backbone of the PVC chain. These groups cause the fransition reaction of the instable bonding between the stabilizers and the PVC chain. This not only changes the composition of the materials but also changes the physical conformation. The latter deeply influence the duration of R-PVC Products used in chemical environment.