论文部分内容阅读
本工作试用了氮气和空气存在下进行接枝。研究了接枝温度、时间和接枝量的关系。并与真空条件所得结果进行比较。认为影响接枝因素主要是温度,与上列介貭(空气、氮气、真空)无关。 用溶胀和浊度滴定等法证明了聚乙烯与丙烯腈,苯乙烯接枝共聚物的生成,用抽提法鉴定接枝共聚物中均聚丙烯腈含量在1％以下。 接枝对聚乙烯的热机械性能和耐溶剂性能的影响十分显著,聚乙烯接上一定量的丙烯腈后可提高软化温度,且不溶于热甲苯。接上一定量的苯乙烯可提高流动温度。根据热机械曲綫上的高弹态和溶胀曲綫上溶胀平衡的出现,得知接枝共聚物中已有交联。从X射綫衍射图得知,当温度增加,聚乙烯的结晶度降低,而聚丙烯腈的衍射环仍然存在。 以上是接枝后提高聚乙烯性能的两个原因。 由于高低密度聚乙烯的结晶度不同,当两者接枝量相同时,无论在溶剂中的稳定性和热机械曲綫上的行为都与低密度聚乙烯有显著区别。
This work trial of nitrogen and air in the presence of grafting. The relationship between grafting temperature, time and grafting amount was studied. And compared with the results obtained under vacuum conditions. The main factors that affect grafting are temperature and are unrelated to the medium (air, nitrogen, vacuum) listed above. The swelling and turbidimetric titration were used to prove the formation of polyethylene and acrylonitrile and styrene graft copolymer. The content of homopolyacrylonitrile in the graft copolymer was less than 1% by the extraction method. Grafting on the thermal mechanical properties of polyethylene and solvent resistance is very significant, polyethylene connected to a certain amount of acrylonitrile can increase the softening temperature, and insoluble in hot toluene. Connected to a certain amount of styrene can increase the flow temperature. According to the thermomechanical curve on the high-elastic and swelling curve on the balance of the swelling appears that the graft copolymer has been cross-linked. From the X-ray diffraction pattern, it is known that as the temperature increases, the crystallinity of the polyethylene decreases while the diffraction ring of the polyacrylonitrile still exists. The above are two reasons for improving the properties of polyethylene after grafting. Due to the different crystallinity of high and low density polyethylene, when both grafted amounts are the same, both the stability in the solvent and the behavior on the thermomechanical curve are significantly different from the low density polyethylene.