聚乙烯醇在阶段性热处理下的结构变化  

Structure Changes of Polyvinyl Alcohol Under Stage Heat Treatment

作　　者：李荣[1] 张军华[1] 

机构地区：[1]高分子材料工程国家重点实验室四川大学高分子研究所,四川成都610065

出　　处：《高分子材料科学与工程》2017年第5期42-46,共5页Polymer Materials Science & Engineering

基　　金：高分子材料工程国家重点实验室自主课题(sklpme2015-2-01)

摘　　要：聚乙烯醇(PVA)在热处理作用下会逐渐发生侧基脱除、断链、环化等复杂的副反应。通过阶段性热处理方法,可望在减少副反应的同时在分子主链上生成双键,从而得到类似聚乙炔的共轭聚合物。文中以PVA1799为原料,通过阶段性加热法,利用在线红外技术,研究了PVA在氮气气氛下不同温度热处理后的结构变化。热处理温度范围为30~330℃,在150℃,180℃,210℃,240℃,270℃,300℃和330℃每个温度点停留30 min。研究发现,PVA的熔点为210℃,在240℃开始发生结构变化,并在分子主链生成双键和羰基。当温度超过300℃,有少量二氧化碳(CO_2)放出,开始出现更为复杂的副反应。The elimination of side groups, chain scission, cyclization and other complicated reactions can occur gradually in poly （vinyl alcohol） （PVA） when heated. Through stage heat treatment, it’s hopeful to reduce side reactions and produce double bonds in PVA macromolecule, which is a proper method for preparing the conjugated polymers such as polyacetylene. In this paper, the structure changes of PVA1799 under stage heat treatment were studied by on-line FT-IR technology. The temperature range was from 30 ℃ to 330 ℃ and the sample were held for 30 min at 150 ℃, 180 ℃, 210 ℃, 240 ℃, 270 ℃, 300 ℃ and 330 ℃. It is found that the melting point of PVA is 210 ℃. The initial structure change of PVA takes place at 240 ℃ resulting in the accumulation of carbonyl groups and double bonds in PVA molecules. When the temperature is more than 300 ℃, it is observed that a small amount of carbon dioxide is produced meaning more complicated side reactions begin to appear.

关 键 词：聚乙烯醇 阶段性热处理 温度依赖性红外 移动窗口二维红外光谱 

分 类 号：TQ325.9[化学工程—合成树脂塑料工业]