超高分子量和低分子量聚乙烯醇的合成工艺研究
发布时间:2018-07-28 16:50
【摘要】:本论文主要以醋酸乙烯酯(VAc)为原料、水作溶剂制备超高分子量的聚醋酸乙烯酯,研究了不同引发剂种类、引发剂浓度、单体浓度、温度、时间对聚醋酸乙烯酯聚合度的影响。结果表明,最优的工艺条件为:以过硫酸钾-亚硫酸氢钠为引发剂,引发温度为25 ℃,引发剂与单体的摩尔比为1:3000,单体的质量分数为30%,反应时间为8小时,得到分子量最高为786700的聚醋酸乙烯酯。进一步利用甲醇、氢氧化钠对其进行醇解得到聚乙烯醇。通过红外光谱(IR)、核磁(NMR)、凝胶渗透色谱(GPC)、示差扫描量热法(DSC)、热失重分析(TGA)、力学性能等对聚乙烯醇进行表征。结果表明,得到的聚乙烯醇热稳定性较好,200 ℃下失重3%左右,满足热处理要求,结晶熔化温度达到206 ℃,硬度较高,不易发生形变。研究了以醋酸乙烯酯为原料、偶氮二异丁腈(AIBN)为引发剂、甲醇作溶剂,合成低聚合度聚醋酸乙烯酯。考察了不同引发剂浓度、单体浓度、时间、温度对其聚合度的影响。结果表明,最优的工艺条件为:引发剂与单体的摩尔比为1:50,单体和溶剂的体积比为1:1,反应温度65 ℃,反应时间为3 h,得到分子量最低为21200的聚醋酸乙烯酯。对其进行醇解,得到聚乙烯醇。通过以上测试方法对其进行结构表征及性能分析。结果表明,200 ℃下,失重2.8%,热稳定性较好;断裂伸长率远高于市场上样品,其韧性很好。
[Abstract]:In this paper, vinyl acetate (VAc) was used as raw material and water as solvent to prepare polyvinyl acetate. The effects of different initiators, initiator concentration, monomer concentration, temperature and time on the degree of polymerization of polyvinyl acetate were studied. The results showed that the optimum technological conditions were as follows: potassium persulfate and sodium bisulfite as initiator, initiation temperature 25 鈩,
本文编号:2150933
[Abstract]:In this paper, vinyl acetate (VAc) was used as raw material and water as solvent to prepare polyvinyl acetate. The effects of different initiators, initiator concentration, monomer concentration, temperature and time on the degree of polymerization of polyvinyl acetate were studied. The results showed that the optimum technological conditions were as follows: potassium persulfate and sodium bisulfite as initiator, initiation temperature 25 鈩,
本文编号:2150933
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