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摘要： 高分子改性常见的就是通过物理，化学或者机械方法进行改性的。其方法主要有共聚，共混，接枝，交联等。其改性目的是发挥和保留聚合物原有的优点，抑制和克服聚合物原有的缺点，并且根据需求赋予其新的性能；改善高分子的加工工艺性能和降低材料的生产成本。但是现在每种改性方法都存在一定的缺点，我们发现直接将高分子溶解并在其支链上改性的实验较少，而其又具有成本低，实验步骤少，可操作性强，实验环境要求低，安全等优势。所以值得重点去研究并加以推广。因此本文主要通过上述方法即酯交换反应方法制备络合基团，用以改性聚醋酸乙烯酯，通过红外定性和定量的方法来判断聚醋酸乙烯酯是否改性成功。通过红外光谱图的定性分析可以看出，硫酸催化乙酰乙酸乙酯改性聚醋酸乙烯酯红外光谱图中烯醇式C=C双键的吸收峰强度比甲醇钠催化乙酰乙酸乙酯改性聚醋酸乙烯酯的吸收峰强度大很多，并且通过红外定量分析即PeakFit分峰拟合可以求出，在甲醇钠催化改性聚醋酸乙烯酯之后，净增加的烯醇式C=C的百分比为46.27%，而浓硫酸催化改性聚醋酸乙烯酯之后，净增加的烯醇式C=C的百分比为76.34%，所以从数据可以看出从研究发现浓硫酸是最好的酯交换反应催化剂。而改性聚醋酸乙烯酯可以作为凝胶添加剂，用来增强湿凝胶强度，预期具有防止凝胶开裂，性能好的特点。69502
毕业论文关键词：聚醋酸乙烯酯；高分子改性；酯交换；乙酰乙酸乙酯
Study on Modification of Polyvinyl Acetate with Complex Ligand
Abstract: Polymer modification is common through physical, chemical or mechanical methods to modify. The main methods are copolymerization, blending, grafting, crosslinking and so on. The purpose of the modification is to exert and retain the original advantages of the polymer, to inhibit and overcome the original shortcomings of the polymer, and according to the needs of its new performance; improve the processing performance of polymers and reduce the cost of production of materials. But， there are some shortcomings of each modification method. We found that the polymer directly dissolved and modified in its branch has a low cost, less experimental steps, operable, safety and other advantages. So it is worth focusing on research. Therefore, in this paper, mainly through the above method that the transesterification reaction to graft complex groups was used to modify the polyvinyl acetate. The success of the modification was investigated by the infrared qualitative and quantitative methods. It can be seen from the qualitative analysis of infrared spectroscopy that the absorption peak intensity of ene alcoholic C = C double bond in the infrared spectrum of polyvinyl acetate modified with acetoacetylate was higher than that of the un-modified one. The infrared quantitative analysis results showed that the sodium methoxide catalyzed modification of polyvinyl acetate gave a net increase in the enol type C = C percentage of 46.27 %, nd concentrated sulfuric acid catalyzed one had a net increase in the enol type C = C percentage of 76.34%. So from the data it can be found that concentrated sulfuric acid is the best transesterification catalyst. The modified polyvinyl acetate can be used as a gel additive, which was used to enhance the wet gel strength and to prevent gel cracking, resulting in good performance characteristics.
Keywords: polyvinyl acetate; polymer modification; transesterification; ethyl acetoacetate
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1 绪论