EVA皂化水解及水解产物序列结构的研究

Study on the Saponification Hydrolysis of EVA and the Sequence Structure of Its Hydrolysate

为得到不同水解程度的EVA皂化产物,以乙烯-醋酸乙烯酯共聚物(Ethylene-vinyl acetate,EVA)为原料,甲苯为溶剂,氢氧化钠为催化剂使EVA中的乙酰基在碱性作用下进行水解而得到水解产物。通过化学滴定法研究了EVA在不同水解温度、水解时间、碱浓度下的皂化度,并利用红外、核磁对水解产物的结构进行了分析。结果表明:通过控制水解温度、水解时间和碱浓度实现了EVA的可控皂化度,并经13C-NMR分析得出EVA皂化产物有九种不同的序列结构。该研究为今后对EVA进行化学改性提供了基础。

In order to prepare EVA hydrolysate with different hydrolysis degrees, the aeetyl group of EVA is hydrolyzed under the eondition of alkaline to get the hydrolysate with using EVA as the raw material, toluene as the solvent and sodium hydroxide as the catalyst. Saponification degree of EVA at different hydrolysis temperature, hydrolysis time and alkali concentration has been studied by titration. And the structure of hydrolysate is analyzed by FTIR and NMR. The results showed that the saponification degree of EVA ean be dominated by eontrolling the hydrolysis temperature, hydrolysis time and alkali concentration. And 9 different sequence structures of saponification products of EVA have been found by ^13 C - NMR. It will provide scientific basis for ehemieal modification of EVA in the future.