十一烯酸/马来酸酐共聚物的制备与表征

以十一烯酸(UA)和马来酸酐(MAH)为原料，偶氮二异丁腈(AIBN)为引发剂，通过沉淀聚合的方法制备了十一烯酸/马来酸酐共聚物(UMA)，研究了单体配比、引发剂用量及反应温度对共聚反应的影响，通过FT-IR、¹³C NMR、DSC分析和酸酐质量分数的测定对共聚物进行了表征。FT-IR和¹³C NMR结果表明：在实验条件下，十一烯酸(UA)与马来酸酐(MAH)发生了共聚反应。当反应温度为75 ℃、AIBN用量为0.75%时，随着MAH用量的增加，共聚物相对分子质量减小，得率和酸酐质量分数呈现先增大后略有减小的趋势，当UA与MAH的物质的量之比为40:60时共聚物的得率及酸酐质量分数均达到最大值，分别为61.78%和20.05%，与DSC曲线中玻璃化转变温度(T_g)的变化趋势基本一致，即当n(UA):n(MAH)为40:60，T_g达到最大值71.98 ℃。提高引发剂用量和反应温度有利于共聚反应的进行，但相对分子质量有所下降，因此可根据所需聚合物的性质来选择合适的反应条件。

Preparation and Characterization of Undecylenic Acid/Maleic Anhydride Copolymer

Undecylenic acid/maleic anhydride copolymer(UMA) was prepared by precipitation polymerization method with undecylenic acid(UA) and maleic anhydride(MAH) as raw materials, azobisisobutyronitrile(AIBN) as initiator. The influences of monomer ratio, initiator dosage, and reaction temperature on polymerization were studied. The copolymer was characterized by FT-IR, ¹³C NMR, DSC and the mass fraction of anhydride of copolymer was measured. The results of FT-IR and ¹³C NMR showed that the copolymerization of UA and MAH successfully proceeded under the experimental conditions. When the reaction temperature was 75 ℃, the dosage of AIBN was 0.75%, with the increase of the amount of MAH, the molecular weight of copolymer decreased, the conversion rate and anhydride content incresed first and then declined slightly. When n(UA):n(MAH) was 40:60, the conversion rate and mass fraction of anhydride reached the maximum, 61.78% and 20.05%, respectively, which was basically consistent with the change of glass transition temperature(T_g) of DSC curves. Increasing the initiator dosage and reaction temperature was beneficial to the copolymerization but the molecular weight decreased, so the appropriate reaction conditions could be selected according to the properties of the desired polymer. When the n(UA):n(MAH) was 40:60, the T_g reached the maximum, 71.98 ℃.