有机溶剂法合成聚马来酸酐:聚合残液的分析与循环利用

以过氧化苯二甲酰为自由基引发剂,甲苯为溶剂,研究了聚马来酸酐(PMA)最佳合成条件,即引发剂质量分数10%,反应温度95℃,反应时间6 h。通过对聚合残液的MS分析,聚合残液主要成分为马来酸酐(MA),通过聚合残液的酸值分析,得到MA的利用率为63.5%。针对MA利用率较低,将聚合残液循环利用。循环结果表明,经5次循环使用,MA的累计利用率可达90.3%,并随着循环次数增多,MA的累计利用率逐步增大。所合成聚马来酸酐经FTIR1、HNMR分析,结构正确;凝胶渗透色谱(GPC)分析,每次循环产品PMA的平均相对分子质量变化不大,平均相对分子质量Mn保持在930~940,相对分子质量分布系数为1.12。

Synthesis of Polymaleic Anhydride by Organic Solvent Method: Analysis and Recycling of Polymerization Residue

Polymaleic anhydride(PMA)was synthesized with benzoyl peroxide(BPO) as free radical initiator and toluene as solvent. The optimal synthesis conditions were that: the mass percent of initiator Was 10%,the reaction temperature was 95℃.and the reaction time was 6 h. The polymerization residue Was analyzed by MS and the acid-base titration. Results showed that the major component in thepolymerization residue Writ8 maleic anhydride(MA)and the utilization ratio of MA Was 63.5%.Thi spaper gave a technique for recycling the polymerization residue by analyzing the component and thecontent of the solute in the residue. The results showed after 5 cycles, the cumulative utilization ratio could reach 90.3%.With the increase of the recycle times. the cumulative utilization ratio increased gradually. The structure of PMA Was characterized by FTIR and ~1HNMR.The analysis of the gel permeation chromatography(GPC)of the product showed that there Was a little change in the averagemolecular weight of the polymaleic anhydride produced in each cycle. The number average molecularweight(M_n)of PMA wag kept at 930～940 and the distribution of molecular weight Was 1.12.