甲基丙烯酸缩水甘油酯与甲基丙烯酸甲酯的共聚合及竞聚率测定

Copolymerization of GMA and MMA and Determination of Monomer Reactivity Ratio

以N,N-二甲基甲酰胺(DMF)为溶剂,实施了甲基丙烯酸缩水甘油酯(GMA)与甲基丙烯酸甲酯(MMA)的溶液共聚合,测定了共聚物P(GMA-co-MMA)的红外光谱(FT-IR),对其化学结构进行了表征,并采用差示扫描量热法(DSC)测定了共聚物的玻璃化转变温度(Tg)。改变两单体投料比进行共聚合,采用化学分析法测定低转化率下(<7%)共聚物组成,重点研究了两单体的竞聚率。结果表明:GMA与MMA的共聚合易于进行,P(GMA-co-MMA)的玻璃化转变温度(Tg)介于均聚物PGMA(72℃)与PMMA(106℃)之间,当n(GMA)/n(MMA)=4/6时,共聚物的Tg为91℃。采用FR和KT 2种作图法及YBR计算法对单体的竞聚率进行了计算和比较,结果表明:KT和YBR法较为准确,以DMF为溶剂时,GMA与MMA的竞聚率分别为2.14与0.69。

The copolymerization of glycidyl methacrylate （GMA） and methyl methacrylate （MMA） was performed in a solution copolymerization system with N, N-dimethylformamide （DMF） as solvent. The chemical structure of the copolymer P（GMA-co-MMA） was characterized by infrared spectrum （FT-IR）, and the glass transfer temperature （Tg） of the copolymer was determined using differential scanning calorimeter （DSC）. The reactivity ratios of monomers were measured. Varying the feed ratio of the monomers, copolymers with different compositions were prepared, and under low conversion conditions （ 7%）, the compositions of these copolymers were determined by using a chemical analysis method, resulting in the correlative data which is needed in the measurement of the monomer reactivity ratios. The experimental results show that the copolymerization of GMA and MMA can be easy carried out, and Tg of the copolymer is between the glass temperatures of the two homopolymers, PGMA and PMMA. The monomer reactivity ratios were calculated by using two graphical methods, FR and KT methods, and YBR calculative method. The result indicates that when DMF is used as solvent, the reactivity ratios are rGMA = 2. 14 and r;=0. 69, respectively. Besides, the methods of KT and YBR are more accurate among these three methods.