低分子量甲基丙烯酸缩水甘油酯共聚物的制备及扩链改性PA6

Preparation of Low Molecular Weight Glycidyl Methacrylate Copolymer and Chain-extension Modification PA6

以甲基丙烯酸缩水甘油酯(GMA)、甲基丙烯酸甲酯(MMA)为共聚单体,通过添加链转移剂十二硫醇(NDM)及低反应活性单体α-甲基苯乙烯(AMS)合成低分子量的多环氧共聚物,采用凝胶色谱法、红外光谱及核磁共振氢谱表征共聚物的分子量与结构组成。结果表明,共聚物的分子量及产率随NDM、AMS添加量的增大而减小,当NDM添加量为总单体质量的4.0%,AMS占总单体的摩尔分数为3.0%时,所得共聚物(PGMA-3)的M_(w)为4.6×10^(3),产率为90.4%,各结构单元的物质的量比与投料比相近。将PGMA-3对聚酰胺6(PA6)进行扩链改性,探究其添加量对PA6加工性能、熔融结晶性能和力学性能的影响。结果表明,由于PGMA-3的扩链作用,PA6的平衡扭矩及缺口冲击强度增加,而熔融温度、结晶温度和结晶度降低。添加1.0%PGMA-3后,PA6的平衡扭矩增加了91%;添加2.0%PGMA-3后,PA6的熔融温度从221.8℃降至220.0℃,结晶温度从189.7℃降至182.6℃,结晶度从26.6%降至19.8%,缺口冲击强度提高了52%。

Low molecular weight multiple epoxy copolymers were synthesized by using glycidyl methacrylate(GMA)and methyl methacrylate(MMA)as comonomers and adding chain transfer agent dodecanethiol(NDM)and low-reactivity monomerα-methyl styrene(AMS).The molecular weight and structural composition of the copolymer were characterized by gel chromatography,Fourier infrared spectroscopy and hydrogen nuclear magnetic resonance spectroscopy.The results show that the molecular weight and yield of the copolymer decrease with the increase of NDM and AMS addition.When the addition of NDM is 4.0%of the total monomer mass and the mole fraction of AMS in the total monomer is 3.0%,the weight average molecular weight of the obtained copolymer(PGMA-3)is 4.6×10^(3),and the yield remains 90.4%,and the molar ratio of each structural unit is close to the feed ratio.Polyamide 6(PA6)is modified by PGMA-3,and the amount effect on the processability,melt crystallization and mechanical properties of PA6 are investigated.The results show that PGMA-3 could effectively improve the equilibrium torque and impact strength of PA6,but it could reduce the melting temperature,crystallization temperature and crystallinity of PA6.The equilibrium torque of PA6 increases 91%with 1.0%PGMA-3.When the addition of PGMA-3 increases to 2.0%,the melting temperature of PA6 decreases from 221.8℃to 220.0℃,crystallization temperature decreases from 189.7℃to 182.6℃and the crystallinity decreases from 26.6%to 19.8%,while the notched impact strength increases 52%.