研究了单体浓度、配比对丙烯腈/衣康酸单甲酯共聚反应的影响,利用傅立叶红外(FT-IR)、差热扫描量热仪(DSC)、热重分析(TGA)对样品的结构与性能进行分析和表征。结果表明,单体质量百分含量的增大,聚合反应的转化率及分子量增大;衣康酸单甲酯比例的增加,聚合物的转化率及分子量下降;同时发现,衣康酸单甲酯的加入,使环化过程放热起始温度降低,放热峰明显加宽,有效改善了均聚丙烯腈环化过程放热集中的缺点,另外衣康酸单甲酯的加入,有效地提高了聚丙烯腈的热稳定性,这些均有利于聚丙烯腈原丝的预氧化。
The effect of different monomer concentrations and feed ratios on polymerization of acrylonitrile (AN) and monomethyl itaconate (MMIA) were carefully studied. The structure and thermal properties of polyacrylonitrile (PAN) samples were characterized via differential scanning calorimeter (D S C), fourier-transform infrared spectra (FT-IR) and thermogravimetrie analysis (TGA). The Results indicate that the conversion rate of the polymerization and the average molecular weight of the products increase with the increase of monomer concentration, and decrease with the increase of feed ratio of MMIA. Meanwhile, with the addition of MMIA the initiation temperature of eyclization of copolymers decreases and the exothermic peaks are significantly broadened, which effectively overcome the disadvantage of the concentration of the cyclization heat emission of homopolymer. Furthermore, the addition of MMIA also improves the thermal stability of PAN. These are beneficial to pre-oxidation of precursor fiber.