酸性可染腈纶共聚物的合成及性能表征

Synthesis and property characterization of acid dyeable acrylonitrile copolymer

分别选择甲基丙烯酸二甲氨乙酯(DEMA)和甲基丙烯酰氧乙基三甲基氯化铵(DMC)作为第三单体,采用间歇法丙烯腈水相沉淀聚合制备不同分子组成的酸性可染腈纶共聚物,通过核磁共振氢谱、凝胶渗透色谱、差示扫描量热、上染率等分析测试对共聚物的结构和性能进行了表征。结果表明:引发剂一锅法投料的聚合过程呈现出"死端聚合"的特点,共聚物相对分子质量分布为多峰分布,而采用引发剂半连续加入的方式,制得的共聚物的黏均相对分子质量为50 000~60 000,聚合物多分散性指数为5~10,相对分子质量分布为单峰分布,且转化率提高至70%左右;共聚物中丙烯腈质量分数为90.3%时,其玻璃化转变温度为101.2℃;共聚物的染色性能与第三单体含量和分子结构相关,以DEMA为第三单体时,其上染率对染浴酸值依赖性较强,而采用DMC为第三单体时,其染色性能对染浴的p H值不敏感,即使在弱酸性染浴(p H值为5.0)中亦具有良好的染色性能,上染率大于95%。

Acid-dye dyeable acrylonitrile copolymers with different molecular composition were prepared by using dimethylamino ethyl methacrylate（ DEMA） or methacryloyloxyethyl trimethyl ammonium chloride（ DMC） as the third monomer via batch precipitation polymerization in aqueous phase. The structure and properties of the obtained copolymers were characterized by hydrogen nuclear magnetic resonance spectroscopy,gel permeation chromatography,differential scanning calorimetry,dye up-take test and so on. The results showed that the polymerization process using one-pot initiator feeding method showed the characteristic of ＂ dead-end polymerization＂,which led to the multimodal molecular weight distribution; the obtained copolymer had the viscosity-average relative molecular mass of 50 000-60 000,the polydisperity index of 5-10,the monomodal molecular weight distribution and conversion rate up to 70% or so when the polymerization was initiated by semicontinuous process; the glass transition temperature was 101. 2 ℃ when the mass fraction of acrylonitrile was 90. 3% in the copolymer; the dyeing property of the copolymer was related to the third monomer content and the molecular structure; the dye up-take was strongly dependent on the acid number of the dye bath when DEMA was used as the third monomer; the dyeing property of the copolymer was not sensitive to the p H value of the dye bath and remained fairly good with the dye up-take above 95% even in weak acid dyeing bath（ pH value of 5. 0） when DMC was used as the third monomer.