丙烯酸和丙烯酰胺共聚合的竞聚率测定及其共聚物的吸湿性能研究

Determination of reactivity ratio of copolymerization of acrylic acid and acrylamide and research on the moisture absorption properties of copolymer

水溶液聚合法合成了聚丙烯酸-丙烯酰胺P(AA-AM)。系统研究不同单体配比、单体总浓度等条件对P(AA-AM)吸湿性能的影响。正交实验确定最佳反应条件,其最高吸湿率达1.05g/g。吸湿实验结果发现P(AA-AM)共聚物的吸湿性能优于其相应的均聚物和传统的无机吸湿材料硅胶和分子筛。采用红外光谱法确定共聚物组成,再由Fineman-Ross方程计算单体竞聚率。得知丙烯酸的竞聚率大于丙烯酰胺的竞聚率且均<1,表明聚合物有共聚趋势。SEM照片显示加脲后,共聚物生成孔洞结构,其有效吸湿比表面积增加。TGA分析进一步证明P(AA-AM)共聚物的生成。

In this paper,poly[acrylic acid-co-acrylamide] was synthesized by means of aqueous solution polymerization.The factors such as monomer ratios,total monomer concentration,urea content,temperature and so on influencing on moisture absorption property were investigated.The optimum moisture absorbency of PAA/U reached 1.05g/g based on the orthogonal experiment results.The moisture absorption ability of poly[acrylic acid-co-acrylamide] was superior to corresponding homopolymers and traditional inorganic moisture absorbents.Copolymer composition was determined by infrared spectroscopy method and then monomer reactivity ratios were obtained according to Fineman-Ross equation.The calculation results indicated that the reactivity ratio of acrylic acid（r1） was higher than acrylamide＇s（r2） and both values were less than 1,which demonstrated the tendency of alternatihg copolymerization between AA and AM.The SEM photograph revealed that copolymer had porous structure and its specific surface area was increased,after urea added.TGA analysis verified the formation of copolymer.