【摘要】 本文以水作介质,Fenton’s试剂(Fe²⁺—H₂O₂)为引发剂,研究了丙烯酸丁酯与玉米淀粉接枝共聚的反应规律,探讨了接枝共聚的机理。发现[H₂O₂]/[FAS]摩尔比,反应中生成的Fe³⁺对接枝反应有很大的影响,加入络合剂将Fe³⁺掩蔽,可以显著提高接枝效率。对骨架淀粉进行氧化、糊化等处理,可以提高其反应活性,获得良好的接枝效果。实验结果表明,在[H₂O₂]/[FAS]=10.541,[NaF]=10.6×10^-3mol/L,pH=2～4,Starch:BA:H₂O=2.16:1:10.02,30℃下反应小3时,单体转化率和接枝效率均可达90％以上。用IR,’H-NMR和SEM等手段对接枝共聚物的结构与形态进行了表征,证明反应物确为丙烯酸丁酯与玉米淀粉的接枝共聚物。接枝反应不仅发生在淀粉表面,也在其内部发生。由于接枝侧链的“搭桥”,形成了松散且具有孔洞的无规交联结构。更多还原

【Abstract】 The successful grafting of BA on corn starch involved the creation of radicals on the backbones of starch. In this paper, we reported the regularities of graft copolymerization of BA on corn starch by using Fenton’s reagent (Fe²⁺—H₂O₂) as initiator, and disscussed the mechanism of graft copolymerization It was shown that the graft indexes were considerably affected by [H₂O₂]/ （FAS） molar ratio, Fe³⁺, which was formed during the reaction. Adding suitable complexing agents to cover the Fe³⁺, would give rise to grafting remarkably. The activity of backbones of starch could be raised by pretreating it with oxidizing and gelatinating. There fore, good grafting would be obtained. The experimental results showed that the monomer conversion （C%）, graft efficiency （GE%） would reach over 90% at Starch: BA : H₂O = 2.16 : 1 :10.02, [H₂O₂]:[FAS]=l0.54:1, [NaF]=10.6×10^-3mol/l, pH = 2～4, at 30℃ in 3 hrs. The structure and morphology of St-g-PBA were characterized with IR, 1H-NMR and SEM. The results indicated that the reaction products were real St-g-PBA, and the graft reaction occurred not only in the surface of corn starch, but also in its interior. Due to the "bridging" of graft side chains, there were cavities and random crosslinking in the state of aggragation.更多还原