BmimCl离子液体中纤维素-聚己内酯的合成与表征

Synthesis and Characterization of Cellulose-Graft-PCL Using an Ionic Liquid as a Reaction Medium

以阔叶浆纤维素为原料,钛酸四正丁酯为催化剂,离子液体1-丁基-3-甲基咪唑氯盐(BmimCl)为溶剂,均相条件下与ε-己内酯单体进行开环聚合制备纤维素-聚己内酯接枝共聚物,探讨了单体与催化剂用量、反应温度与时间等条件对纤维素接枝率的影响,并用热重分析、X-射线衍射、核磁共振氢谱等手段对接枝共聚物进行了表征。结果表明,当ε-己内酯与纤维素摩尔比为21 mol/mol,反应时间为24 h,反应温度为120℃,催化剂与纤维素质量比为12%时,纤维素的接枝率最高达到86.7%;纤维素接枝ε-己内酯后,纤维素结晶结构被破坏,热稳定性下降,核磁共振氢谱分析显示ε-己内酯在与纤维素接枝反应的同时发生了自聚反应,生成聚己内酯。

Cellulose-graft-polycaprolactone(cellulose-g-PCL)was prepared under homogeneous condition bygrafting of hardwood pulp with caprolactone(CL).Ring-opening polymerization was carried out successfullyusing Ti(O-n-Bu)4as a catalyst in an ionic liquid1-butyl-3-methylimidazolium chloride(BmimCl).The graft rateof cellulose of the obtained cellulose-g-PCL was analyzed.The effect of PCL,catalyst,reaction temperature andtime on ring-opening polymerization was investigated.The structure of the cellulose-g-PCL was characterized bythermal gravimetric analysis(TGA),X-ray diffraction(XRD)and1H-NMR.The optimal reaction conditions wereas follows:The amount of catalyst was12%(based on the weight of cellulose),the mole ratio of CL to cellulosewas21mol/mol and the ring-opening polymerization was carried out at120℃for24h.The TGA results showedthat the thermal stability of cellulose-g-PCL decreased compared with that of cellulose and PCL.The XRD resultssuggested that cellulose crystalline structure in cellulose-g-PCL was destoried.The1H-NMR results showed thatPCL generated during the process of ring-opening polymerization.