二醋酸纤维素与聚乙二醇单甲醚接枝共聚物的合成与表征

Study on the Graft Reaction of MPEG with CDA by the Means of Orthogonal Experiments

采用聚乙二醇单甲醚 (MPEG)作为改性剂 ,与二醋酸纤维素 (CDA)进行接枝反应。用正交实验法研究了聚乙二醇的分子量、二醋酸纤维素与聚乙二醇的配比、2 ,4-甲苯二异氰酸酯的用量、催化剂的用量和反应时间对接枝反应的影响 ,确定了最佳的配方和工艺。对相应的接枝共聚物进行了FTIR ,DSC ,1 HNMR和1 3CNMR的表征分析。结果表明 :在1 5 38cm- 1 出现酰胺Ⅱ带氨基甲酸酯的吸收峰 ,在 1 60 4cm- 1 出现芳香环的吸收峰 ;从DSC分析可知 ,由于MPEG被固定后 ,链段运动自由度受到限制 ;用1 HNMR和1 3CNMR核磁共振技术研究了二醋酸纤维素和聚乙二醇的接枝共聚物 ,并确定了1 HNMR和1 3CNMR谱中各谱峰的归属 。

Methoxy polyethylene glycol (MPEG), which grafted with cellulose diacetate (CDA), was applied as a modifier. The effects of molecular weight of MPEG, the ratio of MPEG and CDA, the weight of 2,4-tolune diisocyanate (TDI), the weight of catalyst and reaction time were studied and the optimal formula and technology were determined by the means of orthogonal experiments. FTIR, DSC, 1 HNMR, 13 CNMR of graft copolymers of cellulose diacetate with methoxyl polyethylene glycol (CDA-g-MPEG) were investigated. It was illustrated in FTIR spectra that CDA-g-MPEG had amide II band of carbamate (-NHCOO-) in 1538cm -1 and conjugate vibration band of aromatic ring in 1604 cm -1 . It was also illustrated in DSC that realistic phase change enthalpy of MPEG in CDA-g-MPEG was smaller than theoretic phase change enthalpy because freedom of segment was limited after the MPEG segments were fixed to the CDA. 1 HNMR and 13 CNMR studied the graft structure in CDA-g-MPEG. 1 HNMR and 13 CNMR spectra of CDA-g-MPEG were assigned completely. The results provide basis for conformation of grafting reaction between CDA and MPEG.