壳聚糖接枝乙酸乙烯酯共聚物的制备及表征

Perparationand characterization of graft copolymer of Chitosan with Vinyl acetate

以壳聚糖(CTS)和乙酸乙烯酯(VAc)为原料,采用过硫酸铵(APS)为引发剂,制备了CTS与VAc的接枝共聚物(CTS-g-VAc),考察了乙酸乙烯酯的用量、引发剂浓度、反应温度和反应时间对接枝共聚反应的影响,并用FT-IR、TG和XRD对接枝共聚物的结构进行了表征。实验结果表明,接枝共聚物的最佳制备条件为:CTS用量2.0 g,VAc用量7 g,反应时间4 h,反应温度为65℃和过硫酸铵用量为0.07 g,在该条件下制备的接枝共聚物的接枝率和接枝效率分别为163%和49%。FT-IR显示共聚物在1 727 cm-1处出现一个新峰,即C=O伸缩振动吸收峰,TG显示共聚物的分解温度比CTS稍高,说明接枝物的热稳定性比CTS稍好,XRD显示衍射峰从2θ=10°移到到2θ=15°,且峰值碱弱,说明侧链的引入改变了CTS的结晶结构。以上表征结果表明CTS与VAc发生了接枝共聚反应。

Chitosan graft vinyl acetate copolymer was preparated using chitosan （ CTS） and vinyl ac-etate （ VAc） as materials, ammonium persulfate （ APS） as initiator. The effect of dosage of VAc, concentration of initiator, reaction temperature and reaction time on the graft copolymerization were investigated. The construction of copolymer was characterized by FT-IR, XRD and TG. The results of experiment showed that the optimum reaction conditions were as follows： CTS 2. 0 g, VAc 7 g, （ NH4 ） 2 S2 O8 0. 07 g, reaction time 4 h, reaction temperature 65 ℃. Under this condition the graft yield and graft efficiency of the prepared copolymer were 163% and 49%, respectively. FT-IR spectra show that a new absorbance peak corresponds to the appearance of the carbonyl group ab-sorption band at 1 727 cm-1 . TG analysis reveals that decomposition temperature of the copolymer is higher than the CTS and thermal stability is better than the CTS. XRD shows that the diffraction peaks by the 2θ=10＆#176; move on to 2θ=15＆#176; with lower peak value, due to the introduction of side chain and the change of the crystal structure of the CTS. The above results of characterization show that graft copolymerization of CTS with VAc already occured.