热塑性魔芋葡甘聚糖材料的合成及表征

Synthesis and Characterization of Thermoplastic Konjac Glucomannan

以资源丰富的天然可降解高分子材料魔芋葡甘聚糖(KGM)为原料,乙酸乙烯酯和丙烯酸甲酯为接枝单体合成了不溶于水的可降解热塑性KGM(TKGM)新材料。当以过硫酸铵为引发剂时接枝效果较好,且当引发剂浓度为8mmol/L、反应温度70℃、反应时间3h、单体浓度0.49mol/L时,KGM可获得较高的接枝率和接枝效率。采用傅立叶红外光谱(FT-IR)、偏光显微镜(POM)照片、低温差示扫描量热仪(DSC)和综合热分析等对改性材料的结构和性能进行了分析表征。结果表明:合成了KGM和乙酸乙烯酯、丙烯酸甲酯的接枝共聚物;KGM原有的结晶结构被破坏,分子结构呈现无序化;玻璃化转变温度(Tg)仅为13.14℃,且在102.5℃处有明显的熔融吸热峰,分解和熔融温差达200℃以上,具有较好的热塑加工性能。

A novel material, namely thermoplastic konjac glucomannan （TKGM） was synthesized from konjac glucomannan （KGM）, vinyl acetate（VAc） and methyl acrylate（MA） for the first time in this research. This novel material is water resistant and degradable. The grafting efficiency was preferable when graft copolymerization was initiated by ammonium persulfate. The optimal condition of reaction corresponds to 8 mmol/L for ammonium persulfate, reaction time 3 h, reaction temperature 70 ℃ and concentration of 0.49 mol/L for vinyl acetate and methyl acrylate. The structure and properties of TKGM were characterized by FT-IR, polarizing optical microphotography （ POM ） , low temperature differential scanning calorimetry （ DSC ） and TG-DSC. The results indicated： a graft copolymerization reaction was taken place between KGM and VAc, MA. The original crystal configuration of KGM was destroyed, and the molecular structure was disordered. The glass transition temperature （ Tg ） of TKGM was only 13.14 ℃, and there＇s an obvious melting decalescence peak at 102 ℃, the difference between decomposed temperature and melting temperature is above 200 ℃. This means that TKGM has a good thermoplasticization property.