魔芋飞粉/淀粉/PVA共混膜的制备及膜特性研究

摘要

研究魔芋飞粉、淀粉与聚乙烯醇(PVA)共混的膜制备条件和膜性能.以魔芋飞粉、淀粉、PVA为主要原料,以甘油为增塑剂,通过流延成膜法制备魔芋飞粉/淀粉共混薄膜,以耐水性和力学性能优化飞粉/淀粉/的配比、PVA的浓度、用量,并从共混膜的相容性和热稳定性角度进行表征来研究共混机理.共混膜的最佳飞粉/淀粉配比为1:3,PVA最佳用量为6%50 mL每5克飞粉/淀粉,此时吸水倍数为0.78 g/g,穿刺力为100.85 N.PVA用量越大,膜耐水性和机械强度越大,但相容性越差;飞粉的添加量越大耐水性稍有下降,但机械强度明显上升.共混膜全反射红外光谱中出现3700~3000 cm-1的峰变窄、2927.7、2850.4、1574.6和1545.5 cm-1出现强烈的尖锐峰、1400~800 cm-1处峰强减弱,可能葡甘聚糖与淀粉大分子间形成物理键合作用;飞粉淀粉共混膜的横截面微形貌呈现均匀的网络结构,全淀粉或全飞粉出现分层和断层的不均一现象.飞粉与淀粉有较好的相容性,添加适量PVA共混后可制备耐水性和机械性能良好的共混膜.%To study the preparation conditions and film properties of konjac fly powder,starch and polyvinyl alcohol(PVA). The blend film was prepared by a solution casting method,the raw material are starch,konjac flying powder,PVA and glycerol is plasticizer. The mass ratio of powder/starch and concentration of PVA were studied through water resistance and mechanical properties examined. The blending mechanism was researched by the characterizing of compatibility and thermal stability by thermogravimetric analysis (TG),fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM). The optimum ratio of the flying powder/starch mixed film is 1:3,the optimum concentration of PVA was 6% 50 mL every 5 g pow-der/starch. And then the water absorption ratio and puncture force were 0.78 g/g and 100.85N. The more the amount of PVA added,the stronger the water resistance and mechanical properties of the film. In FT-IR,the peak width of 3700~3000 cm-1 narrowed down. The peak intensity of 2927.7,2850.4,1574.6 and 1545.5 cm-1 increased violently. But the peak intensity of 1400~800 cm-1 decreased. It is speculated that the physical bonding between konjac glucomannan and starch macromolecules. The SEM page of cross section of fly powder/starch blend film showed a uniform network structure and the whole starch or all fly powder film appeared delamination and fault inhomogeneity. The fly powder has good compatibility with starch and can be prepared by adding proper amount of PVA.