热塑性木薯淀粉/聚乙烯醇复合材料的制备、结构与性能研究

摘要

采用熔融法制备热塑性木薯淀粉(TPS)/聚乙烯醇(PVA)复合材料,研究PVA和增塑剂的种类、用量对TPS/PVA复合材料的加工、力学性能、回生行为及结构影响.研究结果发现随着PVA用量的增加,TPS/PVA复合材料的塑化时间缩短、塑化扭矩和平衡扭矩增大;随着甘油增塑剂用量的增加,TPS/PVA复合材料的塑化时间、扭矩降低.TPS/PVA-1788复合材料的塑化时间、塑化扭矩和平衡扭矩均比TPS/PVA-1799复合材料的小;采用尿素/甲酰胺复配增塑TPS/PVA复合材料的塑化时间、塑化扭矩和平衡扭矩比使用甘油小.随着PVA用量的增加,TPS/PVA复合材料的拉伸强度增加;TPS/PVA-1799复合材料的拉伸强度比TPS/PVA-1788复合材料的高.使用甘油增塑TPS/PVA复合材料的拉伸强度高于使用尿素/甲酰胺复配增塑剂.随着回生时间增加,TPS/PVA复合材料的回生焓增加.添加PVA加速TPS的回生过程,随着PVA用量进一步增加,TPS/PVA复合材料回生降低.PVA能削弱TPS的氢键作用,提高TPS塑化程度,有利于TPS/PVA复合材料的均匀性.%Thermoplastic cassava starch (TPS)/polyvinyl alcohol (PVA) composites were prepared by melting mixing. Effects of PVA type/contents and plasticizer on processing, mechanical properties, retrogradation behavior and structure of TPS/PVA composites were investigated. The results indicate that the plasticizing time of TPS/PVA composite is decreased and the plasticizing and equilibrium torques are increased with the increase of PVA contents, while the plasticizing time and torques of TPS/PVA composites are decreased with the increase of glycerol plasticizer contents. The plasticizing time, plasticizing torques and equilibrium torques of the TPS/PVA-1788 composite are lower than those of the TPS/PVA-1799 composite, and these values of the urea/formamide plasticized TPS/PVA composite are lower than those of the composite plasticized by glycerol. The tensile strength of the TPS/PVA-1799 composite is higher than that of the TPS/PVA-1788 composite. The tensile strength of the TPS/PVA composite plasticized by glycerol is higher than that of the composite plasticized by urea/formamide. With the increase of retrogradation time, the retrogradation enthalpy of the TPS/PVA composite is increased. The addition of PVA can accelerate the retrogradation process of TPS. However, the retrogradation of the TPS/PVA composite is decreased with further increase of PVA contents. PVA can weaken hydrogen bonding of TPS and improve plasticizing degree of TPS, which is beneficial to the uniformity of TPS/PVA composites.