【作者】 杨晋辉；

【导师】 于九皋；

【作者基本信息】 天津大学 ， 应用化学， 2007， 博士

【摘要】 当前,传统塑料面临石油原料日益枯竭的资源问题和塑料废弃物污染的环境问题。淀粉是一种来源广泛,价格低廉、可资源再生的原料,热塑性淀粉材料可以替代源于石油产品的传统塑料,被认为是最具发展前景的生物降解材料之一。本文在查阅大量文献基础上,设计用简单易得原料乙二胺和甲酸乙酯合成出一种含有双酰胺键的小分子化合物:乙二撑二甲酰胺,将其用于热塑性淀粉的制备,系统研究了乙二撑二甲酰胺塑化热塑性淀粉(EPTPS)的性能。与传统甘油塑化热塑性淀粉(GPTPS)相比,EPTPS具有较大的断裂伸长率,较好的耐水性能,但拉伸强度下降;研究发现塑化剂含量为30%时,所得热塑性淀粉材料的力学性能较好;对其耐回生性能研究发现乙二撑二甲酰胺可以抑制淀粉的重结晶,但是由于乙二撑二甲酰胺熔点较高,易结晶析出,所以导致了EPTPS在保存一段时间之后的性能变差。对不同原始含水量的淀粉所制备热塑行淀粉研究表明,材料的力学性能与淀粉原始含水量有较大关系,当原始含水量为13%左右时,所得EPTPS的综合力学性能最好。EPTPS虽然具有较大的断裂伸长率,但拉伸强度较低,在EPTPS中加入微晶纤维素,可以加强热塑性淀粉的力学强度;由于微晶纤维素是一种疏水性物质,所以微晶纤维素增强热塑性淀粉的耐水性能得到进一步提高;然而,微晶纤维素的加入并不能抑制塑化剂的析出。将乙二撑二甲酰胺与山梨醇混合作为塑化剂来制备热塑性淀粉(ESPTPS),实验结果证明混合塑化剂可以有效地抑制淀粉回生,由于塑化剂之间在热加工过程中相互作用,当塑化剂比例合适时,塑化剂将不再结晶析出。另一方面,混合塑化剂比EPTPS具有较大的拉伸强度,其综合力学性能优于单一塑化剂塑化热塑性淀粉,耐水性能与GPTPS相比得到进一步改善。更多还原

【Abstract】 Much effort has recently been made to develop biodegradable materials because of the worldwide environment and resources problems resulted from petroleum- derived plastics. Starch, a natural renewable polysaccharide obtained from a great variety of crops, is one of the promising raw materials for the production of biodegradable plastics.Based on the references reported previously, a novel plasticizer contain two acyl-amine group named ethylenebisformamide is synthesized and used to the preparation of EPTPS. The properties of EPTPS are investigated in detail. The elongation at break and water resistance of EPTPS are better than that of the conventional glycerol plasticized starch (GPTPS), however, the tensile stress of which decrease. EPTPS with 30% plasticizer content will give better mechanical properties. Ethylenebisformamide can restrain the retrogradation of starch, however, the mechanical properties of EPTPS are worsened after conditioned for a period of time because of the separation of the plasticizer out of the TPS matrix. Water represent an important role on TPS and the moisture content in starch affect significantly the properties of TPS. From our research, EPTPS prepared with original water content of 13% possess of good mechanical properties.The elongation at break of EPTPS is higher than that of conventional GPTPS, however, the tensile stress of which is rather low. As reported before, celluouse can reforce the polymers. In our investigation, we choose microcrystalline cellulose to reforce EPTPS. SEM micrograph shows the dispersion of microcrystalline cellulose in TPS and a good adhesion between starch and microcrystalline cellulose. The mechanical properties of EPTPS are reinforced with the introduction of microcrystalline cellulose to the TPS matrix. The water resistance of microcrystalline cellulose reinforced EPTPS is ameliorated because of the hydrophobic character of microcrystalline cellulose.The addition of microcrystalline cellulose can reforce the EPTPS in some extent, however, the separation of plasticizer is not restrained. The combination of two different plasticizers may be give good results. The mixture of ethylenebisformamide and sorbitol is used to the preparation of ESPTPS. The result reveals that this mixed plasticizer can also restrain the retrogtadation of the starch. It is hypothesized that strong interaction between ethylenebisformamide and sorbitol occurs, which restrain the separation of plasticizer out of the TPSs matrix when the proportion of these two plasticizer is appropriate. On the other hand, the mixed plasticizer (ethylenebisformamide and sorbitol) plasticized starch possess of better mechanical properties than the single plasticizer (including glycerol, ethylenebisformamide and sorbitol) plasticized ones. The water resistance of EPTPS is also better than that of the conventional GPTPS.更多还原