【作者】 奚冬雷；

【导师】 刘晓亚； 陈明清； 杨成；

【作者基本信息】 江南大学 ， 应用化学， 2005， 硕士

【摘要】 本文对大豆分离蛋白接枝改性及应用进行了研究。大豆分离蛋白分散在8M尿素水溶液中,在N₂保护下,以Ce⁴⁺-S₂O₈^2-为复合引发剂,分别合成了大豆分离蛋白接枝聚苯乙烯共聚物（SPI-g-PSt）、大豆分离蛋白接枝聚醋酸乙烯酯共聚物（SPI-g-PVAc）,并对它们在可降解大豆蛋白膜方面的应用做了初步研究。用傅立叶红外光谱仪（FTIR）、核磁共振波谱仪（NMR）、差示扫描量热仪（DSC）对SPI-g-PSt进行了表征,证明了苯乙烯已成功接枝到了大豆分离蛋白上。并讨论了反应时间,引发剂浓度,单体浓度,反应温度等反应条件对接枝率（G%）和接枝效率（E%）的影响。结果表明,接枝率（G%）和接枝效率（E%）在25h后达到最大值;随引发剂用量和反应温度的增加,接枝率（G%）和接枝效率（E%）先增加后减小;随单体浓度的增加,接枝率（G%）增大,接枝效率（E%）先增加后减小。采用傅立叶红外光谱仪（FTIR）、差示扫描量热仪（DSC）对SPI-g-PVAc进行了表征,证明醋酸乙烯酯已成功接枝到大豆蛋白上。通过一系列单因素实验,讨论了反应时间,引发剂浓度,单体浓度,反应温度等反应条件对接枝率（G%）和接枝效率（E%）的影响。结果表明,反应条件对SPI接枝醋酸乙烯酯反应的影响同它们对SPI接枝苯乙烯的规律相似。以SPI-g-PSt或SPI-g-PVAc为主要成膜物质,以去离子水配制成成膜液,在成膜液中加入甘油,调节pH值,用流延法分别制成了SPI-g-PSt膜和SPI-g-PVAc膜。研究了pH值、增塑剂、接枝率等因素对膜的性能如抗拉强度（TS）、断裂伸长率（E）、水蒸气透过系数（WVP）等的影响。结果表明,与SPI膜相比,SPI-g-PSt膜的抗拉强度增强,WVP值减小;SPI-g-PVAc膜的断裂伸长率有了很明显的提高,WVP值也有所下降。接枝率为25%时,SPI-g-PSt膜的性能较好;而SPI-g-PVAc膜在接枝率为20%时力学性能较好。在去离子水中将大豆分离蛋白分别与羧乙基纤维素共混配制成成膜液,并加入甘油,调节pH值,用流延法分别制成大豆分离蛋白—羧乙基纤维素可食性膜,研究了纤维素含量、增塑剂等因素对膜性能的影响。结果表明,随纤维素含量的增加,WVP值减小,抗拉强度增大,而伸长率呈先减小后增大的趋势;随甘油含量的增加,WVP值增大,抗拉强度逐渐下降,伸长率逐渐增加。更多还原

【Abstract】 The synthesis and application of soy protein isolate grafted copolymers have been investigated.SPI-g-PSt and SPI-g-PVAc were synthesized in 8 moL/L urea aqueous solution initiated byammonium cerous nitrate-potassium persulfate under the protection of nitrogen (N2). Further, theapplication of the soy protein isolate grafted copolymers in the field of SPI edible films was studied.SPI-g-PSt copolymer was characterized by Infrared Spectrometer, Nuclear Magnetic Resonanceand Differential Scanning Calorimetry. The results indicated the styrene has been grafted on the SPI.The influence of reaction conditions on percentage graft and percentage efficiency was investigated.The percentage graft and percentage efficiency increase at first and then decrease with the increaseof the initiator concentration, the monomer concentration and the reaction temperature. With theincrease of reaction time, the percentage graft and percentage efficiency increase.SPI-g-PVAc copolymer was characterized by IR and DSC. The influence of reaction conditionson percentage graft and percentage efficiency was also investigated. The results indicated that theeffects of reaction time, initiator content, monomer content and reaction temperature on thecopolymerzization of SPI with VAc is similar to effects of these reaction conditions on thecopolymerization of SPI with styrene.SPI-g-PSt films and SPI-g-PVAc films were prepared from the aqueous solution of SPI-g-PStcopolymers and SPI-g-PVAc copolymers. Tensile strength(TS), the elongation(E) and the watervapor permeability(WVP) of these films were determined. The influence of pH value, plastizercontent and graft ratio on the properties of films were studied. The results indicated that TS valuesof SPI-g-PSt films were higher than those of SPI films, E values of SPI-g-PVAc films were higherthan those of SPI films;the results also indicated TS and E of SPI-g-PSt films, SPI-g-PVAc filmsand SPI films increased with the increasing of pH values. The WVP values of SPI-g-PSt andSPI-g-PVAc films were lower than those of SPI films.The edible films were prepared from the aqueous solution of soy protein isolate and carboxyethylcellulose, with various concentrations of plastizer and with various carboxyethyl cellulosecontents.With the increasing of carboxyethyl cellulose contents, WVP and TS of the edible filmsincreased, E of the edible films decreased firstly and then increased. With the increasing of plastizercontents, WVP and E of the edible films increased, TS of the edible films decreased.更多还原