环氧硅氧烷与胶原多肽界面接枝反应及梯度膜的制备研究

Narrow distribution polydimethylsiloxane (PDMS-H) with different degree of polymerization was synthesized by anionic polymerization, and then α-[3-(2, 3-epoxy-propoxy) propyl]-ω-butyl- polydimethy siloxanes (PDMS-E) was prepared by allyl glycidyl ether (AGE) and PDMS-H. PDMS-E grafted gelatin (PGG) polymers were synthesized prepared from mono epoxy terminated polydimethylsiloxane (PDMS) macromonomer and gelatin for improving their flexibility and hydrophobicity. The grafting reaction between gelatin and PDMS-E in heterogeneous system was firstly discussed. Necklace structure formed from gelatin and surfactant and Latex particles structure of PDMS-E played a crucial role in deciding the degree of grafting in the two-phase system and the structure of PDMS-E grafted gelatin (PGG) polymers in alkaline solution. Gelatin film was prepared by mixing these PGG polymers. The conditions including temperature, proportioning and evaporation speed of solvent were studied for controlling the Si gradient in the films. The work was essential for providing a theoretical basis for explain heterogeneous reaction in gelatin and PDMS immiscible system, and leading to better control of the structure/performance relationship in gelatin gradient film materials. The work is remarkable for resolving the important problem which consists in the field of leather finishing agent.

以六甲基环三硅氧烷为主要原料、正丁基锂做引发剂，用阴离子聚合法制备单分散单端含氢硅油，含氢硅油与烯丙基缩水甘油醚进行硅氢加成，合成单环氧硅氧烷，通过伯胺基与环氧基的开环加成反应，实现环氧硅氧烷对胶原多肽的接枝改性。项目首次研究多肽和环氧硅氧烷的异相反应体系中多肽串珠结构和环氧硅氧烷乳胶粒结构对接枝反应动力学与接枝率的影响规律；将不同链长环氧硅氧烷改性的多肽进行复配，调节组分含量、乳液浓度、成膜温度、水分挥发速度等因素，制备硅氧烷在膜内呈微相分离，在膜表面富集，从底表面到上表面呈梯度分布的薄膜。项目中多肽-硅氧烷梯度膜构筑技术是高分子材料科学领域备受关注的创新性研究。 膜内硅氧链将发挥增塑作用，改善膜的柔韧性，表面富集硅氧链将赋予薄膜优良的抗水性，这正是蛋白涂饰剂的关键技术指标。研究结果将为利用制革下脚料中的胶原蛋白开发新一代蛋白涂饰剂提供理论依据和实验方法，经济效益和社会效益显著。

以六甲基环三硅氧烷为主要原料，用正丁基锂引发阴离子聚合制备单分散单端含氢硅油，再与烯丙基缩水甘油醚进行硅氢加成，合成单环氧硅氧烷，通过伯胺基与环氧基的开环加成反应，实现环氧硅氧烷对胶原多肽的接枝改性。项目研究了多肽和环氧硅氧烷的异相反应体系中多肽-阴离子表面活性剂复合行为对接枝率的影响规律，建立了亚浓溶液中十二烷基硫酸钠（SDS）/多肽、十四烷基磺酸钠（STSo）/多肽的复合物模型，明确了阴离子表面活性剂与胶原多肽之间的非共价键互作用使多肽链在界面伸展或卷曲，并且影响体系自由能，导致伯氨基转化率发生变化。探讨了环氧聚硅氧烷接枝多肽的聚集行为和固态行为，研究表明SDS、STSo与多肽分子之间的静电、疏水相互作用影响多肽二级结构和接枝率，驱使接枝物组装为核壳、多层或六角形等不同形态聚集体，溶剂挥发过程中，聚集体经过聚并、扩散和重新排列，形成不同相分离结构。该研究为梯度膜制备提供研究基础；制备了不同尺寸单分散环氧聚硅氧烷乳胶粒，明确SDS用量是影响环氧硅氧烷乳胶粒尺寸的关键。首次研究了环氧聚硅氧烷乳胶粒尺寸对接枝反应动力学和接枝率的影响规律，结果表明随乳胶粒尺寸增加，乳胶粒表面电荷密度降低，环氧基在乳胶粒表面暴露量增加。伯氨基转化率随乳胶粒尺寸增加而增加，拟合直线斜率变化趋势表明，在粒径P<~450nm，450nm<P<650nm，P>650nm三个尺寸范围内，伯氨基转化率的增加速率持续加快。动力学表明反应分为缓慢增加、快速增加和平稳变化三个阶段。.分别以溶剂辅助的大分子自组装法和填充法构筑多肽梯度膜，调节基材种类、成膜温度、水分挥发速度、溶剂、多肽梯度网孔模板等因素，制备硅氧烷在膜表面富集，在膜内呈微相分离，从底表面到上表面呈梯度分布的薄膜。膜内硅氧链将发挥增塑作用，改善膜的柔韧性，表面富集硅氧链将赋予薄膜优良的抗水性，这正是蛋白涂饰剂的关键技术指标。研究结果将为利用制革下脚料中的胶原蛋白开发新一代蛋白涂饰剂提供理论依据和实验方法，经济效益和社会效益显著。