【作者】 赵婵；

【导师】 杨大令；

【作者基本信息】 大连理工大学 ， 材料学， 2007， 硕士

【摘要】 聚二甲基硅橡胶（PDMS）是一种综合性能优异的高分子材料，主链上的Si-O键极易内旋转，分子链非常柔顺，具有高的透气性能，可将其应用在分离膜领域。但是PDMS的缺点是分离系数低，如α_O2／N2只有2.0。在侧基引入一定量乙烯基，制成聚乙烯基二甲基硅橡胶（PVDMS），利用交联来改善膜分离性能，是一种简便有效的方法。虽然低乙烯基含量PVDMS已商品化，但市售PVDMS的乙烯基含量很少，一般为0.1～0.3mol％，不能起到提高膜性能的作用。本实验合成了一系列高乙烯基含量的硅橡胶，乙烯基含量由5～25mol％，详细研究其合成工艺，并进行了结构表征；将自制硅橡胶作为涂层材料，应用在气体分离复合膜上，选择合适的底膜材料，确定最佳的涂层液配方及涂敷条件，考察操作压力、硅橡胶分子量及乙烯基含量对复合膜的透气性和选择性的影响，同时与两种进口硅橡胶进行性能比较，并对复合膜进行了红外表征。研究表明，在以KOH为催化剂，MM^ⅵ为封端剂，D₄和D₄^ⅵ为原料合成高乙烯基含量硅橡胶的反应中，反应温度在140℃左右、反应时间为180～210min，MM^ⅵ加入量在0.9～1.8wt％之间、KOH催化剂加入量为0.01～0.015wt％，所制得硅橡胶的粘度适中，性能稳定。FT-IR和¹H-NMR分析表明产物是PVDMS，且乙烯基摩尔含量与预期值基本一致。取3.0g乙烯基含量为5mol％的PVDMS，用96.66g石油醚溶解后，分别加入0.20g含氢硅油和0.14g氯铂酸催化剂溶液，搅拌均匀，在PEI多孔底膜上涂敷两遍，80℃下，硫化4h，所得复合膜的性能最好。随着压力的不断升高，气体的渗透速率呈上升趋势，分离系数略微下降。选用特性粘度为0.22～0.32dl／g左右，乙烯基含量为5～10mol％的硅橡胶，所制得的气体分离复合膜的性能良好，在透气性能损失较少的情况下，显著提高了气体的分离性能，α_O2／N2在2.3～2.6左右。另外，自制乙烯基含量为5mol％的硅橡胶膜性能优于美国的Dow—184并与德国Wacker—VP7660性能相近，可以替代这两种硅橡胶；而乙烯基含量为10mol％的硅橡胶分离系数可达2.6，在医用保健富氧膜应用上具有明显优势。FT-1R分析表明涂层存在PVDMS的交联反应，且反应完全；美国DOW—184为聚二甲基硅氧烷结构，德国Wacker—VP7660为含有苯基结构的硅橡胶。更多还原

【Abstract】 The poly(dimethysiloxane) (PDMS) is a polymer material on excellent syntheticperformance. The bond of Si-O in the main chain is so easy to internal rotation, that themolecular chains is very soft. Thus the PDMS has high permeability which could be appliedto the field of separation membranes. But the low separation factor is a disadvantage ofPDMS, for example the separation rate of oxygen/nitrogen is only 2.0.The convenient and valid method is to synthesize poly(dimethyvinylsiloxane) (PVDMS)by induct some vinyl in side group, and then improve the separation factor by cross-linking.Though the low vinyl content of PVDMS is a commercial product, the vinyl content is toofew in markets, only 0.1～0.3mol％, which could not improve the membrane performance.A series of high vinyl content PVDMS were synthesized which vinyl content was5～25mol％. The synthetic technics were investigated carefully and the chemical structurewere characterized by FTIR and ~1H-NMR. The composite membranes for gas separation wereprepared by coating the PVDMS solution. The experimental contents were comprised by thechoice of appropriate substrate membrane, the confirmation of optimum coating liquidformula and coating conditions, the investigation of the effects of the feed pressure, themolecular weights and the vinyl content in permeability and selectivity of compositemembranes, the comparison of two kinds of imported silicone rubber and the FTIRcharacterizations.The result showed that when the catalyst was KOH, the blocking agent was MM~ⅵ, theraw materials were D4 and D4~ⅵ, the best synthetic technics were reaction temperature 140℃,reaction time 180～210min, mass fraction of MM~ⅵ0.9～1.8wt％, mass fraction of KOH0.01～0.015wt％. And at the moment the product has right viscosity and stable performance.The product structure was characterized by FTIR and ~1H-NMR, and the vinyl content was thesame as expectation.The composite membrane was formed by coating the solution which was comprised by3.0g PVDMS—5mol％, 99.66g petroleum ether, 0.20g hydrogenous silicon oil, 0.14gchloroplatinic acid catalyst twice on the PEI porous substrate membrane, then vulcanizing 4hours at 80 temperature. The performance of composite membrane was best. When thepressure was increased, the permeation rate has a rising trend and the separation rate was alittle lowering. When the viscosity of PVDMS was 0.22～0.32dl/g, the vinyl content was 5-10mol％, the performance of composite membrane was good, the separation rate of oxygen/nitrogen was in the range of 2.3～2.6. Moreover, the performance of PVDMS—5mol％wasbetter than Dowe—184 of USA, and similar to Wacker—VP7660 of Germany, The separationrate of PVDMS—10mol％could reach to 2.6 which could be used in medical oxygen-enriching membrane. At last, analysis of FT-1R showed that the cross-linking reactions ofPVDMS was existent and complete, the structure of Dowe—184 was PDMS and the Wacker—VP7660 contained phenyl.更多还原