【作者】 高健；

【导师】 杨大令；

【作者基本信息】 大连理工大学 ， 膜科学与技术， 2008， 硕士

【摘要】 在通用高分子气体分离膜材料中,硅橡胶（PDMS）因其具有很高的透气系数而备受关注;但是它的氧氮分离系数(α_o2/N2=2.0)较低、成膜性较差,在很大程度上限制了它的应用。以辛基取代PDMS链中的部分甲基,合成出甲基辛基硅橡胶。柔性基团辛基的引入,可以使透气性些许降低的情况下,提高膜的分离性能。本文采用了两步合成法合成了聚甲基辛基硅氧烷（POMS）。第一步,以α-辛烯和2,4,6,8-甲基环四硅氧烷（D₄^H）为原料,以氯铂酸为催化剂,利用硅氢加成反应合成了四甲基四辛基环四硅氧烷(D₄^Oct)。应用傅立叶转换红外线光谱（FTIR）,核磁共振波谱（¹H-NMR）对产物进行了表征。并且利用¹H-NMR考察了反应条件对体系中Si-H键的转化率的影响。结果显示:当2,4,6,8-四甲基环四硅氧烷（D₄^H）与α-辛烯的摩尔比为1:12,反应温度为65℃,反应时间为20h,催化剂用量为0.6g时,Si-H的转化率达到97.3%,β-加成产物100%。第二步,以D₄和D₄^Oct为单体、三氟甲基磺酸CF₃SO₃H为催化剂,MM^ⅵ为封端剂,利用开环共聚合成了聚甲基辛基硅氧烷。傅立叶转换红外线光谱（FTIR）和核磁共振波谱（¹H-NMR）分析表明产物是POMS,且辛基摩尔含量的实测值与理论值基本一致。实验结果表明:当反应温度为60℃、反应时间为120min、催化剂用量为0.02wt%、MM^ⅵ用量在1.4～1.9wt%之间时,POMS的粘度适中,性能稳定。采用浸渍涂敷法制备了以PEI为底膜材料、硅橡胶（POMS）为涂层的复合膜,考察了POMS浓度、催化剂用量等因素对复合膜性能的影响,确定了适宜的涂层液配方和涂敷条件:其中硅橡胶（POMS）、交联剂、催化剂、溶剂之比为3.0:0.06:0.12:96.82时为最佳值,涂敷三次,在80℃下,硫化3h所得复合膜的性能最好。实验表明:随着操作压力的不断升高,气体的渗透速率呈上升趋势,分离系数略微下降。选用辛基含量为10mol%的硅橡胶,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2.35左右。FTIR分析表明涂层存在POMS的交联反应,且反应完全。更多还原

【Abstract】 Among the universal polymer materials of gas separation membrane,silicone rubber （PDMS）has always been focused just because of its high gas permeability.However,its separation coefficient(α_O2/N2=2.0)and membrane formability are bad,which limited its practical value.Polyoctylmethylsiloxane was synthesized by induct some octyl in side group, The induct of soft octyl can improve the performance of membrane and ensure the separation rate rising and the permeation rate not or a little lowering.In this study,Polyoctylmethylsiloxane was synthesized by two-step method.The first step:2,4,6,8-tetramethyloctylcyclotetrasiloxane was synthesized by hydrosilylation of 2,4,6,8 -tetramethylcyclotetrasiloxan and a-octene in the presence of platinum catalyst.The structure of the sample was characterized with FTIR and ¹H-NMR.And the effects of various reaction conditions,such as the reaction temperature,reaction time,et al,on the conversion of Si-H were investigated by the ¹H-NMR.The conversion of Si-H reached 97.3%at 65℃after 20h with 0.6g catalyst and the molar ratio of D₄^H to a-octene was 1:12.The structure of product was 100%β-adduct in regioselectivity confirmed by ¹H-NMR.The second step:Polyoctylmethylsiloxane was synthesized by ring-opening polymeriza -tion of octamethylcyclotetrasiloxane,2,4,6,8-tetramethyloctylcyclotetrasiloxane and MM^ⅵas the blocking agent in the presence of CF₃SO₃H catalyst.The product structure was characterized by FTIR and ¹H-NMR,and the octyl content was the same as expectation.The result showed the best synthetic technics were reaction temperature 60℃,reaction time 120min,mass fraction of CF₃SO₃H 0.02wt%,mass fraction of MM^ⅵ1.4-1.9wt%.And at the moment the product has right viscosity and stable performance.The composite membrane was formed by coating the solution which was comprised by 3.0g POMS—10mol%,96.82g petroleum ether,0.06g hydrogenous silicon oil,0.12g chloroplatinic acid catalyst three times on the PEI porous substrate membrane,then vulcanizing 3 hours at 80 temperature.When the pressure was increased,the permeation rate has a rising trend and the separation rate was a little lowering.When the octyl content was 10mol%,the performance of composite membrane was good,the separation rate of oxygen/ nitrogen was about 2.35.At last,analysis of FTIR showed that the cross-linking reactions of POMS was existent and complete.更多还原