结构可控聚合物的合成对于高分子材料结构与性能研究及应用具有重要的理论和实际意义。乙烯基聚硅氧烷广泛用于硅橡胶、硅树脂材料的合成与改性。以环硅氧烷[八甲基环四硅氧烷(D 4)、四甲基四乙烯基环四硅氧烷(D Vi 4)]为单体,采用阴离...结构可控聚合物的合成对于高分子材料结构与性能研究及应用具有重要的理论和实际意义。乙烯基聚硅氧烷广泛用于硅橡胶、硅树脂材料的合成与改性。以环硅氧烷[八甲基环四硅氧烷(D 4)、四甲基四乙烯基环四硅氧烷(D Vi 4)]为单体,采用阴离子开环聚合的方式制备乙烯基聚硅氧烷(Vi-PMVS),利用1 H NMR、29 Si NMR、FTIR表征分析产物的结构;根据29 Si NMR谱图和凝胶渗透色谱(GPC)分析分子量(M n)及其分布。重点探索乙烯基聚硅氧烷分子量与分子量分布的影响因素。结果表明:通过控制单体和封端剂的比值、催化剂的种类与用量、聚合温度和聚合时间等,可以调控乙烯基聚硅氧烷的分子量及其分布。其中单体的添加顺序及其方式对分子量的影响最为显著;当两种单体的投料比为1∶1,分批逐滴加入D 4和D Vi 4单体,聚合物的分子量分布最低,聚合物的分子量也可以得到很好控制。展开更多
Pervaporation(PV),as an environmental friendly and energy-saving separation technology,has been received increasing attention in recent years.This article reviews the preparation and application of macroporous ceramic...Pervaporation(PV),as an environmental friendly and energy-saving separation technology,has been received increasing attention in recent years.This article reviews the preparation and application of macroporous ceramic-supported polymer composite pervaporation membranes.The separation materials of polymer/ceramic composite membranes presented here include hydrophobic polydimethylsiloxane(PDMS) and hydrophilic poly(vinyl alcohol)(PVA),chitosan(CS) and polyelectrolytes.The effects of ceramic support treatment,polymer solution properties,interfacial adhesion and incorporating or blending modification on the membrane structure and PV performance are discussed.Two in-situ characterization methods developed for polymer/ceramic composite membranes are also covered in the discussion.The applications of these composite membranes in pervaporation process are summarized as well,which contain the bio-fuels recovery,gasoline desulfuration and PV coupled proc-ess using PDMS/ceramic composite membrane,and dehydration of alcohols and esters using ceramic-supported PVA or PVA-CS composite membrane.Finally,a brief conclusion remark on polymer/ceramic composite mem-branes is given and possible future research is outlined.展开更多
文摘结构可控聚合物的合成对于高分子材料结构与性能研究及应用具有重要的理论和实际意义。乙烯基聚硅氧烷广泛用于硅橡胶、硅树脂材料的合成与改性。以环硅氧烷[八甲基环四硅氧烷(D 4)、四甲基四乙烯基环四硅氧烷(D Vi 4)]为单体,采用阴离子开环聚合的方式制备乙烯基聚硅氧烷(Vi-PMVS),利用1 H NMR、29 Si NMR、FTIR表征分析产物的结构;根据29 Si NMR谱图和凝胶渗透色谱(GPC)分析分子量(M n)及其分布。重点探索乙烯基聚硅氧烷分子量与分子量分布的影响因素。结果表明:通过控制单体和封端剂的比值、催化剂的种类与用量、聚合温度和聚合时间等,可以调控乙烯基聚硅氧烷的分子量及其分布。其中单体的添加顺序及其方式对分子量的影响最为显著;当两种单体的投料比为1∶1,分批逐滴加入D 4和D Vi 4单体,聚合物的分子量分布最低,聚合物的分子量也可以得到很好控制。
文摘Pervaporation(PV),as an environmental friendly and energy-saving separation technology,has been received increasing attention in recent years.This article reviews the preparation and application of macroporous ceramic-supported polymer composite pervaporation membranes.The separation materials of polymer/ceramic composite membranes presented here include hydrophobic polydimethylsiloxane(PDMS) and hydrophilic poly(vinyl alcohol)(PVA),chitosan(CS) and polyelectrolytes.The effects of ceramic support treatment,polymer solution properties,interfacial adhesion and incorporating or blending modification on the membrane structure and PV performance are discussed.Two in-situ characterization methods developed for polymer/ceramic composite membranes are also covered in the discussion.The applications of these composite membranes in pervaporation process are summarized as well,which contain the bio-fuels recovery,gasoline desulfuration and PV coupled proc-ess using PDMS/ceramic composite membrane,and dehydration of alcohols and esters using ceramic-supported PVA or PVA-CS composite membrane.Finally,a brief conclusion remark on polymer/ceramic composite mem-branes is given and possible future research is outlined.
