分别将四甲基二乙烯基二硅氧烷(DVTMS)和2,4,6,8-四甲基-2,4,6,8-四乙烯基环四硅氧烷(TMTV)与交联剂聚二甲基硅氧烷(PDMS)的B组分(B)聚合形成两种聚硅氧烷DB和TB,涂覆于聚丙烯腈(PAN)表面形成过渡层DB(TB)/PAN,涂覆PDMS分离层得3层结构的PDMS/DB(TB)/PAN渗透汽化复合膜,用于1%正丁醇水溶液的分离,表征了过渡层的结构,研究了硅氧烷/交联剂比和膜液中固形物含量对复合膜渗透汽化性能的影响.结果表明,在分离层和过渡层总厚度相同的情况下,涂覆DB和TB有效提高了膜的渗透汽化性能,最佳膜配方DVTMS:B=3:1(ω)及DB含量5%(ω)时,PDMS/DB/PAN膜的分离因子为40.96,渗透通量为628.40 g/(m^2·h);TMTV:B=1:1(ω)及TB含量为3%(ω)时,PDMS/TB/PAN膜的分离因子为41.58,渗透通量为540.00 g/(m^2·h).PDMS/DB/PAN膜和PDMS/TB/PAN膜的分离因子分别比相同分离层厚度的PDMS/PAN膜的分离因子提高8.5%和10.2%,渗透通量提高29.5%和11.3%.
Two kinds of polyorganosiloxane(POS), DVTMSB(DB) and TMTVB(TB), were synthesized by copolycondensation of 1,3-divinyltetramethyldisiloxane(DVTMS) or tetravinyltetramethylcyclotetrasiloxane(TMTV) with component B in polydimethylsiloxane(PDMS), respectively. The PDMS/DB(TB)/PAN composite membranes with tri-layer, a polyacrylonitrile(PAN) support layer, a DB(TB) transition layer and a PDMS active layer were prepared by sequential coating methods and used to the separation of 1%(ω) aqueous solution of n-butanol by means of pervaporation. The effects of mass ratio of DVTMS or TMTV to B and the mass content of DB and TB in casting solution on pervaporation performance were investigated. The results showed that the addition of DB or TB enhanced pervaporation performance of composite membrane with a same total thickness of separation and transition layer. To 1%(ω) aqueous solution of n-butanol, the separation factor was 40.96 and permeation flux was 628.40 g/(m^2·h) of PDMS/DB/PAN composite membrane, under the mass ratio of DVTMS:B of 3:1 and the concentration of DB in transition layer solution of 5%(ω), and the separation factor was 41.58 and permeation flux was 540.00 g/(m^2·h) of the PDMS/TB/PAN, under the mass ratio of TMTV:B of 1:1 and the concentration of TB in transition layer solution of 3%(ω). Thus, the separation factors were increased by 8.5% and 10.2%, along with the permeation fluxes were increased by 29.5% and 11.3%, respectively, of PDMS/DB/PAN composite membrane and PDMS/TB/PAN composite membrane compared with the same thickness PDMS/PAN composite membrane under the optimized conditions.