CCl4等离子体表面改性聚三甲硅基丙炔膜

ＣＣｌ_４等离子体表面改性聚三甲硅基丙炔膜邱雪鹏，许观藩，林晓，郑国栋，徐纪平（中国科学院长春应用化学研究所长春１３００２２）关键词聚三甲硅基丙炔，等离子体改性，氧氮气体透过选择性聚三甲硅基丙炔（ＰＴＭＳＰ）具有优异的气体透过性，但其氧氮选择性差，可?..     

聚三甲硅基丙炔的表面氟化改性及氧氮透过性

对聚三甲硅基丙炔（ＰＴＭＳＰ）进行表面氟化改性，改性膜的氧氮选择性提高，气体透过稳定性增加．用ＸＰＳ谱分析改性后的膜表面，其表面结构发生了显著变化。     

聚三甲硅基丙炔的紫外辐照研究I．聚三甲硅基丙炔均质膜在空气中的紫外辐照

聚１－三甲硅基丙炔膜经紫外线辐照后其氧氮选择性提高，用ＸＰＳ及水接触角法研究了膜的表面组成对透气性的影响。     

聚三甲硅基丙炔的紫外辐照研究

聚１－三甲硅基丙炔膜经紫外线辐照后其氧氮选择性提高，用ＸＰＳ及水接触角法研究了膜的表面组成对透气性的影响。     

聚1—三甲硅基丙炔膜的溴化和气体透过性

在新的气体分离膜材料中,聚1-三甲硅基丙炔(PTMSP)以其高的气体透过性和优异的成超薄膜性而引起各方面的兴趣。目前的研究热点是如何提高PTMSP的氧氮透过分离系数(ao_2/N_2)和气体透过稳定性。Langsam用氮稀释的氟气对PTMSP膜进行表面氟化处理,大幅度地提高了膜的ao_2/N_2,但处理过程中伴随着剧烈的裂解,控制困难。Gozds以N-溴代丁     

聚1—三甲硅基丙炔的改性及其氧氮透过性

80年代才研制的聚1-三甲硅基丙炔(PTMSP)的T_g高于200℃,而它在室温的气体透过性呈橡胶态聚合物的特性,透氧和透醇速率极高,Po_2达5×10~3Barrer,是一代新型富氧膜材料。但TMSP制备和聚合难度大。目前尚只有日、美等国取得一些进展,他们     

等离子体改性提高PTMSP膜氧氮选择性

膜材料中迄今以聚三甲基硅基丙炔(PTMSP)的透气速率最大,其氧透过速率比PDMS高一个数量级,但氧氮分离系数小,透气性不稳定。改性PTMSP,以提高其透气选择性和透气速率稳定性引起人们的极大关注。本文报道,在外极管式电容耦合反应器中,     

含1-(2-甲氧乙基)茚基和二(三甲硅基)胺基的稀土有机配合物的合成和表征

无水三氯化稀土（ＬｎＣｌ３），二（三甲硅基）胺基钾（ＬｉＮ（ＳｉＭｅ３）２〗及１－（２－甲乙基）茚室温上在四氢呋喃溶剂中反应，得到了４个含１－（２－甲氧乙基）茚基和二（三甲硅基）胺基的稀土金属有机物｛（Ｃ９Ｈ６ＣＨ２Ｃ２ＯＭｅ）Ｌｎ〖Ｎ（ＳｉＭｅ３）２〗２（Ｌｎ＝Ｎｄ，Ｓｍ，Ｄｙ，Ｙｂ）｝，这些配合物均经元素分析、ＩＲ和ＭＳ表征。     

含有机硅多嵌段共聚物的研究Ⅳ.含有机硅多嵌段共聚物的富氧功能

研究了几种新型含有机硅二元和三元多嵌段共聚物的氧、氮选择透过性能。其中双酚A聚羟基醚-聚二甲基硅氧烷二元多嵌段共聚物-(PHE-PDMS)_n的透氧系数Po_2=510Barrer、氧氮分离系数a o_2/N_2=2.2,聚苯醚-聚二甲基硅氧烷-聚对羟基苯乙烯三元多嵌段共聚物-(PPO-PDMS-pHS)_n的Po_2=156 Barrer、do_2/N_2=2.4,两者都具有良好的力学性能。此外,含有机硅三元多嵌段共聚物与聚三甲硅基丙炔(PTMSP)起薄复合后,改善了PTMSP超薄膜的透气稳定性。其JO_2≈1.0×10~(-3)cm~2/cm~2·s·cmHg,do_2/N_2≥2.0。     

三甲基硅取代PPO和三苯基硅取代PPO及其气体选择透过性能

讨论了聚２，６－二甲基－１，４－苯撑氧（ＰＰＯ）与三甲基氯硅烷和三苯基氯硅烷的反应，合成了一系列取代含量不同的三甲基硅取代ＰＰＯ（ＴＭＳ－ＰＰＯ）和三苯基硅取代ＰＰＯ（ＴＰＳ－ＰＰＯ）。研究了取代基团不同和取代含量变化对聚合物的气体选择透过性能的影响。发现ＴＭＳ－ＰＰＯ的气体透过系数随三甲基硅取代量加大而增高，分离系数下降，ＴＰＳ－ＰＰＯ的气体透过系数和分离系数都随三苯基硅取代量的增加而下降，ＴＰ     

Hydrocarbon/hydrogen mixed gas permeation in poly(1-trimethylsilyl-1-propyne) (PTMSP), poly(1-phenyl-1-propyne) (PPP), and PTMSP/PPP blends

The gas permeation properties of poly(1-trimethylsilyl-1-propyne) (PTMSP), poly(1-phenyl-1-propyne) (PPP), and blends of PTMSP and PPP have been determined with hydrocarbon/hydrogen mixtures. For a glassy polymer, PTMSP has unusual gas permeation properties which result from its very high free volume. Transport in PPP is similar to that observed in conventional, low-free-volume glassy polymers. In experiments with n-butane/hydrogen gas mixtures, PTMSP and PTMSP/PPP blend membranes were more permeable to n-butane than to hydrogen. PPP, on the other hand, was more permeable to hydrogen than to n-butane. As the PTMSP composition in the blend increased from 0 to 100%, n-butane permeability increased by a factor of 2600, and n-butane/hydrogen selectivity increased from 0.4 to 24. Thus, both hydrocarbon permeability and hydrocarbon/hydrogen selectivity increase with the PTMSP content in the blend. The selectivities measured with gas mixtures were markedly higher than selectivities calculated from the corresponding ratio of pure gas permeabilities. The difference between mixed gas and pure gas selectivity becomes more pronounced as the PTMSP content in the blend increases. The mixed gas selectivities are higher than pure gas selectivities because the hydrogen permeability in the mixture is much lower than the pure hydrogen permeability. For example, the hydrogen permeability in PTMSP decreased by a factor of 20 as the relative propane pressure (p/p_sat) in propane/hydrogen mixtures increased from 0 to 0.8. This marked reduction in permanent gas permeability in the presence of a more condensable hydrocarbon component is reminiscent of blocking of permanent gas transport in microporous materials by preferential sorption of the condensable component in the pores. The permeability of PTMSP to a five-component hydrocarbon/hydrogen mixture, similar to that found in refinery waste gas, was determined and compared with published permeation results for a 6-Å microporous carbon membrane. PTMSP exhibited lower selectivities than those of the carbon membrane, but permeability coefficients in PTMSP were nearly three orders of magnitude higher. © 1996 John Wiley & Sons, Inc.     

Chemical modification of poly(substituted-acetylene): II. Pervaporation of ethanol / water mixture through poly(1-trimethylsilyl-1-propyne) / poly(dimethylsiloxane) graft copolymer membrane

Poly(1-trimethylsilyl-1-propyne)/poly(dimethylsiloxane) (PTMSP/PDMS) graft copolymer was prepared to evaluate the permeation characteristic at pervaporation of aqueous ethanol solution through the graft copolymer membrane. For the preparation of PTMSP/PDMS graft copolymer, an improved synthetic procedure was released in this paper, which comprised a one-pot reaction of PTMSP in lithium bis(trimethylsilyl)amide followed by treatment with hexamethylcyclotrisiloxane and trimethylchlorosilane. PDMS content of the graft copolymer was controlled in the range 5–74 mol%. Very tough and thin membranes could be prepared from these copolymers having various PDMS content by the solvent casting method. The permselectivity of the membranes was investigated by pervaporation of ethanol/water mixture at 30°C. Preferential permeation of ethanol was observed for the membranes. It was also found that the selectivity of every copolymer membrane was higher than that of the PTMSP membrane. Moreover, the selectivity depended on the PDMS content of the graft copolymer. The separation factor and permeation rate assumed the maximum values at 12 mol% PDMS content. At the maximum point, 7 wt% aqueous ethanol solution was concentrated to about 70 wt% ethanol solution, and the separation factor and permeation rate were 28.3 and 2.45 × 10^?3g · m/m² · h, respectively. Such a high permselectivity for ethanol might be due to a delicate alteration of membrane structure, which was induced by the introduction of a short PDMS side chain into a PTMSP backbone.     

Long-term permeation properties of poly(1-trimethylsilyl-1-propyne) membranes in hydrocarbon—Vapor environment

Poly(1-trimethylsilyl-1-propyne) (PTMSP), a high free-volume glassy di-substituted polyacetylene, has the highest gas permeabilities of all known polymers. The high gas permeabilities in PTMSP result from its very high excess free volume and connectivity of free volume elements. Permeability coefficients of permanent gases in PTMSP decrease dramatically over time due to loss of excess free volume. The effects of aging on gas permeability and selectivity of PTMSP membranes continuously exposed to a 2 mol % n-butane/98 mol % hydrogen mixture over a period of 47 days are reported. The permeation properties of PTMSP membranes are quite stable when the polymer is continuously exposed to a gas mixture containing a highly sorbing organic vapor such af n-butane. The n-butane/hydrogen selectivity was essentially constant for the 47-day test period at a value of 29, or 88% of the initial value of the as-cast film of 33. Condensable gases such as n-butane may serve as a “filler” in the nonequilibrium free volume of the polymer, thereby preserving the high level of excess free volume. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35 : 1483–1490, 1997     

Polymer characterization and gas permeability of poly(1-trimethylsilyl-1-propyne) [PTMSP], poly(1-phenyl-1-propyne) [PPP], and PTMSP/PPP blends

Pure gas and hydrocarbon vapor transport properties of blends of two glassy, polyacetylene-based polymers, poly(1-trimethylsilyl-1-propyne) [PTMSP] and poly(1-phenyl-1-propyne) [PPP], have been determined. Solid-state CP/MAS NMR proton rotating frame relaxation times were determined in the pure polymers and the blends. NMR studies show that PTMSP and PPP form strongly phase-separated blends. The permeabilities of the pure polymers and each blend were determined with hydrogen, nitrogen, oxygen, carbon dioxide, and n-butane. PTMSP exhibits unusual gas and vapor transport properties which result from its extremely high free volume. PTMSP is more permeable to large organic vapors, such as n-butane, than to small, permanent gases, such as hydrogen. PPP exhibits gas permeation characteristics of conventional low free volume glassy polymers; PPP is more permeable to hydrogen than to n-butane. In PTMSP/PPP blends, both n-butane permeability and n-butane/hydrogen selectivity increase as the PTMSP content of the blends increases. © 1996 John Wiley & Sons, Inc.     

Transport of organic vapors through poly(1-trimethylsilyl-1-propyne)

Poly(1-trimethylsilyl-1-propyne) [PTMSP], a high-free-volume glassy polymer, has the highest gas permeability of any known synthetic polymer. In contrast to conventional, low-free-volume, glassy polymers, PTMSP is more permeable to large, condensable organic vapors than to permanent gases. The organic-vapor/permanent-gas selectivity of PTMSP based on pure gas measurements is low. In organic-vapor/permanent-gas mixtures, however, the selectivity of PTMSP is much higher because the permeability of the permanent gas is reduced dramatically by the presence of the organic vapor. For example, in n-butane/methane mixtures, as little as 2 mol% n-butane (relative n-butane pressure 0.16) lowers the methane permeability 10-fold from the pure methane permeability. The result is that PTMSP shows a mixed-gas n-butane/methane selectivity of 30. This selectivity is the highest ever observed for this mixture and is completely unexpected for a glassy polymer. In addition, the gas mixture n-butane permeability of PTMSP is considerably higher than that of any known polymer, including polydimethylsiloxane, the most vapor-permeable rubber known. PTMSP also shows high mixed-gas selectivities and vapor permeabilities for the separation of chlorofluorocarbons from nitrogen. The unusual vapor permeation properties of PTMSP result from its very high free volume - more than 20% of the total volume of the material. The free volume elements appear to be connected, forming the equivalent of a finely microporous material. The large amount of condensable organic vapor sorbed into this finely porous structure causes partial blocking of the small free-volume elements, reducing the permeabilities of the noncondensable permanent gases from their pure gas values.     

Macrochain configuration, stucture of free volume and transport properties of poly(1-trimethylsilyl-1-propyne) and poly(1-trimethylgermyl-1-propyne)

The relationship between poly(1-trimethylsilyl-1-propyne) (PTMSP) and poly(1-trimethylgermyl-1-propyne) (PTMGP) microstructure, gas permeability and structure of free volume is reported. n-Butane/methane mixed-gas permeation properties of PTMSP and PTMGP membranes with different cis-/trans-composition have been investigated. The n-butane/methane selectivities for mixed gas are by an order higher than the selectivities calculated from pure gas measurements (the mixed-gas n-butane/methane selectivities are 20?C40 for PTMSP and 22?C35 for PTMGP). Gas permeability and n-butane/methane selectivity essentially differ in polymers with different cis-/trans-composition. Positron annihilation lifetime spectroscopy investigation of PTMSP and PTMGP with different microstructure has determined distinctions in total amount and structure of free volume, i.e. distribution of free volume elements. The correlation between total amount of free volume and gas transport parameters is established: PTMSP and PTMGP with bigger free volume exhibit higher n-butane permeability and mixed-gas n-butane/methane selectivity. Such behavior is discussed in relation to the submolecular structure of polymers with different microstructure and sorption of n-butane in polymers with different free volume.     

Polymeric complex membranes for olefin/paraffin separation

Semi-crystalline polyethylene (PE), rubbery silicone rubber (SR) and glassy poly[(l-trimethylsilyl)-l-propyne] (PTMSP) were modified for olefin/paraffin separation. The polymers were first grafted with the acrylic acid (AA) and then incorporated with silver ions for forming the complex membranes such as PE-g-AA-Ag⁺, SR-g-AA-Ag⁺ and PTMSP-g-AA-Ag⁺ The complex membranes were activated by glycerol solvation and subsequently showed high selectivity in olefin/paraffin separation. The silver ion distribution, the kinetics of olefin binding to PE-g-AA-Ag⁺, the gas permeation properties and the sorption behaviors were studied. A novel dry complex membrane for olefin/paraffin separation based on AgClO₄ complexing with PTMSP main-chain was also studied.     

Insight into reverse selectivity and relaxation behavior of poly[1-(trimethylsilyl)-1-propyne] by flux-lateral force and intrinsic friction microscopy

Novel scanning force microscopy techniques (SFM) were employed to investigate poly[l-(trimethylsilyl)-1-propyne] (PTMSP), a high-free volume, highly permeable reverse-selective membrane material. This study reports, for the first time, reverse selectivity in relation to the interfacial gas adsorption capacity of the PTMSP membrane with the gas permeants CO₂ and helium. With flux-lateral force microscopy (F-LFM), mechanical property changes caused by permeant gas infiltration were recorded within the polymer interfacial downstream region. In conjunction with bulk permeation measurements and varying sequential exposure to the two permeants, CO₂ is found to saturate the membrane faster, i.e. at a lower differential pressure by about 0.3 bar, in comparison to helium. It is also identified as modifying agent for PTSMP causing a significant change in the mechanical properties of the polymer matrix, which consequentially leads to a considerable helium transport reduction, and thus, an increase in reverse selectivity from 1.2 to 4.7. Also in this study, thermally available activation modes of 6–8 kcal/mol were revealed by intrinsic friction analysis (IFA) that were attributed to backbone methyl-group rotations in accordance with conformational calculations. Bulk thermally activated modes were found to be modestly affected by interfacial constraints on the sub-100 nanometer scale, which is an important finding for interpreting interfacial constraints in PTMSP nanocomposites involving silicon-oxides.