改性聚苯醚膜对有机混合液的渗透汽化分离

研究了溴代ＰＰＯ地质膜以各种胺化学交联后对氯代烃如氯仿、氯代苯的水溶液的渗透汽化分离性能，以及对甲醇／正戊烷／乙醇／正戊烷等有机液的分离性能。通过和聚乙烯基吡咯烷酮物理共混，提高ＢＰＰＯ膜的极以改善对醇类／正戊烷混合的液的分离选择性。     

高硅ZSM—5沸石填充硅橡胶膜的醇—水渗透蒸发分离性质

高硅ZSM－5沸石填充疏水性硅橡胶蓦地低浓度醇－水体度醇－水体的渗透蒸发性质的研究有明，提高沸石硅铝比，增加填充量以及进行酸处理皆有利于改善膜对醇－水的分离系数和通量。料液的成，浓度以及温度对膜的分离性质也有显著影响。     

疏水改性PDMS渗透蒸发膜分离苯/水体系

甲基三乙氧基硅烷;聚二甲基硅氧烷膜;疏水改性PDMS渗透蒸发膜分离苯/水体系     

Synthesis and characterization of poly(amide sulfonamide)s (PASAs)

New diamino monomers IIa – IIg were synthesized in a two-step reaction sequence starting from p-acetamidobenzenesulfonyl chloride. Solution polymerization of these monomers in DMAC with terephthaloyl or isophthaloyl chloride resulted in the formation of a series of 14 poly(amide sulfonamide)s (PASAs) in excellent yield (> 95%). The polymers have in-trinsic viscosities of 0.32–1.11 dL g^?1. Except for polymers IIIa ? p and IIId - p , all other PASAs were readily soluble in aprotic polar solvents including DMAC, DMF, and DMSO. Thermogravimetric analyses of the polymers showed moderate thermal stability with 10% weight loss being recorded in the range of 325–408°C. In addition, these polymers exhibit moderate chemical stabilities toward alkali, acidic, and chromic acid solution. © 1995 John Wiley & Sons, Inc.     

HPTLC Separation of Homologous and Isomeric Poly(ethyleneamine)s

Abstract

A simple, reliable HPTLC method has been developed for analysis of poly(ethyleneamine)s (PEAs). Ethylenediamine and all dimeric, trimeric, and tetrameric PEAs are separated without prior derivatization. Treatment with fluorescamine and visualization under ultraviolet light detects each PEA in quantities as low as 100 ng.     

渗透汽化法分离二氧六环－水混合物

研究了二氧六环一水混合物在ＰＶＡ（聚乙烯酸）－ＰＡＮ（聚丙烯腈）复合膜中的渗透汽化分离性能。结果表明透过速率Ｑ和分离系数α均随料液温度的提高而增大。α随料液中二氧六环浓度的提高而增大，Ｑ的变化趋势相反．有代表性的数据是在９０℃对９５％的二氧六环水溶液，α可达１９８１，Ｑ＝７３．８ｇ／ｍ２·ｈ．在低浓度二氧六环溶液时扩散过程对选择性起主要作用。而高浓度时溶解选择性是主要的，随着分离温度的提高，扩散或溶解均提高了选择性。     

渗透汽化膜分离研究的新进展

渗透汽化膜分离技术是当前分离膜研究领域的前沿课题之一.作为化学分离中的重要组成部分,近年来受到高度重视.本文按渗透汽化膜分离的三大类混合液体系有机液脱水、从水相中分离有机物和有机混合液的分离,综述了近几年渗透汽化膜分离技术研究的新进展.其中,又重点报道了有机混合液分离的最新研究成果,将其分为:极性/非极性化合物、芳香烃/脂肪烃体系、芳香烃/脂环烃体系、同分异构体、多元体系和汽油脱硫等六部分进行了详细叙述.文章最后还对渗透汽化膜分离研究进行了展望.     

Pervaporation Separation and Catalysis Activity of Novel Zirconium Silicalite-1 Zeolite Membrane

Novel zirconium silicalite‐1 zeolite membrane was hydrothermally prepared on the mullite porous support at 150–185°C for 40–72 h by an "in situ" method using tetraethyl orthosilicate (TEOS), zirconium butoxide (ZBOT) and tetrapropylammonium hydroxide (TPAOH) as silica source, zirconium source and organic structure directing agent, respectively. X‐ray diffraction (XRD) patterns, fourier transformed infrared (FT‐IR) spectra, and inductively coupled plasma‐atomic emission spectrometry (ICP) of the accompanying zeolite powder confirmed that the zirconium was isomorphously incorporated into the zeolite framework. The surface chemical compositions of the obtained membrane were measured with an energy‐dispersive X‐ray spectral analyzer (EDS), and the membrane morphologies were observed by a scanning electron microscope (SEM). The results showed that the zeolite crystals growing on the support were zirconium silicalite‐1 zeolites, and the dense membrane layer was composed of the well inter‐growing zeolite crystals. The zirconium silicalite‐1 zeolite membrane, which was derived from the synthesis solution having a molar ratio of 1.00SiO₂:0.01ZrO₂:0.17TPAOH:120H₂O, showed high ethanol permselectivity with a flux of 1.01 kg/(m²·h) accompanied with a separation factor of 73 for ethanol/water (5/95, w/w) system under a pervaporation condition at 60°C. Moreover, this membrane displayed pervaporation‐aided catalysis activity for iso‐propanol oxidation with hydrogen peroxide as oxidant, and the corresponding iso‐propanol conversion was 35%.     

聚乙烯醇／壳聚糖共混膜优先透醇性能的研究

聚乙烯醇／壳聚糖共混膜优先透醇性能的研究王新平，沈之荃，张富尧，林荣轩（浙江大学高分子系，化学系，杭州，３１００２７）关键词渗透蒸发，聚乙烯醇／壳聚糖共混物膜，乙醇水溶液本文首次报道利用亲水性的聚乙烯醇和壳聚糖制得具有很高的乙醇优先透过选择性的透醇型...     

Liquid Adsorption Chromatography Separation of Star Poly(methyl methacrylate)s

Liquid adsorption chromatography, in combination with full adsorption–desorption and precipitation–redissolution techniques, is a powerful procedure for the fractionation of mixtures in the synthesis of star polymers. An easy separation of 4‐ and 6‐arm star poly(methyl methacrylate)s from their single arm precursors could be carried out by both procedures, with differences of separation efficiency also depending on the molecular weight of the precursor and the number of arms.

Size exclusion chromatograms of retained and eluted fractions obtained by liquid adsorption chromatography/full adsorption–desorption separation with a tetrahydrofuran/cyclohexane eluent system (53:47 wt.‐%) for a crude reaction mixture (dotted line) containing a 4‐arm star PMMA polymer and a single‐arm precursor (solid lines a and b, respectively).     

PTMSP与PMP膜渗透汽化分离性能的研究比较

制备了聚三甲基硅丙炔与聚4－甲基戊烯－1均质膜，研究比较了这两种膜的分子结构与其对吡啶、丁酮和四氢呋喃三种有机液；水混合体系的渗透汽化特性同的关系，并进行了理论解释。     

Poly(cyclodiborazane)s

This paper summarizes our recent works on the synthesis and properties of the organoboron polymers, especially poly(cyclodiborazane)s. The polymers consist of boron–nitrogen four-membered rings, and are highly stable against air and moisture. The obtained polymers exhibited interesting properties as a novel type of π-conjugated polymers with intramolecular charge transfer structure. Their stability and potential as functional materials would be important and informative both in industry and boron chemistry.     

Poly(thioester)s

Syntheses and properties of aliphatic and aromatic polythioesters (PTEs) were reviewed including polythiocarbonates and polythiourethanes. The content is subdivided into the following sections: PTEs of aliphatic α‐mercapto carboxylic acid, PTEs of ω‐mercapto carboxylic acids, PTEs derived from α,ω‐dimercapto alkanes, aromatic poly(thioester)s, aliphatic poly(thiocarbonate)s, aliphatic poly(thiourethane)s and aromatic polythiocarbonates. The synthetic strategies reviewed in this article include anionic and cationic ring‐opening polymerizations, polycondensations in bulk, polycondensations in solutions, interfacial polycondensations and in vitro enzymatic polycondensations.     

Synthesis of Poly(lactide)s with Modified Thermal and Mechanical Properties

The use of poly(lactide)‐based materials is, in part, limited by their physical and mechanical properties. This article reviews the methods that have been employed to enable enhancement of the materials properties through synthetic manipulation of the polymer structure including block copolymer synthesis and modification of the lactide monomer structure, focusing on the application of ring‐opening polymerization. In turn the effect of these structural modifications on the properties of the resultant materials are reported.

     

Relaxation in Poly(alkyl methacrylate)s: Crossover Region and Nanophase Separation

Relaxations in a poly(alkyl methacrylate) series are systematically influenced by chemical modifications like the variation of side‐chain length, random copolymerization, or molecular weight. Recent results concerning the influence of chemical modifications on special parts of the relaxation chart are reviewed. The discussion is focused on two points: (i) The influence of chemical modifications on the crossover region of dynamic glass transition, where the relaxation times of α relaxation and Johari Goldstein mode β approach each other, is discussed. A general crossover scenario with a separate onset of cooperative α relaxation is observed for all lower members of this series. High temperature process a above and cooperative α relaxation below the crossover are shown to be distinct processes. Chemical modifications related to an increase in free volume shift this scenario mainly to lower frequency and temperature. Further details depend on the specific modification. (ii) The nanophase separation of incompatible main‐ and side‐chain parts in all higher members of the poly(alkyl methacrylate) series is discussed. This effect is concluded from the coexistence of two dynamic glass transitions in these homopolymers, the conventional a (or α) process and an additional low temperature glass transition α_PE . It is shown that the low T_g process is related to cooperative motions in the polyethylene‐like side‐chain parts. The existence of static nanodomains in the range 0.5 to 1.5 nm is confirmed by means of wide and small angle X‐ray scattering data. The estimated nanodomain size is compared with the size of dynamic heterogeneities estimated independently from calorimetric data for the polyethylene‐like glass transition using the fluctuation approach.     

Studies on the Phase Separation of Poly(Ether Imide)‐Modified Cyanate Ester Resin

Abstract

A high temperature thermosetting bisphenol‐A dicyanate (BADCy) was blended with a novel thermoplastic poly(ether imide) (PEI) at various composition. The phase separation behavior during isothermal curing was studied by differential scanning calorimeter (DSC), time‐resolved light scattering (TRLS), scanning electron microscopy (SEM), and rheological measurements. The results suggested that the phase structure changed from separated phase, via co‐continuous phase, to phase inversion with the increase of the PEI content. The curing conversion of BADCy was slightly affected by the composition in the blend and the curing rate was decreased with the increase of PEI content. The co‐continuous phase morphology was attributed to a spinodal decomposition. The initial concentration of PEI had an effect on the rheological behavior during phase separation. It was found by tensile test that the blend with 15 wt.% PEI had higher tensile strength and elongation at break than that without PEI.