Structure and Properties of Polyurethane/Polyvinylidene Difluoride Blending Hollow Fiber

IntroductionMembrane with the property of pressure-responsibili-ty ,PR,is one kind of membranes , and the pores of thismembrane can be changed reversibly with pressure in a se-paration system. This thus provides the membrane with agreat deal of advantages . For example ,the first is that thePR membranes can separate different masses by varyingpressures relating to its varying pore sizes ,and the secondis the regeneration of a fouled PR membrane easily becausethe pores could be enlargedin cle…     

Rheological Properties of Soy Protein Isolate and Polyurethane in the PAN/DMSO Solution

The rheological properties of soy protein isolate (SPI) and polyurethane (PU) in the PAN/DMSO solution were investigated in this study. The results showed that all these solutions possessed pseudo-plastic solution properties. There are opposite effects of SPI and PU in the PAN/DMSO solution. Their apparent viscosity, degree of non-Newtonian fluid, and extent of structuralization of blend system increase with the addition of SPI, whereas, all of these decrease with the addition of PU. Moreover, the rheologic...     

Swelling behaviors and pervaporation properties of CA/PAN composite membranes for separation of caprolactam/water mixtures

The composite membranes with cellulose acetate (CA) as the separating layer material and polyacrylonitrile (PAN) as the supporting layer material were prepared for separating caprolactam (CPL) from CPL/water mixtures by pervaporation technique. The swelling experiments were carried out to investigate the effects of swelling time and CPL concentration on the degree of swelling. The results showed that the CA membrane reached swelling equilibrium within 24 h, and the degree of swelling first slightly decreased then increased with the increase of CPL concentration in the feed under the experimental conditions. Respectively comparing flux with permeance, and separation factor with selectivity, we found out that the separation performance of the CA/PAN composite membrane is more strongly dependent on its hydrophilic/hydrophobic nature as well as on the effects of operating parameters, such as feed composition concentration and feed temperature.     

聚丙烯腈超滤膜低温氧等离子体表面改性

研究了聚丙烯腈 (PAN)平板超滤膜的低温氧等离子体表面改性 .结果表明 ,改性后的 PAN超滤膜透水率降低 ,截留率上升 .研究了低温等离子体条件 (放电功率、反应腔压力、改性处理时间 )对改性结果的影响 .实验研究表明 ,低温等离子体表面改性技术可用于 PAN超滤膜的改性 .     

Structure and Properties of Polytetrafluorethylene and Polyurethane Layered Membrane for Protective Clothing

IntroductionProtective clothing articles used for wear in wetconditions ; in outdoor activities ; in handling hazardouschemicals , in preventing contamination, in avoidinginfection, should in each instance protect the wearer bypreventing leakage of water or other fluids andmicroorganisms into the article while keeping the wearercomfortable by allowing perspiration to evaporate from thewearer to the outside of the article .In additionto the above ,the amount of stretch and its recovery and the …     

大豆分离蛋白/二氧化硅改性水性聚氨酯膜性能的研究

采用溶胶-凝胶法制备了大豆分离蛋白/二氧化硅杂化溶胶,并应用于水性聚氨酯的改性.采用流延法制备大豆分离蛋白/二氧化硅/水性聚氨酯共混膜,红外光谱研究表明大豆分离蛋白、二氧化硅和水性聚氨酯间发生了多层次的氢键作用,以膜的拉伸强度、断裂伸长率和溶失率为指标,研究了各组分混配比例对共混膜力学性能及耐溶剂性能的影响.通过接触角、热重分析、扫描电镜和原子力显微镜分析讨论了共混膜的亲水亲油性、耐热性能,以及膜表面的形态形貌.结果表明,大豆分离蛋白/二氧化硅添加量为6％（质量分数）、两者之间质量比为1∶1时,改性膜的力学性能最优,耐溶剂性随添加量增加而改善.     

改性聚酰亚胺膜的水蒸气渗透性和空气除湿性能

考察了改性聚酰亚胺(P I)膜的亲水性、水蒸气渗透性、制膜混合溶液的表观粘度。结果表明:随着季胺盐含量的增加,膜的亲水性增强,水分子的渗透系数增加,同时水分子的渗透受膜的厚度和相对湿度的影响,制膜混合溶液的表观粘度增大,出现了盐增粘现象。测试了一系列共混改性中空纤维膜组件的除湿性能,增大压力和增加吹扫气流量,对组件除湿十分有利,尽管在低吹扫气量的情况下,组件的除湿性能并不是一直随着膜的亲水性增强而提高,但是适当增加亲水性盐的含量,膜的除湿性能会得到有效改善。     

小截留分子量共混超滤膜的研究(Ⅲ)--PVDF与PVAc共混超滤膜的后处理及化学稳定性比较

以聚偏氟乙烯 (PVDF)和聚醋酸乙烯酯 (PVAc)共混 ,采用相转化法制备亲水性小截留分子量共混超滤膜 .对PVDF和PVAc共混前后超滤膜化学稳定性进行比较 .结果表明 ,共混超滤膜具有良好的化学稳定性 .在相同截留率的前提下 ,用弱溶剂后处理 ,共混超滤膜的水通量得到较大程度的提高 .     

高分子量聚丙烯酸改性聚乙烯醇膜的耐水性能

将高分子量聚丙烯酸（PAA）与聚乙烯醇（PVA）混合,制备成PAA/PVA混合膜并对其进行热处理。考察了PAA分子量及其含量对混合膜耐水性能的影响,研究了热处理工艺条件对混合膜在沸水环境下的保留率。结果表明,随着PAA分子量和在混合膜中含量的增加,混合膜的耐沸水性能显著提高;当PAA加入量为30%（质量分数）,热处理温度和时间分别为160～180℃、3～5min时,混合膜的综合性能最佳;热处理后混合膜的玻璃化转变温度T_g提高到102℃,有效扩大了膜的使用温度范围。     

戊二醛交联PVA/PAN复合膜渗透汽化性能的实验研究

研究了戊二醛交联时间对PVA/PAN复合膜分离性能的影响,并用于乙醇水溶液的分离。结果表明,交联处理存在着最优时间。对应于最优交联时间的膜,当料液中乙醇质量分数(wE)为96.2%,料液温度(t)为70℃时,渗透通量(J_t)为337(g·m^-2·h^-1),分离因数(α_W/E)为389.7。进一步考察了料液质量分数为30%～98.3%,料液温度为50～78℃时,交联膜的分离性能。     

MDI对聚氨酯／聚乳酸热塑性弹性体的增容作用

以生物材料聚乳酸（PLA）、聚氨酯（PU）弹性体为原料,4,4’-二苯基甲烷二异氰酸酯（MDI）为增容剂,制备了共混型热塑性弹性体（PU／PLA TPV）;研究了MDI对PU／PLA TPV性能的影响。结果显示：MDI能明显提高PU／PLA TPV力学强度,当MDI用量为7份时（PU100,PLA60,DCP3,SA1,均为质量份）,PU／PLA TPV综合性能最佳;MDI可改善PU／PLA TPV耐热性能,并且提高PU的玻璃化转变温度;通过SEM观察,增加MDI用量,PU／PLA TPV试样的断面表现出“脆-韧”转变;通过FTIR分析,MDI上的异氰酸根与PLA的羟基能够发生化学键合反应,使PLA与PU之间的界面张力减小,PU与PLA的相容性提高。     

丙烯酸改性水性聚氨酯结构设计及其规律

采用丙烯酸树脂（ＰＡ或ＰＡ′） 对水性聚氨酯（ＰＵ） 改性,研究了经丙烯酸树脂改性的水性聚氨酯的结构设计及其规律．结果表明,通过ＰＵ分子链与ＰＡ分子链形成化学键,能使材料中ＰＵ 分子链与ＰＡ分子链具有较高的相容性和共混程度;采用机械共混方式,能使机械共混物ＰＵ 分子链、ＰＡ 分子链之间达到有限的共混程度;实施核壳型聚合方式,能使材料ＰＵ分子链与ＰＡ或ＰＡ′分子链之间处于一定的微相分离状态．     

电场作用下PAN/PS共混膜特性的研究

以分子量67000的牛血清蛋白为超滤分离对象,通过膜通量、截留率、膜通量衰减程和恢复率等膜参数的测定,考察了外加直流电场作用聚丙烯腈/聚砜共混膜的分离性能。结果表明：外加正电场共混膜的膜通量和截留率都有所提高,+120V/cm时,分别提高了85％和1.1％,而膜通量衰减程度,在+60V/cm时,由 57.14％降低到26.33％,经过“电场自洁净”的共混膜其膜通量的恢复率可达到90％以上,能较大地改善膜的抗污染性能。     

聚乙烯醇／聚氨酯共混薄膜制备及性能研究

采用流延成膜的方法制备了聚乙烯醇（PVA）／聚氨酯（PU）共混薄膜．当PU摩尔分数小于10％时，可得均一连续的共混膜．通过扫描电子显微镜（SEM）、原子力显微镜（AFM）、示差扫描量热仪（DSC）、拉伸测试及表面接触角测试等手段对PVA／PU共混膜的形貌及性能进行了研究．实验结果表明，PU可以与PVA形成分子间氢键，破坏了PVA分子内及分子间氢键，进而改善PVA薄膜的性能．     

Influence of the Surfactants on Microstructure and the Properties of Wet Coagulation Polyurethane Film.

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聚芳硫醚砜纳滤膜的制备及耐溶剂特性表征

以聚芳硫醚砜（PASS）为材料,采用浸没沉淀相转化法制备出平板纳滤膜,研究了制膜过程中工艺参数如聚合物浓度等对膜结构与分离性能的影响,确定最佳制膜条件为：聚合物质量分数22%,刮膜温度80℃,滞空时间0s,凝固浴为纯水。在0.5MPa压力下,最佳条件下制备膜的纯水通量为50.0L/(m ²·h),质量分数为0.01%的刚果红水溶液通量为47.6L/(m ²·h),对刚果红截留率为96.0%。耐溶剂实验结果表明,有机溶剂包括甲苯、二乙醚、甲醇、乙酸乙酯、正己烷和酸碱处理（pH=0～14）对PASS膜通量有较大影响,而对截留率影响不明显,显示出膜具有良好的耐溶剂特性。     

高性能TDE-85/E-51环氧树脂的聚氨酯增韧改性

以混合芳胺为固化剂,通过聚氨酯（Pu）对4,5-环氧环己烷-1,2-二甲酸二缩水甘油酯（TDE-85）与二酚基丙烷缩水甘油醚（E-51）环氧树脂的混合树脂体系的改性,制备了高性能聚氨酯改性环氧树脂（PU／EP）。通过红外光谱图、扫描电镜（SEM）、热重（TG）分析及力学性能的表征讨论PU／EP体系的结构与性能特征。研究结果表明：PU和EP分子链之间存在着化学接枝反应,能有效地改善PU／EP体系中PU和EP分子间的相容性及相互贯穿;与TDE-85与E-51的混和环氧树脂比,PU改性TDE-85与E-51的混和环氧树脂仍然具有很强的耐热性能,并且冲击强度、拉伸强度均获得显著提高;PU／EP体系断口裂纹呈明显的韧性断裂特征,说明TDE-85与E-51的混和环氧树脂PU改性增韧效果明显。     

聚氨酯微孔膜的防水透湿性及电镜分析

以聚氨酯微孔膜的电膜照片，分析在不同组成和不同的成型条件下制取的膜的结构和性能，得到了采用配比为１０／０５／０５的ＮＮ二甲基甲酰胺／四氢呋喃／乙二醇的混合溶剂和高温分级快干条件下形成的ＰＵ膜．该膜具有细密微孔结构和优良的防水透湿性     

管式超滤器澄清柠檬汁的研究

本文研究了超滤法生产柠檬澄清汁的可行性，探讨了膜孔径、温度、压力对澄清汁透液通量和成分的影响。试验结果表明：选用切割分子量为３万的聚丙烯腈膜，在温度５０℃、平均压力０．２２ＭＰａ条件下，能得到稳定的、色泽风味俱佳的澄清汁，其平均透液通量为１８．１６ｋｇ／ｍ２·ｈ。污染的超滤膜用化学清洗液低压湍流清洗，在１小时内，透水通量能恢复到９５％以上。     

Enhancement of the thermal and mechanical properties of polyurethane/ polyvinyl chloride blend by loading single walled carbon nanotubes

Structural, thermal, and mechanical properties of pure blend and nanocomposites based on polyurethane (PU) and polyvinyl chloride (PVC) doped with low different content of single walled-carbon nanotubes (SWCNTs) were studied. The nanocomposites at different concentration were prepared via casting technique. The interaction between PU/PVC and CNTs were examined via FT-IR studies. The changes in the structures of the nanocomposites were examined using X- Ray Diffraction (XRD), and the results indicated that the amorphous domains of nanocomposites increased with increasing SWCNTs content. Transmission electron microscope (TEM) observation indicated that SWCNTs surface was wrapped with the polymer with the thermal properties of nanocomposites improved. The mechanical behavior of the nanocomposites was evaluated as a function of SWCNTs content. The main enhancement in tensile properties was observed, e.g., the tensile strength and elastic modulus increased compared with the pure blend, which may be attributed to the interaction and adhesion between CNTs and the polymer matrices due to the hydrogen bonding between carbonyl groups (C=O) of polymer blend chains and carboxylic acid (COOH) groups of CNTs.