一种含有高分子液晶超滤膜的制备与性能

将自制的一种主链聚酯型高分子液晶添加到聚砜铸膜液中,在温度为８０℃下,制成了对牛血清白蛋白截留率大于９０％的超滤膜,研究了高分子液昌的添加对所制超滤膜性能的影响。结果表明,在相同实验条件下,含高分子液晶超滤膜的截留率相对于不含高分子液晶的超滤膜有较大提高,从６０％～７０％提高到９０％以上,考察了相关制膜参数如溶剂、高分子液晶浓度、添加剂种类、用量、聚砜的浓度、铸膜气氛温度、蒸发时间等对含高分子液晶超滤膜性能的影响。     

新型聚醚砜/磺化聚醚砜共混超滤膜制备方法的研究

基于自制的磺化聚醚砜(SPES)溶液,直接将SPES溶液与聚醚砜(PES)共混配制铸膜液,制备新型的聚醚砜/磺化聚醚砜(PES/SPES)共混超滤膜,简化了制膜过程.考察了铸膜液中PES与SPES总固含量、凝固浴温度、预蒸发时间和添加剂对PES/SPES共混膜结构与性能的影响.研究发现,随铸膜液温度的降低和铸膜液中酸含量的增加,铸膜液的比浓黏度增加;制备的共混膜断面为致密皮层和多孔支撑层组成的不对称结构;随铸膜液PES/SPES总固含量的增加,共混膜的水通量降低,截留率升高;随凝固浴温度升高和预放置时间延长,共混膜水通量增加,截留率降低;聚乙二醇200(PEG200)和丙酮的加入有利于改善膜性能,当加入量为2%时,共混膜的水通量都高于460L/(m~2·h),对PEG6000截留率都大于85%.     

壳聚糖超滤膜的研究

以壳聚糖为原料，2％乙酸为溶剂，选择适当的膜液组成和制备条件，可以制得截留分子量为67000的超滤膜．该膜对0．1％牛血清蛋白的截留率可达90％以上．研究了铸膜液组成和若干因素对膜性能的影响．     

感光性丙烯腈共聚物超滤膜的制备

以感光性单体和丙烯腈共聚合成了共聚物膜材料，并制备出具有光敏特性的超滤膜；扫描电子显微镜图像显示所制备的高聚物膜具有超滤结构；膜的透过实验表明，所制备的膜具有较高的纯水通量及对蛋白质截留率，并初步探讨了铸膜液浓度对膜性能的影响．     

制膜工艺条件对PVC/SPES共混膜性能的影响

采用溶剂-非溶剂扩散致相分离的方法,在不同制膜条件下(铸膜液聚合物含量、铸膜液温度、凝胶浴温度和凝胶浴组成)制备了PVC/SPES共混膜,并对膜的纯水通量、截留率、断裂强度、耐污染性能和膜的断面结构等性能进行了测试,从而探讨制膜工艺条件对PVC/SPES共混膜微观结构及性能的影响.通过对不同聚合物含量的共混膜的纯水通量、截留率、机械性能和耐污染性能测试比较,得到PVC/SPES共混膜的最佳制膜条件:聚合物质量分数为16％,铸膜液温度为70℃,凝胶浴温度为20℃,凝胶浴为纯水.     

PMIA和氯化锂含量对PMIA平板超滤膜结构与性能的影响

研究了聚合物聚间苯二甲酰间苯二胺(PMIA)与LiCl的含量对PMIA平板超滤膜的结构和性能的影响,以DMAc为溶剂,氯化锂为致孔剂,制备了基于无纺布支撑的PMIA平板超滤膜,进行了聚合物PMIA及LiCl的含量对铸膜液黏度、膜的形貌结构、膜表面电势及分离性能的影响分析.结果表明,提高铸膜液中PMIA及LiCI的含量,铸膜液黏度均明显升高,膜断面海绵结构增多,孔隙率下降.制备的PMIA膜表面水接触角均低于70°,显示出良好的亲水性.超滤实验结果表明,PMIA与LiCl质量分数分别为14%及5%条件下制备的PMIA平板超滤膜,在0.1 MPa操作压力下,膜具有361.5 L/(m~2·h)的纯水通量及96.3%的BSA截留率.PMIA膜在100 mg/L BSA溶液超滤运行0.5 h后通量趋于稳定,初步研究表明PMIA膜具有良好的抗污染性能.     

CA/CTA共混不对称纳滤膜制备过程中的影响因素探讨

用相转化法制备ＣＡ／ＣＴＡ不对称纳滤膜．二醋酸纤维素（ＣＡ）和三醋酸纤维素（ＣＴＡ）的相对比例,混合溶剂以及其中高挥发性组分的比例,添加剂在铸膜液中的含量,铸膜液浓度以及制膜条件（蒸发时间,凝胶浴组成和温度,热处理时间）对所制膜的性能都有很大的影响．这些因素主要是通过改变皮层中高聚物聚集体孔和网络孔的大小和数目来影响所制膜的性能．高聚物聚集体孔的大小和数目对所制膜的通量和截留率起主要作用．     

改性聚偏氟乙烯超滤膜的制备与性能的研究

以接枝马来酸酐的改性聚偏氟乙烯(PVDF-g-MAH)为膜材料,采用浸没沉淀相转化方法制备超滤膜.在绘制PVDF-g-MAH-溶剂-水体系的三元相图基础上,研究并讨论铸膜液中溶剂体系、聚合物浓度以及添加剂浓度配比对膜性能和结构的影响,比较了接枝前后超滤膜的亲水性和抗污染性.研究结果表明:在聚合物-溶剂二元体系发生相分离过程中,4种溶剂体系所需非溶剂(水)的量的顺序为:DMAC>NMP>DMF>DMSO;以DMAC溶剂制备的铸膜液,制得的膜表面相对致密,纯水通量小,截留率高;随着聚合物浓度的提高,膜的通量下降,截留率提高;同时SEM照片也显示了随聚合物浓度的增加,超滤膜表层趋于致密,支撑层指状孔孔径缩小,孔数增多;超滤试验结果表明,在截留率相同的前提下,用PVDF制备的超滤膜纯水通量为104.6 L/(m2·h),而PVDF-g-MAH制得的超滤膜纯水通量为230L/(m2·h),同时对比了连续超滤BSA溶液12 h后的膜通量衰减状况,两种膜的通量的衰减率分别为36%和15.4%,表明以改性材料制备的超滤膜的亲水性和抗污染性能均得到提高.     

铸膜液成分对聚砜超滤膜的影响

以聚砜(PSF)为膜材料,以聚乙二醇(PEG)、聚乙烯吡咯烷酮(PVP,K30)为添加剂,以N,N-二甲基乙酰胺(DMAc)为溶剂,采用相转化法制备聚砜超滤膜。实验研究了铸膜液中PSF浓度、PEG浓度和PVP浓度对超滤膜性能的影响。正交试验结果表明,PSF浓度对超滤膜性能影响最为显著,PEG浓度的影响最不显著;PSF浓度对超滤膜3个性能指标的影响性均为高度显著;PVP的浓度对纯水通量有一定影响,对BSA通量和BSA截留率为无明显影响。实验最终确定最佳超滤膜铸膜液配比为:PSF浓度为15%(wt,质量分数,下同),PVP浓度为5%,PEG浓度为4%。     

乙醚对酚酞基聚芳醚砜超滤膜性能和结构的影响

以新型耐高温工程塑料——含酚酞侧基的聚芳醚砜(PES-C)为膜材料,N,N-二甲基乙酰胺(DMAc)为溶剂,加入一种易挥发添加剂:乙醚.通过改变铸膜液中添加剂乙醚的含量,采用相转化法在平板刮膜机上制备了一系列超滤膜,考察了添加剂乙醚含量对铸膜液黏度、凝胶速度、膜性能和结构的影响,研究了PES-C/DMAc体系中添加剂乙醚作用的规律.结果发现,乙醚的加入,会使溶剂对聚合物溶解能力降低.乙醚含量的增加,使铸膜液黏度增加,凝胶速度下降,水通量降低,截留率上升.所制备的超滤膜的结构为指状孔结构,但是随着乙醚用量的增加,皮层增厚,过渡层中指状孔减少.     

PPENK增韧改性BMI树脂体系的制备与性能

采用溶液法制备了杂萘联苯聚芳醚腈酮(PPENK)/双马来酰亚胺树脂(BMI)共混体系。通过差示扫描量热法(DSC)对共混体系固化反应动力学进行了研究,固化活化能为85.8 kJ/m2。采用冲击和拉伸实验考察了PPENK含量对共混体系力学性能的影响,共混体系的冲击强度为1.83 kJ/m2～2.95 kJ/m2,拉伸强度为68 MPa～84 MPa,拉伸模量为1.14 GPa～1.53 GPa。通过对固化物断面的扫描电镜(SEM)分析了增韧机理,改性后的BMI树脂在断裂时发生了塑性变形。通过热重分析法(TGA)研究了体系的耐热性,共混体系在氮气气氛中5%热失重温度为420℃～426℃。     

Properties and in vitro biological evaluation of nano-hydroxyapatite/chitosan membranes for bone guided regeneration

Nano-hydroxyapatite(n-HA)/chitosan(CS) composite membranes were prepared by solvent casting and evaporation methods for the function of guided bone regeneration (GBR). The effect of n-HA content and solvent evaporation temperature on the properties of the composite membranes was studied. The n-HA/CS membranes were analyzed by scanning electron microscopy, Fourier transformed infrared spectroscopy, X-ray diffraction, swelling measurement, mechanical test, cell culture and MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenylte-2H-tetrazolium bromide) assay. The results show that the surface roughness and micropores of the composite membranes increase with the rise of n-HA content, suitable for adhesion, crawl and growth of cells. The hydroxyapatite holds nano size and distributes uniformly in the composite membranes. Chemical bond interaction exists between Ca ions and –OH groups of n-HA and –NH₂ or –OH groups of CS. The n-HA content and solvent evaporation temperature have obvious influence on the swelling ratio, tensile strength and elongation rate of the composite membranes. Cell culture and MTT assays show that n-HA and its content can affect the proliferation of cells. The n-HA/CS composite membranes have no negative effect on the cell morphology, viability and proliferation and possess good biocompatibility. This study makes the n-HA/CS composite membrane be a prospective biodegradable GBR membrane for future applications.     

乙基纤维素平板膜用于O2—N2气体分离性能和结构研究

本文工作中选用乙基纤维素为膜材料,用无纺布做增强材质,考察了膜液浓度、添加剂种类及用量、蒸发时间、凝胶温度、热处理等因素对O_2-N_2分离性能的影响,并用扫描电镜观察所得膜的形态结构。     

新型杂萘联苯聚芳醚腈(酮)耐高温绝缘漆的研制

系统地研究了杂萘联苯PPEN（K）聚合物在绝缘漆领域的应用,考察了PPENK中腈、酮含量对绝缘漆性能的影响,发现当N／K=1／1时,绝缘漆具有优异的机械性能;对比了PPENK、PPENKK、PPEN和PPEN—BPA几种聚合物所制备的绝缘漆的性能,认为以PPENK树脂为主要成膜物制得的绝缘漆综合性能最优;在此基础上,选择适当的涂线工艺,成功地研制出了新型PPENK漆包线,其机械性能、电性能和热性能都远远高于220级聚酰亚胺漆包线国家标准要求。     

Separation of CO2 and CH4 through two types of polyimide membrane

Two asymmetric polyimide membranes that have a thermal stability up to 550 K and good resistance to solvents were prepared. Some membrane-forming conditions such as coagulation solution, evaporation and immersion time were examined. Regarding the coagulation solution, a water–methanol mixture gives good membranes in eleven solutions tested. The permeabilities of two asymmetric polyimide membranes for CO₂ and CH₄ pure gases were determined at 25°C and at applied pressures up to 0.25 MPa. The prepared polyimide membranes, 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA)-4,4′-diaminodiphenyl ether (ODA) and 1,2,3,4-butanetetracarboxylic dianhydride (BDA)-4,4′-diaminodiphenyl ether (ODA) exhibited higher selectivity and permeability for CO₂/CH₄.     

Influence of preparation procedure and ferric oxide nanoparticles addition on transport properties of homogeneous cation-exchange SPPO/SPVC membrane

Homogeneous cation-exchange membranes were prepared through evaporation and phase inversion methods using sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO) and sulfonated polyvinylchloride as binders. The effect of polymers blend’s ratio and preparation method on structure and electrochemical properties of the prepared membranes were evaluated. The microstructures of the membranes were investigated by scanning electron microscopy (SEM) and the sulfonation of polyvinylchloride was confirmed by elemental analyses. Moreover, the membranes performance was evaluated by ion-exchange capacity (IEC), fixed ion concentration, membrane potential, transport number, permselectivity, areal resistance, ionic permeability, flux of ions, current efficiency, membrane oxidative stability, mechanical properties and water content tests. The results indicated that IEC and water content were affected by the SPPO content and microstructures of the membranes. The results showed increased efficiency and suitable electrochemical properties for membranes prepared by the evaporation method in comparison with others. Also, \(\hbox {Fe}_{2}\hbox {O}_{3}\) nanoparticles were synthesized at room temperature by a simple sonochemical reaction between ferric chloride and NaOH. The results revealed that the addition of different amounts of \(\hbox {Fe}_{2}\hbox {O}_{3}\) nanoparticles to the polymeric matrix could affect the hydrophilicity and transport properties of ion-exchange membranes.     

退火对有序孔洞氧化铝膜荧光性能的影响

用阳极氧化法在草酸溶液或硫酸溶液中制备了有序阵列孔洞的氧化铝膜．研究了在不同温度下、不同气氛中退火对多孔氧化铝膜荧光性能的影响．结果表明,随着退火温度的升高,发光带的强度也随之增强;与此同时,发光带的峰位出现蓝移．当退火温度Ｔ_ａ＝５００℃时,在草酸中制备的氧化铝膜的发光强度最强;而在硫酸中制备的膜,其发光最强的退火温度为４００℃．当 Ｔ≤４００℃时,氧化铝膜的发光强度基本上与退火气氛无关;当 Ｔ_ａ＝５００℃时,在草酸中制备的膜在空气中退火后的发光强度高于在真空中退火后的发光强度．在草酸中制备的氧化铝膜的发光带明显比在硫酸中制备的膜强得多．电子自旋共振的实验结果表明,蓝光发光带来自多孔氧化铝膜中的Ｆ^＋心．我们还对多孔氧化铝膜发光特性的机制进行探讨．     

Screening the fabrication conditions of ultrafiltration membranes by using the uniform design and regression analysis methods

In this work, the concerned casting conditions for the fabrication of the ultrafiltration (UF) membrane from polysulfone were the gelation medium used, the temperature of the gelation bath, the gelation period, and the evaporation time of the cast sheet. The uniform design method was applied to substantially reduce the number of experiments for studying the influence of each of four casting conditions introduced in the preparation of UF-membranes. The pure water flux and the molecular weight cutoff (MWCO) of each of the four macromolecule-standards, namely egg white lysozyme, egg white albumin, bovine serum albumin and bovine γ-globulius, of each prepared UF-membrane were determined. These experimental responses were then analyzed by using a non-linear model with the backward regression method. The results of this work showed that the uniform design-non linear model (UD-NLM) method can substantially reduce the number of experimental runs for predicting the influences of the studied casting conditions on the ultrafiltration performance of the prepared asymmetric polysulfone membranes.     

Influence of Aging on the Physical-Mechanical Properties of Acrylic Resin Films Cast from Aqueous Dispersions and Organic Solutions

The physical-mechanical properties of the enteric copolymers, poly(methacrylic acid, ethyl acrylate) Eudragit® L100-55, and Eudragit® L30D have been investigated. Free films of the copolymer containing varying levels of glyceryl triacetate (triacetin) and citrate ester (Citroflex®) plasticizers were prepared by both aqueous and solvent casting techniques. Conditioned films were stored at different humidities and temperatures for predetermined time periods prior to testing. Free films with plasticizer concentration ranging from 0 to 30% by weight of the polymer demonstrated that physical aging at room temperature resulted in physical-mechanical changes as the stress-strain curves indicated a decrease in the percent elongation with increases in the tensile strength. Films prepared from the aqueous latex approached a constant state of equilibrium at a faster rate than films prepared from isopropyl alcohol, where the mechanical properties approach a relatively constant value. Free films containing varying amounts of the plasticizer, triethyl citrate, were stored under different humidity and temperature conditions. In addition, a headspace-gas chromatography (HSGC) method was developed to correlate solvent residues with mechanical properties. The results indicated that an increase in temperature and humidity accelerated the rate of solvent evaporation as a function of time. High vacuum and low humidity conditions were demonstrated to be ineffective conditions for solvent removal. Solvent residues were found in all films after 48 hours of exposure to temperatures up to 60°C and/or exposure to relatively high humidity conditions. A direct relationship between plasticizer content and rate of solvent evaporation from the film was established. Higher concentrations of the plasticizer were found to augment the evaporation of the solvents. This enhanced evaporation was due to the stronger molecular interaction forces between the polymer and the plasticizer than between the polymer and the solvent.     

Preparation Methods of Biodegradable Microspheres on Bovine Serum Albumin Loading Efficiency and Release Profiles

The solvent evaporation and multiple phase methods for preparing poly-(d, l) lactide microspheres of bovine serum albumin (BSA) were compared. The effects of poly (vinyl alcohol) concentration and external aqueous phase temperature on the loading efficient of BSA microspheres prepared by multiple phase emulsion method were evaluated as well. The BSA loading efficient of microspheres by multiple phase emulsion method was much higher than that by solvent evaporation method. The high aqueous solubility of BSA contributes to the low loading efficieny in the solvent evaporation method, suggesting that this method is inappropriate for proteins with high water solubility. The loading efficieny of microspheres, whcih were prepared by multiple phase emulsion method, increased with PVA concentration but decreased with external aqueous phase temperature. The burst phenomenon of release profiles of microspheres was influenced by poly (vinyl alcohol) concentrations and the external aqueous phase temperature. Considering the duration sustained release, 0.5% w/v of poly (vinyl alcohol) is most appropriate among the concentrations tested for preparing BSA microspheres by multiple phase emulsion method.