PAN/PS共混超滤膜的制备及性能研究

采用共混法制备聚丙烯腈(PAN)/聚砜(PS)超滤膜,以聚丙烯腈作为第一组分(连续相),聚砜为第二组分(分散相),用相转化法流延成膜;研究共混比、聚合物浓度、添加剂、凝胶浴等对共混膜水通量和截留率的影响,并采用扫描电镜对膜的结构形态进行了观察。结果表明:PAN/PS共混膜与PAN膜具有相似的化学稳定性,但较PAN膜具有更好的分离透过性。     

聚丙烯腈/醋酸纤维素共混超滤膜的研制与改性

研究了聚丙烯腈 /二醋酸纤维素 (PAN/CA)共混超滤膜的性能与聚合物共混比、聚合物质量分数等的关系 .结果表明 ,加有氯化锂 (LiCl)的二甲基乙酰胺 (DMAC)是PAN/CA共混体系的良溶剂 .当聚合物的质量分数为 14 % ,PAN/CA共混比为 5 0 / 5 0时 ,所制得的共混超滤膜的性能较好 .对共混超滤膜进行水解改性的实验发现 :膜的截留率上升 ,水通量下降 .用酱油、药酒为料液的超滤实验表明 :共混膜和水解改性膜的耐污染性能优于聚丙烯腈 (PAN)、聚砜 (PS)和磺化聚砜 (SPS)膜     

PVDF/PAN共混膜及其水解后pH值响应行为研究

对聚偏氟乙烯(PVDF)/聚丙烯腈(PAN)共混体系的相容性进行了分析,通过溶液相转化法制备了PVDF/PAN共混膜,研究了共混比对膜性能的影响,通过红外和DMA探讨了PVDF与PAN之间的相互作用。结果表明,PVDF/PAN为部分相容体系,二者在成膜过程中存在相互作用,显著提高了共混膜的水通量;在碱性条件下,对所得共混膜进行水解,制得水通量随测试体系pH值变化的共混膜,探讨了其水通量的pH值响应程度与PVDF/PAN共混体系组成变化之间的关系。     

淀粉/聚丙烯腈共混改性纤维的研究

以二甲基亚砜(DMSO)/二甲基乙酰胺(DMAc)为复合溶剂,制备了淀粉(St)/聚丙烯腈(PAN)共混纺丝溶液,纺制了St/PAN共混改性纤维,分析和讨论了St/PAN纺丝溶液的混溶性,初步研究了St/PAN共混改性纤维的性能.结果表明,虽然St与PAN热力学不相容,但选用适当的复合溶剂,仍可制得具有较好动力学稳定性和纺丝可纺性的溶液,进而制备力学性能较好的St/PAN共混改性纤维.     

蔗糖对聚丙烯腈膜的共混改性研究

用蔗糖对聚丙烯腈(PAN)膜进行共混改性,利用相转化法制得PAN共混膜。研究了PAN用量、蔗糖用量、添加剂的种类和用量及凝固浴的种类等制膜条件对PAN共混膜的结构和性能的影响。结果表明:当PAN用量为12%(wt,质量分数,下同),蔗糖用量为6%,添加剂聚乙二醇用量为2%,凝固浴为纯水时,制得的PAN共混膜的水通量和孔隙率最大分别达到421L/m~2·h和85%。     

PAN/CA共混复合膜的气体分离与力学性能

聚丙烯腈（PAN）具有较高的气体渗透性,但拉伸强度低,不适宜直接制膜。为达到气体分离膜在力学强度方面的使用要求,利用PAN与乙酸纤维素（CA）共混改善其拉伸性能。结果表明,采用相转化法制备的PAN/CA共混基膜,随着CA与PAN共混比的增加,拉伸强度有明显的上升趋势,由1.74MPa增加到2.08MPa。当共混比为0....     

聚砜—聚醚砜共混膜相容性及凝胶特性研究

研究了聚砜（PSF）与聚醚砜（PES）共混膜的相容性及其凝胶特性．首先,通过计算PSF－PES共混体系的混合热,从理论上预测该共混体系相容性,并用反相气相色谱法（IGC）测定相互作用参数．研究PSF－PES共混体系相容性与组成的关系;通过粘度测定研究了共混制膜液的溶混性;探讨了共混制膜液的凝胶特性．研究结果表明,PSF－PES共混体系为部分相容体系,且其溶混性与组成有关,共混可明显改变制膜液的凝胶特性．     

PVC/PAN共混膜的制备与性能

采用溶液相转化法制备了聚氯乙烯(PVC)/聚丙烯腈(PAN)共混膜,研究了(PVC)/(PAN)共混体系的相容性,并通过红外光谱(FT-IR)、扫描电子显微镜(SEM)等对PAN水解前后共混膜结构、形貌和性能进行了表征与分析。结果表明,(PVC)/(PAN)为部分相容体系,在成膜过程中产生明显界面微孔结构;共混膜中的PAN发生水解后,生成大量酰胺、羧酸、羧酸盐等亲水基团,改善了共混膜的亲水性(膜的水接触角从87.48°降低到65.12°),提高了共混膜的通透性(膜的纯水通量从84.17 L/(m2.h)升高到343.7 L/(m2.h))。     

高剪切应力对PS/SEBS/CaCO3材料力学性能影响

采用在材料熔融挤出共混过程中提高双螺杆挤出机螺杆转速的方法,研究了较高螺杆转速条件下双螺杆挤出机的高剪切应力对PS/SEBS/CaCO3共混材料力学性能的影响。结果表明,双螺杆挤出机的高剪切应力可促进SEBS橡胶颗粒和碳酸钙颗粒聚集体的分散、引发聚苯乙烯(PS)、SEBS分子链的断链反应、形成大分子自由基、产生原位增容作用,并引起共混材料力学性能的明显改善。在220℃的挤出温度下,当螺杆转速由120 r/min提高至960 r/min时,其PS/SEBS/CaCO3共混材料的缺口冲击强度将由5.7 kJ/m2提高至11.0 kJ/m2,同时共混材料的拉伸强度和弯曲强度也获得一定的增加。双螺杆挤出机的熔融挤出温度对PS/SEBS/CaCO3共混材料力学性能的影响存在最佳值。     

DMFC用磺化聚醚醚酮/聚苯胺共混型质子交换膜的研究

磺化聚醚醚酮膜(SPEEK)是直接甲醇燃料电池(DM FC)用质子交换膜的候选材料之一,但是当温度和磺化度(D S)较高时,该膜在甲醇水溶液中溶胀非常严重,甚至溶解,其使用温度受到限制。将磺化度为50.11%的SPEEK和聚苯胺(PAN I)共混制膜,希望利用酸碱之间的相互作用对SPEEK进行改性。研究结果表明,PAN I的加入使SPEEK/PAN I共混膜的使用温度有较大提高,并且该膜还具有较高的电导率和较好的阻醇性能。     

聚偏氟乙烯/聚丙烯腈共混超滤膜的研究

讨论了聚偏氟乙烯／聚丙烯腈共混体系的相容性,对ＰＶＤＦ／ＰＡＮ共混体系的相容性进行了理论分析和相容性预测,并通过实验对相容性进行了评价。结果表明,ＰＶＤＦ／ＰＡＮ属部分共混体系。利用该体系可制得性能优良的ＰＶＤＦ／ＰＡＮ共混超滤膜,讨论了铸膜液的组成、制膜条件对膜性能的影响。并对膜性能和膜结构进行了测试。得到了较好的结果。     

PVC/PVDF/PMMA共混膜的研制

采用剪切黏度法对聚氯乙烯(PVC)/聚偏氟乙烯(PVDF)/聚甲基丙烯酸甲酯(PMMA)体系的相容性进行研究,结果表明,该体系为部分相容体系,在此基础上采用稀溶液黏度法对各共混配比的相容性进行预测.对相容性较好的PVC/PVDF/PMMA共混体系由相转化法制备共混膜,并用扫描电镜对共混膜的形态结构进行了观察.对共混膜的...     

Effect of membrane hydrophilization on ultrafiltration performance for biomolecules separation

This paper compares the performance of different hydrophilization methods to prepare low fouling ultrafiltration (UF) membranes. The methods include post-modification with hydrophilic polymer and blending of hydrophilic agent during either conventional or reactive phase separation (PS). The post-modification was done by photograft copolymerization of water-soluble monomer, poly(ethylene glycol) methacrylate (PEGMA), onto a commercial polyethersulfone (PES) UF membrane. Hydrophilization via blend polymer membrane with hydrophilic additive was performed using non-solvent induced phase separation (NIPS). In reactive PS method, the cast membrane was UV-irradiated before coagulation. The resulting membrane characteristic, the performance and hydrophilization stability were systematically compared. The investigated membrane characteristics include surface hydrophilicity (by contact angle /CA/), surface chemistry (by FTIR spectroscopy), and surface morphology (by scanning electron microscopy). The membrane performance was examined by investigation of adsorptive fouling and ultrafiltration using solution of protein or polysaccharide or humic acid. The results suggest that all methods could increase the hydrophilicity of the membrane yielding less fouling. Post-modification decreased CA from 44.8 ± 4.2^o to 37.8 ± 4.2^o to 42.5 ± 4.3^o depending on the degree of grafting (DG). The hydrophilization via polymer blend decreased CA from from 65^o to 54^o for PEG concentration of 5%. Nevertheless, decreasing hydraulic permeability was observed after post-modification as well as during polymer blend modification. Stability examination showed that there was leaching out of modifier agent from the membrane matrix prepared via conventional PS after 10 days soaking in both water and NaOH. Reactive PS could increase the stability of the modifier agent in membrane matrix.     

Plasma modification of polyacrylonitrile ultrafiltration membrane

Polyacrylonitrile (PAN) ultrafiltration (UF) membranes were modified by plasma treatments and plasma polymerization. Influences of plasma modifications on membrane characteristics were investigated. The obtained results indicated that plasma treatments using non-polymer-forming plasma gases such as Ar, He and O₂ led to the increase of membrane surface hydrophilicity and membrane permeability. By using O₂ plasma treatment, UF property of PAN membranes could be improved with the enhancement of membrane flux meanwhile its albumin rejection was almost maintained. The experimental results also showed that plasma polymerization using acrylic acid vapor as monomer and PAN UF membrane as a substrate led to the formation of reverse osmosis membrane due to the deposition of plasma polymer layer onto substrate membrane surfaces. Plasma techniques can control membrane pore size and have a potential to improve the membrane characteristics by using their advantages.     

多元合金超滤膜研制

主要研究了聚醚砜（PES）,聚砜（PSF）和磺化聚砜（SPSF）共混所形所的多元合金超滤膜的性能和膜的孔径分布特性,初步探讨了多元合金超滤膜的成孔机理,并对共混体系的组成及相容性与合金超滤膜性能问题的关系作了详细讨论,研究结果且明,共混可明显改善超滤膜的孔径分布和膜的孔结构,为制备高性能越滤膜提供一种有效途径。     

Study on the interfacial micro-voids of poly(vinylidene difluoride)/polyurethane blend membrane

The poly(vinylidene difluoride)/polyurethane (PVDF/PU) blend membrane was prepared using the method of immersion-precipitation process. The influence of the miscibility of the two polymers on the formation of the interfacial micro-voids (IFMs) of the blend membranes was analyzed by the theory of thermodynamics and discussed with DMA, DSC and SEM. The effect of working pressure on the pure water flux (PWF) of the IFMs was also studied using membrane instrument. Results show that the IFMs are formed due to the miscibility of PVDF and PU. The existence of IFMs attributes much to the PWF of the PVDF/PU blend membrane, and the PWF of the IFMs is related not only to the miscibility of PVDF and PU but also to the deformation of IFMs under working pressure.     

用鸡蛋清中的卵清蛋白测定常用超滤膜的切割分子量

提出了一种测定超滤膜切割分子量的简便方法,该法以鸡蛋清代替生化试剂作为标准分子量蛋白质,以卵清蛋白的截留率而不是截留率一分子量曲线作为判据来确定膜的切割分子量,切割分子量的确定范围为1万～6万．讨论了配制卵清蛋白溶液的适宜pH范围为10～11,实际使用质量分数为0．03％NaOH溶液即可;证明了用生化试剂和鸡蛋清配制的卵清蛋白溶液具有相同的分光光度性质,共享同一条浓度-吸光度工作曲线;阐明了比尔定律的适用范围,只需控制超滤前溶液的起始吸光度E。＝0．200左右就可用吸光度代替浓度计算膜对蛋白质的截留率;测定了不同鸡蛋中的卵清蛋白含量在10％～15％之间,同一只鸡蛋的蛋清中卵清蛋白的含量分布是相当均匀的;用已知切割分子量的膜测定了对卵清蛋白的截留率,并据此提出了确定切割分子量的判据;用细胞色素C的截留率证明了本法的适用性;还证明了用0．03％NaOH溶液配制的卵清蛋白溶液可在4～5℃下存放2～3周．