聚四氟乙烯拉伸微孔膜制备工艺探索

介绍了聚四氟乙烯拉伸微孔膜的制备方法、成孔机理及结构特征;对国内外聚四氟乙烯拉伸微孔膜加工工艺研究进展进行了归纳总结,并指出了不同工艺参数下制备的膜材料的特征及性能;展望了聚四氟乙烯拉伸微孔膜的发展前景。     

聚四氟乙烯拉伸微孔膜的结构与性能

通过挤出、压延和拉伸等工序制备了聚四氟乙烯微孔膜，采用扫描电镜（SEM）分析了微孔膜的微观结构；采用差示扫描量热法（DSC）和广角X衍射（WXRD）表征了拉伸前后聚四氟乙烯结晶度的变化；研究了拉伸温度、拉伸倍率和拉伸速率对微孔膜力学性能的影响。结果表明：聚四氟乙烯微孔膜具有小岛状结点和与拉伸方向平行的微细纤维组成的微观结构；拉伸使PTFE的结晶度显著降低；拉伸工艺是制备微孔膜的关键因素，拉伸温度220～320℃，拉伸倍率为8倍时，微孔膜的最大拉伸强度可达8．5MPa；此外较大的拉伸速率可获得尺寸分布更均匀的微孔。     

一种透湿型病毒阻隔聚四氟乙烯复合膜的制备方法

本发明涉及一种透湿型病毒阻隔聚四氟乙烯复合膜的制备方法,其步骤是：先将一条聚四氟乙烯双向拉伸微孔膜均匀地附着在一条织物型基带上,所述聚四氟乙烯双向拉伸微孔膜两侧边通过粘接胶条与所述织物型基带粘接固定;然后使用涂层机将透湿型聚氨酯或嵌段聚醚酯溶液连续均匀地涂覆在所述聚四氟乙烯微孔膜上,     

PTFE微孔薄膜在油水分离中的应用研究

研究了疏水性聚四氟乙烯(PTFE)微孔膜的结构、润湿性、可重复使用性以及在不同温度、pH下对煤油、汽油和柴油的分离速率的影响。结果表明,在常温下,PTFE微孔薄膜对含油废水中油的去除率可达90%以上;PTFE微孔薄膜油水分离速率不受含油废水中pH的影响,但随着温度的升高而加快;对不同的含油废水有着不同的分离速率,其中对汽油的分离速率最高,稳定后可达800 L/(m2.h),煤油次之,对柴油的分离效率最低,低至稳定后为650L/(m2.h)。另外,由于PTFE微孔膜采用的是表面过滤的方式,所以膜具有非常好的可重复使用性,是一种非常理想的油水分离膜。     

功能化聚四氟乙烯微孔膜的研究进展

功能化PTFE微孔膜兼具PTFE微孔膜的优异特性及功能高分子的特殊性能,选择性透过、催化、传输药物、抗菌、质子交换等特殊功能的聚四氟乙烯（PTFE）微孔膜极具应用潜力。本文综述了PTFE微孔膜的特性,总结了近年来采用辐射接枝、表面沉积、涂覆或共混等方法功能化PTFE微孔膜的最新研究进展及其在化工、医学、服装、电子等领域功能化应用的最新成果,并指出目前存在的问题,对今后的研究提出了展望。     

PTFE/ZrO2复合微孔膜结晶性能的研究

以聚四氟乙烯（PTFE）乳液为原料,选定化学稳定性、热稳定性优异的纳米二氧化锆（ZrO2）为增强剂,制备出PTFE/ZrO2复合微孔膜,并通过X射线衍射仪对PTFE/ZrO2复合微孔膜样品的结晶性能进行了表征,使用单因素法讨论了ZrO2的含量、拉伸倍数、热处理温度及热处理时间等因素对PTFE/ZrO2复合微孔膜结晶性能的影响。结果表明,复合微孔膜的结晶度与拉伸倍数、热处理温度和热处理时间成正比,与ZrO2含量成反比;ZrO2含量为7 %、拉伸倍数为1~2.5倍、热处理温度为310 ℃、热处理时间为10 min时,制成的复合微孔膜综合性能最佳。     

胶水粘合法制备非对称固液分离膜的探索

探索使用胶水粘合法制备非对称固液分离膜,即用胶水粘合法对聚丙烯微孔膜和聚丙烯针刺非织造布进行粘合获得非对称固液分离膜,聚丙烯微孔膜使非对称固液分离膜表面具有良好的孔径尺寸,探讨了热压温度和时间对非对称固液分离膜各项性能的影响.     

聚四氟乙烯微孔膜的研究进展

聚四氟乙烯微孔膜具有化学性质稳定、透光率高、透水率高、耐高温、抗腐蚀等优点,应用非常广泛。本文综述了聚四氟乙烯微孔膜的制备方法及在电学、医学、化工、服装等多个领域的最新应用,并指出了其存在的问题及今后的发展方向。     

膜裂法聚四氟乙烯纤维生产技术与研究

以聚四氟乙烯树脂为原料,经过拌料、挤压、推压、压延等工艺制备聚四氟乙烯微孔膜,再经过膜裂切割法等深加工工艺,制备聚四氟乙烯长短纤维、基布和覆膜滤料等深加工产品。     

用于膜蒸馏的超疏水聚四氟乙烯/POSS纳米纤维膜

正膜蒸馏(MD)是一种采用疏水微孔膜、以膜两侧的蒸汽压力差为驱动力的膜分离过程,可用于盐水和废水处理。MD系统中,核心是膜材料,膜的疏水性、微孔性是膜蒸馏中膜材料选择的关键因素。聚四氟乙烯(PTFE)因突出的疏水性,优异的耐热性和耐化学性成为MD膜的理想材料。但聚四氟乙烯是非极性的,不能被普通极性溶剂溶解,因而加工性差。商用聚四氟乙烯膜通常采用浸渍和糊状挤出成型,加工过程中会引     

聚偏氟乙烯微孔膜制备方法研究进展

介绍了浸没沉淀法、热致相分离法以及蒸发助热致相分离法制备聚偏氟乙烯(PVDF)微孔膜的研究进展.重点介绍了溶剂、凝固浴组成、凝固浴温度、添加剂和蒸发时间等因素对浸没沉淀法制备PVDF膜的影响,并对制备PVDF膜的发展提出建议和展望.同时简单介绍了PVDF微孔膜的亲水性改性.     

Tuning the water permeability of ultra-high molecular weight polyethylene microporous membrane by molecular self-assembly and flow field

We have systematically studied phase separation behavior in ultra-high molecular weight polyethylene/liquid paraffin/dibenzylidene sorbitol (UHMWPE/LP/DBS) ternary blends. The aim of this paper is to investigate the combined effect of DBS and flow field on the structure and water permeability of UHMWPE microporous membrane. The experimental results show that DBS molecules self-assemble into fibrils firstly during cooling and the blends exhibit a gel-like state before liquid–liquid phase transition. The relaxation time of DBS fibrils is quite long, which shows a great sensitivity to flow field as compared to UHMWPE chain. UHMWPE microporous membrane was prepared via thermally induced phase separation method. DBS fibrils, as in situ formed nucleating agent, decrease the pore size and water permeability and enhance mechanical properties of membrane remarkably. Shear flow can result in alignment of DBS fibrils, which facilitates the nucleation of UHMWPE and induces the lamellae aligned perpendicular to flow direction. This feature was used to design thermal and mechanical histories and obtained oriented UHMWPE microporous membrane. In comparison to the isotropic UHMWPE microporous membrane, the oriented UHMWPE microporous membrane provides low tortuous paths across the membrane and produces high water permeability.     

UHMWPE微孔膜的制备及其性能研究

用热致相分离法制备超高相对分子质R聚乙烯(UHMWPE)微孔膜,并通过调节成型条件(UHMWPE的含量及其相对分子质量、冷却速率)实现了UHMWPE微孔膜微观结构的可控化,研究了成型条件对微孔膜的结晶性能和力学性能的影响.结果表明,在UHMWPE含量和相对分子质量增大,冷却速率加快时,微孔膜的结晶度降低,平均孔径和孔隙...     

中空纤维膜组件分离酸性气体

研究了气体膜分离与溶剂吸收相结合的分离技术.以NaOH水溶液为吸收剂,在中空纤维膜组件中实现二氧化硫气体的选择性吸收.研究了在三种不同结构的疏水性聚丙烯中空纤维膜组件中,吸收剂浓度、液速、气速、气液两相在膜组件内的流程、膜结构等对分离过程的影响;根据膜结构的实际参数确定了多孔膜的曲率因子,总传质系数的计算值与实验值相符.     

高分子量聚乙烯微孔膜的研究进展

高分子量聚乙烯膜材料由于具有突出的强度、抗冲击性、耐腐蚀性等综合性能而越来越受到人们的广泛重视。本文讨论了采用热致相分离法(TIPS)制备高分子量聚乙烯微孔膜的一般过程及热致相分离机理,介绍了近年来国内外高分子量聚乙烯微孔膜的研究进展。     

Synthesis and performance of microporous inorganic membranes for CO2 separation: a review

Removal of CO₂ by membrane technologies is one promising approach as compared to other CO₂ capture technologies due to advantages such as simpler operation, higher reliability, lower capital and operating cost, higher energy efficiency, and a cleaner process. In the field of CO₂ gas separation, inorganic membranes have been attracting a lot of attention. Three classes of microporous membrane family, i.e. microporous silica membranes, microporous carbon membranes and zeolite membranes, have been widely studied due to their potential in separating CO₂ gas molecules, contributed by their distribution of selective micropores which are almost identical to the required molecular sizes for diffusing CO₂ gas. This paper review various methods to fabricate the above three types of microporous membranes, at the same time, looking at other researchers employing these methods to fabricate microporous membranes for CO₂ separation.     

聚丙烯微孔膜研究进展

聚丙烯（PP）是一种价格低廉的塑料，是目前最主要的制备高分子微孔膜的材料之一。笔者综述了近年来PP微孔膜制备方法的研究进展，重点介绍了熔纺拉伸法（MSCS）、热致相分离法（TIPS）、共混拉伸法、熔融烧结法等PP微孔膜的常用制备方法，并对相关的影响因素进行了讨论。     

High-density polyethylene (HDPE) hollow fiber membrane via thermally induced phase separation. I. Phase separation behaviors of HDPE–liquid paraffin (LP) blends and its influence on the morphology of the membrane

Phase separation behaviors of the blends that consist of high-density polyethylene (HDPE) and LP was investigated by means of thermal analysis. The miscibility of the two components was evaluated in terms of the Flory–Huggins interaction parameter, determined from the Hoffman–Weeks plot, gave a value of 0.36. This leads us to a conclusion that this blend system is applicable to the preparation of microporous hollow fiber membrane by melt spinning of the blend. The homogeneous blends in the molten state become heterogeneous systems to yield microporous HDPE membranes in the course of cooling due to thermally induced phase separation. The influence of the phase separation on the membrane morphology was also discussed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2135–2142, 1999     

Control of transport properties with a microporous membrane reactor to enhance yields in dehydrogenation reactions

The dehydrogenation of isobutane has been studied in a membrane reactor using either a mesoporous alumina membrane or a microporous zeolite membrane. It has been shown that for both membranes an increase in the isobutene yield is observed when compared to a conventional reactor. However, these increases are related to two different phenomena: a complete mixing of reactants, products and sweep gas in the case of the mesoporous membrane and a continuous separation of hydrogen when the microporous zeolite membrane was used.     

聚丙烯微孔膜的研究进展

介绍了由熔融纺丝-冷却拉伸法和热致相分离法制备聚丙烯微孔膜的原理和过程。对当前膜研究领域的热点即膜的亲水化改性研究进行了重点评述,包括暂时性改性和永久性改性。阐述了各种改性方法的特点,着重讨论了亲水化改性对膜性能如膜的微孔孔径、孔隙率、透水量等的影响,强调膜表面亲水性的提高可改善膜的耐生物污染性。指出聚丙烯微孔膜的应用领域和发展前景。