弹性聚四氟乙烯／聚氨酯复合薄膜性能的研究

在聚四氟乙烯树脂（PTFE）中加入热塑性弹性体聚氨酯（TPU），制备出了有弹性的微孔复合薄膜，有效地改进了唧双向拉伸薄膜受力后的回复性。在复合薄膜中，加入经偶联剂处理的纳米二氧化硅，有利于TPU在PTFE中的均匀分散，从而提高复合薄膜的弹性。随着TPU含量的增加薄膜回复性也提高，双向拉伸倍率的增大可以导致薄膜回复性能有所下降，SEM分析证明了在PTFE中加入TPU可以增大复合薄膜的微孔尺寸。     

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。     

覆膜滤料用聚四氟乙烯微孔膜的制备及其性能研究

针对市场上常用4种SSG范围的聚四氟乙烯(polytetrafluoroethylene,简称PTFE)树脂原料,采用双向拉伸法制备PTFE微孔膜,分析微孔膜性能的差异,并确定最适用于覆膜滤料用PTFE树脂原料.分析了不同分子量PTFE树脂原料的相对标准密度(SSG)、粒径、挤出压力和含水率等参数,采用不同分子量树脂原料来制备PTFE微孔膜,并表征PTFE微孔膜力学、厚度、结晶度、孔径、孔隙率和透气性能.研究表明:SSG的大小会影响PTFE微孔膜的力学性能(最大力、断裂伸长率)和孔结构(孔径、孔隙率),随SSG的增大呈现先上升后下降的趋势,在2.170～2.189范围内达到最优;结晶度与SSG的大小成正相关,而微孔膜透气性能主要与其孔结构有关,与孔径和孔隙率的变化趋势具有一致性.得出结论:PTFE树脂原料SSG分布在2.170～2.189范围时,制备的PTFE微孔膜最适用于覆膜滤料领域.     

水泥行业用覆膜滤料的制备及其性能研究

水泥行业排放要求越发严苛,对覆膜滤料的要求越来越高。该文针对覆膜滤料阻力高、精度低、使用寿命短等问题,采用聚四氟乙烯(PTFE)和聚全氟乙丙烯乙烯(FEP)为原料,通过双向拉伸法制备PTFE/FEP复合膜,提高膜透气和力学性能,控制孔径,经过和玻纤布覆合后,形成覆膜滤料,提高了覆膜滤料的透气和使用寿命。对比了PTFE/FEP复合膜和同工艺下PTFE微孔膜的透气率、厚度、力学和微孔性能的变化,对覆膜后滤料的基本性能也进行了对比分析,研究表明,PTFE/FEP复合膜的透气率和力学性能优于同工艺下PTFE微孔膜,且经过热压覆合后滤料的透气率、耐磨性优于同工艺下PTFE微孔膜覆膜滤料,可有效降低阻力、保证精度、提升寿命。     

聚四氟乙烯微孔膜及其过滤材料制备研究

采用三拉伸工艺制备聚四氟乙烯微孔膜,研究不同工艺对e PTFE膜的孔径及结构的影响,并通过对薄膜与不同滤料基材的复合方式研究制备高效除尘滤料。     

三维立体拉伸聚四氟乙烯微孔膜工艺

研制开发了1套适合三维立体拉伸聚四氟乙烯微孔薄膜的设备和工艺,介绍了设备结构和工艺流程。与传统双向拉伸工艺对比,该工艺制备的微孔薄膜孔径大小可控性强、孔径差异小、薄膜厚度均匀。     

聚四氟乙烯微孔膜的研究进展

聚四氟乙烯（PTFE）微孔膜具有独特的纤维—＂结点＂微观结构,不仅具有良好的化学稳定性、热稳定性、抗腐蚀等性能,还具有高透光率、防水、透气等特性。PTFE微孔膜主要采用机械拉伸法制备。本文综述了近年来PTFE微孔膜的制备工艺、形成机理,详细阐述了填充、接枝等改性方法的研究进展以及其在化工、建筑、医学等领域应用的最新研究成果,并指出目前存在的问题,对今后的研究提出了展望。     

溶胶-凝胶法制备有机/无机复合疏水薄膜的研究

研究了以聚四氟乙烯(PTFE)、硅溶胶为主要原料，利用溶胶-凝胶法在玻璃表面制备了SiO2／聚四氟乙烯有机／无机复合薄膜。分别用XRD，IR，SEM，TG-DTA等测试手段分析了涂膜在热处理过程中所发生的物理-化学变化，以及薄膜材料的组成、结构、表面形貌。研究表明：在复合薄膜材料中，PTFE与SiO2形成相互贯穿的无规网状结构，薄膜与基材附着力良好，表面呈现出良好的疏水性能。     

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。     

膜裂切割法聚四氟乙烯纤维的制备及其力学性能

以不同聚四氟乙烯分散树脂为原料,通过混料、熟化、预成型、压延、双向拉伸及膜裂切割等工艺,制备了高性能聚四氟乙烯(PTFE)纤维.试验结果表明:树脂原料的优劣、热处理温度及拉伸工艺是影响PTFE纤维力学性能的主要因素,PTFE纤维的拉伸倍数应该控制在32～49之间,最佳的拉伸温度在240～320℃之间.     

Fabrication and characterization of PFSI/ePTFE composite proton exchange membranes of polymer electrolyte fuel cells

PFSI/ePTFE composite proton exchange membranes were fabricated by impregnating perfluorosulfonic acid resin (PFSI resin, Nafion) into chemically modified expanded PTFE (ePTFE) matrix. Chemical modification of sodium-naphthalene treatment and N-methylol acrylamide (NMA) grafting decreased the contact angle of the as-received ePTFE from 125 ± 0.5° to 67 ± 0.5°, effectively converting the as-received hydrophobic ePTFE to a hydrophilic ePTFE matrix. The composite membrane fabricated with the hydrophilic ePTFE have higher impregnated PFSI loading, much lower porosity and better PTFE/PFSI interface contact, as compared to the composite membranes with the as-received ePTFE. This leads to much lower gas permeability and significantly improves the durability under an accelerated dry/wet cycle test. The fuel cell made from the PFSI/ePTFE composite membranes with hydrophilic ePTFE showed superior performance as compared to that with the composite membrane made from the as-received ePTFE and Nafion 211 membrane.     

Fabrication and characterization of a novel Nafion-PTFE composite hollow fiber membrane

Nafion has been widely used in electrochemistry, but there are only a few reports on its application in other fields, such as, gas separation, even though it exhibits good performance. The primary reason for that is the high cost of Nafion and making a composite membrane with a thin Nafion layer is a potential solution to solve this problem. In this study, a novel Nafion-PTFE composite hollow fiber membrane, which had a thin (~5 μm) and detect-free Nafion layer on PTFE surface, without Nafion filling substrate pores was developed, differing from the reported ones in which Nafion resin was required to impregnate into porous PTFE membrane as thorough as possible to ensure the ion conductivity and operation stability. The surface morphology, crystallite, solubility in ethanol/water mixture, and water uptake of membranes were systemically investigated. The gas permeance tests were also conducted. The permeances of different gasses of prepared composite membranes were significantly enhanced compared with the commercial membranes due to the decrease of Nafion thicknesses, while the selectivity remained the same, verifying the detect-free structure of Nafion layer on PTFE substrate. This study provided a good reference for the preparation and application of low-cost Nafion composite membranes.     

聚四氟乙烯油封在车辆上的应用研究

通过对影响油封密封性的主要因素以及油封在车辆上的使用环境分析,选用了丁腈橡胶、填充聚四氟乙烯（PTFE）、氟橡胶、PTFE复合材料4种密封材料,并对所制成的不同结构的油封进行了对比试验。结果证袜,PTFE复合材料具有良好的耐高低温性、自润滑性、耐磨性和耐压性。PTFE复合油封能提高车辆的密封性,满足车辆的使用要求。     

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。     

利用醋酸纤维/聚四氟乙烯复合膜中的微结构固定化脂肪酶

脂肪酶的固定化是降低其使用成本的有效途径之一.提出了利用亲水/疏水复合膜中的微结构固定化脂肪酶的新思路.首先制备由致密的亲水层和多孔的疏水层组成的醋酸纤维素/聚四氟乙烯（CA/PTFE）复合膜,然后利用复合膜的特殊微结构,用超滤的方法实现了脂肪酶的固定化.扫描电镜照片结果表明,大部分被截留的酶位于复合膜的界面处.制备得到的固定化酶膜应用于水解橄榄油的反应,其最高催化活力达到1.24 μmol FFA·min^-1·cm^-2,大大高于文献报道值.同时研究了固定化脂肪酶膜的催化动力学,考察了亲水层厚度和脂肪酶负载量对固定化效果的影响,优化了固定化条件.在经过10次（50 h以上）的重复使用后,固定化酶膜的活力仅降低了20%.     

填充聚四氟乙烯油封的研究与发展

综述了聚四氟乙烯油封的结构、密封机理、材料的性能,提出了在我国大力发展聚四氟乙烯油封的前提条件。     

聚四氟乙烯膜及应用1998-2017文献计量分析

对汤森路透科学网络数据库(WOS)核心合集中,关于聚四氟乙烯(PTFE)膜的出版物进行文献计量概述。根据1998-2017年核心合集的2 555篇论文,从基本增长趋势分析、关键词分析、突发检测等方面展开研究。结果表明,PTFE膜研究最具生产力的国家为中国、美国和日本,且世界各国、机构和研究者之间的合作日益频繁。通过关键词识别出4个聚类,表明PTFE膜研究的主要方向包括膜改性、膜分离、在能源电池和口腔医学中的应用。PTFE膜在膜燃料电池气体扩散层和膜蒸馏方面的应用研究成为近年的研究热点。     

Modification of a Poly(tetrafluoroethylene) Porous Membrane to Superhydrophilicity with Improved Durability

The commercial fluorocarbon surfactant (FCS) DuPont? Zonyl 321 fluorinated cationic surfactants, was employed to modify both flat‐sheet and hollow‐fiber poly(tetrafluoroethylene) (PTFE) porous membranes. The variation of morphology, wettability, and hydrophilicity durability to acid and alkali as well as the filtration performance of both membranes were investigated. Such superhydrophilic membranes showed better wetting stability and higher resistance to acid and alkali solutions. Moreover, both membranes exhibited good filtration performance.     

氟树脂性能与加工应用(续16)

介绍了聚四氟乙烯分散液的概念和有关性能.叙述了PTFE玻璃布及其衍生产品和PTFE多孔金属的性能和用途,制备原理、方法和工艺.     

Comparative Study of Separation of Acetonitrile from Aqueous Solutions by Pervaporation using Different Membranes

Pervaporation of acetonitrile-water mixtures was carried out using three commercial membranes, viz: polydimethylsiloxane (PDMS), polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF). The effects of feed concentration and feed temperature on the pervaporation performance, total and partial permeate fluxes, as well as acetonitrile selectivity, were investigated. It was found that increase in temperature yields higher total fluxes and lower selectivity for acetonitrile-water system. Changing concentration of acetonitrile in the range concerned leads to significant effect on total flux and selectivity. PDMS membrane was found to be most selective for acetonitrile separation. The total flux through the membranes was found to be in the order of PTFE > PVDF > PDMS, and the acetonitrile selectivity was found to be in the order of PDMS > PVDF > PTFE. The activation energies of water and acetonitrile associated with the permeation process for the PDMS, PTFE, and PVDF membranes were calculated to be in the ranges of 0.29–0.99, 0.6–0.87, 0.45–2.73 kJ/mol for acetonitrile and 1.23–1.95, 1.37–1.71, 1.16–3.37 kJ/mol for water at different concentrations, respectively.