壳聚糖/聚偏氟乙烯复合质子交换膜的研究进展

综述了国内外各类质子交换膜的结构及性能,并对壳聚糖(CS)和聚偏氟乙烯(PVDF)作为质子交换膜的研究进展作了详细介绍。提出采用天然高分子CS填充PVDF质子交换膜,来提升膜的综合性能,并展望了此复合膜的研究和应用前景。     

聚(偏氟乙烯-co-六氟丙烯)接枝马来酸酐胶粘剂的合成

以聚(偏氟乙烯-co-六氟丙烯)、KOH(氢氧化钾)、MA(马来酸酐)、2,5-二甲基-2,5-二(叔丁基过氧基)己烷和TAIC(三烯丙基异氰脲酸酯)等为主要原料,合成了PTFE(聚四氟乙烯)材料/金属粘接用单组分含氟胶粘剂。探讨了PTFE材料的表面处理、KOH溶液处理以及接枝率等对该胶粘剂粘接性能的影响。研究结果表明:当PTFE表面经0.6 mol/L的萘-钠溶液处理10~15 min后,其表面对水的接触角相对最小,由原来的112.9°降至59.4°;当KOH溶液浓度为0.6 mol/L、处理时间约15 min和w(MA)=10%(相对于总原料质量而言)时,相应的含氟胶粘剂的粘接性能相对最好,其PTFE/不锈钢胶接件的T-剥离强度(4.72 kN/m)相对最大。     

聚氨酯/聚偏氟乙烯六氟丙烯纳米纤维疏水海绵的制备及吸油性能研究

在较小接受距离6 cm和高相对湿度90％下,通过静电纺丝技术,成功制备聚偏氟乙烯-六氟丙烯(PVDF-HFP)纳米纤维功能化商用聚氨酯疏水吸油复合海绵.采用扫描电子显微镜、傅里叶变换红外光谱仪和X射线衍射仪对材料的形貌结构进行表征,并研究了复合海绵的吸油性能.结果表明,由于N,N-二甲基甲酰胺(DMF)溶剂的作用,PV...     

偏氟乙烯-六氟丙烯共聚物溶剂浇铸膜的非等温结晶动力学行为

利用示差扫描量热法(DSC)研究偏氟乙烯-六氟丙烯(PVDF-HFP)共聚物溶剂成膜前后的非等温结晶动力学,结果表明,PVDF-HFP共聚物的结晶对降温速率有一定的依赖关系,成膜后的共聚物与成膜前的共聚物对比发现,成膜后的共聚物的结晶温度升高,结晶速率加快,结晶时间t1/2缩短.用Jeziomy法处理非等温结晶过程较理想.Jeziomy法求出的结晶指数n的值在3～4之间,成膜前后的结晶速率常数kc影响较小.n和kc随降温速度的增大而增大,并且成膜后的共聚物的n和kc大于加工前的树脂的n和kc.Kissinger方法计算的PVDF-HFP共聚物成膜前后的结晶活化能分别为119.97kJ/mol和168.29kJ/mol.     

热致相分离法制备聚(偏氟乙烯-六氟丙烯)/离子液体凝胶膜及 气体渗透性能

采用热致相分离（TIPS）法制备p(VDF-HFP)/[BMIM]PF6凝胶膜,对该膜的内部结构及机械性能进行表征,探讨了[BMIM]PF6添加量对凝胶膜的CO2/N2渗透性能影响。结果表明：随着[BMIM]PF6添加量的增加,p(VDF-HFP)/[BMIM]PF6体系的凝胶温度逐渐降低,凝胶膜的聚合物骨架结构由致密变成疏松的球晶结构;同时[BMIM]PF6的添加降低了凝胶膜的结晶度,改善了p(VDF-HFP)链段的柔韧性,因而膜的CO2和N2渗透系数显著增加,CO2/N2渗透选择性则先升高后降低;凝胶膜受扩散过程控制,当[BMIM]PF6添加量（质量分数）由0增加到60%时,凝胶膜的CO2渗透性系数从0.2 Barrer增加到94.3 Barrer。     

基于PVDF薄膜辐照接枝制备质子交换膜

含氟磺酸型质子交换膜是一类具有高热稳定性、化学稳定性及良好力学性能的离子交换膜,具有极其广阔的应用前景。采用⁶⁰Co辐照接枝技术,在聚偏氟乙烯（PVDF）基膜上产生自由基聚合位点,进而接枝对苯乙烯磺酰氯单体,经过一定条件酸碱处理得到一种新型偏氟磺酸型质子交换膜。并对其进行红外分析,结果显示PVDF膜上成功接枝上了对苯乙烯磺酰氯单体;定量研究了在相同辐照总剂量、不同剂量率条件下,所得质子交换膜的质子传导率、吸水率及离子交换容量与接枝率的关系,结果表明：当剂量率为40 Gy·min^-1时,所得质子交换膜接枝率为52.7%,吸水率为36.85%,80℃时质子传导率达到136 mS·cm^-1,离子交换容量为1.274 mmol·g^-1。     

聚偏氟乙烯/聚离子液体共混膜的优化制备

研究制备了由聚离子液体(PIL)改性的聚偏氟乙烯(PVDF)共混膜,探讨了凝固浴组成的变化对PVDF共混膜的影响。通过FTIR、XPS、SEM分析了膜表面的组成及膜孔结构;通过水接触角和机械强度测试分析了膜的性能,并研究了膜对橙黄Ⅳ的吸附容量。实验表明:随着凝固浴中DMF含量的增加,膜的水接触角从77.79°减小到51.94°,亲水性显著增强,膜对橙黄Ⅳ的吸附容量从7.7 mg/g增加到16.1 mg/g,实现对PVDF膜的优化改性。     

增强型聚偏氟乙烯微孔膜的研制

通过相转化法制备无纺布支撑的增强型聚偏氟乙烯微孔膜,确定二甲基乙酰胺(DMAC)为溶剂,氯化锂为第二添加剂,以水作为凝胶浴.研究了添加剂组成和浓度、凝胶浴组成和浓度、凝胶浴温度、热处理条件等因素对聚偏氟乙烯膜性能的影响.     

聚偏氟乙烯功能膜研究进展

聚偏氟乙烯(PVDF)机械性能、耐老化及耐化学腐蚀等性能优良,广泛应用于膜分离与膜过程领域,但其亲水性能差、易受污染使其在膜分离方面的应用受到限制,对其亲水性和抗污染性是目前研究的重要课题;其β晶型的特殊结构使PVDF具有优异的介电性、压电性和铁电性等,在介电材料、压电材料等领域应用愈来愈广,但晶型的多样性及聚集状态使得其电学性能不稳定,因此控制β晶相的含量及其有序聚集状态是能量存储和转换材料领域研究的前沿趋势。     

A microporous gel electrolyte based on poly(vinylidene fluoride-co-hexafluoropropylene)/fully cyanoethylated cellulose derivative blend for lithium-ion battery

A gel polymer electrolyte based on the blend of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and fully cyanoethylated cellulose derivative (DH-4-CN) was prepared and characterized. Thermal, mechanical, swelling, liquid electrolyte retention and electrochemical properties, as well as microstructures of the prepared polymer electrolytes, were investigated using thermogravimetric analysis, electrochemical impedance spectroscopy, linear sweep voltammetry, and scanning electron microscopy. The results showed that the addition of DH-4-CN could obviously improve the conductivity of PVDF-HFP based electrolyte. The maximum ionic conductivity of 4.36 mS cm⁻¹ at 20 °C can be obtained for PVDF-HFP/DH-4-CN 14:1 in the presence of 1 M LiPF₆ in EC and DMC (1:1, w/w). The dry blend membranes exhibit excellent thermal behavior. All the blend electrolytes are electrochemically stable up to about 4.8 V vs. Li/Li⁺ for all compositions. The results reveal that the composite polymer electrolyte qualifies as a potential application in lithium-ion battery.     

树枝状大分子/聚(N-异丙基丙烯酰胺)纳米粒子的制备

使用溴乙酰溴对第四代聚丙烯亚胺树枝状大分子 (DAB-32)进行改性,成功合成了树枝状大分子引发剂DAB-32-Br。以DAB-32-Br/CuBr/Bpy为催化引发体系,分别在水和水/乙醇反应介质中,实现了N－异丙基丙烯酰胺（NIPAAm）的原子转移自由基聚合（ATRP）,得到粒径在60－150 nm范围内的树枝状大分子/聚（N－异丙基丙烯酰胺）纳米粒子。与水介质中ATRP相比,在水/乙醇介质中所得聚合物纳米粒子更加规则,而且粒子间聚集程度较低。     

Preparing polymer brushes on poly(vinylidene fluoride) films by free radical polymerization

Grafting of polymer brushes on the poly(vinylidene fluoride) (PVDF) films was carried out by the surface‐initiated free radical polymerization. Surface‐initiators were immobilized on the PVDF films by surface hydroxylation and esterification of the surface‐tethered hydroxyl groups with 4,4′‐azobis(4‐cyanopentanoic acid) (ACP). Homopolymer brushes of methyl methacrylate (MMA) were prepared by free radical polymerization from the azofunctionalized PVDF surface. The chemical composition and topography of the graft‐functionalized PVDF surfaces were characterized by X‐ray photoelectron spectroscopy (XPS), attenuated total reflectance (ATR) FTIR spectroscopy, and atomic force microscopy (AFM). Kinetics study revealed an exponential increase in the graft concentration of polymer brushes with the reaction time, indicating that the chain growth from the surface was consistence with a chain polymerization. Water contact angles on PVDF films were reduced by surface grafting of MMA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 857–862, 2006     

Preparation of SBS/poly(styrene–methyl methacrylate) thermoplastic interpenetrating polymer network

SBS as polymer I, poly(styrene–methyl methacrylate) polymerized by atom transfer radical polymerization as polymer II, and a thermoplastic interpenetrating polymer network of SBS/poly(styrene–methyl methacrylate) were prepared by the sequential method. The effects of the polymerization temperature, the composition of the catalyst, the ratio of the monomers studied, and the kinetics at 90°C were also investigated. It was shown that when polymerization was initiated by a BPO/CuCl/bpy (BPO:CuCl:bpy = 1:1:3) system at 90°C, the mass averaged molecular weight of the poly(styrene–methyl methacrylate) increased with monomer conversion, and the polydispersities were kept very low. Fourier transform infrared spectroscopy and gel permeation chromatogram showed that poly(styrene–methyl methacrylate) with low polydispersities had been synthesized. Thus, a thermoplastic interpenetrating polymer network comprised of both narrow molecular‐weight‐distribution components was successfully prepared. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2007–2011, 2003     

“Smart” membrane materials: Preparation and characterization of PVDF‐g‐PNIPAAm graft copolymer

In this research, a smart membrane material of graft copolymer of poly(vinylidene fluoride) with poly(N‐isopropylacrylamide) (PVDF‐g‐PNIPAAm) was synthesized by atom transfer radical polymerization (ATRP) using poly(vinylidene fluoride) (PVDF) as a macroinitiator and direct initiation of the secondary fluorinated site PVDF facilitates grafting the N‐isopropylacrylamide comonomer. The copolymers were characterized by Fourier transform infrared (FTIR), ¹H NMR, gel‐permeation chromatography (GPC), and X‐ray photoelectron spectroscopy (XPS). The temperature‐sensitive membrane was prepared from the PVDF‐g‐PNIPAAm graft copolymers by the phase inversion method. The effects of temperature on the flux of pure water of membrane was investigated. The results showed that alkyl fluorides were successfully applied as ATRP initiators in the synthetic condition and the flux of pure water through the PVDF‐g‐PNIPAAm membrane depended on the temperature change. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1482–1486, 2007     

Preparation and characterization of antifouling poly(vinylidene fluoride) blended membranes

Poly(vinylidene fluoride) (PVDF) membranes have been widely used in microfiltration and ultrafiltration because of their excellent chemical resistance and thermal properties. However, PVDF membranes have exhibited severe membrane fouling because of their hydrophobic properties. In this study, we investigated the antifouling properties of PVDF blended membranes. Antifouling PVDF blended membranes were prepared with a PVDF‐g‐poly(ethylene glycol) methyl ether methacrylate (POEM) graft copolymer. The PVDF‐g‐POEM graft copolymer was synthesized by the atom transfer radical polymerization (ATRP) method. The chemical structure and properties of the synthesized PVDF‐g‐POEM graft copolymer were determined by NMR, Fourier transform infrared spectroscopy, and gel permeation chromatography. To investigate the antifouling properties of the membranes, we prepared microfiltration membranes by using the phase‐inversion method, which uses various PVDF/PVDF‐g‐POEM concentrations in dope solutions. The pure water permeabilities were obtained at various pressures. The PVDF/PVDF‐g‐POEM blended membranes exhibited no irreversible fouling in the dead‐end filtration of foulants, including bovine serum albumin, sodium alginate, and Escherichia coli broth. However, the hydrophobic PVDF membrane exhibited severe fouling in comparison with the PVDF/PVDF‐g‐POEM blended membranes. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Grafting polymer from poly(ethylene terephthalate) films by surface‐initiated ATRP

Surface‐initiated atom transfer radical polymerization (ATRP) from poly(ethylene terephthalate) (PET) film was studied. Poly(methyl methacrylate) (PMMA), poly (acrylamide) (PAAM), and their diblock copolymer (PMMA/PAAM) on the surface of PET film were successfully prepared by surface‐initiated ATRP. The structures and properties of the modified PET film were characterized by FT‐IR/ATR, X‐ray photoelectron spectroscopy (XPS), measurements of contact angles, and scanning electronic microscopy (SEM). The results indicate that the surface properties of PET film were greatly improved by grafted polymer. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Proton exchange membranes based on poly(vinylidene fluoride) and sulfonated poly(ether ether ketone)

Blend membranes were obtained by solution casting from poly(vinylidene fluoride) (PVDF) and sulfonated poly(ether ether ketone) (SPEEK) in N,N-dimethylacetamide (DMAc). DSC and XRD were used to characterize the structure of the blend membranes. The effect of PVDF content on the membrane properties was investigated. The methanol permeability, water uptake and the swelling ratio of blend membranes decreased with the increase of PVDF content. Though the proton conductivity decreased upon the addition of PVDF, they were still comparable to that of Nafion^® 117 membrane. Higher selectivities were also found for most blend membranes in comparison with Nafion^® 117 membrane. The effect of methanol concentration on solution uptake, swelling ratio and methanol permeability of the blend membranes was also studied.     

Effects of the solvent polarity on the atom transfer radical polymerization of methyl methacrylate initiated by 4‐(chloromethyl)phenyltrimethoxysilane

The controllability of the atom transfer radical polymerization of methyl methacrylate in the polar solvent N,N‐dimethylformamide and the nonpolar solvent xylene with 4‐(chloromethyl)phenyltrimethoxysilane as an initiator and with CuCl/2,2′‐bipyridine and CuCl/4,4′‐di(5‐nonyl)‐2,2′‐bipyridine as catalyst systems was studied. Gel permeation chromatography analysis established that in the nonpolar solvent xylene, much better control of the molecular weight and polydispersity of poly(methyl methacrylate) was achieved with the CuCl/4,4′‐di(5‐nonyl)‐2,2′‐bipyridine catalyst system than with the CuCl/2,2′‐bipyridine as catalyst system. In the polar solvent N,N‐dimethylformamide, unlike in xylene, the polymerization was more controllable with the CuCl/2,2′‐bipyridine catalyst system than with the CuCl/4,4′‐di(5‐nonyl)‐2,2′‐bipyridine catalyst system. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2751–2754, 2007     

Poly(methylphenylphosphazene)–Graft–Poly(methyl Methacrylate) Copolymers Via Atom Transfer Radical Polymerization

Atom transfer radical polymerization (ATRP) was used to graft poly(methyl methacrylate), PMMA, onto poly(methylphenylphosphazene), [(Me)(Ph)PN] _n , PMPP. A two-step process was used to convert a portion of the methyl substituents on [(Me)(Ph)PN] _n to –CH₂C(CH₃)₂OH groups and then to bromoalkyl groups, –CH₂C(CH₃)₂OC(=O)C(CH₃)₂Br, the latter of which served as initiation sites for ATRP of methyl methacrylate (MMA) in the presence of CuCl/bipyridine. Variations in the length of the grafted chains were investigated and the graft copolymers were compared to the parent polymer and blends of similar composition. The new bromoalkyl derivatives of [(Me)(Ph)PN] _n and the PMPP–graft–PMMA copolymers were characterized by elemental analysis, ¹H and ³¹P NMR spectroscopy, size exclusion chromatography (SEC), and differential scanning calorimetry (DSC). We dedicate this paper to Professor Harry R. Allcock for consistently maintaining the highest standards in his creative, pioneering work in inorganic rings and polymers.