离子液体溶剂热诱导相分离法制备聚偏氟乙烯膜.pdf

2023年第29卷第4期化工生产与技术Chemical Production and Technology研究与开发离子液体溶剂热诱导相分离法制备聚偏氟乙烯膜杨伟明（珠海长先新材料科技股份有限公司，广东 珠海 519000）收稿日期：2023-03-02；修回日期：2023-03-16作者简介：杨伟明（1964），男，本科，工程师，从事高分子化工研究工作。电子邮件：聚偏氟乙烯（PVDF）因其优异的热、化学和机械性能而被公认为一种优良的膜材料1。PVDF已成为近年来膜分离技术中应用最广泛的材料之一，特别是在污水处理等领域。制备工艺对膜的微观结构和性能起着重要的决定作用，非溶剂诱导相分离（NIPS）和热诱导相分离（TIPS）是制备聚合物膜的 2 种主要方法2。与 NIPS 法相比，TIPS法其二元体系更容易控制膜的整体形态。采用TIPS法制备的PVDF膜具有机械强度高、孔径分布窄等优良性能。因此，越来越多的研究人员致力于通过TIPS制备PVDF膜的研究3。邻苯二甲酸二辛酯（DOP）和邻苯二甲酸二甲酯（DMP）是PVDF膜制造中常见的TIPS溶剂4。然而，他们有毒，可能导致癌症。离子液体（IL）无污染、无味、可回收，热化学性质稳定，易于从产品中分离出来。与其他有机溶剂不同的是，离子液体的蒸气压可以忽略不计，一般不进入蒸汽中，因此可以大大改善化学实验中有害气体对空气的污染5。此外，离子液体易于使用，可以回收。它是传统挥发性溶剂的理想替代品，可以有效地缓解环境、人体健康和安全、设备腐蚀等严重问题。研究采用 1-丁基-3-甲基咪唑六氟磷酸盐（BMIMPF6）作为TIPS制造PVDF膜的绿色稀释剂。该稀释剂是一种安全、环保、易回收、不易挥发的稀释剂。通过表征聚偏氟乙烯多孔膜的形貌、水通量、孔隙率和拉伸强度，研究聚合物含量和淬火温度对聚偏氟乙烯多孔膜微观结构和性能的影响。1实验部分1.1试剂PVDF，粉末，自产，型号 CXPVDF-200-6；BMIMPF6，用作绿色稀释剂；乙醇，质量分数94%，用作萃取剂；煤油，作为湿润液用于孔隙度测量；去离子水，采用自制的反渗透系统制备，测定PVDF膜的纯水通量。1.2PVDF膜的制备将PVDF粉末与其所需含量的BMIMPF6液体在180 下混合，搅拌至溶液均匀，即可制备涂料溶液。然后，在180 油浴中放置4 h，以脱气避免气泡。在整个加热过程中，使用氮气防止摘要以离子液体1-丁基-3-甲基咪唑六氟磷酸酯（BMIMPF6）为环保稀释剂，采用热诱导相分离法（TIPS）制备聚偏氟乙烯（PVDF）膜，研究了PVDF含量和淬火温度对PVDF膜的形貌和性能的影响。结果表明，在PVDF膜制备过程中形成球粒结构，但随着PVDF含量的降低，球粒结构变为双连续结构。当PVDF的质量分数为15%时，制备的膜的纯水通量为1 980 L/(m2h)，且具有较高的机械强度。随着PVDF含量的增加和淬火温度的升高，膜的平均孔径和透水性减小。关键词聚偏氟乙烯膜；离子液体；热诱导相分离法中图分类号 TQ325.4文献标识码ADOI 10.3969/j.issn.1006-6829.2023.04.0037研究与开发BMIMPF6在高温下可能发生的氧化。脱气后，将涂料溶液放入厚度为200 m的不锈钢模具中，180 加热10 min。将模具置于一定温度的水中，对新生膜进行冷却。然后将新生膜移入乙醇浴 1 d，提取稀释剂BMIMPF6。最后，在25 下干燥48 h，考察PVDF含量（质量分数分别为15%、20%、25%、30%）和淬火温度（分别为0、20、40、60）对制备的PVDF膜微观结构和性能的影响。当研究淬火温度时，将上升的PVDF膜在所需的淬火温度下保持5 min，然后冷却到25。1.3相图测量采用偏光显微镜观察浊点，以HCR-4型差示扫描量热仪（DSC）测定结晶温度，测量了PVDF/BMIMPF6体系的相图。将不同含量的 PVDF/BMIMPF6在烧瓶中用油浴加热至180。同时搅拌混合物以制备均匀溶液。将少量（约5.0 mg）溶液置于一对显微镜盖之间并冷却至室温后，将样品在偏光显微镜热台上加热至 200，然后以10/min的速度逐渐冷却至20。通过在光学显微镜下观察浊度的外观来目测浊点温度。每个含量测量5次，取平均结果。1.4膜性能测试1）形态。将PVDF膜在液氮中浸泡几秒钟，使膜容易破裂。涂覆钯后，利用场发射扫描电子显微镜（FESEM，S4800型）观察制备的PVDF膜的表面和截面。2）平均孔径、孔径分布和孔隙率。平均孔径和孔径分布采用多孔材料孔径分析仪PSDA-20测量。用称量法测定PVDF膜的孔隙率。测量干质量后，将膜浸泡在煤油中数小时，然后测量湿膜的质量，计算其孔隙率。3）纯水通量。在测量纯水通量（PWF）之前，将PVDF膜放入纯水中预湿24 h以上。在跨膜压力为0.1 MPa时，用不锈钢池（有效面积为4.1cm2）测量预湿膜的纯水通量。在0.15 MPa下运行20 min后，根据收集渗透水的时间计算通量。4）机械强度。利用张力测试仪（SH-20 型）检测所制备PVDF膜的机械强度。将膜切割成宽3.0 mm、长50 mm的样品。然后以50 mm/min的恒定伸长率进行拉伸，直至试样断裂。每片膜检测5次以上。2结果与分析2.1相图分析相图可以反映PVDF和溶剂之间的等热力学性质，是通过相转化制备膜的基本参数；浊点是非离子表面活性剂均匀胶束溶液发生相分离的温度。为控制成膜条件，获得理想的膜结构，对PVDF/BMIMPF6二元体系进行了相分离测量，结果如图1所示。图1PVDF/BMIMPF6体系的相图Fig 1 Phase diagram of PVDF/BMIMPF6system由图 1 可以看出，该相图是典型的半结晶PVDF-稀释剂体系。随着PVDF含量的增加，结晶温度线性升高，浊点曲线降低，2条曲线有相交的趋势。2.2膜形态研究了PVDF含量对膜形态的影响，图2为不同PVDF含量下膜的截面。w=15%w=20%w=25%w=30%图2不同PVDF含量下PVDF膜截面Fig 2 Cross-section of PVDF membranes atdifferent polymer content由图2可以看出，随着PVDF含量的增加，球晶的密度增加，而球晶之间的间隙减小，导致孔杨伟明离子液体溶剂热诱导相分离法制备聚偏氟乙烯膜82023年第29卷第4期化工生产与技术Chemical Production and Technology径变小。在较高的PVDF含量下，随着溶液黏度的增加，表面孔隙度显著下降。对于 TIPS 技术，PVDF在稀释剂高温下溶解，形成均匀的熔体共混物，在低温下出现相分离。在稀释剂萃取和萃取剂蒸发后，稀释剂所占据的空间形成膜孔。因此，膜孔径随着 PVDF 含量的增加而减小。当PVDF的质量分数为15%时，PVDF膜呈模糊球粒结构，球粒呈双连续结构。高PVDF含量的球晶尺寸比低PVDF含量的球晶尺寸小，这可以归因于核密度的增加。随着PVDF含量的增加，溶液中核数增加，球晶数量增加，球晶尺寸减小6。淬火条件在决定最终膜形态方面也起着重要作用。图3为不同淬火温度下制备的PVDF质量分数为25%的膜截面的形貌。0 20 40 60 图3不同淬火温度下制备的膜形貌（w=25%）Fig 3 Film morphology prepared at differentquenching temperatures(w=25%)由图3可以看出，随着淬火温度的升高，球晶尺寸增大，膜的孔径也随之增大（见表1）。这种现象可以用成核-生长（NG）模型来解释7。NG模型表明，更快的冷却速率产生更小的球晶，孔径更小，力学强度更高。在其他条件相同的情况下，冷却速率由温差决定。较高的淬火温度意味着较大的温差，并决定较慢的冷却速度。快速冷却会产生许多原子核，但晶体生长的时间很短。相反，缓慢的冷却产生更长的生长时间，同时产生更大的球晶。2.3膜的厚度、平均孔径和孔隙率不同PVDF含量和不同淬火温度下膜的厚度、平均孔径和孔隙率分别如表1和表2所示。表1不同PVDF含量下膜的厚度、平均孔径和孔隙率Tab 1 Thickness,average pore size and porosity ofmembranes at different PVDF contentw/%15202530厚度/m13212194222461324310平均孔径/m0.440.030.260.030.220.050.150.02孔隙率/%75.33.573.44.270.33.168.44.2表2不同淬火温度下膜的厚度、平均孔径和孔隙率Tab 2 Thickness,average pore size and porosity of membranesat different quenching temperatures/0204060厚度/m19012213122242123413平均孔径/m0.170.030.220.040.240.050.350.05孔隙率/%72.54.676.63.277.63.379.34.5由表1可以看出，随着PVDF含量的增加，膜厚增加。随着PVDF含量的增加，球晶的数量增加，球晶的尺寸减小，从而使平均孔径减小。孔隙度随PVDF含量的增加而降低，这是因为在相分离过程中，单位体积内的PVDF含量增加。由表2可以看出，随着淬火温度的升高，冷却速率降低，平均孔径减小。这一结果与在扫描电镜图像中观察到的现象一致。孔隙率随淬火温度的升高而增大，这是由于较低的冷却速率使球晶生长的时间延长，因而导致膜孔尺寸增大所致。2.4膜的机械性能力学性能是实际应用中需要的一个重要参数。不同PVDF含量和淬火温度下制备的膜的拉伸应力和断裂伸长率如表3和表4所示。表3PVDF含量对膜机械性能的影响Tab 3 The effect of PVDF content on the mechanicalproperties of the membranew/%15202530拉伸强度/MPa0.751.782.862.94断裂伸长率/%26.827.624.327.39研究与开发表4淬火温度对膜机械性能的影响Tab 4 The effect of quenching temperature on themechanical properties of the film/0204060拉伸强度/MPa2.611.981.240.96断裂伸长率/%15.32122.530.2由表3可以看出，随着PVDF含量的增加，拉伸强度显著提高。在固液TIPS膜制备中，晶体成核和生长决定了膜的形态和力学性能。晶体区域之间的空间在稀释剂萃取后变成孔隙。原因是更高的PVDF含量导致更高的成核密度，形成具有更高机械强度的膜，因为增加了完整性。由表4可以看出，随着淬火温度的升高，拉伸强度逐渐降低。如前所述，高淬火温度导致低冷却速率，从而为晶体生长留下较长的时间。球晶尺寸增大，球间空隙增大，孔隙率降低，导致抗拉强度降低。2.5膜的纯水通量研究了不同 PVDF 含量和不同淬火温度下PVDF膜的纯水通量，结果如表5和表6所示。表5不同PVDF含量膜的纯水通量Tab 5 Pure water flux of membrane at different PVDF contentw/%J/(Lm-2h-1)151 980201 750251 21030500表6不同淬火温度膜的纯水通量Tab 6 Pure water flux of membrane at differentquenching temperatures/J/(Lm-2h-1)055020780401 130601 780由表5可以看出，当PVDF的质量分数为15%时，制备的膜的纯水通量达到1 980 L/(m2h)，纯水通量随PVDF含量的增大而减小。由表1可知，随着PVDF含量的增加，膜厚度增加，但平均孔径和孔隙率减小。由表6可以看出，纯水通量随淬火温度的升高而增大。由表2可知，随着淬火温度的升高，膜的厚度和孔隙率增大，但平均孔径减小。当水在一定压力下通过膜孔时，膜孔大小的减小增加了阻力，因此，纯水通量减小。同时，随着淬火温度的升高，PVDF膜的水通量降低。3结论以离子液体BMIMPF6为绿色稀释剂制备PVDF膜。研究了PVDF含量和淬火温度对PVDF膜形貌和性能的影响。结果表明，在PVDF膜制备过程中形成球粒结构，但随着PVDF含量的降低，球粒结构变为双连续结构。当PVDF的质量分数为15%时，制备的膜的纯水通量达到1 980 L/(m2h)，且具有较高的机械强度。随着PVDF含量的增加和淬火温度的升高，膜的平均孔径和透水性减小。综上所述，使用离子液体稀释剂制备PVDF膜是一种相对绿色的途径，并且具有可持续的膜生产，在压电膜制造中具有很强的潜力。参考文献1 张凯博,王琪,李雨娥,等.离子液体改性PVDF膜的应用研究进展J.广东化工,2019,46(19):100-101.2 王薇,孙函舒,丁平.离子液体BmimCl改性PVDF膜的制备与性能J.天津工业大学学报,2020,39(2):1-7.3 程媛媛,杜春慧,吴春金,等.聚离子液体刷接枝改性PVDF膜及其对药物硫酸氢氯吡咯雷分离性能研究J.环境科学学报,2018,38(11):4266-4272.4 房平,朱龙涛,赵敏,等.以离子液体和氧化石墨烯为改性剂制备PVDF抗污染膜J.当代化工,2022,51(10):2327-2331.5 李春.离子液体在高性能聚偏氟乙烯材料中的应用研究D.南昌:东华理工大学,2014.6 骆峰,张军,王晓琳,等.热诱导相分离法制备高分子微孔膜的原理与进展J.南京工业大学学报(自科版),2001,23(4):91-96.7 顾震宇,李文俊.壳聚糖溶液冷冻诱导相分离一种制备高孔隙率膜的新方法J.科学通报,1999,44(9):933-938.杨伟明离子液体溶剂热诱导相分离法制备聚偏氟乙烯膜102023，29（4）Chemical Production and TechnologyABSTRACTSApplication of High Gravity Technique in Chlorination of EpichlorohydrinMAO Wei1,WANG Wensheng2,BAI Jinge1,LAN Kun1(1.Quzhou Juhua Polyamide Fibre LLC;2.Juhua Group Corporation:Quzhou,Zhejiang 324004)Abstract:The chlorination of dichloropropanol from glycerol and hydrogen chloride in the production of epichlorohydrin wasstudied by using high gravity technique.The results show that the residence time of the reaction can be shortened from 10 h to 4 hunder the condition of 110 and 0.15 MPa.Supergravity reaction technology greatly enhance the mass transfer efficiency of glyceroland hydrogen chloride in chlorination reaction,reduce the residence time of reaction,and can greatly reduce the industrial footprintand equipment investmentKeywords:epichlorohydrin;chlorination reaction;hypergravity;mass transfer efficiency;catalysisImprovement of the Synthesis Process of Siagliptin Phosphate IntermediateZHANG Shuqing,XUE Xingxing,XUE Haotian,LIANG Mingming,QI Tintin,SU Weike,ZHOU Jiadi(Zhejiang University of Technology,Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals,Hangzhou 310014)Abstract：The intermediate methyl 4-(2,4,5-trifluorophenyl)-3-oxobutanoate of sitagliptin phosphate was prepared from 1,2,4-trifluorobenzene as the starting material.The results showed that in the chloromethylation reaction,when the molar ratio of 1,2,4-trifluorobenzene to paraformaldehyde,concentrated sulfuric acid,sodium chloride and phase transfer catalyst was 1 2.5 4 3 0.05,the highest yield of 85.2%was obtained at 60 for 5 h.In the Grignard reaction,when 2-methyltetrahydrofuran(2-MeTHF)wasselected as the solvent prepared by the Grignard reagent,the molar ratio of 1,2,4-trifluorobenzene to magnesium was 1 5,and theGrignard reagent was prepared at low temperature.After continuous introduction of carbon dioxide gas for 4 h,the highest yield canreach 88.6%;in the condensation reaction and decarboxylation reaction,2,4,5-trifluorophenylacetic acid was decarboxylatedin methanol solution after condensation reaction with mais acid under the action of dicyclohexylcarbodiimide and 4-dimethylaminopyridine.The molar ratio of condensation reaction was 1 1.2 1.2 1.2,and the highest yield was 86%when thedecarboxylation temperature was 65.The total yield of the three-step reaction was 64.9%.The structure of the product wasconfirmed by NMR and melting point data.Keywords:4-(2,4,5-trifluorophenyl)-3-oxobutyrate methyl ester;Siagliptin phosphate;1,2,4-trifluorobenzene;Grignard reaction;carbon dioxidePreparation of Polyvinylidene Fluoride Membrane by Ionic LiquidSolvothermal Induced Phase Separation MethodYANG Weiming(Zhuhai Changxian New Material Technology Co.LTD.,Zhuhai,Guangdong 519000)Abstract:Polyvinylidene fluoride(PVDF)membranes were prepared by thermally induced phase separation(TIPS)using ionicliquid 1-butyl-3-methylimidazolium hexafluorophosphate(BMIMPF6)as an environmentally friendly diluent.The effects of PVDFcontent and quenching temperature on the morphology and properties of PVDF membranes were studied.The results show that thespherical structure is formed during the preparation of PVDF membrane,but with the decrease of PVDF content,the spherical structurebecomes bicontinuous structure.When the mass fraction of PVDF is 15%,the pure water flux of the prepared membrane is 1 980 L/(m2h),and it has high mechanical strength.With the increase of PVDF content and quenching temperature,the average pore sizeand water permeability of the membrane decrease.ABSTRACTSChemical Production and Technology2023，29（4）Keywords:PVDF membrane;ionic liquid;heat-induced phase separationElectrochemical Properties of Phosphoric Acid-Doped SulfonatedPoly(Arylene Ether)-Poly(N-Vinylimidazole)MembranesSHI Jinyi,WEI Qingling(Department of Applied Chemistry Jilin Institute of Chemical Technology,Jilin,Jilin 132022)Abstract:Phosphoricacid-dopedsulfonatedpoly(aryleneether)-poly(N-vinylimidazole)(SDF-F/PVIm)protonexchangemembranes for high-temperature operation were synthesized using sulfonated poly(arylene ether)(SDF-F)as an acidic polymer andpoly(N-vinylimidazole)(PVIm)as a basic polymer,and heat loss,conductivity,impedance spectra and single-cell performance testswere performed.The results showed that the SDF-F/PVIm membranes were thermally stable.Under anhydrous conditions,thecross-linked membranes have high proton conductivity from 150200 ,and the conductivity increases with increasing oftemperature.The performance of the single cell is excellent at different temperatures,and the maximum power density of 528 mW/cm2can be obtained at 190 without external humidification.The synthesized SDF-F/PVIm is expected to be a new polymerelectrolyte for high temperature PEMFCs.Keywords:sulfonatedpoly(aryleneether)-poly(N-vinylimidazole)protonexchangemembrane;phosphoricaciddoping;electrochemistry;propertiesStudy on the Synthesis Process ofp-Aminophenyl-Hydroxyethyl Sulfone SulfateLAN Xiao(Guangdong Zhonghe high-tech joint stock company,Maoming,Guangdong 525000)Abstract:P-Aminophenyl-hydroxyethyl sulfone sulfate was prepared from p-nitrochlorobenzene by thioether oxidation method.The effects of reaction conditions on the yield of substitution reduction,condensation,oxidation and esterification were discussed.The results showed that the molar ratio of p-nitrochlorobenzene to sodium sulfide was 1 3 and the reaction time was 7 h.In thecondensation reaction,the molar ratio of p-nitrochlorobenzene to chloroethanol is 1 1.8,and the solvent is water.In the oxidationreaction,the molar ratio of p-aminophenyl-hydroxyethyl sulfide to H2O2is 12.5,and the molar ratio of p-aminophenyl-hydroxyethyl sulfide to catalyst sodium tungstate ether is 1:0.1.In the esterification reaction,it was better when the diluted waterwas 40 mL(the mass of p-aminophenyl-hydroxyethyl sulfone sulfate was 5 g).The mass fraction,acid value and ester value ofp-aminophenyl-hydroxyethylsulfonesulfatepreparedundertheoptimizedconditionswere17.9%,97.76%and97.03%,respectively.Keywords:p-aminophenyl-hydroxyethyl sulfone sulfate;nitrochlorobenzene;substitution reduction;condensation;oxidation;esterificationProgress in the Preparation of C3 HydrofluoroolefinsLIN Shuting,ZHANG Jiarong,XIA Yingfan,JIANG Chengjun(School of Biological and Chemical Engineering,Zhejiang university of Science&Technology,Hangzhou 310023)Abstract:Several typical C3 hydrofluoroolefins(HFOs)were introduced.The preparation methods and characteristics of C3 HFOsby hydrofluorination,dehydrofluorination and hydrodehalogenation were described.The application and development of C3 HFOswere prospected.It is believed that the reaction should be dominated by chromium-based catalysts.The selection of catalysts isparticularly important to obtain the target product efficiently.Alkali metal doping is helpful to improve the selectivity of the catalyst.Keywords:HFOs;C3;environment-friendly refrigerant;dehydrofluorination;hydrodehalogenation;progress