PU-EVA共混膜的制备及其气体性能研究

采用溶剂挥发法制备了不同组成聚氨酯(PU)/聚乙烯-聚醋酸乙烯酯共聚物(EVA)及与聚醋酸乙烯酯(PVAc)共混膜,并研究了聚合物种类和添加量对膜的化学结构、表面形貌及O2和N2渗透性能的影响。结果表明,EVA和PVAc与PU的相容性良好。添加EVA28和EVA40后,PU-EVA28和PU-EVA40共混膜的O2和N2气体渗透系数均明显增加;当EVA28的添加量为50%时,膜的O2和N2渗透系数分别可达到25.84 Barrer和8.58 Barrer。添加PVAc后,O2和N2渗透系数呈下降趋势,而PU-PVAc共混膜的O2/N2的选择性随着PVAc的添加量增加而增大,由5.70增加到6.21。     

PU-EVA共混膜的制备及其气体性能研究

采用溶剂挥发法制备了不同组成聚氨酯(PU)/聚乙烯-聚醋酸乙烯酯共聚物(EVA)及与聚醋酸乙烯酯(PVAc)共混膜,并研究了聚合物种类和添加量对膜的化学结构、表面形貌及O2和N2渗透性能的影响。结果表明,EVA和PVAc与PU的相容性良好。添加EVA28和EVA40后,PU-EVA28和PU-EVA40共混膜的O2和N2气体渗透系数均明显增加;当EVA28的添加量为50%时,膜的O2和N2渗透系数分别可达到25.84 Barrer和8.58 Barrer。添加PVAc后,O2和N2渗透系数呈下降趋势,而PU-PVAc共混膜的O2/N2的选择性随着PVAc的添加量增加而增大,由5.70增加到6.21。     

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。     

PEBA/EPH热可逆凝胶膜的制备及其气体分离性能

通过热致相分离法制备了具有高气体渗透性能的聚醚共聚酰胺/乙二醇苯醚凝胶膜(PEBA/EPH),并探讨了EPH含量对其物理化学结构及CO2/N2渗透性能的影响。结果表明,PEBA/EPH凝胶膜具有良好的力学性能及优异的气体渗透性能,EPH的添加使得膜结晶度及熔融温度下降,从而CO2、N2在凝胶膜内的渗透系数显著增加。同时,由于EPH对于CO2具有优先吸附性,凝胶膜的CO2/N2选择性也相应增加。当EPH含量从0%增加到60%时,凝胶膜的CO2渗透系数由234 barrer增加到1 040 barrer,CO2/N2的气体选择系数从22.5增加到40.5。     

羧基化聚酰亚胺膜的制备及其对CO_2/CH_4分离性能的研究

通过羟基聚酰亚胺(HPI)与对氟苯甲酸间的亲核取代反应合成了羧基化聚酰亚胺(CPI),以水为绿色溶剂,采用溶剂挥发法制备了不同羧化度的CPI膜,研究了引入羧基对CPI膜的CO_2、CH_4渗透分离性能的影响。结果表明,随着羧化度的增加,CPI膜的CO_2渗透系数以及CO_2/CH_4的选择性均不断增加,制备的CPI膜打破了trade-off规则。当羧化度为19%、压力为0.1 MPa、温度为25℃时,CO_2的渗透系数为68 Barrer,CO_2/CH_4的选择性达到78,CPI膜比纯HPI膜的CO_2渗透系数和CO_2/CH_4选择性分别提高了467%和224%。     

Fe_2O_3-SiO_2复合粒子的制备及其PU共混膜的氧氮分离性能

采用共沉淀与复配2种方法制备了Fe2O3-SiO2复合纳米粒子,将其添加到聚氨酯(PU)膜中,研究了粒子复合方式对PU共混膜力学性能和O2、N2分离性能的影响。结果表明,通过共沉淀法制备的Fe2O3-SiO2粒子粒径小且均匀,内部存在硅铁固溶体结构,其PU共混膜的机械强度和氧氮分离性能优于复配法制备的Fe2O3/SiO2粒子;当Fe2O3-SiO2添加量为10%时,PU共混膜的O2渗透系数为13.35 Barrer,O2/N2理论分离因子为7.14。     

高内相乳液法制备聚丙烯酰胺多孔水凝胶及应用

以亲水性二氧化硅纳米粒子（N20）和乳化剂Tween80为复合稳定剂,环己烷为油相制备高内相乳液,再以此乳液为模板制备聚丙酰胺（PAM）多孔水凝胶。乳液光学显微镜照片及PAM多孔水凝胶SEM照片表明N20用量及Tween80用量对材料孔径形貌及直径有直接影响;压汞仪数据表明当N20用量为3%、Tween80用量为9%时,多孔水凝胶平均孔径为38.06nm,孔隙率为77.54%,20h饱和吸水率可达402g/g;吸附实验表明PAM多孔水凝胶对Mn(Ⅱ)具有良好的吸附性能,吸附过程符合准二级动力学方程,属于化学吸附,当溶液pH为4时,120min可达吸附饱和,吸附量为474.64mg/g。     

基于共混聚醚共聚酰胺的气体分离膜的制备及性能研究

聚合物共混可以制备出兼有几种聚合物特性的共混膜。为了提高气体分离膜的综合性能,以2种不同型号的聚醚共聚酰胺（具有高选择性的Pebax1657和具有高渗透性的Pebax2533）为膜材料制备了气体分离膜,并对分离膜进行结构表征、分离性能和力学性能测试。结果表明,随着Pebax2533含量的增加,聚酰胺段的链间距逐渐增大,自由体积分数增大,玻璃化转变温度降低,断裂伸长率逐渐提高;与纯Pebax1657膜相比,共混膜的CO2和N2渗透系数同时增大,N2渗透系数增加速度较快;选择性逐渐降低;与纯Pebax膜相比,两者共混后的膜的综合性能有所提高。     

Y型沸石/炭杂化膜的制备及其气体分离性能

以聚酰胺酸为前驱体,Y型沸石为掺杂物,经高温炭化制备了Y型沸石/炭杂化膜.通过纯组分气体(H2,CO2,O2,N2)的渗透实验对杂化膜的气体渗透性能进行测定,并使用透射电镜,X射线衍射对杂化膜的微结构进行表征.研究了沸石的含量以及炭化温度对杂化炭膜的气体渗透性能和微结构的影响.结果表明,随着膜内沸石含量的提高,Y型沸石/炭杂化膜的气体渗透性能明显提高,而随着炭化温度的升高,Y型沸石/炭杂化膜的渗透系数降低,选择性提高.与纯炭膜相比,Y型沸石/炭杂化膜在保持高O2N2选择性的前提下,其渗透性能显著提高.炭化温度为700℃,沸石含量为15%,Y型沸石/炭杂化膜O2的气体渗透系数为501 bareer,O2/N2选择性为15.6.当炭化温度超过800℃以后,杂化膜中的沸石晶体结构被破坏,其气体渗透系数接近纯炭膜的气体渗透系数.因此,保持沸石孔道结构的完整是制备高性能沸石/炭杂化膜的关键因素之一.     

EVA添加量对HDPE/LDPE基抗氧化复合膜性能的影响

以HDPE为复合膜外层,LDPE和EVA的共混物为内层,槲皮素为抗氧化剂,采用共挤流延法制得HDPE/LDPE基抗氧化复合膜。分析了内层膜中EVA添加量对活性膜拉伸性能、热封性能、阻隔性能及抗氧化剂释放速率的影响。结果表明,随着EVA添加量的增加,活性膜的拉伸强度先增大后减小,当EVA添加量为50%时,拉伸强度达到最大值,为22.8 MPa;热封强度由15.4 N/15mm增加到21.1 N/15mm,即热封性能增强;活性膜对水蒸气的阻隔能力减弱,而阻氧能力无显著变化。当EVA添加量为30%、40%、50%、60%、70%时,扩散系数D分别为4.90×10-14、2.70×10-13、5.91×10-13、8.85×10-13、8.85×10-13cm2/s;改变内层膜中EVA的添加量,能够在较大范围内调整活性膜中抗氧化剂的释放速率。     

Poly(ether-b-amide)/Tween20 Gel Membranes for CO2/N2 Separation

Poly(ether-b-amide) (PEBA)/Tween20 gel membranes containing from 0 wt% to 65 wt% of Tween20 in PEBA2533, PEBA3533, and PEBA4033 were prepared by solvent casting method for CO₂/N₂ separation. The gas separation properties of the polymeric gel membranes were tested for single gases of CO₂ and N₂ at 25°C with the feed pressure of 0.6 atm. For all pure PEBA membranes, CO₂ and N₂ permeability decreased as the amount of polyamide block increased, but CO₂/N₂ selectivity increased. For PEBA/Tween20 gel membranes, both the CO₂ permeability and CO₂/N₂ selectivity were greatly enhanced with the increase of Tween20 content. For the membrane of PEBA4033/Tween20-65, CO₂/N₂ selectivity, and CO₂ permeability reached 54 and 146 Barrer, respectively, which is very interesting for potential application in CO₂ removal from flue gas.     

Permeation properties of CO2and CH4in asymmetric polyethersulfone/polyesterurethane and polyethersulfone/polyetherurethane blend membranes

The transport performances of carbon dioxide and methane were studied in polyethersulfone,polyethersulfone/polyeterurethane (PES-ETPU) and polyethersulfone/polyestherurethane (PES-ESPU) blend membranes separately with different compositions.The variations in the structural characteristics of PES membrane after incorporation of ESPU and ETPU were investigated by different techniques.Additionally,the effect of pressure and composition on the permeance of CO2,CH4and ideal selectivity of CO2/CH4were checked on the membranes. The results revealed that the morphology of the blend membranes was affected by two opposite factors:thermo-dynamic enhancement and kinetic hindrance.The membranes with denser sponge layers were formed at lower ratio of PU/PES,while more porous structure with enlarged macrovoids membranes were observed at higher PU content.The results indicated that adding PU to PES membrane,caused permeance improvement of the gases with nearly no change and/or reduction in ideal selectivity of CO2/CH4.Moreover,PES-ETPU membranes showed higher permeability and less CO2/CH4selectivity in comparison with PES-ESPU samples. For PES-ESPU membrane containing 1.5% ESPU,CO2permeance at 10 bar was improved up to 20% with almost no change in CO2/CH4selectivity with respect to PES.Finally,response surface methodology was used to evaluate the effects of the operating parameters on the permeance and ideal selectivity.     

Water-stable ZIF-300/Ultrason(R) mixed-matrix membranes for selective CO2 capture from humid post combustion flue gas

Water stable mixed-matrix membranes (MMMs) were developed to help control the global warming by capturing and sequestrating carbon dioxide (CO2) from post-combustion flue gas originated from burning of fossil fuels.MMMs of different compositions were prepared by doping glassy polymer Ultrason(R) S 6010 (US) with nanocrystals of zeolitic imidazolate frameworks (ZIF-300) in varying degrees.Solution-casting technique was used to fabricate various MMMs to optimize their CO2 capturing performance from both dry and wet gases.The prepared composite membranes indicated enhanced filler-polymer interfacial adhesion,consistent distribution of nanofiller,and thermally established matrix configuration.CO2 permeability of the membranes was enhanced as demonstrated by gas sorption and permeation experiments performed under both dry and wet conditions.As compared to neat Ultrason(R) membrane,CO2 permeability of the composite membrane doped with 40 wt％ ZIF-300 nanocrystals was increased by four times without disturbing CO2/N2 ideal selectivity.In contrast to majority of previously reported membranes,key features of the fabricated MMMs include their structural stability under humid conditions coupled with better and unaffected gas separation performance.     

含Si原子乙烯基单体的聚合及其膜的制备与研究

近年来,含硅聚合物由于其特殊的化学性质而成为科研热点.文章进行了烯丙氧基三甲基硅烷的均聚以及其分别与甲基丙烯酰氧乙氧基三甲基硅烷和乙酸乙烯酯单体的共聚研究.用凝胶渗透色谱仪测试了共聚物的分子量并计算其聚合度,并将所得聚合物做成气体分离膜,采用膜分离测试分析仪测试它们的气体透过性能.结果表明：烯丙氧基三甲基硅烷与乙酸乙烯酯共聚物膜对CO2具有优先选择透过性,在CH4/CO2的气体透过性测试中分离率达到了3.1,在N2/CO2的气体透过性测试中分离率更是达到了11.5.     

Enhanced permeation performance of polyether-polyamide block copolymer membranes through incorporating ZIF-8 nanocrystals

Membrane-based CO2 separation is a promising alternative in terms of energy and environmental issues to other conventional techniques.Polyether-polyamide block copolymer (Pebax) membranes are promising for CO2 separation because of their excellent selectivity,but limited by their moderate gas permeability.In this study,fresh-prepared zeolitic imidazolate framework-8 (ZIF-8) nanocrystals were integrated into the Pebax(R)1657 matrices to form mixed matrix membranes.The resulting membrane exhibits significantly improved CO2 permeability (as high as 300％ increase),without the sacrifice of the selectivity,to the pristine polymer membrane.Several physical characterization techniques were employed to confirm the good interfacial interaction between ZIF-8 fillers and Pebax matrices.The effect of added ZIF-8 fillers on the transport mechanism through MMMs is also explored.Mixed-gas permeation for both CO2/N2 and CO2/CH4 was also evaluated.The separation performance for CO2/CH4 mixtures on the ZIF-8/Pebax MMMs is very close to the Roberson upper bound,and thus is technologically attractive for purification of natural gas.     

小晶粒NaX沸石膜的制备与表征

分别以硅溶胶和异丙醇铝为硅源和铝源,采用预涂晶种的方式,用水热合成法在氧化铝载体上合成出小晶粒NaX分子筛膜. 各组分配比为：SiO2:Al2O3=3.85~4.2, Na2O:SiO2=1.2~1.5, H2O:Na2O=40~60,用扫描电镜、Ｘ射线衍射等手段对沸石膜进行了表征,可以看到分子筛膜生长的晶粒细小,沸石晶体的大小在500~800 nm,生长致密良好,覆盖完全,膜厚约为10 mm. 小晶粒NaX沸石膜的H2渗透率为 2.45′10-6 mol×m2/(s×Pa),H2/N2的理想分离系数达到4.21,H2/C3H8的理想分离系数达到7.56,超过对应的努森扩散值3.74和4.69.     

CO2/N2 separation using supported ionic liquid membranes with green and cost-effective [Choline][Pro]/PEG200 mixtures

The high price and toxicity of ionic liquids(ILs) have limited the design and application of supported ionic liquid membranes(SILMs) for CO_2 separation in both academic and industrial fields. In this work, [Choline][Pro]/polyethylene glycol 200(PEG200) mixtures were selected to prepare novel SILMs because of their green and costeffective characterization, and the CO_2/N_2 separation with the prepared SILMs was investigated experimentally at temperatures from 308.15 to 343.15 K. The temperature effect on the permeability, solubility and diffusivity of CO_2 was modeled with the Arrhenius equation. A competitive performance of the prepared SILMs was observed with high CO_2 permeability ranged in 343.3–1798.6 barrer and high CO_2/N_2 selectivity from 7.9 to 34.8.It was also found that the CO_2 permeability increased 3 times by decreasing the viscosity of liquids from 370 to38 m Pa·s. In addition, the inherent mechanism behind the significant permeability enhancement was revealed based on the diffusion-reaction theory, i.e. with the addition of PEG200, the overall resistance was substantially decreased and the SILMs process was switched from diffusion-control to reaction-control.     

超临界流体沉积制备[Emim][BF4]支撑型离子液体膜及其气体分离性能

为了进一步提高支撑型离子液体膜的制备效率及其CO2气体分离性能,将离子液体[Emim][BF4]以超临界流体沉积法负载到非对称的Al2O3支撑体内,制备了一系列支撑型离子液体膜,分别测定了CO2和N2两种纯气体在其中的渗透率,探究了制备参数(沉积时间、离子液体加入量和共溶剂加入量)对膜性能的影响规律。结果表明,基于[Emim][BF4]制备支撑型离子液体膜时,制备效率高且成品性能好。在最佳制备条件(沉积时间1 h、离子液体加入量1.875 mg/mL和共溶剂加入量11.25vol%)下所制得的支撑型离子液体膜的离子液体的负载量为2.6 mg/g,CO2和N2的渗透率分别为6.4和0.14 GPU,CO2/N2选择性为45.3。该支撑型离子液体膜既接近[Emim][BF4]的理论选择性上限,又达到了Robeson上限,同时具有良好的CO2气体渗透率和CO2/N2选择性。通过对比基于其他三种离子液体的支撑型离子液体膜的制备工艺和成品性能,发现在超临界流体沉积法中,用表面张力更大的离子液体并提高其在超临界流体中的浓度有利于大幅提升制备效率,其中离子液体浓度主要由其种类、加入量和共溶剂加入量等因素决定。选用低黏度和高CO2/N2溶解选择性的离子液体有利于提升支撑型离子液体膜的气体分离性能。