超临界二氧化碳在聚合物整体接枝改性中的应用

聚烯烃膜的整体改性是优化其性能并增加附加值的重要途径之一。常用的方法是在溶液中或者熔融状态下均相共混或接枝,但是对于那些既不溶解亦不熔融的聚合物,非均相法将是最佳的选择。而利用超临界二氧化碳可以将反应单体溶胀进入聚合物基体当中进行聚合反应,生成聚合物共混或接枝聚合物。本文综述了近年来超临界二氧化碳在固相聚烯烃整体接枝改...     

膜相渗透原位化学聚合法制备PAn/CA复合透膜

采用膜相渗透原位化学聚合法,使苯胺(An)原位化学聚合于醋酸纤维素(CA)基体膜的微孔壁中,得到均匀分布的PAn/CA复合导电透膜.通过研究聚合反应条件对复合透膜的导电性能和CO₂/O₂表观分离性能的影响,获得了制备性能较优的PAn/CA复合导电透膜的适宜条件.结果表明,采用膜相渗透化学原位聚合法制备的PAn/CA复合导电透膜,平均孔径明显变小,孔径分布变窄,具有优于CA基体膜的微孔结构形态.     

聚合物Langmuir—Blodgett膜研究进展

聚合物LB膜可用两种方法制备,一种是两亲单体成膜再进行聚合反应,另一种为直接从两亲聚合物在亚相表面铺展成膜并转移。本文综合聚合物LB膜的研究状况,包括两亲聚合物和非两亲聚合物,对聚合物LB膜的成膜特点,结构和性能作了描述,并简要介绍了聚合物LB膜的应用前景。     

聚糠醇炭分子筛膜的制备及O_2/N_2分离性能研究

以草酸为催化剂将糠醇单体直接聚合成所需黏度的聚糠醇液体作为涂膜液,仅需一步涂覆便可在价格低廉的煤基炭管支撑体上制备出高性能的聚糠醇炭分子筛膜.聚糠醇炭分子筛膜的热解过程、微观形貌和分离性能分别采用热重分析、扫描电镜以及O2、N2渗透实验进行表征.实验结果表明制备出的聚糠醇炭分子筛膜表面均匀且无缺陷.聚糠醇在热解过程中最终转化成具有超微孔的乱层石墨微晶结构.热解温度升高导致了起分离作用的有效超微孔尺寸的减小,进而表现出O2、N2的渗透速率逐渐降低,O2/N2的选择性逐渐增大的趋势.不同热解温度下制备的炭分子筛膜的O2渗透性和O2/N2选择性之间关系均超出了传统聚合物膜的Robeson上限.     

扑热息痛分子印迹聚合物膜选择性结合和渗透性质的研究

采用紫外光引发原位聚合的方法制备了具有支撑膜的扑热息痛分子印迹聚合物膜. 紫外分光光度法证明了模板分子与功能单体之间存在相互作用, 并据此选择了聚合反应时合适的溶剂. 用傅立叶红外光谱和扫描电镜分别测定了膜的结构和表面形貌. 渗透实验结果表明渗透时所用溶剂对渗透结果有重要影响. 合适的渗透溶剂可提高印迹膜对模板分子的渗透选择性.     

单体极性对甲基丙烯酸甲酯/丙烯酸丁酯/甲基丙烯酸钠无皂乳液共聚合的影响

研究了少量甲基丙烯酸钠（ＮａＭＡ）存在下单体极性对甲基丙烯酸甲酯（ＭＭＡ）／丙烯酸丁酯（ＢＡ）无皂乳液共聚合的影响．单体极性降低，使粒径减小、聚合速率提高、乳液表面张力和粘度降低、粒子表面电荷密度增大、聚合物分子量提高．ＭＭＡ／ＮａＭＡ无皂乳液聚合物只呈现一个玻璃化温度Ｔｇ，ＢＡ／ＮａＭＡ无皂乳液聚合物呈现两个Ｔｇ，ＭＭＡ／ＢＡ比为２∶１～１∶２的ＭＭＡ／ＢＡ／ＮａＭＡ无皂乳液聚合物呈现四个Ｔｇ，这是由于粒子外面相对富含ＯＳＯ－３和ＣＯＯ－基聚合物的亚层溶解了较多的水，使ＢＡ向粒子中心扩散，ＭＭＡ向外扩散，造成组成差异和相分离而引起的．     

基于相转化全过程的聚合物微孔膜功能化研究进展

传统的相转化过程主要通过相分离的热力学及动力学因素对聚合物膜的微孔结构进行调控,该过程是一个典型的物理过程,不涉及膜的表/界面功能调控。微孔膜的表/界面功能如抗污染性能、抗菌性能和抗凝血性能等对于分离性能具有重要影响。本文提出了基于相转化全过程赋予聚合物微孔膜表/界面特定化学功能的方法,即"化学相转化",其本质是围绕相转化全过程控制功能分子在膜及微孔表面的迁移路径及固定方式,实现了膜的表/界面功能化。总结了通过"化学相转化"进行聚合物微孔膜的表/界面功能化策略,根据功能分子迁移路径可分为:基于铸膜液的由内而外(Inside-out)迁移及原位交联功能化策略、基于凝固浴的由外而内(Outside-in)迁移及离域交联功能化策略、基于微孔膜的自上而下(Top-down)迁移及界面交联功能化策略,从而实现了聚合物微孔膜的表/界面功能化改性及其在水处理、油水分离和血液净化等方面的应用。"化学相转化"理论为高性能、多功能聚合物微孔膜的制备及其分离应用提供了新的研究思路。功能分子的引入也会对相转化过程产生影响,从而影响膜的微孔结构,本课题组将从微孔结构调控和表/界面功能化这两个方面完善"化学相转化"理论。     

聚合物/TiO2杂化纳米纤维微孔膜的制备及其在染料敏化太阳能电池中的应用

利用静电纺丝技术,制备了不同的聚合物/TiO2杂化纳米纤维微孔膜,吸附液体电解质后形成聚合物/TiO2杂化纳米纤维微孔膜准固态电解质,应用于制备准固态染料敏化太阳能电池(DSSCs).测试了电纺聚合物纳米纤维微孔膜电解质的吸液率、孔隙率、离子电导率等参数,研究了纳米纤维微孔膜准固态电解质DSSCs的光伏性能.结果显示,TiO2的掺入可提高聚合物/TiO2杂化纳米纤维微孔膜对液态电解质的浸润扩散性能,从而提高纳米纤维微孔膜对液态电解质的吸附能力.组装的DSSCs的光电转换效率可达液态电解质的90%以上,并具有较好的长期工作稳定性.     

超临界二氧化碳制备聚合物微孔膜的研究进展

超临界二氧化碳做非溶剂制备聚合物微孔膜是一个新的研究热点,具有传质系数高、聚合物膜干燥速度快且不破坏结构、溶剂容易回收、CO2可循环使用、CO2的低毒性与环境友好性等特点.本文介绍采用超临界CO2制备聚合物微孔膜的热力学及动力学原理,重点介绍近年来采用此技术制备微孔膜的研究成果,如以聚苯乙烯（PS）、聚丙烯腈（PAN）、聚醚砜（PES）等为基体的微孔聚合物膜.     

聚酰亚胺-二氧化硅杂化膜的制备及表征

 采用溶胶－凝胶法制备了两类具有不同二氧化硅含量的聚酰亚胺－二氧化硅（PI－SiO2）杂化膜,并用SEM,IR,TG－DTA,氮吸附和气体渗透性能测试等手段对该膜材料的表面形貌、结构、热性能、孔径分布和气体渗透性能进行了表征．结果表明,PI－SiO2膜材料中SiO2粒子的分散良好,与有机相之间存在着分相和键联;膜材料的玻璃化温度θg均随SiO2含量的增加而升高．相比之下,在酸性条件下制备的T系列杂化膜比在碱性条件下合成的S系列杂化膜对θg的影响更大一些;杂化膜具有较好的气体渗透性能和亲水性能,其H2O／N2和H2O／CH4的分离系数远大于努森扩散的理论值．     

Synthesis and study of MPNS/SMA nano-composite tanning agent

The radical polymerization of maleic anhydride（MA）,styrene（ST）with the vinyl groups introduced onto the surface of the nano-sized silica via solution polymerization method was developed.The methacryloxypropyl nano-sized silica（MPNS）was used as macromonomer and polymerized with maleic anhydride and styrene by initiating with BPO in toluene.The structure and properties of MPNS/SMA nano-composite were characterized by FT-IR spectra and TEM.Meanwhile,it was applied as tanning agent compared with the traditional styrene-maleic anhydride copolymer in leather.It was found that the applied leather had better quality characteristics with the addition of the nano-sized silica.     

An efficient nanofiltration membrane based on blending of polyethersulfone with modified (styrene/maleic anhydride) copolymer

In this study, styrene–maleic anhydride (SMA) copolymer was modified by ring opening reaction of its anhydride groups with diethanolamine (DEA). The modified SMA copolymer was blended in different concentrations (2.5, 4 and 5.5 %) with Polyethersulfone (PES) to improve the hydrophilicity of PES membranes and the corresponding blend membrane was prepared through phase inversion. The influence of SMA copolymer on morphology, mechanical properties, water flux, rejection and anti-fouling properties of blend membrane were investigated. The modified SMA and their composition were confirmed by FT-IR and ¹HNMR techniques. The asymmetric structure of membrane was revealed by SEM. The water flux and contact angle results show that the hydrophilicity of membrane surface was increased by addition of SMA copolymer. The better anti-fouling properties of the PES/modified SMA blend membranes in comparison with the PES membrane also confirmed that the hydrophilicity of blend membrane enhances.     

Polymers from renewable resources. II. A study in the radio chemical grafting of poly(styrene‐alt‐maleic anhydride) onto cellulose extracted from pine needles

A binary mixture of styrene and maleic anhydride has been graft copolymerized onto cellulose extracted from Pinus roxburghii needles. The reaction was initiated with gamma rays in air by the simultaneous irradiation method. Graft copolymerization was studied under optimum conditions of total dose of radiation, amount of water, and molar concentration previously worked out for grafting styrene onto cellulose. Percentage of total conversion (Pg), grafting efficiency (%), percentage of grafting (Pg), and rates of polymerization (R_p), grafting (R_g), and homopolymerization (R_h) have been determined as a function of maleic anhydride concentration. The high degree of kinetic regularity and the linear dependence of the rate of polymerization on maleic anhydride concentration, along with the low and nearly constant rate of homopolymerization suggest that the monomers first form a complexomer which then polymerizes to form grafted chains with an alternating sequence. Grafting parameters and reaction rates achieve maximum values when the molar ratio of styrene to maleic anhydride is 1 : 1. Further evidence for the alternating monomer sequence is obtained from quantitatively evaluating the composition of the grafted chains from the FT‐IR spectra, in which the ratio of anhydride absorbance to aromatic (CC) absorbance for the stretching bands assigned to the grafted monomers remained constant and independent of the feed ratio of maleic anhydride to styrene. Thermal behaviour of the graft copolymers revealed that all graft copolymers exhibit single stage decomposition with characteristic transitions at 161–165°C and 290–300°C. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1763–1769, 1999     

Hemocompatibility and ultrafiltration performance of PAN membranes surface‐modified by hyperbranched polyesters

Maleic anhydride was grafted onto a polyacrylonitrile (PAN) membrane surface via ultraviolet irradiation. Then, hyperbranched polyester, with varying numbers of hydroxyl end‐groups (H20, H30, and H40), was grafted onto the PAN membrane surface by the reaction of hydroxyl groups with anhydride groups of maleic anhydride. The modified membranes were characterized by scanning electron microscopy, static water contact angle, and attenuated total reflectance‐Fourier transform infrared spectroscopy measurements. The modified membranes showed a higher water flux and better antifouling properties than pristine PAN membranes, and their hydrophilicity was significantly improved. Membrane biocompatibility was characterized by platelet adhesion, and the results indicate that the modified membranes exhibited good biocompatibility. Copyright © 2016 John Wiley & Sons, Ltd.     

改性聚偏氟乙烯接枝共混聚苯乙烯磺酸膜的制备与性能

将苯乙烯添加到溶有原硅酸钠改性的聚偏氟乙烯(PVDF)N-甲基吡咯烷酮溶液中, 以过氧化苯甲酰(BPO)作引发剂, 苯乙烯直接接枝到原硅酸钠改性的PVDF链上, 成膜后磺化制备了聚偏氟乙烯接枝苯乙烯(PVDF-g-PSSA)膜. 采用傅立叶变换红外光谱(FT-IR)、扫描电镜(SEM)、能量扩散X射线(EDX)和多功能材料实验机表征了膜的结构、形貌及硫和硅的分布、机械强度、溶胀度, 使用阻抗分析和气相色谱仪研究了苯乙烯含量(w)对PVDF-g-PSSA膜的质子导电性能和阻醇性能的影响. 结果表明, 苯乙烯加入后, 原硅酸钠改性的PVDF与苯乙烯进行接枝共聚反应, 苯乙烯磺化反应不只是在膜表面进行, 同时渗入到膜中进行, 机械性能得到了改善. 质子电导率(σ)随苯乙烯质量分数的提高而升高. Na4SiO4为8%和苯乙烯为20%的PVDF-g-PSSA膜, 在25 ℃时溶胀度仅为20.4%, 甲醇透过系数在10-7 cm2·s-1数量级上, 比Nafion115膜的低一个数量级. 该膜具有较高的选择性, 在直接甲醇燃料电池中具有良好的应用前景.     

马来酸酐-苯乙烯多组分单体熔融接枝高密度聚乙烯机理及性能研究

用单螺杆挤出机制备了马来酸酐-苯乙烯(MAH-St)多单体熔融接枝高密度聚乙烯(HDPE)体系,研究发现添加St共同接枝,可以显著提高接枝物的接枝率.随着St的增加,接枝率先增大后有所降低.当两种单体物质的量比约为1:1时,接枝物的接枝率最高,此时接枝物的熔体流动速率(MFR)最小.即MAH接枝率越高,接枝物的MFR越...     

Glass bead grafting with poly(carboxylic acid) polymers and maleic anhydride copolymers

Glass beads were etched with acids and bases to increase the surface porosity and the number of silanol groups that could be used for grafting materials to the surfaces. The pretreated glass beads were functionalized using 3‐aminopropyltriethoxysilane (APS) coupling agent and then further chemically modified by reacting the carboxyl groups of carboxylic acid polymers with the amino groups of the pregrafted APS. Several carboxylic acid polymers and poly(maleic anhydride) copolymers, such as poly(acrylic acid) (PAA), poly(methacrylic acid) (PMA), poly(styrene‐alt‐maleic anhydride) (PSMA), and poly(ethylene‐alt‐maleic anhydride) (PEMA) were grafted onto the bead surface. The chemical modifications were investigated and characterized by FT‐IR spectroscopy, particle size analysis, and tensiometry for contact angle and porosity changes. The amount of APS and the different polymer grafted on the surface was determined from thermal gravimetric analysis and elemental analysis data. Spectroscopic studies and elemental analysis data showed that carboxylic acid polymers and maleic anhydride copolymers were chemically attached to the glass bead surface. The improved surface properties of surface modified glass beads were determined by measuring water and hexane penetration rates and contact angle. Contact angles increased and porosity decreased as the molecular weights of the polymer increased. The contact angles increased with the hydrophobicity of the attached polymer. The surface morphology was examined by scanning electron microscopy (SEM) and showed an increase in roughness for etched glass beads. Copyright © 2007 John Wiley & Sons, Ltd.     

四甲基氢氧化铵改性聚偏氟乙烯一步接枝聚苯乙烯磺酸油水分离膜的制备及性能

利用四甲基氢氧化铵(TMAH)聚偏氟乙烯(PVDF)进行改性,以过氧化苯甲酰(BPO)为引发剂,将苯乙烯磺酸(SSA)接枝到改性的PVDF骨架上,制得聚偏氟乙烯接枝聚苯乙烯磺酸(PSSA-g-PVDF)油水分离膜。 研究了TMAH质量分数对PSSA的接枝率和油水分离膜性能的影响,同时采用傅立叶变换红外光谱(FTIR)、扫描电子显微镜(SEM)和视频光学接触角测量仪测试了膜的结构和表面接触角。 结果表明,TMAH使PVDF脱去部分氟化氢(HF)产生碳碳双键,硫元素均匀地分布在分离膜中。 PSSA的接枝率随着TMAH的质量分数增加而升高,分离膜的水通量随接枝率的升高先增加后降低。 当TMAH质量分数为20%,分离膜的接触角在30 s内降低到37.2°,接枝率和水通量分别为22.1%、643.3 L/(m·h),截留率和水通量恢复率分别达到90.6%和93.7%,衰减率为7.1%。 循环测试显示膜的水通量恢复率和油水通量恢复率均在90%以上。     

Effect of comonomer sorption on radiation-induced copolymer grafting onto polyethylene and EVA films in the vapor phase

Radiation-induced copolymer grafting of acenaphthylene and maleic anhydride onto polyethylene or EVA film in the vapor phase was carried out and the effect of comonomer sorption on the grafting was studied. When polyethylene film was used as a backbone polymer, the sorption of the binary monomers during the grafting increased linearly as the grafting reaction proceeded. The marked increase was probably caused by the formation of a grafted layer. Particularly, the sorption of maleic anhydride was brought about by the existence of a grafted layer. In grafting onto EVA film, the content of maleic anhddride in the grafted copolymer increased with the increasing content of vinyl acetate in EVA. Continuous measurements of sorption of the comonomers onto EVA and grafted EVA films were carried out by use of an electrobalance. The distinctive feature of the sorption was that the equilibrium sorption of acenaphthylene or maleic anhydride onto the grafted EVA film increased and the diffusion constants for both comonomers decreased markedly with increasing percentage of graft. The copolymer grafting was explained from these results by assuming that the monomer molecules are supplied to the propagating chain ends mostly through a sorbed state on the polymer film.     

PSSA pore-filled PVDF membranes by simultaneous electron beam irradiation: Preparation and transport characteristics of protons and methanol

Polystyrene sulfonic acid (PSSA) pore-filled poly(vinylidene fluoride) (PVDF) membranes have been prepared using simultaneous electron irradiation method. Porous PVDF films were grafted by pre-swelling in styrene solution and subsequent irradiation with an electron beam (EB) under nitrogen atmosphere and at ambient temperature. The grafted films i.e. polystyrene (PS) pore-filled PVDF were subsequently sulfonated with a diluted mixture of chlorosufonic acid. The effects of the reaction parameters on the content of PS grafted in the pores of PVDF films were investigated. The chemical and morphological properties of the membranes in comparison with their un-grafted and grafted counterparts were studied by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The transport properties of these membranes such as ionic conductivity and methanol permeability were evaluated and correlated with the content of PS grafted in the pores of the PVDF films. The PSSA pore-filled PVDF membranes with PS content in the pores of 40% and above showed superior performance characteristics compared to Nafion 117 membrane and therefore can be potential alternatives to improve the performance of direct methanol fuel cell (DMFC).