Preparation of carboxylate groups-containing thin films by plasma polymerization

Summary Plasma polymerization in a mixture of acrylic acid and carbon dioxide (CO₂) gas was investigated. The polymer deposition rate in plasma polymerization of acrylic acid increased by admixing CO₂ gas, and polymers containing carboxyl groups were formed. The amount of carboxyl groups alterable to carboxylate anions by treating with 0.1 N KOH solution or NH₃ gas reached twice of that formed in plasma polymerization without CO₂ gas.     

Sulfonic acid group-containing thin films prepared by plasma polymerization

Plasam polymerization of hydrocarbon/sulfure dioxide mixtures, C₂H/SO₂, C₂H₄/SO₂, and CH₄/SO₂ mixtures, was investigated to obtain thin films containing sulfonic acid groups. Plasma polymerization of C₂H₂/SO₂ and C₂H₂/SO₂ mixtures gave filmlike products but that of the CH₄/SO₂ mixtures did not. The plasma polymers possessed much amount of sulfur and oxygen moieties with hydrocarbon chains. The sulfur moieties involved thio, sulfite, and sulfonic acid groups. This groups was a main product and reached 70–80 mol % of the total sulfur moieties. The remains (20–30 mol %) were sulfonic acid and sulfite groups. The oxygen moieties were hydroxyl and carbonyl groups with small amount of carbonxyl groups. The plasma polymers showed and hydrophilicity (the surface energy was 54–56mN/m) and good antithrombogenity.     

Preparation and characterization of PVDF/silica hybrid membranes containing sulfonic acid groups

Organic–inorganic hybrid membranes of poly(vinylidene fluoride)‐cohexafluoropropylene (PVDF‐HFP) and silica composites containing sulfonic acid groups were prepared via in situ polymerization of tetraethoxysilane (TEOS) and sulfosuccinic acid (SSA) using the sol‐gel process. The membranes containing more sulfonic acid groups showed a higher vapor sorption and greater swelling behavior. The bound and free water content of the membrane is proportional to the SSA concentration. However, the hybrid membranes without SSA do not have free water. The ion conductivity of the membranes is proportional to the SSA concentration. Silica content in the hybrid membrane without SSA had great effect on their mechanical properties. Tensile modulus and yield stress increased and yield strain and elongation at break decreased with increased silica content. However, in the case of the hybrid membrane containing SSA modulus, yield stress decreased and yield strain and elongation at break increased with increased silica content due to the weak interactions between the hydrophobic polymer chain and the hydrophilic group of SSA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 209–218, 2004     

Swelling properties of copolymers of styrene and divinylbenzene containing sulfonic and carboxylic acid groups

Copolymers of styrene, divinylbenzene, and acrylic acid that have undergone sulfonation exhibited good water absorbency properties. Removal of the lower molecular weight fraction in the surface region of the copolymer particles by toluene extraction before sulfonation has further increased the water swelling capacity of the sulfonated copolymers. The extent of swelling of the UV‐irradiated copolymer could be related to the ratio of divinylbenzene to styrene. The less crosslinked copolymers were shown to absorb more water. The incorporation of more carboxylate groups in the copolymer could further increase its swelling capacity. Without UV irradiation, the carboxylate containing copolymer was found to absorb more water than the sulfonated copolymer. UV irradiation has induced more effective crosslinking in the carboxylate containing copolymer, hence impairing its water absorbency. By replacing styrene and divinylbenzene partially with butyl acrylate, whereby the amount of crosslinking was reduced, the copolymer was able to absorb water 110 times of its dry weight. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

含磺酸基/羧基水性聚氨酯的合成和表征

以磺酸基聚酯二醇(SIPG)和2,2–二羟甲基丙酸(DMPA)为亲水单体,以聚碳酸1,6–己二醇酯二醇(PHCDL)和异佛尔酮二异氰酸酯(IPDI)、1,6–己二异氰酸酯(HDI)为主要原料,采用预聚体法合成了水性聚氨酯(WPU)乳液。采用粒度分布分析、Zeta电位分析和黏度测试,考察了所制备的WPU乳液的性能。通过热重(TGA)、差示扫描量热(DSC)、动态力学分析(DMA)和拉伸测试对WPU形成的薄膜的热性能和力学性能进行表征。结果表明:WPU乳液粒径为70~100 nm,且具有良好的稳定性;当n(SIPG)∶n(DMPA)为1.5∶1时,制备的WPU乳液的w(不挥发物)高、平均粒径小、粒径分布窄,所得薄膜的力学性能好。     

Preparation and adsorption properties of resins containing amine,sulfonic acid,and carboxylic acid moieties

Completely water‐insoluble resins containing amine, carboxylic acid, and sulfonic acid as ligand groups were synthesized by radical polymerization in solution. The yield was higher than 97%. The resins were characterized by FTIR spectroscopy and thermal analysis. The metal ion retention properties at different pH values were investigated by a batch method. Metal ions studied were: Cu(II), Cd(II), Zn(II), Hg(II), Pb(II), and Cr(III). The metal ion binding ability depended strongly on the pH. The retention properties were also tested under competitive conditions. Elution of the metal ion was investigated in acid medium at different concentrations. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 700–705, 2003     

Preparation and adsorption properties of the chelating resins containing carboxylic,sulfonic, and imidazole groups

The crosslinked poly(1‐vinylimidazole‐co‐acrylic acid), P(VIm‐co‐AA), and poly(1‐vinylimidazole‐co‐2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid) P(VIm‐co‐APSA) were synthesized by radical polymerization and tested as adsorbents under competitive and noncompetitive conditions for Cu(II), Cd(II), Hg(II), Zn(II), Pb(II), and Cr(III) by batch equilibrium procedure. The resin–metal ion equilibrium was achieved before 1 h. The resin P(VIm‐co‐AA) showed a maximum retention capacity (MRC) value for Pb(II) at pH 3 and Hg(II) at pH 1 of 1.1 and 1.2 mEq/g, respectively, and the resin P(VIm‐co‐AA) showed at pH 3 the following MRC values: Hg(II) (1.5 mEq/g), Cd(II) (1.9 mEq/g), Zn(II) (2.7 mEq/g), and Cr(III) (2.8 mEq/g). The recovery of the resin was investigated at 25°C with 1 M and 4 M HNO₃ and 1 M and 4 M HClO₄. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2852–2856, 2003     

含有磺酸和羧酸基团的水性聚氨酯的研究

以聚氧化丙烯二醇(N210)和2,4-甲苯二异氰酸酯(TDI)为原料,通过逐步加聚反应,合成了聚氨酯预聚体;再以羧酸型亲水扩链剂二羟甲基丙酸(DMPA)和自制的磺酸型亲水扩链剂1,2-二羟基-3-丙磺酸钠(DHPA),通过扩链反应,制备了兼有磺酸盐和羧酸盐的水性聚氨酯乳液,烘干制胶膜,并对胶膜进行了红外光谱的表征以及耐水性能和力学性能的测试和分析;测定了乳液的固含量,重点研究了R值,亲水基团含量(DMPA和DHPA在预聚体中的百分含量)和DHPA在亲水基团中的含量对胶膜力学性能的影响。研究结果表明,通过逐步加聚和扩链反应,可成功地制得固含量高达70％的,兼有磺酸和羧酸的水性聚氨酯乳液;且当R值(NCO／OH)为2,亲水基团含量为5％,DHPA在亲水基团中的含量为20％时,胶膜的综合力学性能优良(断裂伸长率高达2 135％)。     

Preparation and metal ion adsorption properties of the resin containing sulfonic acid groups

In this study, we explored a new ion exchange material synthesized by radical polymerization of styrene and 2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid by using 2,2′‐azo‐isobutyronitrile (1 mol %) and divinylbenzene (0.5 mol %) as initiator and crosslinking reagents, respectively. The resin was obtained from a large excess (90%) of styrene in the feed. The yield was 72.3%. The resin was completely insoluble in water and characterized by elemental analysis, FTIR spectroscopy, scanning electron microscopy, and thermal analysis. The metal ion retention capability was investigated for Ag(I), Hg(II), Cd(II), Zn(II), Pb(II), and Cr(III). The effect of pH, time, and resin/metal ion mol ratio on the metal ion retention was studied. Selectivity of the resins from a mixture of metal ions and the maximum retention capacity at optimum pH were also determined. The recovery of the resin by using 1 and 4 M HClO₄ and HNO₃ demonstrated that it is possible to recover the resin above 80%. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1230–1235, 2003     

Preparation of transparent and conducting carbon nanotube/N-hydroxymethyl acrylamide composite thin films by in situ polymerization

The preparation of optically transparent and electrically conductive composite thin films composed of multi-walled carbon nanotube (MWCNT) and poly N-hydroxymethyl acrylamide were fabricated by a simple in situ polymerization technique. The film displays conductivities up to 10³ S/m depending on the MWCNT loading and a sheet resistance as low as 53 Ω/□ for an optical transparency greater than 95% at 550 nm. The dispersability characteristics of the suspension were determined by measuring specific surface charge, rheological behavior and UV–vis spectra.     

A novel route for the preparation of hybrid zwitterionic membranes containing both sulfonic and carboxylic acid groups

A novel route for the preparation of hybrid zwitterionic membranes containing both sulfonic and carboxylic acid groups is reported. Based on this synthetic methodology, a series of membranes were synthesized via sol–gel reaction, zwitterionization process, and the oxidization of the  SH group. FTIR spectra confirmed the corresponding reactions. The properties of these prepared membranes were characterized by ion-exchange capacity (IEC), water content, and pure water flux, etc. The anion-exchange capacity (AIEC), total cation-exchange capacity (CIEC_total), and the CIEC of the sulfonic groups (CIEC_sulf) of the membranes coated for 1–3 times were in the range of 0.017–0.12, 0.1–0.53, and 0.029–0.14 mmol g⁻¹, respectively. The measurement of water content showed that it was independent of pH values whether for the membranes coated once or twice. Pure water flux revealed a downward trend with the increased coating times. The surface SEM images of the produced membranes exhibited that these membranes' textures could be affected highly by the curing temperature, and excessively higher curing temperature would lead the membranes to brittle and chasm. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Alcohophilic gels: Polymeric organogels composing carboxylic and sulfonic acid groups

Polymeric organogels based on acrylic acid (AA) and sodium allyl sulfonate (SAS) were prepared through solution polymerization using a persulfate initiator and a polyethylene glycol diacrylate (PEGDA) crosslinker. FTIR spectroscopy, elemental, and rheological analyses were used for a preliminary characterization. Thermo‐mechanical analysis was also carried out for characterizing samples. Glass transition temperature (T_g) of copolymer was decreased after acid treatment which could be attributed to detachment of ion pairs during the post‐treatment. Due to counterion binding of Na⁺ to form ionomer, the poly(AA‐SAS) gels showed no polyelectrolyte behavior to have high swelling capacity in conventional alcohols, i.e., ethanol and methanol. It was postulated that modification via removing Na⁺ could help breaking ion pair aggregates which leads to swelling enhancement. Thus, poly(AA‐SAS) was treated with hydrochloric acid to remove (Na⁺) counterions. This modification led to the gel transform from ionomer regime to a polyelectrolyte regime in which free mobile ions were existed in the network. The gel swelling capacity was increased due to raise of mobile ions after the treatment. It was found that both of the acid concentration and treatment time had constructive influence on the gel alcohophilicity. The acid‐treated samples could imbibe ethanol and methanol as high as 25.8 and 39.5 g/g, respectively. They may be superior candidates for applications such as pharmaceuticals gels and fire starters. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Liquid-crystalline elastomers produced by chemical crosslinking agents containing sulfonic acid groups

A series of siloxane-based liquid-crystalline (LC) elastomers were synthesized by using chemical crosslinking agents containing sulfonic acid groups. The crosslink densities of the elastomers were determined by swelling experiments. Two kinds of melting temperature corresponding to crystallization of siloxane matrix and crystallization of LC segments were clearly detected. Some of the polymers exhibited smectic mesophase textures or cholesteric mesophase textures. A proposed model containing LC segment structure and ionic crosslinking lamellar structure separated by siloxane chains was given. The ion aggregated in domains forces the siloxane chains to fold and form an irregular lamellar structure. Ionic aggregates and LC segments may be dispersed each other to form multiple blocks with increasing ionic crosslinking content.     

含有磺酸基/羧基高固含量聚氨酯分散体的合成与表征

以磺酸盐聚醚二元醇(SPPG)作为软段亲水单体,DMPA作为硬段亲水单体,聚己二酸己二醇新戊二醇酯(PHNA)、异佛尔酮二异氰酸酯(IPDI)、六亚甲基二异氰酸酯(HDI)、三乙胺(TEA)、哌嗪为原料,采用丙酮法合成了固含量50%以上软硬段均含亲水的聚氨酯分散体(PUD)。研究表明,PUD的ζ电位处于-52～-72mV之间,具有良好的稳定性。亲水基团含量(HGC)、HDI/IPDI摩尔比的增加使胶粒平均粒径变小,粒径分布变窄,黏度增加;—SO3Na/—COOH摩尔比的减小,使小粒子体积分数在21%～28%,黏度显著减小。透射电镜(TEM)显示,分散体胶粒多为大小不一的球形结构,呈多元分布。DMA显示PUD胶膜具有良好的软硬段相容性和耐寒性。     

表面接枝高密度磺酸基聚苯乙烯的制备及表征

以无水溴化铝为催化剂,对氯苯甲醛为醛基化试剂,通过傅克反应在聚苯乙烯微球表面接枝醛基;基于醛基的可氧化性,利用还原剂硝酸铵铈将树脂微球表面的醛基自由基化,引发对苯乙烯磺酸钠在树脂微球表面聚合,并对其进行表征。结果表明,聚苯乙烯微球磺酸化改性成功,优化的磺化工艺条件为:醛基含量1.5 mmol/g的聚苯乙烯微球用量0.3 g,对苯乙烯磺酸钠质量浓度40 g/L,硝酸铵铈质量浓度40 g/L,反应温度70℃,在此条件下制备的树脂表面磺酸基含量为58 mmol/g。     

Preparation and electrochemical properties of gold nanoparticles containing carbon nanotubes-polyelectrolyte multilayer thin films

Multi-walled carbon nanotubes (MWCNT)/polyelectrolyte (PE) hybrid thin films were fabricated by alternatively depositing negatively charged MWCNT and positively charged (diallyldimethylammonium chloride) (PDDA) via layer-by-layer (LbL) assembly technique. The stepwise growth of the multilayer films of MWCNT and PDDA was characterized by UV–vis spectroscopy. Scanning electron microscopy (SEM) images indicated that the MWCNT were uniformly embedded in the film to form a network and the coverage density of MWCNT increased with layer number. Au nanoparticles (NPs) could be further adsorbed onto the film to form PE/MWCNT/Au NPs composite films. The electron transfer behaviour of multilayer films with different compositions were studied by cyclic voltammetry using [Fe(CN)₆]^3−/4− as an electrochemical probe. The results indicated that the incorporation of MWCNT and Au NPs not only greatly improved the electronic conductivity of pure polyelectrolyte films, but also provided excellent electrocatalytic activity towards the oxidation of nitric oxide (NO).     

Synthesis and characterization of bifunctional cellulose-g-poly(glycidyl methacrylate) based cation exchangers containing both sulfonic and carboxylic acid groups

Cellulose-g-poly(glycidyl methacrylate) copolymer was reacted with aqueous solutions containing mixtures of both sodium sulfite and citric acid, in order to synthesize bifunctional cation exchangers containing both sulfonic and carboxylic acid groups. Factors affecting the reaction, such as percent neutralization of citric acid with sodium carbonate, time, temperature, liquor ratio, reagents-to-epoxide molar ratio, and monosodium salt of citric acid-to-epoxide molar ratio were studied. Reaction conditions were selected to prepare five kinds of cation exchangers of different sulfonic and carboxy contents. These exchangers were characterized by potentiometric titrations, durability tests, and water solubility.     

Copolymers of N-vinylcarbazole with monomers containing carboxylic acid groups or carboxylic anhydride groups. I

N-Vinylcarbazole has been copolymerized with olefinic monomers possessing carboxylic acid or carboxylic anhydride functionality to yield copolymers with associated solubility in aqueous alkaline media. The copolymers were prepared to be part of a photoconductive lithographic printing plate assembly. The composition of the copolymers and the reactivity ratios have been evaluated. Copolymerization mechanisms are discussed. Alkali solubility has been measured in terms of the decoating speeds of films of the copolymers from aluminum plates. The major aim of producing an alkali-soluble copolymer that retained the photoconductive properties associated with poly(N-vinylcarbazole) was achieved in part.     

Novel network polymer electrolytes containing fluorine and sulfonic acid lithium prepared by ultraviolet polymerization

Poly(vinyl alcohol) (PVAL) and vinyl acetate‐vinyl alcohol copolymers (VAVAL) were esterified with 3,5‐dinitrobenzoyl chloride using the cycled urea N,N′‐dimethylpropyleneurea (1,3‐dimethyl‐3,4,5,6‐tetrahydro‐2(1H)‐pyrimidinone) (DMPU) as the solvent. Vinyl alcohol‐vinyl‐3,5‐dinitrobenzoate copolymers (VALVDNB) and vinyl acetate‐vinyl‐3,5‐dinitrobenzoate copolymers (VAVDNB) were obtained. High degrees of esterification were obtained when PVAL was esterified (86%). The degree of transformation was determined by ¹H‐NMR as well as by chemical analysis, and the structure of the resulting polymers by means of IR spectroscopy and ¹H‐ and ¹³C‐NMR. The microstructure of PVA, PVAL, VAVAL copolymers and VALVDNB copolymers were determined from ¹H‐ and ¹³C‐NMR techniques. The sequence distributions for VAVAL copolymers prepared by base‐catalyzed transesterification of PVA were blocky, while the distributions were close to random for VALVDNB copolymers obtained by esterification of PVAL. Thermal properties were studied by DSC. The T_g values of VAVAL, VALVDNB, and VAVDNB copolymers as a function of copolymer compositions were determined. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Aging and carbon dioxide plasticization of thin polyetherimide films

Industrial gas separation membranes have selective dense layers with thicknesses around 100 nm. It has long been assumed that these thin layers have the same properties as thick (bulk) films. However, recent research has shown that thin films with such thickness experience accelerated physical aging relative to bulk films and, thus, their permeation properties can differ significantly from the bulk. Thin films made from Extem^® XH 1015, a new commercial polyetherimide, have been investigated by monitoring their gas permeability. The permeability of the thin films is originally greater than the thick films but eventually decreases well below the permeability of the thick film. The CO₂ plasticization of Extem thin films is explored using a series of exposure protocols that indicate CO₂ plasticization is a function of film thickness, aging time, exposure time, pressure and prior history.