Effect of molecular structure on performance of electroactive ionic acrylic copolymer–platinum composites

The character and performance of a new ionic polymer–metal composite (IPMC) prepared with a melt‐processable fluorinated acrylic copolymer were examined. The fluorinated acrylic copolymer was synthesized by the copolymerization of fluoroalkyl methacrylate (DuPont Zonyl) and acrylic acid, and it was compression molded to attain membranes of various thicknesses. The current and displacement responses by electric stimulus were measured to study the effects of the ionic concentration, thickness, and countercation on the actuation of the IPMC. The ionic center of the acrylic copolymer was essential for the actuation of the IPMC; however, too much ionic center induced excessive water uptake, which caused adverse effects on the performance of the IPMC. When the applied voltage was 5 V, the largest current and displacement responses were observed with the IPMC prepared by a fluorinated acrylic copolymer containing 11.8 wt % acrylic acid. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1732–1739, 2005     

New ionic polymer–metal composite actuators based on PVDF/PSSA/PVP polymer blend membrane

Ionic polymer–metal composite (IPMC) actuators that display continuously large actuation displacements without back relaxation and with large blocking force at low direct current (DC) voltages are used as biomimetic sensors, actuators and biomedical devices. This article reports the preparation and actuation performance of new IPMC actuators based on the polyvinylidene fluoride (PVDF)/polystyrene sulfonic acid (PSSA)/polyvinyl pyrrolidone (PVP) polymer blend membrane, which requires low voltage DC. The performance results of the proposed IPMC actuators are compared with Nafion‐based IPMC actuators. In the blend membrane, PVDF is the hydrophobic polymer, PSSA is the polyelectrolyte, and PVP is the hydrophilic basic polymer. The proposed IPMC actuators based on the PVDF/PSSA/PVP blend membrane of polymer mixture ratios of 60/15/25 and 50/25/25 gave higher actuation displacement and higher blocking force at low DC voltages than the Nafion‐based IPMC actuator. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

玉米秸秆接枝丙烯酸-丙烯酰胺树脂的制备与吸水性能

以醚化预处理玉米秸秆(PTCS)为基体,丙烯酸(AA)和丙烯酰胺(AM)为单体,过硫酸钾为引发剂,N,N'-亚甲基双丙烯酰胺(MBA)为交联剂,采用水溶液聚合法制备PTCS接枝AA、AM共聚物[PTCS-g-P(AA-co-AM)]。研究了合成条件对树脂吸水率的影响,考察了树脂重复吸水和保水性能,并用红外光谱(FTIR)、电子扫描电镜(SEM)表征了产物的结构和形貌。结果表明,在m(PTCS):m(AA):m(AM)= 1:5:2,丙烯酸中和度为70%,K₂S₂O₈为0.6%,MBA为0.2%,60℃反应3h条件下,制备高吸水性树脂的吸水率最大,对蒸馏水和0.9% NaCl水溶液的吸水率分别为144.04g/g、30.60g/g,且重复吸水和保水性能良好。     

Influence of additives on the properties of casting nafion membranes and SO‐based ionic polymer–Metal composite actuators

As a typical smart material, ionic polymer metal composite (IPMC) has a sandwich structure, which consists of a base membrane and two thin metallic electrodes on both sides of the base membrane. The properties of the base membrane, Nafion as the most used base material, strongly affect the performance of IPMC actuator. This paper reports the effects of different additives, such as ethylene glycol (EG), dimethyl sulfoxide (DMSO), N, N′‐dimethyl formamide (DMF), and N‐methyl formamide (NMF), on the performances of the casting membranes and SO‐based IPMC actuators. Studies have shown that the microstructures of the casting membranes with EG and DMSO as additives are more loose and amorphous, leading to higher water contents and thus higher conductivity than those with DMF, NMF, and Nafion 117. Among the casting membrane‐based IPMC actuators, EG‐based IPMC actuator has larger deformation and blocking force, higher strain energy density and conversion efficiency at 2 V DC voltage, whose electromechanical properties are most close to that based on Nafion 117. POLYM. ENG. SCI., 54:818–830, 2014. © 2013 Society of Plastics Engineers     

一种疏水缔合聚合物的合成及溶液性能

将十八烷基-二甲基甲代烯丙基氯化铵(C18DMMAAC)作为疏水单体,与丙烯酸(AA)、丙烯酰胺(AM)在水溶液中通过自由基聚合得到疏水缔合聚合物HAPAM-18,通过1HNMR和红外光谱对其结构进行了表征。最佳的聚合反应条件为:n(AM)∶n(AA)∶n(C18DMMAAC)=74.94∶25∶0.06,AA的摩尔中和度为95%,单体总质量分数为20%,引发剂质量分数为0.05%(以单体总质量计),温度45℃,反应时间12 h。研究表明,聚合物溶液的临界缔合质量浓度为2 g/L;聚合物溶液对温度较为敏感,80℃时黏度保留率为70.93%;聚合物溶液仍为剪切变稀的假塑性流体,但表现出良好的抗剪切性能,剪切1 h后黏度保留率达115%;由于设计为含较多阴离子的聚合物,该聚合物的抗盐性较差。     

Enhanced Weathering Resistance of Radiata Pine Wood by Treatment with an Aqueous Styrene/Acrylic Acid Copolymer Dispersion

Radiata pine (Pinus radiata Don.) sapwood was treated with an aqueous dispersion solution of styrene/acrylic acid (St/AA) copolymer (5, 15, or 25%) and the treatment effect on weathering of wood was determined. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy suggested that the St/AA treatment delayed lignin degradation during artificial weathering; the protection effect increased with St/AA concentration. Decrease in water contact angle upon weathering for the treated wood was also slower than for the untreated control. Scanning electron microscopy revealed that the St/AA polymer filled some wood cell lumina, which facilitates to inhibit moisture and light (especially ultraviolet light) penetration into wood. During 12?months of outdoor exposure, the St/AA-treated wood boards had lower moisture content and less detachment of earlywood cells than the untreated controls. Treatments with St/AA stabilized the surface color by inhibiting photo-oxidation of cell wall polymers and propagation of staining fungi. The results suggest that treatment with St/AA can substantially improve wood’s resistance to weathering.     

High-viscoelastic graft modified chitosan hydrophobic association polymer for enhanced oil recovery

The conventional partially hydrolyzed polyacrylamide (HPAM) is greatly restricted by its single linear molecular structure in oil reservoirs with severe reservoir conditions such as high temperature and high salt. In this article, the chitosan (CS) grafted imidazoline monomer copolymer (CS-g-AM/AA/NIDA) was prepared from N-maleyl CS (N-MCS), acrylamide (AM), acrylic acid (AA), 1-(2-N-acryloylaminoethyl)-2-oleoyl imidazoline (NIDA) by free radical copolymerization. The structure was determined by means of Fourier transform infrared spectroscopy, ¹H nuclear magnetic resonance spectroscopy, scanning electron microscope, thermal gravimetric analysis, and so forth, which confirmed the successful preparation of the copolymer with good thermal stability. Under the same conditions, compared with HPAM and copolymer CS-g-AM/AA, CS-g-AM/AA/NIDA greatly increased the viscosity of the aqueous solution and exhibited excellent shear stability (viscosity retention rate 15.62, 4.91, and 11.54% at 510 s⁻¹), temperature resistance (the viscosity retention rate reached 50.89, 24.50, and 36.59% at 120°C) and salt resistance (14,000 mg/L NaCl: viscosity retention rate up to 17.27, 8.26, and 14.60%). In addition, core flooding experiments showed that oil recovery could be enhanced by up to 8.08% by CS-g-AM/AA/NIDA. As a natural polymer material, CS has hardly been reported for polymer flooding, and it is expected to replace general polymers in tertiary oil recovery.     

Synthesis of full interpenetrating network membranes of poly(acrylic acid-co-acrylamide) in the matrix of polyvinyl alcohol for dehydration of ethylene glycol by pervaporation

Polyvinyl alcohol (PVOH) has been chemically modified by crosslink copolymerization of acrylic acid (AA) and acrylamide (AM) in aqueous solution of PVOH and finally crosslinking the copolymer with methylene bis acrylamide (MBA) and PVOH with glutaraldehyde to produce a full interpenetrating network (FIPN) membrane. Accordingly, three such fully crosslinked IPNs i.e. FIPN25, FIPN50 and FIPN75 have been synthesized with different mass ratio of PVOH:copolymer i.e. 1:0.25 (FIPN25), 1:0.50 (FIPN50) and 1:0.75 (FIPN75). These full IPN membranes were used for pervaporative dehydration of ethylene glycol (EG). All of these IPN membranes were characterized with various conventional methods like FTIR, mechanical properties, DTA and SEM. The performances of the membranes were evaluated in terms of sorption and pervaporative dehydration of EG. The IPN membranes were found to show preferential sorption and diffusion for water. Flux and water selectivity of these membranes were found to increase with increasing amount of copolymer in PVOH matrix. However, among the three membranes, FIPN75 were found to show the highest flux but lower selectivity for water while FIPN50 membrane showed optimum performance in terms of both flux and selectivity. Diffusion coefficient and plasticization interaction of water and EG through all the IPN membranes were determined using modified solution-diffusion model.     

Surface modification of polyamide TFC membranes via redox‐initiated graft polymerization of acrylic acid

In this work, the redox‐initiated graft polymerization of acrylic acid (AA) onto the surface of polyamide thin film composite membranes has been carried out to enhance membrane separation and antifouling properties. The membrane surface characteristics were determined through the attenuated total reflection Fourier transform infrared spectra, scanning electron microscopy, atomic force microscopy, and water contact angles. The membrane separation performance was evaluated through membrane flux and rejection of some organic compounds such as reactive red dye (RR261), humic acid, and bovine serum albumin in aqueous feed solutions. The experimental results indicated that the membrane surfaces became more hydrophilic and smoother after grafting of AA. The modified membranes have a better separation performance with a significant enhancement of flux at a great retention. The fouling resistance of the modified membranes is also clearly improved with the higher maintained flux ratio and the lower irreversible fouling factor compared to the unmodified one. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45110.     

Synthesis and characterization of a salt‐resisting superabsorbent based on poly(acrylic acid) with sodium tungstate as a crosslinker

A novel salt‐resistant superabsorbent polymer was synthesized by solution polymerization from the monomer acrylic acid (AA) with potassium persulfate as the initiator. Sodium tungstate was first employed as a crosslinker in the preparation to achieve a better crosslinked polymer (WPAA). In addition to the xerogel WPAA, sodium hydroxide and tris(2‐hydroxyethyl)amine (TEA) were introduced for the preparation of WPAA–sodium and WPAA–TEA hydrogels, respectively. The effect on the water absorbency of factors such as the reaction temperature, degree of neutralization of AA, and amounts of the crosslinker sodium tungstate and the initiator were investigated. The crosslinked xerogels were characterized with infrared spectroscopy. These crosslinked superabsorbent composites with sodium tungstate were characterized with thermogravimetric analysis and scanning electron microscopy. The water absorbencies of these superabsorbent composites in water and saline solutions were investigated. Results obtained from this study showed that under the same synthesis conditions, in comparison with superabsorbent composites with an aluminum salt as a crosslinker and styrene as a graft copolymer, the salt resistance of the superabsorbent composite synthesized with sodium tungstate as a crosslinker was obviously enhanced. Moreover, the WPAA–TEA xerogel had absorbency values of 223.6 and 81.9 g/g for distilled water and a 0.9 wt % NaCl solution, respectively, and it showed better salt resistance and a better water‐absorbing rate than the WPAA–sodium xerogel because of the modification with triethanolamine. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Functional copolymer/organo‐montmorillonite nanoarchitectures. IX. Synthesis and nanostructure–morphology–thermal behaviour relationships of poly[(maleic anhydride)‐alt‐(acrylic acid)]/organo‐ montmorillonite nanocomposites

Functional copolymer/clay hybrids were synthesized by radical‐initiated interlamellar copolymerization of maleic anhydride/maleic acid and acrylic acid with 2,2′‐azobis(2‐methylpropionamidine) dihydrochloride as a water‐soluble ionizable radical initiator in the presence of reactive (octadecylamine‐montmorillonite (ODA‐MMT)) and non‐reactive (dimethyldodecylammonium‐montmorillonite) organoclays at 60 °C in aqueous medium under nitrogen atmosphere. The monomers were dissolved in aqueous medium, and the two types of clay particles used were easily dissolved and dispersed partially swollen, respectively, in deionized water. Structure, thermal behaviour and morphology of the synthesized nanocomposites were investigated using Fourier transform infrared spectroscopy, X‐ray diffraction, differential scanning calorimetry, thermogravimetric analysis, and scanning and transmission electron microscopy. It is demonstrated that intercalative copolymerization proceeds via ion exchange between organoclays and carboxylic groups of monomers/polymers, which essentially improves interfacial interactions of polymer matrix and clay layers through strong hydrogen bonding. In the case of intercalative copolymerization in the presence of ODA‐MMT clay, a similar improvement is provided by in situ hydrogen bonding and amidolysis of carboxylic/anhydride groups from copolymer chains with primary amine groups of ODA‐MMT. The nanocomposites exhibit higher degree of intercalation/exfoliation of copolymer chains, improved thermal properties and fine dispersed morphology. Copyright © 2011 Society of Chemical Industry     

High Polymer Content 2,5‐Pyridine‐Polybenzimidazole Copolymer Membranes with Improved Compressive Properties

Three series of polybenzimidazole (PBI) random copolymers (2,5‐pyridine‐r‐meta‐PBI, 2,5‐pyridine‐r‐para‐PBI, and 2,5‐pyridine‐r‐2OH‐PBI) were synthesized and cast into phosphoric acid (PA) doped membranes using the PolyPhosphoric Acid (PPA) Process. Copolymer composition was adjusted using co‐monomers that impart high and low solubility characteristics to simultaneously control overall copolymer solubility and gel membrane stability. Measured under a static compressive force at 180 °C, copolymer membranes generally exhibited decreased creep compliance with increasing polymer content. Within each series of copolymer membranes, increasing polymer contents proportionally reduced the phosphoric acid/polymer repeat unit (PA/PRU) ratios and their respective proton conductivities. Some copolymer membranes exhibited comparable fuel cell performances (up to 0.66 V at 0.2 A cm⁻² following break‐in) to para‐PBI (0.68 V at 0.2 A cm⁻²) and equal to 3,5‐pyridine‐based high solids membranes. Furthermore, 2,5‐pyridine copolymer membranes maintained a consistent fuel cell voltage of >0.6 V at 0.2 A cm⁻² for over 8600 h under steady‐state operation conditions. Phosphoric acid loss was monitored during long‐term studies and demonstrated acid losses as low as 5.55 ng cm⁻² h⁻¹. The high‐temperature creep resistance and long‐term operational stabilities of the 2,5‐pyridine copolymer membranes suggest that they are excellent candidates for use in extended lifetime electrochemical applications.     

Retention properties of arsenate anions of water‐soluble polymers by a liquid‐phase polymer‐based retention technique

The retention properties of arsenic ions from an aqueous solution by water‐soluble cationic polymers and cationic–anionic copolymers were investigated. Poly[(3‐methacryloylamine)propyl]trimethylammonium chloride [P(ClMPTA)] and poly[(3‐methacryloylamine)propyl]trimethylammonium chloride–co–acrylic acid [P(ClMPTA‐co‐AA] were synthesized by radical polymerization. The copolymers were prepared with feed mole ratios of ClMPTA to AA of 1 : 1, 1 : 2, and 2 : 1. The copolymer compositions were evaluated by FTIR spectroscopy, TG‐DSC, and elemental analysis. The liquid‐phase polymer‐based retention (LPR) technique was used. This technique consists of retention of arsenate anions by the quaternary ammonium salt of a water‐soluble polymer in a filtration membrane cell. It was shown that the polymers could bind H₂AsO species from an aqueous solution more selectively at pHs of 6 and 8, than at a pH of 4. An increase in the polymer concentration was associated with increased retention capacity but not linearly. At the highest concentration the influence of pH was better observed. Investigation of copolymers showed the concerted action of polycations and polyanions on the ability to retain arsenic. At the lowest pH, the role of ionic strength of the media had a remarkable effect on the retention ability, independently of copolymer composition. At a pH of 6 a copolymer polycation/polyanion composition of 2 : 1 had the highest selective effect. At a pH of 8, a nonequimolar copolymer composition showed the same efficiency for the retention of arsenate species. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2677–2684, 2006     

蔗渣纤维丙烯酸高吸水树脂的制备

以蔗渣纤维为原料,丙烯酸为接枝单体,N,N-亚甲基双丙烯酰胺为交联剂,K2S2O8为引发剂,通过溶液聚合的方法合成了蔗渣纤维（sugarcanebagasse,SCB）与聚丙烯酸（polyacrylicacid,PAA）的接枝共聚高吸水树脂（scB—g—PAA）。研究了丙烯酸用量、引发剂用量、交联剂用量以及中和度对吸水树脂吸水倍率的影响,结果表明,该接枝共聚吸水树脂的最佳合成条件是以丙烯酸用量为标准,蔗渣纤维、K2S2O8、交联剂用量分别是10％、2％、0．1％,中和度为80％,共聚物吸水倍率最高为765．7g·g-1。     

离子聚合物金属复合材料的电形变性能研究

以乙烯-乙烯醇共聚物（EVOH）的主链为骨架,利用直接磺化反应制得离子聚合物膜（EVOH—g—SO3H）,然后以戊二醛为交联剂对其进行交联改性,得到EVOH—g—SO3H交联基体膜（EVOH—g—GSO3H）。最后采用化学还原工艺得到了以EVOH—g—GSO3H为基体的离子聚合物金属复合材料（IPMC）。讨论了磺化度、失水速率、负载电压等对IPMC电形变性能的影响。结果表明：磺化度dx为15．64％、33．25％、43．53％的IPMC顶点最大形变位移分别为7．53mm、17．02mm、32．11mm。涂有油脂保护层的IPMC失水速率和失水量均比未涂保护层的要小,涂有油脂保护层的IPMC顶点最大形变位移可达29．02mm,IPMC可以连续形变32次。负载电压越高形变量越大,频率越高形变量越小。     

Surface characteristics of water‐soluble cationic fluoro copolymers containing perfluoroalkyl,quaternized amino,and hydroxyl groups

Various water‐soluble cationic fluoro copolymers in quaternized form with perfluoroalkyl, amino, and hydroxyl groups were prepared by varying the contents of perfluoroalkyl ethyl acrylate (FA), 2‐(dimethylamino) ethyl methacrylate (DAMA), and 2‐hydroxyethyl methacrylate (HEMA). The solvent polymerization was carried out in acetone, with the subsequent addition of acetic acid to form a quaternized polymer. Polyurethanes films were prepared by curing aqueous solutions containing water‐soluble cationic fluoro copolymers and a blocked isocyanate at 190°C. The surface characteristics of the water‐soluble cationic fluoro copolymers and the polyurethanes were investigated on the basis of FA and DAMA contents. The contact angles for both water and methylene iodide (MI) on the cationic fluoro copolymer and the polyurethane increase steadily as FA content increases, and decrease gradually with increasing DAMA content. The contact angles on the polyurethane are slightly higher than those on the cationic fluoro copolymer. The cationic fluoro copolymer and the polyurethane with FA content of 40 wt % and DAMA content of <30 wt % show extremely low surface free energies of 13–15 dynes/cm. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3702–3707, 2002     

3D-Printed Poly(acrylic acid–vinylimidazole) Ionic Polymer Metal Composite Actuators

Ionic polymer–metal composites (IPMC)—constructed using an ionic polymer sandwiched between metal electrodes—have shown great potential for the fabrication of soft actuators. IPMC architectures have many advantages including low actuation voltage, fast response, basic control, and relatively light weight. Poly(acrylic acid) (PAA)-based ion exchange membranes are of particular interest for IPMC devices due to their large ion exchange capacity and ease of preparation; however, they suffer from relatively weak mechanical strength. Here, PAA-based soft actuators are synthesized with enhanced mechanical properties and proton conductivity through the incorporation of hydrogen bonding interactions with imidazolium groups via copolymerization with 1-vinylimidazole. In addition to examining the impact of composition on physiochemical (swelling, glass transition, decomposition, Young's modulus, etc.) and electrochemical (specific capacitance) properties, an additive manufacturing process, digital light projection (DLP), is utilized to fabricate complex geometries demonstrating the potential for the fabrication of IPMC devices with complex actuation modalities. Planar DLP 3D-printed IPMC actuators of varied polymer compositions are fabricated with activated carbon and copper electrodes, and their actuation performance is evaluated in air, where large bending deformation is observed (14°–37°).     

AM-AA-ADMOAB共聚物的合成及其水溶液的黏度性能

通过丙烯酰胺 (AM)、丙烯酸 (AA)与甲基丙烯酰氧乙基二甲基辛基溴化铵 (ADMOAB)共聚 ,合成了疏水化水溶性共聚物 (HAPAM)。考察了HAPAM的组成、质量浓度及无机盐对其水溶液黏度行为的影响。发现组成对黏度有直接影响 ,水溶液黏度随共聚物的质量浓度增加而增大并存在临界缔合质量浓度 ρ ,ρ 与其组成紧密相关。结果表明 :由于在聚合物中引入了疏水结构及两性离子结构 ,这类聚合物表现出较好的抗盐性能     

工艺因素对黄胞胶接枝丙烯酸高吸水性树脂吸水性能的影响

以黄胞胶(XG)、丙烯酸(AA)为主要原料,N,N′-亚甲基双丙烯酰胺(MBAA)为交联剂,过硫酸铵(APS)为引发剂,合成了XG接枝AA高吸水性树脂。通过单因素试验研究了单体配比、中和度、引发剂用量、交联剂用量、反应时间和反应温度等对该树脂吸水性能的影响,采用正交试验法优选出最佳制备工艺条件,并对接枝共聚物的结构进行了表征。结果表明:影响树脂吸水性能的主要因素是引发剂用量、单体配比和交联剂用量;最佳制备工艺条件为m(AA)∶m(XG)=6∶1,AA中和度为60%,w(交联剂)=0.4%和w(引发剂)=1.0%(均相对于XG而言),反应温度为60℃;在此工艺条件下制取的树脂,其最大吸水倍率为904g/g;接枝共聚物在1630cm-1处出现C=O特征吸收峰,说明AA已成功接枝在XG链上。     

聚(丙烯酸-丙烯酰胺)接枝辛基酚聚氧乙烯醚丙烯酸酯两亲性共聚物的合成及表征

以辛基酚聚氧乙烯醚丙烯酸酯(C8PhEO10Ac)为大分子单体,丙烯酸(AA)、丙烯酰胺(AM)为共聚单体,采用大分子单体接枝共聚法,制备了一种两亲性接枝共聚物(AA-AM-g-C8PhEO10Ac),用静态光散射(SLS)与GPC联用技术测得接枝共聚物的分子量为9.51×105,用FTIR、1H NMR和TG/DTA等手段对共聚物的结构及性能进行了表征。采用透射电子显微镜(TEM)对聚合物在水溶液中的自组装行为进行了初步研究。结果表明,AA-AM-g-C8PhEO10Ac在水溶液中自组装,形成球型胶束,随着浓度增大,趋向于形成更大的自组装体。