One-step synthesis of carbon functionalized with sulfonic acid groups using hydrothermal carbonization

Carbon functionalized with sulfonic acid groups has been synthesized using the one-step hydrothermal carbonization of furaldehyde and hydroxyethylsulfonic acid aqueous solution at 180 °C for 4 h. The carbon exhibited high acidity and comparable activities to sulfuric acid for the traditional acid-catalyzed reactions, which indicated that it has great potential for environment-friendly processes. The copolymerization method provides an efficient procedure for the synthesis of various functionalized carbons by one-step hydrothermal carbonization.     

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。     

含磺酸基介孔分子筛SBA-15-SO3H催化合成油酸乙酯

采用水热法直接合成含磺酸基的介孔分子筛SBA-15-SO₃H。以油酸和乙醇为原料催化合成油酸乙酯，进行了不同催化剂的对比实验以及催化剂组成、反应温度、酸醇物质的量比和催化剂用量等反应条件的考察。得到最佳反应条件：温度130 ℃，n(酸)∶n(醇)=1∶2.5，反应时间4 h，催化剂质量分数为10%。     

含磺酸基的介孔分子筛SO3H-SBA-15催化合成油酸丁酯

采用水热法直接合成了含磺酸基的介孔分子筛SO3H-SBA-15.以油酸与正丁醇为原料催化合成油酸丁酯,进行了不同催化剂的对比实验以及反应条件包括催化剂用量、反应温度、反应时间、酸醇摩尔比的考察.得到最佳反应条件为：催化剂质量分数为10%,反应温度120 ℃,反应时间3 h,酸醇摩尔比1∶2.     

Catalytic applications of sulfonic acid functionalized mesoporous organosilicas with different fraction of organic groups in the pore wall

Organosulfonic acid functionalized mesoporous organosilicas with different fraction of organic groups in the pore wall was synthesized in the presence of P123 (EO₂₀PO₇₀EO₂₀) by controlling the molar ratio of tetramethoxysilane (TMOS) to 1,2-bis(trimethoxysilyl)ethane (BTME) in the initial mixture during the co-condensation process of silane precursors in acidic medium. Structural characterizations (X-ray diffraction, nitrogen sorption analysis, and transmission electron microscopy) show that all materials have ordered hexagonal mesoporous structure with large pore diameter (7–9 nm). The existence of ethane and sulfonic acid groups in the material was verified by ²⁹Si MAS and ¹³C CP MAS NMR and X-ray photoelectron spectroscopy (XPS). The mesoporous solid acids can adsorb both water and hexane (the adsorption capacity for water and hexane is 240 and 600 mg/g, respectively) due to the existence of surface hydroxyl groups, propyl sulfonic acid group, and the ethane moiety. These mesoporous solid acids are efficient catalysts for the dehydration of 1-butanol and the hydration of propylene oxide (PO).     

Miscibility, crystallization and morphologies of syndiotactic polystyrene blends with isotactic polystyrene and with atactic polystyrene

Two-component blends of differing polystyrene (PS), one syndiotactic (sPS) and the other isotactic (iPS) or atactic (aPS), were discussed. The phase behavior, crystallization and microstructure of binary polystyrene blends of sPS/iPS and sPS/aPS with a specific composition of 5/5 weight ratio were investigated using optical microscopy (OM), differential scanning calorimetry, wide-angle X-ray diffraction, scanning and transmission electron microscopy (SEM and TEM). Based on the kinetics of enthalpy recovery, complete miscibility was found for the sPS/aPS blends where a single recovery peak was obtained, whereas phase separation was concluded for the sPS/iPS blends due to the presence of an additional recovery shoulder indicating the heterogeneity in the molten state. These findings were consistent with OM and SEM observations; sPS/iPS exhibits the dual interconnectivity of phase-separated phases resulting from spinodal decomposition.Both iPS and aPS have the same influence on the sPS crystal structure, i.e., dominant β-form sPS and mixed α-/β-form sPS obtained for melt-crystallization at high and low temperatures respectively, but imperfect α-form sPS developed when cold-crystallized at 175 °C. Co-crystallization of iPS and sPS into the common lattice was not observed regardless the thermal treatments, either cold or melt crystallization. Due to its slow process, crystallization of iPS was found to commence always after the completion of sPS crystallization in one-step crystallization kinetics. Segregation of rejected iPS component during sPS crystallization was extensively observed from TEM and SEM images which showed iPS pockets located between sPS lamellar stacks within spherulites, leading to the interfibrillar segregation, which was similar with that observed in the sPS/aPS blends. The addition of iPS (or aPS) component will reduce the overall crystallization rate of the sPS component and the retardation of crystal growth rates can be simply accounted by a dilution effect, keeping the surface nucleation intact. The phase-separated structure in the sPS/iPS blend shows a negligible effect on sPS crystallization and the signature of phase separation disappears after sPS crystallization. Depending on the relative dimensions of the segregated domains and iPS lamellar nucleus, subsequent crystallization of iPS can proceed to result in a crystalline/crystalline blend, or be inhibited to give a crystalline/amorphous blend morphology similar with that of sPS/aPS blends.     

Synthesis and proton conductivity of sulfonic acid functionalized zeolite BEA nanocrystals

The objective of this study is to prepare sulfonic acid functionalized zeolite BEA nanocrystals, and determine the bulk proton conductivity of this new material. Phenethyl functionalized zeolite BEA nanocrystals are synthesized using a mixture of fumed silica and phenethyltrimethoxysilane as silica sources. Contact of the phenethyl zeolite BEA nanocrystals with concentrated sulfuric acid removes the organic structure-directing agent (SDA) and simultaneously sulfonates the phenethyl moieties. Detailed characterizations of the zeolite BEA nanocrystals are performed using dynamic light scattering (DLS), Fourier transform Raman spectroscopy (FT-Raman), ²⁹Si cross-polarization magic angle spinning nuclear magnetic resonance spectroscopy (²⁹Si CPMAS NMR), ¹³C CPMAS NMR, ¹H MAS NMR, thermogravimetric (TGA) analyses, transmission electron microscopy (TEM) and powder X-ray diffraction (XRD). Sulfonic acid functionalized zeolite BEA nanocrystals have proton conductivities in the range of 1.2 × 10⁻³–1.2 × 10⁻² S/cm compared to 1.5 × 10⁻⁴ S/cm for unfunctionalizated zeolite BEA.     

磺酸功能化离子液体催化合成乙酸正丁酯

为符合绿色化学的要求,解决传统酯化反应催化剂浓硫酸设备腐蚀、副反应多等问题,以价格低廉的吗啡啉为原料,设计合成了1-(3-磺酸基)丙基-3-甲基吗啡啉甲磺酸盐[Mor-C_3SO_3H]MeSO_3等4种磺酸功能化离子液体,利用傅里叶变换红外光谱和核磁氢谱对产品的结构进行了表征,并通过催化合成乙酸正丁酯考察离子液体的催化活性。结果表明:当乙酸与正丁醇摩尔比为1.2∶1,催化剂[Mor-C_3SO_3H]MeSO_3用量为正丁醇质量的5%,带水剂环己烷用量为正丁醇质量的20%,在95℃下,反应5 h,乙酸正丁酯收率可达96.44%,离子液体经回收干燥重复使用7次酯收率仍在94%以上。     

Electrochemical properties of polyethylene membrane modified with sulfonic and phosphonic acid groups

Ion-exchange membranes modified with sulfonic (-SO₃H) and phosphonic acid (-PO₃H) groups were prepared by radiation-induced grafting of glycidyl methacrylate (GMA) onto polyethylene (PE) films and sub-sequent sulfonation and phosphonation of poly(GMA) graft chains. The surface area, thickness and volume of grafted PE film increased with increasing grafting yield. The specific electrical resistance of PE membrane modified with the -PO₃H and -SO₃H groups decreased with increasing the ion-exchange capacity. The PE membrane modified with -PO₃H group had a lower specific electrical resistance than that of PE membrane modified with -SO₃H group.     

Preparation and characterization of polystyrene sulfonic acid-co-maleic acid copolymer modified silica nanoparticles

Two types of silanes, including 3-glycidoxypropyltrimethoxysilane (GPTMS) and 3-aminopropyltriethoxysilane (APTES), were grafted onto polystyrene sulfonic acid-co-maleic acid (PSSA_MA) first, followed by the grafting reaction to the silica surface. The modification of PSSA_MA onto silica was confirmed through FTIR (Fourier transform infrared spectrum), NMR (Nuclear magnetic resonance), and TGA (Thermogravimetric analysis). The grafting ratio of PSSA_MA via APTES with 1-ethyl-3-(3- dimethylaminopropyl)-carbodiimide (EDC) activation reached 18.0 %. As for GPTMS case, the grafting ratio reached 14.4 %, which was slightly lower than that of APTES case. The grafting mechanisms for both cases were elucidated. The epoxysilane was found to react with maleic acid groups on PSSA_MA only. On the other hand, the aminosilane not only interacted with sulfonic groups but also activated maleic acid groups via EDC. However, without the use of the coupling agent, the grafting degree of PSSA_MA was only 3 %, which signified the essential role of coupling agents in this organically modified silica. The average particle size of silica was around 200 nm with or without organic modification from transmission electron microscopy (TEM) and Zetasizer analysis. The APTES-modified samples showed the highest improvement in the ion adsorption capacity in all investigated cases.     

Fatigue crack initiation and propagation in polyamide-6 and in polyamide-6 nanocomposites

Recent developments in polymer nanocomposites have led to improvements in conventional short-term, but the long-term mechanical properties have received little attention. The objective of the present study was to characterize the effect of nanoparticles on the fatigue crack initiation and propagation mechanisms and on the fatigue properties of polyamide-6 (PA6) nanocomposite (PA6NC) prepared by in situ polymerization with montmorillonite clay. Two approaches were employed: fatigue life measurements and crack growth monitoring. Compared with non-filled PA6 at the same stress amplitude, the number of cycles to fracture was higher for the nanocomposite, which suggests an increase in the intrinsic resistance of the material to crack initiation. However, the crack growth rate results indicated that nanoparticles decreased the resistance to crack propagation. Post-fatigue fractographic observations indicated a change in the fatigue crack propagation mechanism resulting from the addition of nanoparticles, primarily attributed to the increase in yield stress, which favors the development of a fibrillated deformation zone. The fibrillation process in the relatively high crack propagation rate regime appeared to be preceded by plastic deformation at approximately constant volume. Most of the effect of nanoparticles on the fatigue behavior and properties results probably from the mechanical reinforcement on the microstructure and its effect on the yield stress and Young's modulus rather than from the effect of the inorganic filler to act as a stress concentrator. Polym. Compos. 25:433–441, 2004. © 2004 Society of Plastics Engineers.     

Ionomeric blends. IV. Miscibility of urethane elastomers with styrene–styrene sulfonic acid copolymer

Blends were prepared from two kinds of urethane elastomers, containing 1,4-butanediol or 3,3′-dichloro-4,4′-diamino-diphenyl-methane as chain extenders, with lightly sulfonated polystyrenes. Dynamic mechanical studies show that strong interactions occur between the sulfonic acid and the urethane or urea moieties on the polyurethane chains. These strong interactions are clearly seen in the composition dependence of the loss tangent peaks (due to the glass transitions) for both the high temperature and the low temperature glass transitions of the blends. They are further confirmed by model studies.     

Effects of oxidative functionalized and aminosilanized carbon nanotubes on the crystallization behaviour of polyamide-6 nanocomposites

The purpose of this study is to investigate effects of oxidative functionalized and aminosilanized carbon nanotubes on the (1) isothermal and (2) non-isothermal crystallization kinetics of polyamide-6 by DSC analyses, and (3) crystal structure of injection molded specimens by XRD analyses. Nanocomposites were compounded by using melt mixing technique via twin screw extrusion. Due to basically very effective heterogeneous nucleation effect, both increasing amount and surface functionalization of carbon nanotubes by oxidation and aminosilanization resulted in higher relative crystallinity for all three cases. The increases were as much as 40 % for the isothermal and non-isothermal crystallization, and it was up to more than two times in the injection molding. Crystallization parameters and Avrami constants indicated that crystallization rate increases in isothermal crystallization while it decreases in non-isothermal crystallization due to the delayed conformational mobility of polymer chains via physical hindrance of carbon nanotubes. Parameters also revealed that growth mechanism of crystallites might change during isothermal crystallization while there was no significant change during non-isothermal crystallization. XRD deconvolution analyses indicated that during injection molding, due to the constraints of carbon nanotubes only α-crystal structure was formed.     

Synthesis,characterization and catalytic activity of MCM-41-type mesoporous silicas functionalized with sulfonic acid

This paper reports the results obtained in the synthesis, characterization and catalytic activity of thiol-MCM-41 materials synthesized using an improved method of preparation.This novel method of synthesis includes the partial replacement of the surfactant used previously — hexadecyltrimethylammonium bromide, for a shorter chain surfactant such as dodecyltrimethylammonium bromide. It also includes the use of tetramethylammonium hydroxide (TMAOH) as co-structuring agent instead of NaOH. The materials obtained from this modified gels present a higher order in the channels arrangement confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements.These materials incorporates an important amount of thiol groups which can be oxidized with H₂O₂ in order to obtain the corresponding sulfonic groups, with a very strong acidity. The catalysts so obtained have been tested in the esterification of glycerol with fatty acids — oleic and lauric. The results obtained indicate that the catalysts prepared with mixtures of surfactants are more selective to the monoglycerides than the ones synthesized only with hexadecyltrimethylammonium bromide, probably due to the higher order in the channels packing.     

粒径对磺酸官能化介孔材料性能的影响

以聚乙氧基-聚丙氧基-聚乙氧基三嵌段共聚物(P123)为模板剂、正硅酸乙酯(TEOS)为硅源,保持P123和TEOS的浓度比,改变P123和TEOS在合成体系中的浓度,水热法合成了系列具有不同粒径的介孔分子筛SBA-15.采用后合成法,将3-巯基丙摹三甲氧基硅烷(MPTMS)嫁接到具有不同粒径的介孔分子筛SBA-15表面上,经氧化后得到含有强酸性的磺酸基因的固体酸样品SBA-15-SO_3H.采用SEM、XRD、FT-IR、TG-DTA、N_2吸附以及酯化反应考察了粒径对所制备的SBA-15-SO_3H的物化性能和催化性能的影响.结果表明,SBA-15的粒径大小对MPTMS在其上的嫁接量没有很人影响,但对后续氧化过程有较大的影响,SBA-15粒径的减小有利于巯基被氧化为磺酸基,导致磺酸的负载量随着粒径的减少而增大.SBA-15-SO_3H在乙酸和乙醇的酯化反应中表现出不同的催化性能,催化性能的差异是粒径大小、酸量及磺酸基和巯基相互作用的综合结果.     

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     

表面带磺酸基团的聚苯乙烯微球的制备及其对蛋白质的吸附

研究了运用分散聚合法,在乙醇/水混合介质中,制备2-丙烯酰胺基-2-甲基丙磺酸(AMPS)与苯乙烯(St)的共聚微球。运用红外、核磁共振、激光光散射和扫描电子显微镜对功能微球进行表征。阐述了该微球对牛血清蛋白(BSA)的吸附量与吸附时间和pH值的关系。结果表明:功能微球对BSA的吸附先随时间的增长而增大,一段时间后达到平衡吸附。当pH值接近BSA等电点(pI=4.7)时,BSA的吸附量达到最大值。     

pH-controlled uphill transport of ammonium ions through polymer membranes with sulfonic acid groups

Uphill transport of ammonium ions through a membrane with sulfonic acid groups were investigated with pH-controllers which keep the solution at a constant pH. A membrane with sulfonic acid groups was prepared by casting an aqueous solution containing poly(styrenesulfonic acid) and poly(vinyl alcohol) on a glass plate. When a membrane with one side alkaline and the other acidic was fixed as a diaphragm in a cell, ammonium ions were transported from the alkaline side to the acidic side through the membrane against the concentration gradient of the adjacent solutions. Uphill transport of ammonium ions with pH-controllers was more efficient than without, thus keeping the pH difference between both sides of the membrane constant, which is a driving force for the uphill transport. Furthermore, the effect of pH of the acidic side on the uphill transport was investigated and the mechanism of the pH-controlled uphill transport is discussed.