氯磺酸磺化聚苯乙烯-二乙烯基苯树脂

以氯磺酸为磺化试剂制备磺化聚苯乙烯(SPS)树脂。研究了反应时间、温度、磺化试剂用量、溶剂体系及用量等对反应的影响。通过对反应条件的优化,结果表明:溶剂可为氯仿或CCl4。最佳溶剂用量为10ml.g-1树脂。最佳反应时间为30min,磺化剂与树脂最佳摩尔比为1∶1。控制磺化剂用量、反应时间,可在0～5.4mmol.g-1磺酸基担载量范围可控。该方法具有反应温度低、时间短、投料量少,磺化度高,保护环境等优点。     

The Nature of the Internal Acid Solution in Sulfonated Poly(styrene-co-divinylbenzene) Resins

The acidities of a series of fully hydrated sulfonated poly(styrene-co-divinylbenzene) resins with varying levels of sulfonation from 0.80 to 5.25 mequiv g^-1 have been characterized. Enthalpies of neutralization with aqueous NaOH have been measured by titration calorimetry. The degrees of acid dissociation () have been measured using FT-Raman spectroscopy, based on the intensity of the –SO₃ ^- stretching band at 1033 cm^-1. The same measurements have been made on aqueous solutions of p-toluenesulfonic acid (p-TsOH), on the basis that these solutions are analogs of the internal solutions in the hydrated resin gels. For resins with low levels of sulfonation, and therefore relatively dilute internal acid solutions, the internal and the equivalent p-TsOH solutions are similar. However, significant differences are seen in highly sulfonated resins where the internal solution concentration is above 4.0 mol kg^-1. At these concentrations, p-TsOH solutions show essentially complete dissociation and enthalpies of neutralization typical of a strong, fully dissociated acid in aqueous solution. In contrast, the acid groups in hydrated resins are largely undissociated and exhibit numerically higher enthalpies of neutralization, and catalytic activity measurements indicate that these acid groups are stronger than normal. It is proposed that this acidity enhancement is associated with networks of sulfonic acid groups which form in highly sulfonated resins. Although such networks have been previously proposed in dehydrated resins, this paper reports the first evidence for their existence in resins under conditions of full hydration.     

Transesterification of brazilian vegetable oils with methanol over ion-exchange resins

The transesterification of several Brazilian vegetable oils with methanol was carried out at 60°C in the presence of several ion-exchange resins having different structures. The vegetable oils used were from Babassu coconut, corn, palm, palm kernel, and soybean. The effect of the methanol/oil mole ratio and the influences of the structure of the ion-exchange resin and the type of vegetable oil used on the catalytic activity of the ionexchange resins were investigated. The resins used were Amberlyst 15, Amberlyst 31, Amberlyst 35, and Amberlyst 36. Amberlyst 15 produced the best results for the transesterification of vegetable oils. The methyl ester yield is higher for palm kernel oil and Babassu coconut oil than for soybean oil, probably owing to their higher content of shorter-chain FA. Therefore, it was shown that the catalytic activity of the resin depends on the FA composition of the vegetable oil employed.     

The Influence of Solvent on the Acidity and Activity of Supported Sulfonic Acid Catalysts

The acid strengths and catalytic activities of sulfonic acids supported on polystyrene resins and ordered mesoporous HMS and SBA-15 silicas are compared. Acid strengths are measured by acid–base titration calorimetry in terms of the molar enthalpies of neutralisation with either NaOH or n-butylamine in water, acetonitrile and cyclohexane. Catalytic activities (turnover numbers) are reported in model reactions in water, 1,2-dichlorobenzene and anisole, and compared with acid strengths. In water, sulfonated resins are both stronger acids and more active catalysts than sulfonated silicas. Catalytic activities in water correlate well with these measured acid strengths. In acetonitrile the order of acid strengths is reversed and the sulfonated silicas are the stronger acids. Catalytic measurements in 1,2-dichlorobenzene, a similar dipolar aprotic solvent, show the same reversed order of activities. In the non-polar solvent cyclohexane (where only macroporous sulfonated resins show measurable acidity) the sulfonated silicas are again the stronger acids but by a larger margin. Catalytic activities in anisole, which is also only very weakly solvating towards sulfonic acid groups, show a similar trend. The results illustrate the role of the solvent in controlling the acid strength of solid acid catalysts, and the importance of taking this into account when designing acid catalysts for liquid phase processes.     

Preparation and characterization of high loading porous crosslinked poly(vinyl alcohol) resins

Porous crosslinked poly(vinyl alcohol) resin beads have been prepared by a two-step pathway involving a pre-crosslinking reaction followed by a reverse suspension crosslinking reaction with epichlorohydrin as crosslinker. The reaction conditions have been optimized for the two steps in order to obtain resins with various pores sizes. The crosslinking density of these resins was calculated from their swelling properties by a modified Flory equation. High loading of hydroxyl groups is one of the important characteristics of these resins (attaining ca. 17 mmol/g). The porosity, pore volume, pore structure and the swelling behavior in water of these resins have been studied.     

Batch and column adsorption of perfluorooctane sulfonate on anion exchange resins and granular activated carbon

Perfluorooctane sulfonate (PFOS) has been detected widely in the natural water matrix and is persistent, bioaccumulative, and toxic. To prevent the adverse effects of PFOS contamination on human health and the environment, effective removal techniques are needed. Adsorption is considered an effective technique for PFOS removal. In this study, five anion exchange resins and granular activated carbon (GAC) were examined to evaluate their performance for the removal of PFOS in both batch and column experiments. Experimental adsorption data for all of the adsorbents exhibited a high correlation with the Freundlich isotherm (R² = 0.95 – 0.98). Most of the anion exchange resins demonstrated a higher adsorption capacity than the GAC. PFA300 had the highest adsorption capacity (455 mg/g). Continuous adsorption of PFOS was performed in column experiments using the same adsorbents that had been used in the batch experiments. The experimental breakthrough curves were set at C/C₀ = 0.1. PFA300 showed the longest operation time before reaching the breakthrough point. The Yoon and Nelson model was used to predict the half‐saturation time of the anion exchange resins. Moreover, the anion exchange resins exhibited high recovery of PFOS by an organic solvent. Continuous PFOS adsorption on a column can be achieved using anion exchange resins for water/wastewater treatment. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39782.     

Adsorption of Cu(II) ions from aqueous solutions using ion exchange resins with different functional groups

The extraction of heavy metals from industrial effluents using efficient adsorbents is crucial for wastewater treatment and beneficial for metal recycling. In this study, the removal of Cu(II) from an acidic solution by commercial resins Dowex G-26 and Puromet™ MTS9570 was investigated. The influences of contact time, solution concentration, pH, temperature, and a resin dosage on the adsorption process were studied with batch technique. The optimum adsorption conditions were obtained at a concentration of 1100 mg/L Cu, contact time of 30 min, pH 3.5, and resin dosage of 0.025 g/ml for the removal of 99.9% and 90% of copper ions by G-26 and MTS9570, respectively. The experimental data of copper adsorption were analyzed using the Langmuir, Freundlich, and Temkin isotherm models. The highest metal uptakes of 41.67 and 37.70 mg/g were observed for Dowex G-26 and MTS9570, respectively. It was found that both resins had higher adsorption capacities than the substances reported in the literature. The adsorption kinetic studies showed that the copper adsorption process could be better described by the pseudo-second order model. Adsorption occurs spontaneously under endothermic conditions, which indicates the endothermic nature of the process.     

Polymer swelling. XXIII. Molecular structure–affinity correlation studies involving poly(styrene-co-divinylbenzene) exposed to acyclic olefinic liquids

The adsorption parameters (α) of 45 olefinic liquids with respect to poly(styrene-co-divinylbenzene) were established gravimetrically in the usual way. Those for the structures that comprise R_aR_bCCR_cR_d, where each R is H or an alkyl group, can be fitted to log α_f = log α_i − D_s(N_f − N_i) relationships, where N_i and N_f are the initial and final number of mass units in the subseries of the above general molecular structure (GMS). The constant α_i reflects the number of methyl groups in lieu of H atoms and their positional relationship to each other on the double bond, whereas the constant D_s reflects the unit change in log α_i caused by incrementation of a (CH₂)_nR substituent from n = 1 to its allowable limit while the rest of the molecular structure is kept constant. The results observed thereby confirm that these adsorption phenomena involve a liaison between the pendent phenyl groups of the sorbent polymer and the double bond of the sorbate liquid. The adsorption data accumulated in these studies show that in the cases of olefinic liquids carrying other kinds of functional groups, such as aromatic or ether groups, the adsorption preference usually favors the other functionality, leaving the olefinic group in the “nonadsorbed” portion of the adsorbed molecule where it can exert a positive influence on adsorptivity due to dynamic associative interactions with the mobile sorbed molecules of its own kind. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1583–1609, 1999     

Preparation of ethyleneamine functionalized crosslinked poly(acrylonitrile-ethylene glycol-dimethacrylate) chelating resins for adsorption of lead ions

Removal of lead ions was investigated by ethylenediamine, triethylenetetramine and tetraethylenepentamine functionalized polymeric adsorbent. Macroporous acrylonitrile-ethylene glycol-dimethacrylate copolymer beads were synthesized by suspension polymerization as already reported.^[17] The adsorbent was prepared by amination of copolymer synthesized from acrylonitrile-ethylene glycol-dimethacrylate. The adsorption study for removal of lead ions using functionalized poly(AN-EGDMA) copolymer as an adsorbent was carried out at room temperature at various solution concentrations of 0.483–2.4154 mmol/l at pH 4.6. Functionalized polymers were studied by Fourier transform infrared spectroscopy (FTIR). Scanning electron microscope-X-ray energy dispersive spectrometer (SEM-EDAX) was utilized to study an increase in nitrogen content of functionalized polymers.     

Comparison of ion-exchange resins for efficient cobalt(II) removal from acidic streams

The ion-exchange method was applied for cobalt(II) removal from acidic streams using Lewatit MonoPlus TP 220, Purolite A 830, Lewatit SR 7, Purolite S 984, Purolite A 400 TL, Lewatit AF 5, Dowex PSR 2, and Dowex PSR 3. The effects of phase contact time, acid concentration, initial Co(II) concentration, and temperature were evaluated. The cobalt(II) desorption, ion exchanger reuse, and attenuated total reflection with the Fourier transform infrared spectroscopy, column studies were also performed. Lewatit MonoPlus TP 220 exhibits the highest sorption capacities and sorption follows the pseudo-second-order kinetics. The Freundlich model fitted the experimental data adequately. Desorption of cobalt(II) loaded is not quantitative. Sorption capacity reduction after three cycles of sorption–desorption (static method) was not observed.     

Acid-Base Properties of Zirconium, Cerium and Lanthanum Oxides by Calorimetric and Catalytic Investigation

The combined use of calorimetric and catalytic methods for the investigation of the acid-base properties of oxide systems is discussed with reference to the authors' work on pure and doped zirconia samples, ceria-zirconia and ceria-lanthana solid solutions. Adsorption microcalorimetry of ammonia and carbon dioxide had been used to characterize the samples, whose chemical and thermal history was taken into account. The catalytic behavior of these samples in the conversion of 4-methylpentan-2-ol, route to 4-methylpent-1-ene (starting product for the manufacture of polymers of superior technological properties), had also been studied. On the basis of the calorimetric data, a rationale for interpreting the data for the transformation of 4-methylpentan-2-ol is formulated, which takes into account the role of the concentration and strength of the sites in governing the competition among the various mechanisms for dehydration and dehydrogenation.     

Esterification of free fatty acids in waste cooking oils (WCO): Role of ion-exchange resins

Although WCO plays a crucial role for the economical production of biodiesel, free fatty acid (FFA) level in the nature of WCO cause saponification problems during transesterification. Acidic ion-exchange resins can be used to decrease WCO free fatty acid level. In this study, activities of resins (Amberlyst-15 (A-15), Amberlyst-35 (A-35), Amberlyst-16 (A-16) and Dowex HCR-W2) in direct FFA esterification were examined in the temperature range of 50–60 °C and the effect of catalyst amount (1–2 wt%) on FFA conversion was also analyzed. FFA conversion increased with increasing reaction temperature and catalyst amount. Order of catalytic activities was found as A-15 > A-35 > A-16 > Dowex HCR-W2. This was related to the size of average pore diameters and magnitude of BET surface area.     

Irradiation‐induced grafting of poly(vinylidene fluoride)‐graft‐poly(styrene sulfonic acid) for the preparation of planar and tube‐shaped air‐drying membranes

A novel air‐drying membrane was developed and investigated as an alternative for planar and tube‐shaped drying membranes composed of Nafion^®. The new membrane is based on poly(vinylidene fluoride) (PVDF) polymer types grafted with polystyrene sulfonic acid. Modification of the PVDF membrane by chemical grafting was initiated via γ‐irradiation of pre‐made film and tube‐shaped samples. The grafting was conducted while the pre‐irradiated PVDF samples were immersed in styrene monomer solution. Three unique characterization methods were introduced to evaluate the ion exchange and barrier functions of the membrane. This investigation focuses on optimizing the degree of grafting yield, and subsequently the control of the membrane's overall functional performances, through (1) monitoring the PVDF's degree of crystallinity and (2) monitoring the styrene monomer solution temperature, respectively. Different levels of crystallinity were achieved by melt blending the PVDF‐copolymer with PVDF‐homopolymer, in various mixing ratios. Another variable examined in this investigation was the introduction of an ionic complex on the sulfonic acid end groups, and its effect on the membrane functional performance was studied. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

新型聚三唑酯和聚三唑醚树脂的合成及性能

合成了三种含酯基和三种含醚键的炔单体,通过核磁共振氢谱(¹H NMR)、红外光谱(FT-IR)、质谱(MS)、液相色谱(LC)对其结构进行了表征。用这六种炔单体与叠氮单体反应制备了一系列新型聚三唑酯树脂(PTAE)和聚三唑醚树脂(PTAO)。利用差示扫描量热分析(DSC)、FT-IR、动态力学热分析(DMA)、力学试验机和热失重分析(TGA)表征了树脂的固化行为、固化树脂的力学性能、耐热性和热稳定性。结果表明PTAE和PTAO树脂易溶于有机溶剂,可低温(60℃)固化,固化树脂的弯曲强度超过了100 MPa,可达158 MPa,玻璃化转变温度(T _g)超过180℃,高者达251℃,热分解温度可达360℃。     

Preparation and characterization of poly(urea-formaldehyde) microcapsules filled with epoxy resins

The preparation of microcapsules applied to the fabrication of self-healing composites has been paid more attentions. A new series of microcapsules were prepared by in situ polymerization technology with poly(urea-formaldehyde) (PUF) as a shell material and a mixture of epoxy resins (diglycidyl ether of bisphenol A: DGEBPA) and 1-butyl glycidyl ether (BGE) as core materials. The microencapsulating process of core material was monitored using optical microscopy (OM). The chemical structure of microcapsule was characterized using Fourier-transform infrared spectroscopy (FTIR). Morphology and shell wall thickness of microcapsule were observed using metalloscope (MS), scanning electron microscopy (SEM) and OM, respectively. The effects of different pre-polymers, weight ratios of urea to formaldehyde (U-F) and the agitation rates on the physical properties of microcapsules were investigated. The storage stability of microcapsules at different times and temperatures was analyzed. The thermal properties of microcapsules were investigated using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results indicate that PUF microcapsules containing epoxy resins can be synthesized successfully, and during the microencapsulation, the epoxide rings in epoxy resins are hardly affected by the surrounding media. The rough outer surface of microcapsule is composed of agglomerated PUF nanoparticles. The size and surface morphology of microcapsule can be controlled by selecting different processing parameters. The microcapsules basically exhibit good storage stability at room temperature, and they are chemically stable before the heating temperature is up to approximately 238 °C.     

Determination of the glass transition temperature of poly(styrene-co-divinylbenzene) by inverse gas chromatography

Inverse gas chromatography (i.g.c.) was used to characterize the supermolecular structure of modified, moderately crosslinked poly(styrene-co-divinylbenzene) (5–20 wt%) and to determine the interactions with normal alcohols (C₁C₆). For all copolymers a decrease of retention time with increasing molecular weight of alcohols from C₁ to C₃ followed by an increase for C₄ to C₆ alcohols was observed. It was found that with propanol or butanol the measured T_g values were close to those measured by d.s.c. The T_g values for poly(styrene-co-divinylbenzene) containing 5, 10 and 20 wt% divinylbenzene were: 102°C, 116°C and 133°C respectively. The highest alcohols (C₅ and C₆) acted as plasticizers and reduced the apparent T_g value. The relationship between the isosteric heat of adsorption and the number of carbon atoms in the alcohols was nonlinear with a minimum corresponding to butanol.     

Viscoelastic behaviour of epoxy resins modified with poly(methyl methacrylate)

The viscoelastic behaviour of a stoichiometric diglycidyl ether of bisphenol-A, (DGEBA), 4,4′-diaminodiphenylmethanes (DDM)s epoxy matrix modified with several amounts of poly(methyl methacrylate) (PMMA) has been studied by dynamic-mechanical analysis. Mixtures pre-cured at 80°C ranged from transparency to opacity as thermoplastic content changed from 5 to 15wt%. These changes have been attributed to variations in the ratio between polymerization rate and phase separation rate when PMMA content increased in the mixtures. When PMMA segregated from the epoxy matrix during curing, it had no influence on the crosslinking density of the epoxy phase. The clear decrease of temperature and activation energy of the β relaxation with respect to those values for the neat matrix, observed for the 5wt% PMMA-containing mixture but not for the 15wt% PMMA-containing one, are proposed to be a consequence of physical interactions between the PMMA chains and some epoxy oligomers. The dissimilar variation of the height of the ω relaxation with frequency when compared to that for the other relaxations studied, outlines the significance of physical factors influencing this relaxation. © 1998 Society of Chemical Industry     

双马来酰亚胺及聚醚酮树脂改性环氧树脂的研究进展

综述了双马来酰亚胺及聚醚酮类树脂改性环氧树脂的研究及应用情况。     

Preparation of phosphoric acid resins with large cation exchange capacities from macroreticular poly(glycidyl methacrylate-co-divinylbenzene) beads and their behavior in uptake of metal ions

In order to prepare phosphoric acid resins (RGPs) with large cation exchange capacities, effects of porosity and cross-linking of the precursory poly(glycidyl methacrylate-co-divinylbenzene) beads on their functionalization with phosphoric acid were studied. Two series of precursory copolymers were prepared: one was prepared by changing the amount of divinylbenzene (1–25 mol %) but by fixing that of isobutyl acetate (porogen) at 140 vol % per monomer mixture; the other by changing the amount of the porogen (40–160 vol %) but by fixing that of the cross-linker at 10 mol %. It was clarified that porosity of the precursors plays an important role in the functionalization. Highly porous precursors were functionalized with high efficiency; for example, even the precursors containing 10 mol % of divinylbenzene resulted in RGPs having cation exchange capacities as large as 6–7 meq/g, so long as BET specific surface areas of the precursors were greater than ca. 30 m²/g. The selectivity study has revealed that RGP exhibits the characteristic metal ion selectivity. Lithium ion was adsorbed in preference to sodium and potassium ions; and so-called hard Lewis acid cations, such as uranyl, ferric, and aluminum ions, are adsorbed even from strongly acidic media (1 < pH < 2). Among common divalent metal ions, in addition, the resin exhibits the highest selectivity toward lead ion. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1327–1334, 1997