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Beena Mathew P. M. Madhusudanan V. N. Rajasekharan Pillai 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10):1781-1800
Abstract Amino groups were incorporated into polyacrylamides with 2?20 mol% of crosslinking agents by transamidation with ethylenediamine. Divinylbenzene, N,Nv′-methylene-bis-acrylamide, and tetraethyleneglycol diacrylate were used as the crosslinking agents. The complexation of these resins, which contain ligand functions in different macromolecular structural environments, was investigated with Cu(II) ions. The Cu(II) uptake of these different resins was correlated with the molecular character and degree of crosslinking in the polymer matrix. The time course and kinetics of complexation depend on the nature of the crosslinking agent in the polymer matrix. The swelling behavior of the uncomplexed and complexed resins, structural characteristics, and thermal decomposition behavior were followed by IR, EPR, and thermal analysis. The swelling characteristics of the complexed resins are lower than those of the uncomplexed resins. Complexation resulted in shifting of the IR absorptions. The EPR parameters depend on the nature of crosslinking and are in agreement with the distorted tetragonal geometry of the Cu(II) complexes. The thermal decomposition behavior also depends on the nature and the degree of crosslinking in the polymer matrix. 相似文献
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Chitosan resins, which clinically served as adsorbents in hemoperfusion therapy, were prepared with reversed-phase suspension methodology using three differently structured crosslinking agents, methanal, glyoxal and glutaraldehyde. And the glyoxal and glutaraldehyde crosslinked chitosan resins were reduced with NaBH4 afterwards. By analyzing the results from FTIR and SEM, it was found that the reduction treatment to the adsorbents efficiently improved the chemical stability of these chitosan resins, and the shifts in crosslinking agents exerted influences over the morphologies of the adsorbents obviously. After being put to use in the adsorption tests upon some model uremic middle molecular toxins and BSA in vitro, all three adsorbents demonstrated a fairly realistic adsorption capability to the model toxins but little to BSA. And the adsorption process reached the equilibrium in a clinically qualified short time. But the adsorption capacities of these adsorbents to the model toxins were quite different. It 相似文献
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《Thermochimica Acta》1987,109(2):297-301
Several new polymethylol epoxy resins have been synthesised in a one pot reaction system and characterised. The new resins are derived from epichlorohydrine, formaldehyde and several aromatic phenols: phenol, biphenylol, bisphenol-A, bisphenol-S, sulphone, and DDT. The rate of crosslinking has been studied at different temperatures (120–180°C) by determining the amount of H2O evolved from the crosslinking reaction using a DuPont moisture evolution analyser; the activation energy of setting has been determined from Arrhenius plots. The results are 57.1, 50.0, 42.9, 75.2, 11.3 and 74.3 kJ mol−1 for resins I–VI respectively. The set resins show good thermal stability and are resistant toward chemicals and solvents; these resins also set catalytically at room temperature. 相似文献
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Chitosan resins, which clinically served as adsorbents in hemo perfusion therapy, were prepared with reversed-phase suspension
methodology using three differently structured crosslinking agents, methanal, glyoxal and glutaraldehyde. And the glyoxal
and glutaraldehyde crosslinked chitosan resins were reduced with NaBH4 afterwards. By analyzing the results from FTIR and SEM, it was found that the reduction treatment to the adsorbents efficiently
improved the chemical stability of these chitosan resins, and the shifts in crosslinking agents exerted influences over the
morphologies of the adsorbents obviously. After being put to use in the adsorption tests upon some model uremic middle molecular
toxins and BSA in vitro, all three adsorbents demonstrated a fairly realistic adsorption capability to the model toxins but
little to BSA. And the adsorption process reached the equilibrium in a clinically qualified short time. But the adsorption
capacities of these adsorbents to the model toxins were quite different. It had been found that with the growing of fatty
chain length of crosslinking agent, these adsorbents showed a gradually increased adsorption capacity to the model toxins,
and the glutaraldehyde crosslinked chitosan resin behaved best. 相似文献
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Fatty acid-based alkyd resins prepared with different amounts of glycerol and pentaerythritol were characterized. Sacha inchi oil and linseed oil (comparative purposes) were used as fatty acids’ sources. FT-IR and 1H NMR spectroscopy were done for alkyd structural verification. Alkyd resins were evaluated through physico-chemical (colour, density, viscosity) and thermal characterization. Film coating performance (drying, hardness, chemical resistance) was also studied. The oxidative crosslinking time tendency was corroborated by the quartz crystal microbalance (QCM) technique. Alkyd resins obtained with fatty acids from sacha inchi and linseed oils had similar properties. Results indicated that lighter resins can be obtained from sacha inchi oil, whereas pentaerythritol increases viscosity and thermal stability, and retards drying time of fatty-acid based alkyd resins. 相似文献
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Irmgard Bergmann U. Müller M. Rätzsch M. Steiner 《Monatshefte für Chemie / Chemical Monthly》2006,137(7):881-886
Summary. The crosslinking behavior of MFRs (melamine formaldehyde resins) in the presence of wood was investigated. The influence of
various factors (wood content, resin structure, etc.) on the crosslinking temperature of the resins was examined using DMTA and DSC/TGA. Fully methylated MFRs turned out to
be more stable in the presence of wood than partially methylated MFRs. A dependence of the crosslinking temperature on the
wood content was found. Model reactions with wood components demonstrated, that cellulose, hemicelluloses, and lignin affect
the crosslinking temperature to different extends, whereas hemicelluloses (xylan) showed the strongest effect. Solvents, especially
water, led to a further decrease of the crosslinking temperature of wood/MFR compounds. 相似文献
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Irmgard Bergmann U. Müller M. R?tzsch M. Steiner 《Monatshefte für Chemie / Chemical Monthly》2006,285(12):881-886
The crosslinking behavior of MFRs (melamine formaldehyde resins) in the presence of wood was investigated. The influence of
various factors (wood content, resin structure, etc.) on the crosslinking temperature of the resins was examined using DMTA and DSC/TGA. Fully methylated MFRs turned out to
be more stable in the presence of wood than partially methylated MFRs. A dependence of the crosslinking temperature on the
wood content was found. Model reactions with wood components demonstrated, that cellulose, hemicelluloses, and lignin affect
the crosslinking temperature to different extends, whereas hemicelluloses (xylan) showed the strongest effect. Solvents, especially
water, led to a further decrease of the crosslinking temperature of wood/MFR compounds. 相似文献
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A combination of photochlorination of p-xylene and succedent Friedel-Crafts alkylation polymerization was firstly used in the preparation of the hypercrosslinked adsorptive resin.The data of GC-MS and GC showed that a series of chlorizates were produced when p-xylene was photochlorinated.Hypercrosslinked resins could be synthesized by copolymerization,self-polymerization of chlorizates or post crosslinking reaction.The chemical structure and micromorphology of the porous resins were characterized by BET,FT-IR,SEM and elementary analysis(EA).The results showed that the novel adsorptive resins possess high BET surface near to 1038 m~2/g and large pore volumes range from 0.5 to 1.2 cm~3/g. 相似文献
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C. Carfagna E. Amendola M. Giamberini A. G. Filippov R. S. Bauer 《Liquid crystals》1993,13(4):571-584
By endcapping mesogenic rigid rod molecules with reactive epoxy groups a novel class of liquid-crystalline thermoset has been obtained. In fact is has been shown that the nematic molecular arrangement is sustained over the crosslinking reaction of liquid-crystalline epoxy resins when the curing reaction is carried out in the thermal stability range of the liquid-crystalline phase. Calorimetric analysis was used in characterizing the isothermal cure. An unsophisticated model is proposed for evaluating the activation energies of the crosslinking reaction. For liquid-crystalline epoxy resins lower activation energies result with respect to the cure reactions for non liquid-crystalline epoxy resins. 相似文献
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《高分子科学杂志,A辑:纯化学与应用化学》2013,50(3):239-257
Optical materials, such as ophthalmic lens, are thermosetting resins, which require crosslinking agents. An optical resin, having a high refractive index, is usually produced by radical copolymerization in which high index crosslinking monomers are significantly important. We provide here the resins prepared by radical polymerization of novel bifunctional thiomethacrylates as high index crosslinkers. 相似文献
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C. Martín J. C. Ronda V. Cdiz 《Journal of polymer science. Part A, Polymer chemistry》2006,44(5):1701-1710
Boron‐containing novolac resins were synthesized by the modification of a commercial novolac resin with different contents of bis(benzo‐1,3,2‐dioxaborolanyl)oxide. These novolac resins were crosslinked with diglycidyl ether of bisphenol A (DGEBA), and their thermal, thermodynamomechanical, and flame‐retardant properties were evaluated. The boron‐containing novolac resins were less thermally stable than the unmodified novolac resin. Their modification degree and DGEBA content were related to the crosslinking density of the materials. The boron‐containing novolac resins generated boric acid at high temperatures and gave an intumescent char that slowed down the degradation and prevented it from being total. They also showed good flame‐retardant properties. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1701–1710, 2006 相似文献
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R. Arshady 《Colloid and polymer science》1990,268(10):948-958
A survey of the development of hydrophilic resins based on dimethylacrylamide (DMA) is presented. It describes the preparation of DMA-based resins by suspension copolymerization of DMA and acrylamide-based crosslinking and functional monomers. Swellability data for a number of DMA-based resins are tabulated, demonstrating that the resins swell to approximately the same extent in dichloromethane as they do in water, methanol, dimethylformamide or dimethylsulphoxide, but they swell only slightly or not at all in tetrahydrofuran. Typical chemical reactions employed for quantitative estimation or derivatization of resin-bound functional groups, including those involving intra-resin crosslinking, are discussed. The development of composite polymer supports, in which the DMA-based polymer is supported on kieselguhr particles or an amphiphilic ion exchange polymer is supported on DMA-based resin beads, is also covered briefly. 相似文献
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Novel bismaleimides (BMIs) were prepared from functional monomaleimides and diglycidyl ether of bisphenol A (DGEBA) and some of them were shown to have good processibility and improved water resistance while retaining characteristic thermal stability of polyimide. Functional monomaleimides were synthesized via the condensation reaction of maleic anhydride with either aminobenzoic acid or aminophenol. Crosslinking reaction of thus obtained BMIs was carried out with or without catalyst at the temperature range of 100–250°C. The type of the functional group species and their position in monomaleimides significantly affected the crosslinking behavior of the resulting BMIs and the thermal property of their crosslinked products. BMIs with meta linkage, obtained from meta monomaleimides, exhibited much faster thermal crosslinking behavior than corresponding para BMIs. When the molecular weight of BMI was larger, the crosslinking density became smaller and Tg was lower as expected, while the viscosity started to increase at a higher temperature. Glass transition temperatures of the crosslinked resins were in the range of 160–250°C and these resins showed excellent thermal stability up to 370°C. 相似文献
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C. Martín J. C. Ronda V. Cdiz 《Journal of polymer science. Part A, Polymer chemistry》2006,44(11):3503-3512
Boron‐containing novolac resins were prepared through the modification of a commercial novolac resin with different contents of bis(benzo‐1,3,2‐dioxaborolanyl) oxide. Their thermal and flame‐retardant properties were measured. Then, they were crosslinked with hexamethylenetetramine, and their thermal, thermodynamomechanical, and flame‐retardant properties were evaluated. Their modification degree was related to the segmental motion of the materials. The crosslinking of the boron‐modified novolac resins with hexamethylenetetramine was slower and not as extensive as that of commercial novolac resins because the nitrogen from intermediate species coordinated with boron. The thermal degradation of the boron‐containing novolac resins generated boric acid at high temperatures and gave an intumescent char that slowed the degradation and prevented it from being complete. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3503–3512, 2006 相似文献