共查询到20条相似文献,搜索用时 296 毫秒
1.
Resole phenol-formaldehyde resins were prepared and modified with the prepared resorcinol-formaldehyde resins. The optimum conditions of formulation and curing processes were studied to obtain modified wood adhesives characterized by high-tensile shear strength values. This study indicated that the more suitable conditions are equal weight ratios of phenol-formaldehyde to resorcinol-formaldehyde resins in the presence of paraformaldehyde (10 or 15 wt%) of the resin content as a curing agent at 80 or 25°C for 40 min or 100–110 days, respectively. The activation energies of the curing reactions for phenol-formaldehyde/resorcinol-formaldehyde resin samples were determined. Metallic and glass coatings from the previous pure resins and their formulated cured mixtures were prepared and evaluated as varnishes or paints. Copyright © 1998 John Wiley & Sons, Ltd. 相似文献
2.
本文报道了以多乙烯多胺为主链的巯基胺树脂与二硫化碳反应,合成了四种新型的氨基二硫代甲酸型螯合树脂,这类树脂对贵金属具有高的吸附容量和优良的吸附选择性。并通过红外光谱和X光电子能谱研究树脂及其金属螫合物。 相似文献
3.
The aim of this investigation was to determine degree of conversion, and flexural and compressive strength of photocurable acrylic resin. The acrylic resins based on bis-phenol A glycidyl dimethacrylate (BisGMA) and triethylene glycol dimethacrylate (TEGDMA) were formulated and then irradiated with red light to form a solid crosslinked polymer. Various post curing conditions were studied to investigate their effects on curing efficiency. Degree of conversion was analyzed by means of Fourier Transform Infrared Spectroscopy (FTIR) to monitor the quantity of remaining acrylic double bond in the cured resin. Three-point bending and compressive strength were tested using Universal Testing Machine (UTM) to evaluate the mechanical performance. Our investigation demonstrated that the formulated acrylic resins were possibly polymerized under irradiation with red light and degree of conversion and mechanical properties were closely correlated. 相似文献
4.
复合多孔树脂以其调湿速度快、湿含量高等特点比传统多孔硅胶更适合作为智能调湿材料。本文利用氢氧化铝高温分解产生活性氧化铝并释放水蒸气的致孔途径制备出复合多孔树脂。通过TG、SEM、 FTIR、XRD和氮气吸附等手段表征了该树脂的形貌和结构特征,测试了复合多孔树脂分别在高湿和低湿环境的调湿性能和饱和湿含量,讨论了多孔树脂在不同温度条件的调湿性能和在25℃时对微量甲醛的吸附性能。结果表明:本文的致孔方法能有效地使树脂内部形成多孔结构。复合多孔树脂具有良好的调湿和甲醛吸附性能。在制备过程中通过控制树脂内部的孔参数,材料能将空间相对湿度在4h内调控并维持在50%-60%的范围之内,且不受温度变化的影响,甲醛吸附量为5.55ppm/g。材料可以作为智能调湿材料用于文物保护,为文物存放环境创造一个恒湿干净的空间。 相似文献
5.
Procedures are described to prepare γ-aminobutyrohydroxamate resin and its N-methyl and O-methyl derivatives. With the aid of a chemical method, IR and electronic spectra, and potentiometry, the chelating properties of these resins are compared with each other. The selectivity of resins for various metals is expected to be comparable to complexing properties of a monomer having a structure similar to that of active groups. This correlation was made quantitatively by measurement of metal capacity, fraction of sorption, pH and period for extraction of half the metal ions, stability constants etc. Not only γ-aminobutyrohydroxamate resin but also its N-methyl and O-methyl derivatives exhibit much potential for application in chelation ion chromatography. 相似文献
6.
用离子交换树脂法吸附柠檬酸溶液中的金属离子,苯乙烯系阳离子交换树脂的吸附性能较好,它对镍、铝离子的吸附容量均较大,且吸附前后柠檬酸溶液的浓度变化较小.静态条件下树脂对镍的吸附容量为16.83mg Ni/g干树脂,对铝为21.36mg Al/g干树脂;动态条件下树脂对镍的吸附容量为6.78mg Ni/g干树脂,对铝为31.8mgAl/g干树脂,吸附液流速为1m/h~3m/h.吸附后的柠檬酸溶液可循环使用.当用1mol/L硫酸解吸时,树脂对镍铝的解吸率可达90%以上.当硫酸中Ni2 为1.70mmol/L,Al3 为7.40mmol/L时,树脂的解吸率仍可达80%以上. 相似文献
7.
Sema Demirci Çekiç 《Analytica chimica acta》2004,505(1):15-24
XAD copolymer resins may be functionalized with heavy metal ion-selective ligands either by covalent linkage to the polymer backbone or by impregnation. These resins may be tailored to be specific for certain heavy metals by adjusting the adsorption and elution parameters, thereby enabling simple and cost-effective spectrophotometric and flame atomic absorption spectrometry (FAAS) determinations of these metals without requiring the more sophisticated coupled instrumental techniques. For the synthesis of o-aminobenzoic acid (ABA)-immobilized XAD-4 copolymer resin that is expected to preconcentrate a number of transition and heavy metals, the azo-linkage method was chosen. For this purpose the copolymer was nitrated, reduced to the corresponding amine, converted to the diazonium salt with nitrite, and reacted with o-aminobenzoic acid to produce the XAD-ABA sorbent. This sorbent was capable of preconcentrating Pb(II), Cd(II), Ni(II), Co(II) and Zn(II) from weakly acidic or neutral aqueous solution. The retained metals were eluted with 1.0 M HNO3 from the resin column, and were subsequently determinated with by flame atomic absorption spectrometry. The developed resin preconcentration and determination method was successfully applied to the analysis of a synthetic metal mixture solution, a certified reference material (CRM) of coal sample, and brackish lake water. 相似文献
8.
G.M. Greenway S.M. Nelms I. Skhosana S.J.L. Dolman 《Spectrochimica Acta Part B: Atomic Spectroscopy》1996,51(14):1909-1915
A small range of new commercially available chelating resins are compared with a resin prepared in-house in terms of their applicability for on-line preconcentration and matrix separation. The flow injection manifold was designed for rapid matrix separation and the resins were tested for the determination of Cull, ZnII, CdII, MnII and NiII. The resin based on controlled pore glass was found to be better for this rapid procedure because it did not require conditioning, although the polymer based resins had better capacities. The commercially available controlled pore glass based iminodiacetate (IDA) resin had a comparable performance to the in-house controlled pore glass 8-hydroxyquinoline (CPG-8-HQ) resin. The IDA resin had a much higher capacity than the 8-HQ, however as with all IDA based resins, some retention of Call was observed. The sample throughput was 12 h−1. 相似文献
9.
10.
The chelating resin Metalfix Chelamine and the strong cation exchanger Dowex 50W-X4 were studied for the off-line pre-concentration of Cd, Co, Cu, Ni and Zn prior to the measurements by the inductively coupled plasma atomic emission spectrometry. Different approaches to the recovery of metals were investigated and compared: the elution with the solutions of HCl and HNO3 and the decomposition of the resins with the adsorbed metals by means of the high-pressure microwave assisted system. Due to the problem arisen with the quantitative elution of the metals from the resins, which bound the analytes very strongly, the procedure of the digestion of the resin after the pre-concentration step was preferable to the plain elution, giving significantly better recoveries of the metals. The chosen procedure was applied for the determination of traces of Cd, Co, Cu, Ni and Zn in beer. For the analysis, mineralised and not mineralised beer samples were treated with Dowex 50W-X4 resin in order to assess the total content of Cd, Co, Cu, Ni and Zn and the fraction of the cationic labile species of the analytes, respectively. The increase in the sensitivity allowed determination of the selected metals at concentrations of order of 1 ng ml−1. The accuracy of the entire procedure was verified by the recovery test in the spiked samples of beer. The proposed method provides full recovery for Cd (101±1%), Co (99±2%) and Zn (106±3%) and reasonably high recovery for Cu (84±1%) and Ni (89±1%). 相似文献
11.
通过酚醛树脂羟基活性基团与6-氯-5,12-萘并萘醌(1)接枝反应,制备了3种有光致变色性的酚醛树脂:萘并萘醌酚醛树脂(2),甲基萘并萘醌酚醛树脂(3)和氯代萘并萘醌酚醛树脂(4).在四氢呋喃(THF)溶液中,3种光致变色聚合物有与6-苯氧基-5,12-萘并萘醌相似的光致变色行为.同时,发现聚合物骨架上的取代基对聚合物的变色速度影响较小,聚合物的平均分子量影响聚合物的变色速度. 相似文献
12.
High performance matrix is the key base for preparing advanced composites via resin transfer molding (RTM). A novel high performance modified maleimide‐triazine (BT) resin system (coded as MBT) for RTM was developed, which is made of 4,4′‐bismaleimidodi‐ phenylmethane, o,o'‐diallylbisphenol A, 2,2′‐bis (4‐cyanatophenyl) isopropylidene, and hyperbranched polysiloxane (HBPSi). The effects of HBPSi on the processing and performance parameters of MBT system are evaluated. Results show that the processing characteristics of the MBT system are greatly dependent on the content of HBPSi in the system, while three MBT resins developed in this paper have significantly better integrated properties than BT resin. For example, compared to original BT resin, MBT resins have enlarged pot life (>8 hr) and good reactivity; more interestingly, cured MBT resins exhibit better dielectric properties and moisture resistance; in addition, MBT resins with suitable content of HBPSi have improved flexural and impact strengths as well as outstanding thermal property, suggesting that MBT system is the right kind of matrices with great potentiality for fabricating advanced structural and functional composites via RTM technique. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
13.
14.
15.
QU Rongiun WANG Chunhua NIE Zongjun YANG Shouting WANG Jingliang WANG Shen 《Chinese Journal of Reactive Polymers》1999,(Z1)
1INTRODUCTIONCarboxymethyl-chitosan(CMXTS)isakindofwatersolublelinearpolymerpreparedfromcarboxymethylationofchitosan(CTS).DuetoitsEDTA-likemolecularstructUre,ithasgoodchelatesorptionpropertiesformetalionslll.However,itiseasytorunoffinwateranddifficulttoberegenerated.Henceitmustbechemicallycross-linkedbeforebeingusedaschelateresin.Thecommonreagentsforcross-linking,suchasepichlorohydrin,chloromethylthiirane['1andpolyethyleneglycoldiglycidylether'],havedifunctionalgroups,whichreactwith'… 相似文献
16.
Positive photoresist systems comprising phenolic resin and quinonediazide are studied in detail. The structure of several novolak resins, which were synthesized from multi-substituted phenols, are analyzed with 13C-NMR. It is proved that these phenols are useful for the structural control of novolak resins. Phenols with two methyl substituents at meta-positions especially show a remarkable structural effect to control methylene bond types of novolak resins. The alkaline dissolution rate is also investigated on novolak resins synthesized from multi-substituted phenols to understand both the dissolution inhibition effect and the dissolution promotion effect. Key-structure of novolak resins for realizing high resolution is elucidated. In addition, the molecular design concept of novolak resin is clarified from several standpoints. Unsubstituted aromatic carbon of resin, hydrophobic effect of methyl substitutent and suitable structure of low Mw parts of novolak resin are also explored. Furthermore, it is proposed that a resist using a resin, which is based on the molecular design concept, has enough potential to produce critical dimensions of 0.2 μm or less taking advantage of phase-shifting technology. 相似文献
17.
酚醛树脂分子量及分布的表征方法有很多,如蒸气压渗透法(VPO)、气相色谱、高压液相色谱和凝胶渗透色谱等,但由于酚醛树脂存在众多异构体,这些方法均有一定限制性.场解吸质谱(FD-MS)方法的特点是只给出样品固有组分的分子峰,不产生碎片离子峰,用于酚醛树脂的表征,可以直接得出树脂所有固有组分的分子离子峰值,及树脂不同缩合度组分的相对含量,非常适用于组份繁多的酚醛树脂的的分子量及分布表征研究.以苯酚、甲酚及甲醛等原料分别制备了Resole型苯酚-甲醛树脂、Novolac型苯酚-甲醛树脂、Novolac型甲酚树脂及混酚-甲醛树脂,利用FD-MS对制备的几种不同类型酚醛树脂的分子量及分布进行了研究.结果表明,通过FD-MS谱图分析还可以得到树脂缩聚程度、原料种类、树脂特性等信息,对于鉴别及剖析各种类型酚醛树脂方便有效. 相似文献
18.
An experimental investigation of wear of glass fibre-epoxy resin and glass fibre-polyester resin composite materials 总被引:2,自引:0,他引:2
Hasim Pihtili 《European Polymer Journal》2009,45(1):149-154
In this paper, the effects of resin content on the wear of woven roving glass fibre-epoxy resin and glass fibre-polyester resin composite materials have been examined. Furthermore, composite materials are experimentally investigated under different loads and speeds by using a block-on-shaft wear tester. The influences of two thermosetting resins epoxy and polyester on the wear of glass-woven roving reinforced composites under has been investigated dry conditions. The glass fibre-epoxy resin and the glass fibre-polyester resin composite materials specimens have been tested under different experiment conditions. Tests were conducted for 0.39 and 0.557 m/s speeds, at two different loads of 5 and 10 N. The weight losses were measured after measuring different sliding distances. Wear in the experiments was determined as weight loss. For each experiment, one specimen was used. The amount of wear was measured before the experiment and after the experiment with the apparatus of balance scales with the accuracy of 10−3 g. Glass fibre-epoxy resin composites generally showed higher strength and minimum wear when compared with glass fibre-polyester resin composites materials. In addition, Scanning electron microscopy (SEM) is used to study the worn surface to verify the results. 相似文献
19.
C. Nobre M.J. Santos D. Torres O. Rocha I. Rocha E.C. Ferreira L.R. Rodrigues 《Analytica chimica acta》2009,654(1):71-78
Adsorption equilibrium of fructose, glucose and sucrose was evaluated on sulfonated poly(styrene-co-divinylbenzene) cation-exchange resins. Two types of resins were used: potassium (K+) gel-type and sodium (Na+) macroporous resins. Influence of the cation and effect of the resin structure on adsorption were studied. The adsorption isotherms were determined by the static method in batch mode for mono-component and multi-component sugar mixtures, at 25 and 40 °C, in a range of concentrations between 5 and 250 g L−1. All adsorption isotherms were fitted by a linear model in this range of concentrations. Sugars were adsorbed in both resins by the following order: fructose > glucose > sucrose. Sucrose was more adsorbed in the Na+ macroporous resin, glucose was identically adsorbed, and fructose was more adsorbed in the K+ gel-type resin. Data obtained from the adsorption of multi-component mixtures as compared to the mono-component ones showed a competitive effect on the adsorption at 25 °C, and a synergetic effect at 40 °C. The temperature increase conducted to a decrease on the adsorption capacity for mono-component sugar mixtures, and to an increase for the multi-component mixtures. Based on the selectivity results, K+ gel-type resin seems to be the best choice for the separation of fructose, glucose and sucrose, at 25 °C. 相似文献
20.
Peng Zhao 《Tetrahedron letters》2008,49(18):2951-2955
A new SASRIN resin derivative, SASRIN-TOPCAT resin, was synthesized by the reaction of SASRIN resin with 2-thiopyridyl chloroformate. The new resin can be used for the loading of alcohols and thiols under neutral conditions, and the release of alcohol from the resin is achieved by the treatment of 1% TFA in CH2Cl2 for 15-60 min. Compared to the other reported resins, SASRIN-TOPCAT resin is more suitable for the loading of alcohols in solid-phase organic synthesis. 相似文献