Influence of glass transition temperature of crosslinked unsaturated polyester resin/styrene formulations on the final conversion after an isothermal curing at 100°C

SMC (sheet molding compound) is a composite based on fibers‐reinforced unsaturated polyester (UP) resin molded usually at 140°C to 170°C under a pressure of 60 to 100 bars. In order to develop new SMC formulations that can be molded at lower temperature (100°C) for economic and environmental reasons, the formulation of the composite had to be completely modified, both to allow a rapid reaction at 100°C, but also to avoid a vitrification phenomenon due to the fact that the glass transition temperature (Tg) of the SMC parts becomes, during the molding process, higher than the mold temperature. In this paper, the relation between the molding temperature, the glass transition temperature, and the final conversion of UP resin/styrene formulations has been underlined. The Tg of the cured resin was decreased by two different ways. The first way involved the reduction of the crosslinking density of the UP resin by using a blend of two resins, a pure maleic and a more flexible one. This blend allows to adjust the Tg over a temperature range from 197°C (Tg of the pure UP resin) to 75°C (Tg of the pure flexible resin). The second way consisted in the addition of butyl methacrylate (BuMA), a reactive plasticizer, to the formulation, allowing a decrease of the final material's Tg from 197°C to 130°C by replacing 35 wt% of styrene by BuMA. These two methods allow to obtain a final conversion of 99% after 8 minutes of molding at 100°C.     

聚苯乙烯基N,O-二酰基磺酰羟胺树脂: 一种双酰基转移试剂在合成酰胺库中的应用

用聚苯乙烯基磺酰羟胺树脂1与酰氯2反应合成了聚苯乙烯基N,O-二酰基磺酰羟胺树脂3. 树脂3作为一种新的双酰基转移试剂可与胺4发生酰基转移反应, 合成了含有24个结构类似的酰胺化合物库. 改变酰氯的种类, 结果发现双对硝基苯甲酰树脂3a的活性较高. 双酰基树脂3胺解结果表明, 由脂肪族胺得到的酰胺收率较芳香族胺高. 当解脱试剂同时含有羟基和氨基时, 双酰基树脂3能选择性地在氨基端发生酰基转移, 而羟基端不受影响.     

紫外光固化聚氨酯丙烯酸酯树脂的流变行为

合成了一系列紫外光因化聚氨酯丙烯酸酯聚合物,研究了分子量、原料配比、反应方式、含水量、溶剂等对其流变行为的影响。实验表明,控制剂聚物分子量,干燥原料,以ＨＥＡ先与异氰酸酯反应的加料方式合成的树脂,流动性较好。在此基础上合成了较好流动性和光固化性能的蓖麻油紫外光固化树脂。     

环氧树脂水性化体系研究进展

系统地介绍了目前国内外环氧树脂水性化的研究进展,总结了环氧树脂水性化体系的特点与应用,并提出一种水性环氧树脂乳液制备的新方法。     

Glass fibre sizing effect on dynamic mechanical properties of cyanate ester composites I. Single frequency investigations

In order to investigate sizing effect in composite materials, we studied three types of composites, with different sizings. Dynamic mechanical analysis appeared to be a good way to characterize the α relaxation process of composites and their interphases. Results showed that α relaxation temperature shifted to higher temperatures for composites without sizing. Study of sizing extract/resin blend showed too that interphase was a mixture of polyvinyl acetate and cyanate resin. The results allow us to deduce that a plastification effect of resin by sizing could occur, with modification of crosslink density. Moreover, we can think that all resin is affected by sizing and the conversion rate in interphase is not total.     

N-2-氯苄基苯甲酰胺的固相合成及其晶体结构分析

N-2-氯苄基苯甲酰胺采用固相法制备.聚苯乙烯磺酰氯(1)在吡啶存在下与2-氯苄胺反应得到N-2-氯苄基磺酰胺树脂(2),进一步在吡啶催化下用苯甲酰氯进行酰化得到N-2-氯苄基-N-苯甲酰基磺酰胺树脂(3).用TiCl₄/Zn/THF试剂处理,从树脂3上解脱得到产物N-2-氯苄基苯甲酰胺(4),产率92%.N-2-氯苄基苯甲酰胺的晶体属于单斜晶系,P2₁空间群,晶胞参数:a=0.7149(3)_nm,b=0.8772(4)_nm,c=0.9704(4)_nm;β=95.172(7)°;晶体结构中存在两种分子间氢键相互作用.     

酚醛树脂胶粘剂的复合改性

采用有机硅和蔗糖对酚醛树脂胶粘剂进行复合改性,以提高树脂胶膜的柔韧性,并使产品具有较高的粘接强度。通过考察改性剂有机硅种类、改性剂加入时间、加入量对产品性能的影响,结果发现:在反应开始时加入总质量1.5%的有机硅(8427)和总质量0.9%的蔗糖,反应所得产品分子量及粘度适中,粘接强度高达6MPa,游离甲醛含量低至0.067%。采用FT-IR和TG对产品结构及性能进行分析,由此可知,改性后的酚醛树脂胶粘剂有大量—Si—O—生成,其柔韧性和耐热性有很大的提高。     

Resin Swelling in Mixed Solvents Analysed using Hansen Solubility Parameter Space

The swelling of resins (Merrifield and HypoGel 200) in mixtures of two solvents was generally found not to vary linearly with the relative amount of each solvent in the mixture. Hansen solubility parameter (HSP) space could be used to define high, medium and low swelling regions for each resin. The variation of resin swelling with binary solvent composition could then be explained based on the HSP parameters of the two solvents and the way in which the line connecting the points corresponding to the two pure solvents bisected the swelling region for the resin. The applicability of the methodology was demonstrated by showing that an appropriate mixture of two green solvents was more effective for solid-phase peptide synthesis on Merrifield resin than use of either individual solvent and could completely replace the use of traditional polar aprotic and chlorinated solvents for this application. It was also shown that the high resin swelling area of Merrifield resin can be used to predict mixtures of green solvents that will dissolve linear, unfunctionalised polystyrene.     

Synthesis of the hydrophobic–hydrophilic macroporous poly divinylbenzene/poly(sodium acrylate) IPN resin and adsorption performance for berberine

The macroporous polydivinylbenzene/poly(methyl acrylate) interpenetrating polymer network (PDVB/PMA IPN) was prepared by the sequential suspension polymerization method, and was modified to be hydrophobic–hydrophilic macroporous polydivinylbenzene/poly (sodium acrylate) IPN (PDVB/PNaA IPN) by converting the PMA to PNaA under the condition of base. The effects of different mass ratio of the two networks and different cross‐linking degree of the second network on the pore structure and adsorption capacity of PDVB/PNaA IPN resin were studied. The PDVB/PNaA IPN resin whose adsorption quantity is the biggest was chosen to study further. The pore structure, the weak acid exchange capacity, the water retention capacity, and the swelling ability of PDVB/PNaA IPN resin were measured. The study focused on the adsorption isotherms of berberine at different temperatures. Isosteric adsorption enthalpy, adsorption Gibbs free energies can be calculated according to thermodynamic functions. The results show that the saturated adsorption quantity of berberine is up to 109.4 mg ml^?1 (wet resin) by the way of dynamic adsorption and desorption experiment. The resin could be reused by the mixture with 0.5% sodium chloride and 80% ethanol. On the one hand the hydrophobic PDVB in the PDVB/PNaA IPN resin has the ability of adsorption using π–π interaction, and on the other hand the hydrophilic PNaA in the PDVB/PNaA IPN resin has the ability of adsorption using ion exchange interaction. An important conclusion can be drawn that the PDVB/PNaA IPN resin has a promising application prospect in extracting and separating quaternary ammonium type alkaloids such as berberine. Copyright © 2009 John Wiley & Sons, Ltd.     

IRA-200 resin-supported platinum(II) complex for photooxidation of olefins

Cyclometalated platinum(II) 4,6-diphenyl-2,2′-bipyridine complex is supported on a commercially available cationic ion-exchange resin (amberlite IRA-200). Photophysical and ESR determinations indicate that the combined photosensitized system is able to generate singlet oxygen with high quantum yield upon irradiation of light in the visible region. The platinum(II) complex loaded on IRA-200 resin is stable and the photooxidation occurs in an environmentally friendly way. Only a simple filtration is needed to recycle the expensive metal catalyst.     

一种加成固化型热固性树脂PN-PAA固化过程和热稳定性研究

研究了炔丙基醚化酚醛树脂(PN)与聚芳基乙炔树脂(PAA)的反应性共混物(以下简称PN-PAA共混树脂)的相容性,并对共混树脂的固化过程和固化物的耐热性进行了表征.相态、DSC、SEM、TEM等测试结果均表明共混树脂及其固化物是完全相容的均相体系.凝胶时间、粘度、DSC等结果表明共混树脂固化工艺性优良,适合多种成型工艺(如RTM),显著改善了PAA树脂的固化工艺缺陷.DMA、TGA等分析表明共混树脂固化物具有很高的耐热性,可作为新型的防热复合材料和高温结构材料的基体.     

N-对甲基苄基苯甲酰胺的固相合成及其晶体结构分析

标题化合物采用固相法合成: 聚苯乙烯磺酰氯树脂1与对甲基苄胺反应得到N-对甲基苄基磺酰胺树脂2, 用苯甲酰氯酰化得到N-对甲基苄基-N-苯甲酰基磺酰胺树脂3。用TiCl4/Zn/THF处理从树脂3上经自由基解脱的方法得到N-对甲基苄基苯甲酰胺4, 产率为76%。晶体结构在Bruker SMART 1000 CCD X-射线衍射仪上, 用石墨单色器单色化的MoK嵘湎?l = 0.071073 nm)测定。非氢原子坐标用直接法解出, 用最小二乘法对非氢原子进行各向异性温度因子修正。N-对甲基苄基-苯甲酰胺: 化学计量式为: C15H15NO, Mr = 225.28, 晶体属于正交晶系, Pna21空间群。晶胞参数: a = 0.9549(6), b = 1.1169(7), c = 1.1774(7) nm, V = 1.2557(13) nm3, Z = 4, Dc = 1.192 g/cm3, m = 0.075 mm-1, F(000) = 480;最终结构偏离因子R = 0.0478, wR = 0.1013, S = 0.912。化合物4的晶体结构中有分子间氢键相互作用。     

Nonisocyanate based polyurethane/silica nanocomposites and their coating performance

A series of silica nano-particles with different size were prepared by sol–gel technique, then surface modification by using cyclic carbonate functional organoalkoxysilane (CPS) was performed. Various amounts of carbonated silica particles directly added into carbonated soybean oil (CSBO) and carbonated polypropylene glycol (CPPG) resin mixture to prepare polyurethane–silica nanocomposite coating compositions by nonisocyanate route using an aliphatic diamine as a curing agent. Cupping, gloss, impact, and taber abrasion tests were performed on aluminum panels coated with those nano-composite formulations and tensile tests, thermogravimetric and SEM analyses were conducted on the free films prepared from the same coating formulations. An increase in abrasion resistance of CSBO-CPPG resin combination with the addition of silica was observed. In addition, the maximum weight loss of CSBO-CPPG resin combination was shifted to higher temperatures with incorporation of silica nano-particles The positive effect of modified silica particles on thermal stability of CSBO-CPPG system could be explained in such a way that PPG chains are able to disperse particles in the medium throughout the interactions between ether linkages and silanol groups.     

Determination of protonation- and metal complex stability constants for a chelating monomer and its immobilized in polymer resin

An improved method is described for the calculation of complex stability constants for metal–ligand complexes considering ligands immobilized in resin phase. The applicability of it has been proved for N′-benzylethylene diamine N,N,N′-triacetic acid monomer (BEDTA) and for the ion exchange resin developed in the authors laboratory immobilizing this with styrene divinyl benzene. Calcium and magnesium metal ion complexes were investigated. Electrochemical and flame photometric measurements were used to collect equilibrium concentration data. The procedure worked out included the measurement of the quantity of resin bound water. Using these and the other experimentally gathered values and the improved way of calculation metal ligand complex stability constants were determined in aqueous media. Ion exchange chromatographic separation of calcium and magnesium ions was performed with a resin containing column for separation and optimized eluent.     

聚氨酯/环氧树脂互穿网络聚合物的性能研究

互穿聚合物网络（Interpenetrating polymer net-work,简称IPN）广泛应用的为聚氨酯基的互穿网络聚合物。其合成多集中在弹性体方面。本文用同步法合成的聚氨酯／环氧树脂互穿网络硬质泡沫塑料材料（简称PU／ERIPNF）,机械性能较好,并研究了其动态力学性能及形态变化。     

Practical and Theoretic Analysis of Resin Flow in Vacuum Assisted Resin Transfer Molding Processes

In this study, the non-isothermal resin infiltration during the VARTM process has been analyzed and characterized. In particular, the resin flow through the fibers has been described by the Darcy law and introducing the degree of saturation, the percent of void effectively occupied by the resin within a control volume, as variable in order to account for the moving boundary nature of the problem. Some preliminary tests to measure the advancement of a reference substance, pure water, between the reinforcement fibers with embedded optic fibers sensors, show the capability of a new sensorial technology, based on use of non intrusive fiber optic COTS components, assembled into an original way. These sensors will be used for real time monitoring of the resin flow during the experimental infusion tests and for in-situ demonstration of the capability and the reliability of the model, in the aim to assure a “process repeatability”. Due the effectiveness lack of repeatability of VARTM, the Authors propose an approach to extract a parameter during the process, meaning a “Deviation” of modelized output (MOD Modelized Output Deviation). This parameter, obtained by use of optic fibers technology, may improve the standard quality of the production, analyzing and correcting with feed-back capability the efficiency of the moulded manufactured devices.     

An investigation of the accelerated thermal degradation of different epoxy resin composites using X-ray microcomputed tomography and optical coherence tomography

Epoxy resin composites reinforced with hollow glass microspheres, microlight microspheres, 3D parabeam glass, and E-Glass individually were subjected to accelerated thermal degradation conditions. X-ray microcomputed tomography (XμCT) was used to evaluate density changes, reinforcement filler damage, homogeneity, cracks and microcracks in the bulk of the different epoxy resin composites. XμCT 3D images, 2D reconstructed images and voids calculations revealed microspheres damage, filler distributions and showed cracks in all composites with different shapes and volume in response to the thermal degradation conditions. In addition, expansion of air bubbles/voids was observed and recorded in the microsphere and microlight epoxy composite samples. In a complementary way, optical coherence tomography (OCT) was used as a novel optical characterisation technique to study structural changes of the surface and near-surface regions of the composites, uncovering signs of surface shrinkage caused by the thermal treatment. Thus, combining XμCT and OCT proved useful in examining epoxy resin composites' structure, filler-resin interface and surface characteristics.     

Preparation and Property of the Water Absorbent Hybrid Resin

Water absorption material has been attracted much more attention for its wide use in soil and water conservation, agriculture, etc. But this material will actually apply in agriculture, soil and water conservation only when it is cheap enough. Pulp fiber and starch to prepare high absorbing-water resin is a good method for decreasing the cost [1,2]. However, it still has a long way to turn it into reality. Now the montmorillonite is widely used in preparing nanocomposites [3]. But used it in preparing absorbing-water resin has little report. In this article the water absorption hybrid resin has been prepared by one step intercalation polymerization method. In the process of intercalation the partly neutralization acrylic acid and urea have been used as intercalating reagent. Beside that, the urea also has been used as cross-linking agent.     

Enlightening the past: analytical proof for the use of Pistacia exudates in ancient Egyptian embalming resins

Mastic, the resinous exudate of the evergreen shrub Pistacia lentiscus, is frequently discussed as one of the ingredients used for embalming in ancient Egypt. We show the identification of mastic in ancient Egyptian embalming resins by an unambiguous assignment of the mastic triterpenoid fingerprint consisting of moronic acid, oleanonic acid, isomasticadienonic and masticadienonic acid through the consolidation of NMR and GC/MS analysis. Differences in the observed triterpenoid fingerprints between mummy specimens suggest that more than one plant species served as the triterpenoid resin source. Analysis of the triterpenoid acids of ancient embalming resin samples in the form of their methyl- and trimethylsilyl esters is compared. In addition we show a simple way to differentiate between residues of mastic from its use as incense during embalming or from direct mastic application in the embalming resin.     

DSC and TSDC Study of Unsaturated Polyester Resin. Influence of the promoter content

This work reports on the curing kinetics of unsaturated polymer resins (UPRs) cured with styrene, studied by differential scanning calorimetry and Fourier transform infrared spectroscopy. The data lead to determination of the experimental conditions with which to obtain a fully cured material and open the way for study of the relaxation phenomena by means of thermally stimulated depolarization current analysis (TSDC). In relaxation studies on fully cured resins, the TSDC spectra revealed important overlapping of the main relaxation peak with an extra upper peak. The importance of this extra peak a priori prevents further analysis of the main relaxation. To identify the origins of this peak (space charge or other), the purity of the resin was checked by X-ray fluorescence spectroscopy. The use of UPR specimens with different compositions (in terms of the resin/activator/initiator ratio) demonstrated that the bulk of the impurities Cl, K, Ca, Sr, Zr and Ba are due to the promoter. Decoupling of the mixed peaks (α-relaxation and extra) revealed that the a peak is independent of the proportion of the promoter in the resin and that the extra peak is principally due to the presence of these impurities. This revised version was published online in July 2006 with corrections to the Cover Date.