环氧乙烯基酯树脂的性能研究

以环氧树脂和(甲基)丙烯酸为基本原料,合成环氧(甲基)丙烯酸酯树脂并进行了表征。用环氧(甲基)丙烯酸酯以及其它活性单体和添加剂制备出室温快固型双组分树脂,采用正交实验获得制备树脂的最佳配方,并对环氧(甲基)丙烯酸酯树脂的性能进行了分析比较。     

耐腐蚀性乙烯基酯树脂的研究与应用

论述了乙烯基酯树脂优异的耐腐蚀性能,耐腐蚀原理及目前国内外耐腐蚀性乙烯基酯树脂的研究进展和在一些领域的典型应用。     

Effect of diluents on the curing behavior of vinyl ester resin

An acidic vinyl ester resin (～6 mg KOH per gram of solid) was prepared by reacting a bisphenol‐A‐based epoxy resin with acrylic acid in the presence of tributyl amine. The acrylated epoxy resin thus obtained was characterized by Fourier transform infrared spectroscopy. Five samples of vinyl ester resin containing styrene and methyl methacrylate (MMA) in the weight ratios 40:0, 30:10, 20:20, 10:30, and 0:40 were prepared at 30°C, and their curing behavior was studied by differential scanning calorimetry in the presence of benzoyl peroxide (2 phr). Curing behavior was dependent on the ratio of the two monomers used as reactive diluents. The kinetic parameters were determined by Ozawa's method. The energy of activation and frequency factor varied from 17 to 23 kcal mol^?1 and 8.47 × 10⁹ to 5.21 × 10¹² min^?1, respectively and were lowest for the samples containing 30:10 and 10:30 styrene/MMA weight ratios. The curing reactions followed first‐order kinetics and obeyed the Arrhenius rate expression. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1948–1951, 2003     

Effect of diluents on the decomposition behavior of vinyl ester resin

An acidic vinyl ester resin (～6 mg KOH per gram of solid) was prepared by reacting a bisphenol‐A‐based epoxy resin with acrylic acid in the presence of tributylamine. The acrylated epoxy resin thus obtained was characterized by Fourier transform infrared spectroscopy. Five samples of vinyl ester resin containing styrene and methyl methacrylate (MMA) in the weight ratios 40:0, 30:10, 20:20, 10:30, and 0:40 were prepared at 30°C. These samples were cured, using 2 phr benzoyl peroxide, at 90 ± 2 °C for 1 h. The decomposition behavior of all the samples was studied by thermogravimetric analysis (TGA) at 10°C min^?1. The TG and dynamic thermogravimetry (DTG) thermograms showed single‐step degradation in the individual cases of styrene and MMA, whereas a two‐step degradation process was observed when styrene was mixed with MMA in any proportion. For all the samples, the order of the reaction was one for the first step. This value was calculated with the Coats and Redfern equation in accordance with the best‐fit analysis and further confirmed by linear regression analysis. From this value of reaction order (n), the activation energy (E) and pre‐exponential factor (Z) were calculated, and the validity of the data was checked by statistical analysis. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1952–1956, 2003     

VARTM用乙烯基树脂体系流变性能研究

通过测试凝胶时间与温度的关系,得到乙烯基树脂的表观活化能并进行了分析。在粘度实验的基础上,依据双阿累尼乌斯方程建立了与之相吻合的流变模型。结果表明:乙烯基树脂的凝胶时间随温度升高而缩短,其表观活化能仅有3.04 kJ/mol。乙烯基树脂低粘度状态持续时间>30 min,符合树脂传递模塑成型工艺(VAR-TM)对树脂低粘度的要求。最终建立的粘度模型,可有效预测和模拟树脂体系在不同工艺条件下的粘度行为。     

耐腐蚀性乙烯基酯树脂的研究与应用

论述了乙烯基酯树脂优异的耐腐蚀性能、耐腐蚀原理及目前国内外耐腐蚀性乙烯基酯树脂的研究进展和在一些领城的典型应用。     

乙烯基树脂后固化制度的优化研究

采用DSC法研究了乙烯基树脂体系的固化动力学参数,并通过对该体系树脂浇铸体的固化度、力学性能、玻璃化转变温度的测试确定了最佳后固化制度。结果表明,该体系固化反应的表观活化能为56.27 kJ/mol,频率因子为4.96×107/s,反应级数为0.9;最佳后固化制度为100℃/1 h,此时固化度可达94.7%,弯曲强度可达102.6 MPa,拉伸强度可达64.1 MPa,玻璃化转变温度可达107.8℃。     

MFE乙烯基酯树脂的增韧研究

采用有机改性膨润土和聚乙二醇与乙烯基酯树脂复合成功制得纳米复合材料,在保持树脂拉伸、弯曲强度的同时,树脂的断裂伸长率和耐冲击性能得到了大幅度的改善。有机膨润土和聚乙二醇含质量分数为4%和15%,冲击强度为7．58 MPa,断裂伸长率为8．99%。     

双酚A型苯并嗪恶嗪树脂的流变特性研究

以双酚A、苯胺和甲醛为原料制备了双酚A型苯并口恶嗪(BOZ)单体,并对其进行了FT–IR、1H–NMR测试,重点研究了该单体聚合所得树脂的流变特性。在黏度实验的基础上,依据双阿累尼乌斯方程建立了与实验结果较吻合的等温化学流变模型。该模型可较准确地预测体系的低黏度工艺窗口,为该树脂的RTM工艺参数的优化提供科学依据。     

Hybrid carbon-glass fiber vinyl ester resin composites

Hybrid carbon-glass fiber composites of novolak epoxy-based vinyl ester resins have been investigated. The chemical resistance, the thermo-oxidative stability and the mechanical properties such as tensile strength and tensile modulus, as well as flexural strength and flexural modulus, interlaminar shear strength (ILSS) and impact strength have also been estimated. The combination of glass and carbon fibers in the hybrid turns out to be an excellent mix. These composites have good tensile and flexural properties as well as the good chemical resistance of the carbon fibers and the high impact strength of the glass fibers and also the thermo-oxidative stability of highly aromatic vinyl ester resins based on novolak epoxy.     

芳基乙炔树脂的固化反应动力学及流变行为研究

通过对芳基乙炔树脂的固化动力学研究确定其适宜的固化工艺。采用DSC和流变分析得到芳基乙炔树脂的特征固化参数及其固化度与温度的关系曲线。结果表明,树脂的起始反应温度为127.1℃,反应峰值温度164.2℃,终止反应温度195.1℃。固化动力学参数为:表观活化能E=190.12kJ/mol,反应级数n=1.87,频率因子A=1.995×1019。芳基乙炔树脂的加压固化温度为110～115℃,其起始固化温度为115℃。固化工艺为:115℃/8h+120℃/8h+140℃/2h+160℃/2h+180℃/2h+200℃/2h+220℃/4h。芳基乙炔树脂凝胶前固化过程由化学反应控制,凝胶后属于扩散控制,因此在凝胶时需延长固化时间。     

N,N-二乙基苯胺作为VE合成催化剂的研究

在环氧丙烯酸酯（VE）的合成过程中采用N，N－二乙基苯胺（DEAn)作为催化剂，成功地合成了预期产物VE树脂，合成产物色泽浅，粘度低，凝胶时间长。利和化学滴定、红外光谱（FTIR）等分析方法对VE的合成过程进行了跟踪、表征，讨论了DEAn用量对VE树脂及其固化产物性能的影响。     

风力发电机叶片用环氧乙烯基酯树脂

简述了国内外风力发电发展概况及风机叶片成型工艺及要求,研制了风力发电机叶片用MFE-VARIM-200环氧乙烯基酯树脂,对该树脂的粘度、凝胶时间、固化收缩率及固化物的力学性能等进行了测试。结果表明,该液体树脂的粘度(25℃)<0.2 Pa.s,凝胶时间(随环境温度调节引发剂用量)>2 h,线收缩率<0.3%,可以满足真空灌注成型工艺的要求,固化物的力学性能可满足风力发电机叶片对基体树脂的要求。     

The relationship between dielectric and rheological behavior of epoxy resin during cure

Measurement of the frequency-dependent, vector voltage (V_c) provided an in-situ and non-destructive technique to measure continuously the rheological change of a resin due to polymerization, and can be used as the basis of real-time control. The vector voltage depends on the degree of polarization of the dipolar molecules and on the change of viscosity during cure; both result from the modified structure of the epoxy resin during cure, The initial stage of curing, represented by the former portion Of the Vc curve (divided at the minimum of the Vc curve), was caused mainly by the effects of temperature and viscosity. During the latter stage of the cure reaction, Vc alters because of the effect of the lightened matrix structure that inhibits alignment of dipoles. The duration of reaction. temperature of curing and degree of conversion all have the same effects on both vector voltage and viscosity, The minimum value of vector voltage is correlated to the minimum viscosity, and there is a nearly quantitative relationship between them, One can determine the viscosity of the epoxy resin during cure from reading of the vector voltage. Various reaction mechanisms may be explained based on the graphs of vector voltage of various types.     

Toughening of vinyl ester resin using butadiene-acrylonitrile rubber modifiers

A common method for toughening thermoset resins is the addition of butadiene-acrylonitrile based rubber modifiers. A difficulty experienced by diglycidyl ether of bisphenol-A (DGEBA) vinyl esters (VE) compared to other thermosets is the solubility of the butadiene-acrylonitrile modifier. In this study, a miscible system was prepared by reducing the VE monomer molecular weight to 540 g/mol from industrially used monomers possessing molecular weights greater than 700 g/mol. A main objective of this study was to toughen the vinyl ester while limiting plasticization by varying rubber reactivity and concentration. All modified samples experienced a significant increase in fracture toughness with some degree of plasticization, as shown by losses in modulus and glass transition temperature (T_g). Epoxy terminated rubber (ETBN) yielded a higher toughness than vinyl terminated rubber (VTBN) due to the difference in rubber particle formation and resulting morphology. Chemical linkage of VTBN to the vinyl ester matrix hindered complete phase separation, but helped the retention of mechanical properties when compared to ETBN.     

UHMWPE／Epoxy冻胶体系的流变行为研究

研究了环氧树脂(Epoxy)加入后对超高分子质量聚乙烯(UHMWPE)稳态表观粘度、粘流活化能以及复数模量和粘度的影响。结果表明,环氧树脂添加量低于1ω,UHMWPE／Epoxy冻胶体系的表观粘度和粘流活化能都低于空白 UHMWPE冻胶体系;当环氧树脂添加量增加至3 ω以后,冻胶体系的表观粘度和粘流活化能均比空白UHMWPE冻胶体系高。     

酚醛环氧乙烯基酯树脂碳纤维复合材料的制备及性能研究

把酚醛环氧乙烯基酯树脂分别与固化剂过氧化氢异丙苯(CHP)、过氧化苯甲酸叔丁酯(TBPB)、过氧化二异丙苯(DCP)进行混溶,模压成型,碳纤维层合板,进行了力学性能和热稳定性的研究。结果表明,研究的碳纤维-酚醛环氧基乙烯基酯树脂复合材料具有非常好的力学性能及热稳定性,弯曲强度达到1 400～1 900 MPa。     

Thermal behavior of vinyl ester resin matrix composites reinforced with alkali‐treated jute fibers

The thermal behavior of vinyl ester resin matrix composites reinforced with jute fibers treated for 2, 4, 6, and 8 h with 5% NaOH was studied with Thermo‐gravimetric analysis and differential scanning calorimetry. The moisture desorption peak shifted to a higher temperature, from 37 to 58.3°C, for all the treated‐fiber composites because of improved wetting of the fibers by the resin and stronger bonding at the interface. The degradation temperature of the vinyl ester resin in the composites was lowered to 410.3°C from that of the neat resin, 418.8°C. The X‐ray diffraction studies showed increased crystallinity of the treated fibers, which affected the enthalpy of the α‐cellulose and hemicellulose degradation. The hemicellulose degradation temperature remained the same (299.7°C) in all the treated‐fiber composites, but the enthalpy associated with the hemicellulose degradation showed an increasing trend in the treated composites with a small increase in the weight loss. This could be attributed to the increased hydrogen bonding between the more accessible ? OH groups of the hemicellulose in the noncrystalline region of the jute fiber and the resin. The degradation temperature of α‐cellulose was lowered from 364.2 to 356.8°C in the treated composites. The enthalpy of α‐cellulose degradation showed a decreasing trend with a lowering of the weight loss. The crystalline regions of the fiber, consisting of closely packed α‐cellulose chains, were bonded with the resin mainly on the surface through hydrogen bonds and became more resistant to thermal degradation; this reduced the weight loss. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 123–129, 2004     

Curing studies on vinyl ester resin using acrylates as reactive diluents

The curing behavior of bis(methacryloxy) derivatives of diglycidyl ether of bisphenol A (vinyl ester resin) containing acrylates (methyl, ethyl and butyl acrylate) as the reactive diluents (40% w/w) were studied by DSC analysis. Data found in this study indicated that an appreciable curing rate is obtained at lower temperature with increased concentrations of initiator. The acid value, activation energy, Arrhenius factor and specific heat are discussed.