间戊二烯和顺酐反应动力学

C5和顺酐反应合成粗甲基四氢苯酐是生产甲基四氢苯酐及甲基六氢苯酐的关键步骤.为了研究C5中间戊二烯与顺酐反应动力学,选择合适溶剂并设计单因素多水平方案,考察了顺酐与间戊二烯摩尔比(0.4-1.1)、反应温度( 15-45℃)、溶剂(甲基四氢苯酐、甲苯和丙酮)等因素对反应的影响,测定了间戊二烯与顺酐反应的动力学数据.依据...     

Characterization of cure reactions of anhydride/epoxy/polyetherimide blends

The cure kinetics of blends of epoxy (diglycidyl ether of bisphenol A)/anhydride (nadic methyl anhydride) resin with polyetherimide (PEI) were studied using differential scanning calorimetry under isothermal conditions to determine the reaction parameters such as activation energy and reaction constants. By increasing the amount of PEI in the blends, the final cure conversion was decreased. Lower values of final cure conversions in the epoxy/PEI blends indicate that PEI hinders the cure reaction between the epoxy and the curing agent. The value of the reaction order, m, for the initial autocatalytic reaction was not affected by blending PEI with epoxy resin, and the value was approximately 1.0. The value of n for the nth order component in the autocatalytic analysis was increased by increasing the amount of PEI in the blends, and the value increased from 1.6 to 4.0. A diffusion‐controlled reaction was observed as the cure conversion increased and the rate equation was successfully analyzed by incorporating the diffusion control term for the epoxy/anhydride/PEI blends. Complete miscibility was observed in the uncured blends of epoxy/PEI at elevated temperatures up to 120 °C, but phase separations occurred in the early stages of the curing process. © 2002 Society of Chemical Industry     

Aryl phosphinate anhydride curing for flame retardant epoxy networks

An aryl phosphinate anhydride (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide)-methyl succinic anhydride (DMSA), with a pendent phosphorus group was synthesized and used as a reactive type flame retardant. The structure of DMSA was confirmed by FTIR, mass, elemental analysis, ¹H and ³¹P NMR spectroscopies. The aryl phosphinate anhydride was successfully used to cure some commercial epoxides, such as bisphenol A diglycidyl ether (DGEBA) and epoxy-novolac. The epoxy networks obtained were characterized by dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), and the limiting oxygen index (LOI) test. Epoxy resins cured with DMSA exhibit higher LOI values and char yields compared with those cured by commercial anhydrides, such as phthalic anhydride (PA) and hexahydrophthalic anhydride (HHPA). Furthermore, the LOI value and the char yield of the epoxy-resin composites increase with increasing phosphorus content. The flame retardancies of the epoxy-resin composites were significantly improved by using aryl phosphinate anhydride. © 1998 Society of Chemical Industry.     

TGA-FTIR研究环氧/酸酐固化物热降解行为

采用TGA-FTIR联用技术在高纯氮气保护下实时研究了环氧树脂酸酐固化物热降解过程和气相产物。TG和DTG曲线表明,环氧树脂酸酐固化物存在着2个热失重阶段,最大热失重速率峰值温度分别在163℃和389℃,其失重温度范围分别在100~210℃和260~570℃。FTIR谱图表明第一失重阶段主要是体系中所含的水分挥发和/或伯醇脱水及一些小分子物质挥发过程。CO和酮类物质分别产生于280℃和305℃,并一直持续到本实验结束;酸酐类物质在455℃以下时吸收峰的强度很微弱,此后逐步增强。此外,环氧树脂酸酐固化物热降解气相挥发物还有各种碳氢混合物。     

TPP/PMMA复合物促进环氧树脂/酸酐体系的固化动力学研究

以三苯基膦(TPP)和甲基丙烯酸甲酯(MMA)为原料合成了TPP/PMMA复合物,用DSC研究了TPP/PMMA催化双酚A二缩水甘油醚(EP828)/甲基四氢苯酐(MTHPA)体系固化反应动力学。非等温固化动力学研究结果表明,转化率在20%～60%范围内,用Ozawa法能较好地描述环氧树脂/酸酐体系的固化反应过程。     

脂肪醇聚醚型水性胺环氧固化剂的合成及性能

由高级脂肪醇聚氧乙烯醚(OE-6)、甲基四氢邻苯二甲酸酐(MTHPA)经酯化反应得到甲基四氢邻苯二甲酸单酯(MTHPME),而后其与液体环氧树脂(E-51)反应得单环氧甲基四氢邻苯二甲酸双酯(SEMTHPDE),最后经多元胺扩链及苄基缩水甘油醚封端,得到脂肪醇聚醚型水性胺类环氧固化剂(PEAWAECA)。对影响反应的因素:物料配比、反应时间、反应温度及催化剂用量等进行了考察并以红外光谱对产物结构进行了表征。结果表明,MTHPME的最佳合成工艺为:MTHPA与OE-6物质的量比1∶1,反应温度110℃,反应时间2.5 h;SEMTHPDE的最佳合成工艺为:E-51与甲基四氢苯酸单酯物质的量比为1.04∶1,反应温度115℃,反应时间3.5 h,对该产物与水性环氧AB-EP-20复配制备的双组分涂料漆膜性能分析表明,环氧基与胺氢物质的量比为1.1时,涂膜柔韧性达1 mm、铅笔硬度达3 H、附着力达1级、耐冲击性达50 kg/cm,改善了环氧树脂涂膜较脆的缺陷。     

Vapor-phase selective hydrogenation of maleic anhydride to succinic anhydride over Ni/TiO2 catalysts

A series of supported Ni/TiO₂ catalysts were prepared by incipient wetness impregnation method under different calcination temperatures, and the as-prepared catalysts were characterized by X-ray diffraction (XRD), hydrogen temperature-programmed reduction (H₂-TPR) and X-ray photoelectron spectroscopy (XPS). The catalytic properties of these Ni/TiO₂ catalysts were investigated in the vapor phase hydrogenation of maleic anhydride (MA) to succinic anhydride (SA). The results showed that the catalytic activity and the selectivity of the Ni/TiO₂ catalysts were strongly affected by the calcination temperature. The catalyst calcined at 1023 K showed a relatively higher SA selectivity of 96% at high MA conversion (96%) under the tested conditions (493 K and 0.2 MPa). The improvement of SA selectivity could be mainly assigned to the presence of suitable metal–support interaction, which can play a role in catalytic property of active nickel species as electron promoter. Besides, the change of surface properties of TiO₂ support with the increasing calcination temperatures, e.g., the decrease of Lewis acid sites, might also have some positive role in reducing the side-products like γ-butyrolacetone (GBL).     

Epoxy resins toughened by poly(propylene carbonate)

Poly(propylene carbonate) (PPC) was used as a toughening agent for improving the brittleness of cured epoxy resins (EP). Methyl tetrahydrophthatic anhydride (MTHPA) was used as a curing agent. The activation energies for the reactions of PPC/MTHPA and EP/MTHPA measured by FTIR were 115.8 and 66.5 kJ/mol, respectively, while for the composite system of PPC/EP/MTHPA, the activation energy obtained from DSC was 52.9 kJ/mol. Gel contents, DMA, and DSC displayed that the cured resins of PPC/EP/MTHPA were phase-separation crosslinking systems and most of PPC could react with MTHPA or the epoxy group. The toughness of cured resins was reinforced by the addition of PPC. The optimum mechanical properties and toughness for cured resins of PPC/EP/MTHPA corresponded to the system containing 20 phr PPC, which achieved a 33% increase in tensile strength and a 45% increase in the fracture toughness at no expense of the elongation of cured resins. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 2457–2465, 1997     

Synthesis and comparative study of thermal stabilities of the imidization of some maleic anhydride copolymers

In the present study, first, maleic anhydride‐styrene (MA‐St), maleic anhydride‐allyl phenyl ether (MA‐APhE), maleic anhydride‐heptene‐1(MA‐Hp), and maleic anhydride‐allyl propionate (MA‐AP) copolymers have been synthesized in different solvents in the presence of azobisisobutyronitrile (AIBN) at 70°C. Then, these four copolymers have been reacted with aniline at 60°C in N,N‐dimethyl formamide (DMF), and maleamidic acid derivatives of these copolymers have been synthesized. Next, they have been obtained from their maleimide derivatives by heating under vacuum at 150°C. All these polymers have been characterized by Fourier Transform infrared spectroscopy (FTIR) and investigated their thermal properties by using differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA) methods. The analyses results showed that thermal properties of maleimide derivatives of maleic anhydride copolymers changed as depend on the neighbor monomers of maleic anhydride. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2250–2254, 2006     

Molecular Structure of Interphases Between DGEBA/BTDA Adhesives and Silver Substrates Using Surface-Enhanced Raman Scattering

Surface-enhanced Raman scattering (SERS) was used for the non-destructive characterization of interphases between epoxy/anhydride adhesive systems and silver substrates. The normal raman spectrum of benzophenone tetracarboxylic dianhydride (BTDA) was characterized by strong bands near 1785 and 1860 cm^-1 that were assigned to the anhydride groups, a strong band near 1690 cm^-1 that was assigned to the benzophenone C─O stretching mode, and by a strong band near 1620 cm^-1 that was attributed to vibration v(8b) of the benzene rings. The bands due to v(8b) and to the benzophenone C─O stretching mode were prominent in the SERS spectrum of BTDA but the bands related to the anhydride group were missing, indicating that the anhydride groups were hydrolyzed at the silver surface to form carboxylate groups. A band related to a CH out-of-plane bending mode which was absent from the normal Raman spectrum of BTDA was strong in the SERS spectrum, indicating that the molecules were adsorbed onto silver with a flat configuration. SERS spectra obtained from a diglycidyl ether of bisphenol-A (DGEBA) epoxy cured against a silver substrate using BTDA as the curing agent were identical to SERS spectra of BTDA and were independent of the epoxy/BTDA ratio, indicating that the spectra were characteristic of the interface rather than the bulk adhesive and that BTDA was preferentially adsorbed onto the silver substrate. SERS spectra obtained from thin films of BTDA adsorbed onto silver and then overcoated with thick films of epoxy were identical to the spectrum of BTDA and showed no evidence of bands related to DGEBA, supporting the conclusion that the SERS spectrum obtained from the DGEBA/BTDA adhesive was characteristic of the interfacial region.     

Non‐catalytic anhydride curing of hydrogenated bisphenol‐A glycidyl ether with 1,2,4‐cyclohexanetricarboxylic anhydride and light emitting diode encapsulation

Noncatalytic anhydride curing of hydrogenated bisphenol‐A glycidyl ether (YX8000) using hydrogenated trimellic anhydride (1,2,4‐cyclohexanetricarboxylic anhydride, H‐TMAn) and methylhexahydrophthalic anhydride (MeHHPA) were studied. Differential scanning calorimetry data shows no exthothermal under 190°C using MeHHPA without catalyst because of the low reactivity. On the other hand, H‐TMAn had higher reactivity and it can be cured without catalyst. The effect of anhydride concentration both on curing and on properties was studied in detail. For example, the highest T_g was found when YX8000 : H‐TMAn = 100 : 75 or YX8000 : MeHHPA = 100 : 100. The highest curing exothermal was found at similar ratio. Following, the encapsulation of light emitting diode (LED) was prepared with two anhydrides. Surface volume decrease was observed with MeHHPA by its evaporation, but H‐TMAn gave flat surface. After thermal cycle test of these LED, H‐TMAn was found to have better crack resistance than MeHHPA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 962–966, 2006     

脂环族环氧树脂/酸酐体系固化促进剂的研究

利用示差扫描量热仪研究了乙酰丙酮铝、三苯基膦、2-乙基-4-甲基咪唑(2E4MZ)等3种促进剂在脂环族环氧树脂(UVR-6103)/甲基六氢邻苯二甲酸酐(MHHPA)体系中的固化行为,通过Ellerstien方程计算得到了UVR-6103/MHHPA体系在3种促进剂作用下的固化动力学参数,其表观活化能分别为48.6,69.2,90.2kJ/mol,反应级数分别为0.96,2.09和1.60。     

Molecular Structure of Interphases Between DGEBA/BTDA Adhesives and Silver Substrates Using Surface-Enhanced Raman Scattering

Surface-enhanced Raman scattering (SERS) was used for the non-destructive characterization of interphases between epoxy/anhydride adhesive systems and silver substrates. The normal raman spectrum of benzophenone tetracarboxylic dianhydride (BTDA) was characterized by strong bands near 1785 and 1860 cm^?1 that were assigned to the anhydride groups, a strong band near 1690 cm^?1 that was assigned to the benzophenone C─O stretching mode, and by a strong band near 1620 cm^?1 that was attributed to vibration v(8b) of the benzene rings. The bands due to v(8b) and to the benzophenone C─O stretching mode were prominent in the SERS spectrum of BTDA but the bands related to the anhydride group were missing, indicating that the anhydride groups were hydrolyzed at the silver surface to form carboxylate groups. A band related to a CH out-of-plane bending mode which was absent from the normal Raman spectrum of BTDA was strong in the SERS spectrum, indicating that the molecules were adsorbed onto silver with a flat configuration. SERS spectra obtained from a diglycidyl ether of bisphenol-A (DGEBA) epoxy cured against a silver substrate using BTDA as the curing agent were identical to SERS spectra of BTDA and were independent of the epoxy/BTDA ratio, indicating that the spectra were characteristic of the interface rather than the bulk adhesive and that BTDA was preferentially adsorbed onto the silver substrate. SERS spectra obtained from thin films of BTDA adsorbed onto silver and then overcoated with thick films of epoxy were identical to the spectrum of BTDA and showed no evidence of bands related to DGEBA, supporting the conclusion that the SERS spectrum obtained from the DGEBA/BTDA adhesive was characteristic of the interfacial region.     

桐酐与甲基四氢苯酐复合固化环氧体系的性能

研究了不同配比的环氧树脂618/桐酸甲酯酸酐(MeMA)/甲基四氢苯酐(MeTHPA)固化物的固化行为。测定了固化物热变形温度、拉伸强度、弯曲强度、冲击强度及体积电阻等,解析了体系固化前后的红外光谱。结果表明:混合酸酐固化剂中MeTHPA与MeMA的配比为9∶1时,与618环氧树脂固化所得的产物综合性能最佳。2 000 h人工加速老化后其力学性能未见下降。     

Molecular dynamics simulation of crosslinking process and mechanical properties of epoxy under the accelerator

To simulate the crosslinking process of epoxy resin under the accelerator action, the crosslinking system of bisphenol-A diglycidyl ether (DGEBA) as a monomer, methyl tetrahydro-phthalic anhydride (MTHPA) as a thermal curing agent and 2,4,6-tris (dimethylaminomethyl) phenol (DMP-30) as a thermal curing accelerator has been studied using molecular dynamics (MD) simulation. An algorithm that can construct the high-crosslinked system with different crosslinking density is completed based on the Perl language, and the subsequent properties are simulated. The results of molecular dynamics simulation show that modulus have an increasing trend, and glass transition temperature (Tg) raises from 325 K to 480 K when crosslinking density is from 0% to 95.5%. Conversely, cohesive energy density lessens from 620 J/cm³ to 170 J/cm³, solubility and Poisson's ratio decrease, and the tensile strength firstly increases and then diminishes. The friction coefficient decreases firstly and then increases, meanwhile, the temperature suddenly adds by 20 K and the relative concentration distribution (RCD) grows by 1.58 times at the contact surface. This study predicts for the crosslinking process and micro mechanical properties in the DGEBA/MTHPA/DMP-30 system.     

苯并(口恶)嗪改性环氧酸酐体系的固化机理及动力学

利用一种二胺型苯并(口恶)嗪改性环氧酸酐体系。通过FT-IR和DSC分析了改性体系的固化机理。结果表明：共混树脂体系在固化时存在两个反应,首先是环氧树脂与足量的酸酐在咪唑作用下在100℃先开始固化,并在150℃固化2 h后固化完全,之后苯并(口恶)嗪在180℃发生开环聚合。用非等温DSC法研究了该共混体系的固化动力学。采用Flynn-Wall-Ozawa方法求出了共混体系在固化时两个固化反应的活化能,分别为65.27 kJ·mol^-1和92.8 kJ·mol^-1,并利用Friedman方法判断了两个反应都是自催化反应,计算得到自催化模型曲线与实验曲线能较好地吻合。     

Synthesis, characterization, thermal and flame retardant properties of novel aryl phosphinate diglycidyl ether cured with anhydride

A novel aryl phosphinate diglycidyl ether, 10-(2′,5′-diglycidyl ether phenyl)-9,10-dihydro-9-oxa-l0-phosphaphenanthrene-10-oxide (DHQEP), was synthesized. The structure of the diglycidyl ether was characterized by elemental analysis, mass, FTIR, ¹H, ¹³C, ³¹P NMR spectroscopies and X-ray single crystal analysis. In addition, compositions of the diglycidyl ether with three curing agents, e.g. phthalic anhydride (PA), hexahydrophthalic anhydride (HHPA), and aryl phosphinate anhydride (DMSA), were used for making a comparison of its heat and flame retardancy with that of DER331 and DEN438. The resulting aryl phosphinate epoxy-resin composites demonstrated a higher limiting oxygen index (LOT) value as well as a higher char yield, confirming the effectiveness of aryl phosphinate epoxide as a flame retardant for epoxy resins.     

Preparation of potentially electroactive thallium polymers derived from the acidic copolymers of maleic anhydride

Maleic anhydride copolymers with vinyl ethyl ether and N-vinyl-2-pyrrolidone were prepared in tetrahydrofuran at 60°C, using AIBN as initiator. Copoly (MA-VEE) was hydrolysed to various degrees of hydrolysis and the extent of hydrolysis monitored by i.r. Various acidic derivatives of copoly (MA-VEE), copoly(MA-N-vinyl-2-pyrrolidone) and copoly(MA-ethylene) were prepared and characterized by elemental analysis and spectroscopy. The inter- and intramolecular crosslinking of carboxylic groups in copoly(succinic acid-VEE) were studied by g.p.c. Also thallium (III) derivatives of several acidic polymers were prepared and characterized.     

Effects of polypropylene-g-(maleic anhydride/styrene) compatibilizer on mechanical and rheological properties of polypropylene/clay nanocomposites

To enhance the dispersibility of clay in polypropylene (PP) matrix, PP-g-(maleic anhydride/styrene) (MA/ST) was prepared as a compatibilizer by graft copolymerization of maleic anhydride (MA) and styrene (ST) with PP. The addition of ST was known to be effective in improving the graft degree. PP/clay nanocomposites with the compatibilizer were prepared by melt intercalation. The X-ray diffraction (XRD) peaks of (0 0 1) plane of the organo-modified montmorillonite (O-MMT) were shifted to lower angles by an addition of PP-g-(MA/ST), indicating the intercalation capability of PP-g-(MA/ST) in the silicate layers. Transmission electron microscopy (TEM) photographs showed that the O-MMT in the presence of PP-g-(MA/ST) was intercalated and partly exfoliated during melt mixing. The addition of O-MMT and PP-g-(MA/ST) improved the thermal stability, tensile and rheological properties of the nanocomposites.     

Epoxy networks based on solutions of silsesquioxanes functionalized with 3-glycidoxypropyl groups in diglycidylether of bisphenol A (DGEBA)

Summary In previous publications we reported the synthesis and characterization of silsesquioxanes derived from the hydrolytic condensation of (3-glycidoxypropyl) trimethoxysilane (GPMS) using diglycidylether of bisphenol A (DGEBA) as a solvent [1,2]. The reaction product has aliphatic epoxy groups supplied by the silsesquioxane and aromatic epoxy groups supplied by the solvent. Solutions containing 0, 25 and 50% aliphatic epoxy groups, were cured with different hardeners: methyltetrahydrophthalic anhydride (MTHPA), ethylenediamine (EDA) and benzyldimethylamine (BDMA). Silsesquioxane-modified epoxy networks showed a significant increase in the elastic modulus in the rubbery state, the abrasion resistance and the development of strain hardening in uniaxial compression tests. Received: 28 September 2000/Accepted: 27 October 2000