Preparation and characterization of EP/SiO<Subscript>2</Subscript> hybrid materials containing PEG flexible chain

EP/SiO₂ hybrid materials, which contained flexible chain, were prepared by epoxy resin (EP) and polyethylene glycol (PEG)-grafted polysilicic acid (PSA), which was obtained by endcapping polyethylene glycol-1000 with toluene 2,4-diisocyanate (TDI), followed by a reaction with polysilicic acid. The formation of hybrid materials was confirmed by a wide-angle X-ray diffraction (WAXD) and atomic force microscopy (AFM) analysis. Results showed that the EP/SiO₂ hybrid particles were nanosized and the average size was about 20–50 nm. The mechanical properties, dynamic mechanical properties, and thermal properties were evaluated and compared with the corresponding matrix. The improvement in impact properties in hybrid materials was explained in terms of the impact fracture surface analysis by scanning electron microscope (SEM).     

Preparation and characterization of epoxy nanocomposites by using PEO-grafted silica particles as modifier

EP/SiO₂ nanocomposites, which contained PEO flexible chain, have been prepared via epoxy resin and PEO-grafted silica particles. The PEO-silica particles were obtained by endcapping PEO-1000 with toluene 2,4-diisocyanate (TDI), followed by a reaction with silica sols. The chemical structure of the products was confirmed by IR measurements, and the mechanical properties of composites such as impact strength, flexural strength, dynamic mechanical thermal properties were investigated. The results showed that the addition of the PEO-grafted silica particles to the epoxy/DDS curing system, the impact strength is 2 times higher than that of the neat epoxy. While the storage modulus and the glass transition temperature are a little changed. The morphological structure of impact fracture surface and the surface of the hybrid materials were observed by scanning electron microscope (SEM) and atomic force microscopy (AFM), respectively.     

Effect of amino-modified silica nanoparticles on the corrosion protection properties of epoxy resin-silica hybrid materials

In this paper, a series of organic-inorganic hybrid materials consisting of epoxy resin frameworks and dispersed nanoparticles of amino-modified silica (AMS) were successfully prepared. First of all, the AMS nanoparticles were synthesized by carrying out the conventional acid-catalyzed sol-gel reactions of tetraethyl orthosilicate (TEOS) in the presence of (3-aminopropyl)-trimethoxysilane (APTES) molecules. The as-prepared AMS nanoparticles were then characterized by FTIR, 13C-NMR and 29Si-NMR spectroscopy. Subsequently, a series of hybrid materials were prepared by performing in-situ thermal ring-opening polymerization reactions of epoxy resin in the presence of as-prepared AMS nanoparticles and raw silica (RS) particles. The as-prepared epoxy-silica hybrid materials with AMS nanoparticles were found to show better dispersion capability than that of RS particles existed in hybrid materials based on the morphological observation of transmission electron microscopy (TEM). The hybrid materials containing AMS nanoparticles in the form of coating on cold-rolled steel (CRS) were found to be much superior in corrosion protection over those of hybrid materials with RS particles when tested by a series of electrochemical measurements of potentiodynamic and impedance spectroscopy in 5 wt% aqueous NaCI electrolyte. The increase of corrosion protection effect of hybrid coatings may have probably resulted from the enhancement of the adhesion strength of the hybrid coatings on CRS coupons, which may be attributed to the formation of Fe-O-Si covalent bond at the interface of coating/CRS system based on the FTIR-RAS (reflection absorption spectroscopy) studies. The better dispersion capability of AMS nanoparticles in hybrid materials were found to lead more effectively enhanced molecular barrier property, mechanical strength, surface hydrophobicity and optical clarity as compared to that of RS particles, in the form of coating and membrane, based on the measurements of molecular permeability analysis, dynamic mechanical analysis, contact angle measurements and ultraviolet-visible transmission spectra, respectively.     

形状记忆氢化双酚A型环氧树脂的制备与性能

为研究聚丙二醇二缩水甘油醚(JH-230)对热固性形状记忆环氧树脂基本性能的影响,将异佛尔酮二胺(IPDA)与具有不同分子量比的氢化双酚A型环氧树脂(AL-3040)、聚丙二醇二缩水甘油醚(JH-230)共混,经完全固化制备出一种新型的形状记忆氢化双酚A型环氧树脂。借助傅里叶红外光谱仪(FT-IR)、差示扫描量热仪(DSC)、动态热机械分析仪(DMA)和拉伸-回复形状记忆测试分析了热固性形状记忆环氧树脂的分子结构以及JH-230对固化体系玻璃化转变温度、储能模量和形状记忆性能的影响。研究表明,JH-230可以增加固化体系链段的柔韧性;固化体系的玻璃化转变温度与动态模量随JH-230含量的增加而降低;该形状记忆氢化双酚A型环氧树脂体系具有良好的形状记忆性能,且形变完全回复时间随JH-230含量的增加而延长。     

A COMPARATIVE STUDY OF THE PREPARATION AND CHARACTERIZATION OF AROMATIC AND ALIPHATIC BISMALEIMIDES TO PRODUCE MODIFIED SILICONIZED EPOXY INTERCROSSLINKED MATRICES FOR ENGINEERING APPLICATIONS

A novel hybrid intercrosslinked network of hydroxyl-terminated polydimethylsiloxane modified epoxy and bismaleimides [N,N'-bismaleimido-4,4'-diphenylmethane and 1,6-bis(maleimido)hexane] matrix systems were developed. Epoxy resin was modified with 5, 10, and 15% (wt%) of hydroxyl-terminated polydimethylsiloxane using γ-aminopropyltriethoxysilane as crosslinking agent and dibutyltindilaurate as catalyst. The reaction between hydroxyl-terminated polydimethylsiloxane and epoxy resin was confirmed by IR spectral studies. The siliconized epoxy systems were further modified with 5, 10, and 15% (wt%) of both aromatic and aliphatic bismaleimides separately. The castings and E-glass fiber-reinforced composites prepared were characterized for their mechanical properties. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) of the matrix samples were also performed to determine the glass transition temperature (T_g) and thermal degradation temperature of the hybrid intercrosslinked systems. Data obtained from mechanical studies and thermal characterization indicate that the introduction of siloxane into epoxy resin improves the toughness and thermal stability, with reduction in strength and modulus values. The incorporation of aromatic bismaleimide into epoxy resin improved both tensile strength and thermal properties, whereas it was observed that the incorporation up to 5% of aliphatic bismaleimide into epoxy resin decreased the stress-strain value and above 5% increased the strength properties. However, the introduction of both aromatic and aliphatic bismaleimides (aromatic and aliphatic) into siliconized epoxy resin influenced both mechanical and thermal properties according to the percentage content.     

Dielectric response of Ag/BaTiO<Subscript>3</Subscript>/epoxy nanocomposites

Dielectric properties and relaxation phenomena of hybrid material (functionalized nanosilver/BaTiO₃/epoxy) were studied as a function of ceramic content. Nanoparticles were obtained through chemical reduction in ethanol and triethylenetetramine. Epoxy resin, functionalized Ag and BaTiO₃ were mixed and composites were prepared onto glass substrates by dipping technique. Samples containing various amounts of ceramic filler were examined by thermal and SEM analysis. Dielectric measurements were performed at different frequencies and temperatures. It was found that hybrid materials had high permittivities and their relaxation processes were influenced by the epoxy resin near its T _g, while metallic and ceramic content modified the real permittivity values.     

碳纤维/TiO2改性树脂复合材料的制备及力学性能

针对环氧树脂脆性大、与碳纤维形成的界面性能较差等问题,本文选用纳米TiO₂对5284环氧树脂进行改性,并以角联锁机织物为增强体制备了碳纤维/环氧树脂复合材料。使用FT-IR、旋转流变仪、表面张力仪等设备对TiO₂/环氧树脂进行表征,并研究了树脂改性对复合材料压缩与层间剪切性能的影响。研究表明：TiO₂的羟基与环氧树脂的环氧基和羟基发生了反应;经1wt.%TiO₂改性的树脂复数黏度为0.066 Pa·s,纤维与树脂间接触角为28.85°,浸润效果较好;相较于未改性复合材料,树脂改性的复合材料纵向压缩强度与模量分别提高了7.46%和11.03%,横向压缩强度与模量分别提高了6.99%和4.96%,纵向、横向的剪切强度分别提高了6.88%和4.65%。TiO₂改性环氧树脂提高了复合材料的承载能力,改善了界面结合强度。     

环氧树脂/二氧化硅杂化材料的制备与性能

采用溶胶-凝胶技术,以硅酸钠为原料制备聚硅酸/四氢呋喃溶胶,再与环氧树脂（EP）及少量偶联剂3-氨基丙烷乙氧基硅烷（APTES）混合,制备EP/SiO2杂化材料.通过红外光谱、X射线衍射、DSC、TG及扫描电镜（SEM）等测试手段对材料的结构与性能进行了表征.     

煤制油碱性水储罐内表面无溶剂改性环氧防腐蚀涂料涂层的制备及其性能

煤直接液化制油工艺碱性含硫污水储罐内壁的腐蚀特征复杂,内防腐蚀涂层脱落问题是储罐设备安全的隐患,同时也是制约装置长周期运行的瓶颈。以纳米二氧化硅改性环氧树脂、有机硅环氧杂化树脂与双酚A环氧树脂复配,制备无溶剂改性环氧涂料,用于直接液化制油工艺碱性含硫污水储罐内壁的防腐蚀,并在A3钢表面制备无溶剂改性环氧防腐蚀涂层,采用相关标准测试其性能。结果表明:采用纳米二氧化硅改性环氧树脂可以明显改善无溶剂防腐蚀涂料涂层的耐冲击强度、柔韧性以及交联度;硅烷偶联剂与二氧化硅改性环氧涂料使涂层附着力保持时间明显延长;有机硅环氧杂化树脂可以有效改善涂层抗腐蚀介质渗透能力,有机硅环氧杂化树脂与纳米二氧化硅改性环氧树脂则可以极大地减轻涂层表面和涂层本体在腐蚀性介质中的破坏程度,延长防腐蚀涂层使用寿命,满足煤制油工艺中碱性水储罐的防腐蚀要求。     

含磷环氧树脂/聚氨酯梯度材料的合成与表征

以含磷环氧树脂、甲苯2,4-二异氰酸酯(TDI)、聚醚 N403和端羟基聚丁二烯(HTPB)为反应组分,乙酸乙酯(EA)为溶剂,采用预聚体法合成了不同组分比的含磷环氧树脂/聚氨酯材料。利用全反射红外光谱(ATR-FT-IR)、扫描电子显微镜(SEM-EDS)分别研究了材料的组分含量、相形态和元素分布。结果显示：当含磷环氧树脂质量分数为3.0%时,其结合聚氨酯硬段,以分散相粒子(0~15μm)分布在聚氨酯基体中,并且粒子的含量沿厚度方向梯度递增。进一步通过表面水接触角法(SCA)和拉伸试验测定了材料的表面亲水性和力学性能。结果表明,当材料具有梯度相形态时,上下表面的亲水性差异较大,底表面亲水性更强;并且材料具有相对较高的拉伸强度和断裂伸长率。     

环氧树脂/二氧化硅杂化材料的制备与性能表征

溶胶-凝胶法制备环氧树脂/SiO2杂化材料,利用FTIR、SEM和综合热分析仪对杂化材料的结构、显微形态及热性能进行了表征.结果表明,杂化材料中SiO2与环氧树脂两相间存在氢键作用;SiO2质量分数＜7%时SiO2与环氧树脂之间无明显相界面,可获得有机聚合物链段与无机网络互穿的有机/无机杂化材料;SiO2质量分数为11%时材料具有最佳耐热性能.     

Effect of carboxyl-terminated poly(butadiene-co-acrylonitrile) (CTBN) concentration on thermal and mechanical properties of binary blends of diglycidyl ether of bisphenol-A (DGEBA) epoxy resin

Six blend samples were prepared by physical mixing of epoxy resin with varying concentrations of liquid carboxyl-terminated butadiene acrylonitrile (CTBN) copolymer having 27% acrylonitrile content. The blend samples were cured with aromatic amine. A comparative study of Fourier-transform infrared (FTIR) spectra showed the modification as a result of chemical reactions between epoxide group, curing agent and CTBN. The tensile strength of cured blend samples decreased slightly from 11 to 46% where as the elongation-at-break showed an increasing trend with increasing rubber content, i.e., up to 25 phr, in the blend samples. Appreciable improvements in impact strength were also observed in the prepared blend systems. The glass transition temperature (T_g) of the epoxy resin matrix was slightly reduced on the addition of CTBN. The cured resin showed a two-phase morphology where the spherical rubber domains were dispersed in the epoxy matrix.     

MAP-POSS/不饱和环氧树脂混杂光固化膜制备与性能

由KH-570水解缩合制备甲基丙烯酰氧基丙基笼型倍半硅氧烷(MAP-POSS),并将其与不饱和环氧树脂组成自由基-阳离子混杂光固化体系。用红外光谱(FT-IR)表征固化过程特征吸收峰的变化;测试MAP-POSS含量对固化膜表面水接触角、硅元素分布以及涂膜力学性能、热性能的影响。结果表明:MAP-POSS的加入增加了体系的交联度,提高了涂膜的疏水性、热稳定性和玻璃化温度(Tg)。当MAP-POSS含量为12%(质量分数,下同)时,Tg增加了16.9℃。当MAP-POSS含量为15%时,涂膜对水的接触角由58.0°增大到94.2°。MAP-POSS的加入使涂膜的冲击强度先增加后减小。     

环氧-聚氨酯复合乳液的合成及表征

以甲苯二异氰酸酯(TDI-80)、聚醚二醇(N220)、二羟甲基丙酸(DMPA)、环氧树脂为主要原料,合成了环氧-聚氨酯复合乳液。主要讨论了环氧树脂对水性聚氨酯乳液及其涂膜性能的影响。实验结果表明,环氧-聚氨酯乳液的表面张力、粘度,涂膜的硬度、耐水性及力学性能随着环氧树脂用量的增大而增强,但乳液外观和稳定性变差,故适宜的环氧树脂添加量为4%～8%。采用傅里叶变换红外光谱、粒径分析仪、凝胶渗透色谱(GPC)、透射电镜(TEM)对乳液和涂膜进行了表征。傅里叶变换红外光谱分析表明,环氧树脂的环氧基和羟基都参与了反应。粒径分析仪和凝胶渗透色谱分析显示,加入环氧树脂后,水性聚氨酯(WPU)分散体粒径和分子量增大,粒径分布和分子量分布均变宽。     

高导热环氧/有机硅杂化封装胶的制备与性能

以γ-缩水甘油醚氧丙基三甲氧基硅烷为原料,通过水解缩聚制备出有机硅树脂,采用不同尺寸的改性氧化铝填充环氧/有机硅树脂基体以改善其耐热性能,并考察其力学性能、导热性能。结果表明,合成的有机硅树脂能提高封装胶的热分解温度,其热分解温度比环氧树脂高35.66℃。所制备封装胶的导热系数为1.01 W/(m.K),相比单一环氧树脂其导热性能提高了约5倍,其粘接强度为10.27 MPa,该导热封装胶表现出良好的的综合性能,可用于微电子器件封装领域。     

Improvement of epoxy resin properties by incorporation of TiO2 nanoparticles surface modified with gallic acid esters

Epoxy resin/titanium dioxide (epoxy/TiO₂) nanocomposites were obtained by incorporation of TiO₂ nanoparticles surface modified with gallic acid esters in epoxy resin. TiO₂ nanoparticles were obtained by acid catalyzed hydrolysis of titanium isopropoxide and their structural characterization was performed by X-ray diffraction and transmission electron microscopy. Three gallic acid esters, having different hydrophobic part, were used for surface modification of the synthesized TiO₂ nanoparticles: propyl, hexyl and lauryl gallate. The gallate chemisorption onto surface of TiO₂ nanoparticles was confirmed by Fourier transform infrared and ultraviolet–visible spectroscopy, while the amount of surface-bonded gallates was determined using thermogravimetric analysis. The influence of the surface modified TiO₂ nanoparticles, as well as the length of hydrophobic part of the gallate used for surface modification of TiO₂ nanoparticles, on glass transition temperature, barrier, dielectric and anticorrosive properties of epoxy resin was investigated by differential scanning calorimetry, water vapor transmission test, dielectric spectroscopy, electrochemical impedance spectroscopy and polarization measurements. Incorporation of surface modified TiO₂ nanoparticles in epoxy resin caused increase of glass transition temperature and decrease of the water vapor permeability of epoxy resin. The water vapor transmission rate of epoxy/TiO₂ nanocomposites was reduced with increasing hydrophobic part chain length of gallate ligand. Dielectric constant of examined nanocomposites was influenced by gallate used for the modification of TiO₂ nanoparticles. The nanocomposites have better anticorrosive properties than pure epoxy resin, because the surface modified TiO₂ nanoparticles react as oxygen scavengers, which inhibit steel corrosion by cathodic mechanism.     

含炔基酚醛树脂改性PSA及碳纤维布/PSA-EPAN复合材料性能

合成了乙炔基苯基偶氮酚醛树脂（EPAN）,通过溶液共混的方法用其对含硅芳炔树脂（PSA）进行改性,研究了PSA-EPAN树脂的热性能,并制备了PSA-EPAN的碳布预浸料,经热模压制备碳纤维布（T300CF）增强PSA-EPAN复合材料,对其力学性能进行了研究。结果表明：EPAN均匀分布于PSA树脂中,EPAN共混改性PSA树脂的固化温度提高,混入质量分数为7%的EPAN,N₂中固化PSA-EPAN树脂在800℃残留率超过90%,其玻璃化转变温度高于500℃,PSA-EPAN共混树脂浇铸体的弯曲性能高于PSA树脂,达40.7 MPa,提高了95.5%;PSA树脂经T300CF/PSA-EPAN复合材料力学性能显著提高,弯曲强度达到了423.5 MPa,提高了74%,层间剪切强度（ILSS）提高至29.53 MPa,增加了65%。     

聚硅烷改性含硅芳炔树脂的耐热性能研究

含硅芳炔树脂具有优异的耐高温性能,在高温下可形成C/SiC有机无机杂化材料,用聚硅烷对含硅芳炔树脂进行改性以提高其含硅量。采用示差扫描量热(DSC)、红外光谱(FT-IR)分析了改性含硅芳炔树脂的固化行为,采用TGA考察了改性含硅芳炔树脂固化产物及其烧结物的热稳定性能,并用XRD对烧结物进行了分析。研究表明,改性后的含硅芳炔树脂黏度降低、硅含量提高;固化物和烧结物在1200℃下空气中的残留率均提高了40%以上;固化物经1450℃烧结后形成了β-SiC,含聚硅烷30%的改性树脂烧结物中SiC含量达到41%。     

含侧环氧基硅油复合改性环氧树脂的研究

采用侧基环氧化硅油(ES)及其改性物(PSA)来复合改性双酚A型环氧树脂(EP).通过测定复合改性固化物的冲击强度、拉伸强度、断裂伸长率和玻璃化转变温度(Tg),扫描电子显微镜对改性固化物的断裂面形态分析等,系统探讨了复合改性方法、有机硅组成及其含量等对复合改性材料性能的影响.结果表明,采用ES和PSA复合改性EP后,其韧性和耐热性均有不同程度的提高,且以环氧值高的ES和PSA的改性效果更好.其中环氧树脂经10份ES-16或10份PSA-16改性后,Tg由未改性的156.73℃提高到177.35℃,比改性前提高了近20.62℃,均达到了很好的增韧和提高耐热性的效果,符合电子封装等高性能材料的改性要求.     

Studies on mechanical properties of epoxy composites filled with the grafted particles PGMA/Al2O3

In the present work, the epoxy resin composites filled with the particulates of PGMA/Al₂O₃ which were prepared by grafting poly-glycidyl methacrylate (PGMA) onto the Al₂O₃, were obtained by incorporating and curing the resin containing the particulates. The mechanical properties of the resulting resin composites epoxy/PGMA/Al₂O₃ were evaluated and compared with epoxy/Al₂O₃. The morphologies of the fracture surfaces of the filled epoxy resin composites were analyzed by means of scanning electron microscopy (SEM). The results indicate that after grafting polymers onto Al₂O₃ particles, the interfacial combination of epoxy resin with PGMA/Al₂O₃ can be significantly increased due to the higher bonding strength and bonding modulus between them, therefore, the properties of the composites are improved largely. And the higher grafting degree of PGMA, the greater the impact strength and yield strength of the resin composites are, which primarily depends on the structure-properties relationship of the composites. In addition, the additive amount of PGMA/Al₂O₃ particles and the curing agents are also important factors that influence the properties of composites.