碳酸钙在复合改性中的应用

无机填料碳酸钙在聚丙烯复合体系中的应用,研究了碳酸钙的加入对聚丙烯光学性能、分散性、力学性能中的冲击强度的影响,同时深入分析了无机填料对聚丙烯复合体系的增强增韧机理。     

硅微粉填料的种类对环氧灌封材料性能的影响

以E-51为基体树脂,加入增韧剂、稀释剂、填料等制成环氧树脂灌封材料,考察了普通硅微粉与活性硅微粉对体系凝胶时间、力学性能、电性能等方面的影响,结果表明,表面活性硅微粉经表面处理后对体系的增韧增强效果更好。     

SiC晶须,晶板增韧AlN陶瓷的研究

本文利用现代测试技术对ＳｉＣｗ，ＳｉＣｐ增韧ＡｌＮ材料的力学性能，显微结构进行研究，并分析探讨了材料的增韧机理，结果表明；ＳｉＣｗ可有效改善材料的断裂韧性和断裂强度，其增韧机理主要为裂纹偏转和晶须拔出效应，ＳｉＣｐ加入的断裂韧性起到良好的促进作用，但对材料的断裂强度则有不良的作用，其增韧机理主要为裂纹偏转和分枝效应。     

低纳米莫来石填充聚丙烯的力学性能

在双螺杆挤出机中用熔融共混工艺制备纳米莫来石/聚丙烯(PP)复合材料,莫来石的含量为1%、3%、5%、7%和10%.考察了填料含量、硅烷偶联剂KH-550和加入增客剂MAPP(PP接枝马来酸酐)对复合材料力学性能的影响,并用扫描电镜(SEM)观察了复合材料的形貌.结果表明:纳米莫来石粉体作为一种新型的无机矿物填料,在含量较小时(1%左右)对PP基体具有增强增韧作用;用KH-550表面处理和加入MAPP使纳米莫来石在基体中的分散均匀,力学性能有所提高,尤其是加入MAPP效果明显.     

四方氧化锆陶瓷复合材料评述

四方氧化锆陶瓷（ＴＺＰ）通过相变增韧具有很高的强度和断裂韧性，但在中高温下由于相变增韧作用的逐渐消失，力学性能迅速下降。在ＴＺＰ基体中加入第二相粒子成为复合材料，是提高ＴＺＰ韧性和高温力学性能的有效方法。本文综述了晶须、颗粒和片晶增强ＴＺＰ复合材料的增韧机理、性能改善的效果、以及存在的问题，展望了今后的研究方向。     

烧结助剂对自增韧Si3N4陶瓷显微结构和性能的影响

研究了烧结助剂质量分数及比例对热压自增韧Si3N4 陶瓷显微结构和力学性能的影响。结果表明 :材料室温抗弯强度和断裂韧性均在烧结助剂的质量分数为 15 %时达到峰值 ,其中 5 %Y2 O3 10 %La2 O3 85 %Si3N4 体系的抗弯强度达 911.3MPa,断裂韧性达10 .0 2MPa·m1 /2 。同时 ,分析了材料显微结构与力学性能的关系 ,发现自增韧Si3N4 陶瓷中 β-Si3N4 柱状晶直径的双峰分布特征对材料力学性能的提高起着很重要的作用     

碳纳米管增韧陶瓷复合材料研究进展

碳纳米管增韧陶瓷材料在力学性能上具有独特的作用,包括断裂韧性、强度、硬度、耐磨性等。碳纳米管以其优异的力学性能在增韧陶瓷基复合材料方面具有独特优势,但是碳纳米管的纠缠团聚状态严重影响了其应用,碳纳米管的分散一直是碳纳米管复合材料领域的难点。笔者介绍了碳纳米管增韧陶瓷材料的界面及相容性,并探讨了其增韧机理。最后,指出了碳纳米管增韧陶瓷材料的研究方向。     

纳米TiC加入量对TiC高温陶瓷烧结和力学性能的影响

为研究纳米TiC在烧结过程中对TiC基体烧结和力学性能的影响,在粒径约3μm的TiC微粉中分别添加质量分数为0、10%、20%、50%、90%的纳米TiC,采用放电等离子体烧结工艺(于1 600℃烧结5 min,烧结压力50 MPa)制备出了TiC高温陶瓷。利用阿基米德排水法、SEM、压痕法等测试手段表征烧结后陶瓷的烧结性、显微结构及力学性能,并从致密度和显微结构的变化讨论了纳米TiC加入量对TiC陶瓷烧结的影响,从硬度和断裂韧性的变化探讨了纳米TiC量对其力学性能的影响。结果表明:纳米TiC在基体中的分散性是影响TiC陶瓷烧结性和力学性能的主要原因,加入少量(10%质量分数)纳米TiC时,分散性较好,有助于提高TiC陶瓷的烧结性和力学性能;添加纳米TiC可以明显细化TiC陶瓷的显微结构组织;当纳米TiC质量分数为10%时,TiC陶瓷的断裂韧性最大,呈现明显的裂纹偏转、桥接等增韧机制。     

纤维类型对C/SiC复合材料性能的影响

利用化学气相浸渗法制备了Cf-C/SiC复合材料,借助SEM、TEM等研究了纤维类型对Cf-C/SiC复合材料力学性能的影响.实验证明T300碳纤维增韧补强效果优于M40碳纤维,利用T300碳纤维制备出弯曲强度为459M,断裂韧性为20.0MPa*m1/2,断裂功为25170J/m2的Cf-C/SiC复合材料.2种碳纤维增韧效果的差异是由纤维的原始强度、热膨胀系数和弹性常数的不同决定的.     

β-Si3N4晶种对Si3N4陶瓷力学性能和显微结构的影响

采用无压烧结工艺制备了长柱状β-Si3N4品种.研究了晶种尺寸对Si3N4陶瓷力学性能和显微结构的影响.结果表明:在1750℃通过控制保温时间(1h、1.5h和2h)可获得不同尺寸的长柱状β-Si3N4晶种.Si3N4陶瓷加入晶种后,其相对密度和抗弯强度虽略有降低,但断裂韧性得到大幅提高.平均长度为4.51μm,长径比为5.71的品种对Si3N4陶瓷的增韧效果最佳;且随着其添加量的增加,Si3N4陶瓷的断裂韧性先升高再降低,当掺量为2wt％时断裂韧性达到最高(提高了20％以上).显微结构分析表明,Si3N4陶瓷断裂韧性的提高,与因晶种加入而导致的Si3N4晶粒长径比和大长柱状晶粒含量的增加有关.     

刚性聚氨酯增韧改性环氧树脂的研究

在环氧树脂(EP)中加入以对苯二甲酸二甲酯为原料合成的端羟基芳香聚酯及2,4—甲苯二异氰酸酯(TDI),采用原位聚合法制备了刚性聚氨酯(PUR)增韧改性EP。用红外光谱表征了其反应,探讨了端羟基芳香聚酯含量、端羟基芳香聚酯与TDI摩尔比和固化剂用量对改性EP力学性能的影响,并用扫描电子显微镜观察了改性EP的冲击断面。结果表明,在提高EP韧性的同时,改性EP的其它力学性能都得以提高。     

包膜增韧硅微粉对环氧树脂增韧机理的研究

本文首次提出预先对硅微粉进行增韧处理来达到增韧环氧树脂的新思路,并根据断裂理论,采用循环脉冲载荷对增韧硅微粉／环氧树脂复合材料进行冲击性能试验。分析了微裂纹的形成与扩展,探讨增韧硅微粉对环氧树脂的增韧机理。     

填料对环氧树脂混凝土力学性能影响

研究了填料对环氧树脂胶粘剂和树脂混凝土力学性能的影响。碳化硼、氧化铝、水泥和氧化锌均可提高胶粘剂、树脂混凝土强度,其中碳化硼提高幅度最大,因而填料在树脂混凝土中具有重要作用。     

Effect of rubber/matrix interfacial modifications on the properties of a rubber-toughened epoxy resin

The interface of a rubber-toughened epoxy resin was modified by using epoxide end-capped carboxyl-terminated butadiene and acrylonitrile random copolymer (CTBN). The end-capping epoxides were formulated with different ratios of flexible diglycidyl ether of propylene glycol (DER732) and rigid diglycidyl ether of bisphenol-A (Epon 828). The microstructure and the fracture behavior of these rubber-modified epoxy resins were studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. The thermal and mechanical properties were also investigated. With an increase in the amount of end-capping DER732, the interfacial zone of an undeformed rubber particle and the degree of cavitation of the rubber cavity on the fracture surface were greatly increased. At the maximal addition of DER732, fracture energy (GIc) for this toughened epoxy resin containing 10phr CTBN rubber increases up to 2.4 fold compared to that of a conventional CTBN-toughened epoxy resin, but the thermal and the mechanical properties remained quite unaffected. The modification on the interfacial property provides a new technique in the improvement of fracture toughness of a rubber-toughened epoxy resin.     

Novel amine terminated elastomeric oligomers and their effects on properties of epoxy resins as a toughener

The objective of this study was to investigate the effects of amine terminated elastomeric epoxy tougheners on the mechanical and thermal properties of diglycidyl ether of bisphenol A based epoxy resin. The amine terminated polycaprolactone (PCL) (1) and PCL‐PDMS‐PCL (2) based oligomers were synthesized and characterized by FTIR spectroscopy. The stoichiometrical amount of the reactive oligomers as toughener, reactive epoxy resin and the curing agent, 4,4′‐diaminodiphenyl sulfone (DDS) were mixed and degassed. The homogenous mixtures were cured at 120°C into the preheated molds. The mechanical and thermal characterizations of toughened epoxy resin system were evaluated. It has been shown that the mechanical and thermal properties of toughened epoxy system vary as a function of the chemical structure and the concentration of rective oligomers. Higher mechanical properties were obtained for epoxy resin toughened by PCL‐PDMS‐PCL (2) based oligomer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Glass fibre reinforced composites of triglycidyl-p-aminophenol

Glass fibre reinforced epoxy composites were fabricated from the matrix resins diglycidyl ether of bisphenol A (DGEBA) and triglycidyl-p-aminophenol (TGAP) using diethylene triamine as curing agent. The epoxy laminates were evaluated for their mechanical properties, dielectrical properties and chemical resistance. Significant improvement in fiexural strength but a slight deterioration in dielectrical properties were observed on incorporation of an epoxy fortifier into the resin system before fabricating the composites.     

Resin transfer molding (RTM) with toughened cyanate ester resin systems

This investigation explored the feasibility of recently developed toughened cyanate ester networks as candidate materials for high performance composite matrix applications. The resin investigated was a bisphenol-A cyanate ester toughened with hydroxy functionalized phenolphthalein based amorphous poly(arylene ether sulfone). A series of four toughened cyanate ester resins were generated by varying the concentration and the molecular weight of the toughener. The thermoplastic modified toughened networks exhibited improvement in the fracture toughness over the base cyanate ester networks without significant reductions in mechanical properties or glass transition temperature. Carbon fabric composite panels were manufactured by liquid molding processes (resin transfer molding and resin film infusion) with the untoughened and toughened cyanate ester resin systems. The panels were subjected to physical, impact damage, and fracture toughness tests. The results of physical testing indicate consistently uniform quality, and the maximum void content was found to be less than 2%. The toughened cyanate ester composites exhibited significantly improved impact damage resistance and tolerance compared with hot-melt epoxy systems. A marked increase in the mode II composite fracture toughness was observed with an increase in the concentration and the molecular weight of the toughener.     

环氧化端羟基聚丁二烯增韧环氧树脂的研究

使用环氧化端羟基聚丁二烯（EHTPB）对双酚A型环氧树脂进行增韧改性。对EHTPB增韧的固化产物及端羟基聚丁二烯（HTPB）增韧的固化产物进行力学性能测试,运用差示扫捕量热法测试同化产物的玻璃化转变温度,采用扫面电镜观察树脂增韧前后的断面形貌,显示为韧性断裂。各种结果表明,EHTPB对环氧树脂的增韧效果优于HTPB,该增韧剂的加入能够在不明显降低树脂强度的条件下,大幅度提高体系韧性的同时保持树脂的玻璃化转变温度。     

Thermo mechanical behaviour of unsaturated polyester toughened epoxy–clay hybrid nanocomposites

The intercrosslinked networks of unsaturated polyester (UP) toughened epoxy–clay hybrid nanocomposites have been developed. Epoxy resin (DGEBA) was toughened with 5, 10 and 15% (by wt) of unsaturated polyester using benzoyl peroxide as radical initiator and 4,4′-diaminodiphenylmethane as a curing agent at appropriate conditions. The chemical reaction of unsaturated polyester with the epoxy resin was carried out thermally in presence of benzoyl peroxide-radical initiator and the resulting product was analyzed by FT-IR spectra. Epoxy and unsaturated polyester toughened epoxy systems were further modified with 1, 3 and 5% (by wt) of organophilic montmorillonite (MMT) clay. Clay filled hybrid UP-epoxy matrices, developed in the form of castings were characterized for their thermal and mechanical properties. Thermal behaviour of the matrices was characterized by differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA) and dynamic mechanical analysis (DMA). Mechanical properties were studied as per ASTM standards. Data resulted from mechanical and thermal studies indicated that the introduction of unsaturated polyester into epoxy resin improved the thermal stability and impact strength to an appreciable extent. The impact strength of 3% clay filled epoxy system was increased by 19.2% compared to that of unmodified epoxy resin system. However, the introduction of both UP and organophilic MMT clay into epoxy resin enhanced the values of mechanical properties and thermal stability according to their percentage content. The impact strength of 3% clay filled 10% UP toughened epoxy system was increased by 26.3% compared to that of unmodified epoxy system. The intercalated nanocomposites exhibited higher dynamic modulus (from 3,072 to 3,820 MPa) than unmodified epoxy resin. From the X-ray diffraction (XRD) analysis, it was observed that the presence of d ₀₀₁ reflections of the organophilic MMT clay in the cured product indicated the development of intercalated clay structure which in turn confirmed the formation of intercalated nanocomposites. The homogeneous morphologies of the UP toughened epoxy and UP toughened epoxy–clay hybrid systems were ascertained from scanning electron microscope (SEM).     

Utilization of Granite Powder as Filler in PC-Toughened Epoxy Resins: Studies on Physico-Mechanical Properties

The present study reports the possibility of using granite powder, an industrial waste with no end use, as potential filler in polycarbonate (PC)-toughened epoxy resin. Testing data for the physico-mechanical properties such as tensile, flexural, density and void content of the composites, according to the filler loading were catalogued. Incorporation of waste granite powder in toughened resin enhances the mechanical properties when compared to neat epoxy, but reduces significantly with respect to toughened resin matrix.