Incorporation of modified soy protein isolate as filier in BR/SBR blends

The surface modification of soy protein isolate (SPI) and the use of modified SPI as reinforcing filler replaced carbon black in BR/SBR composites were studied. The effects of coupling agents γ-aminopropyltriethoxysilane (KH-550), γ-methacryloxypropyltrimethoxysilane (KH-570), bis-(γ-triethoxysilylpropyl)-tetrasulfide (Si-69), isopropyl tri-(dioctylpyrophosphate) titanate (NDZ-201) on the physical and mechanical properties of the composites were also investigated. Modified SPI was analyzed by Infrared spectra, scanning electron microscopy, and X-ray diffraction. The results showed that the optimal reaction conditions were determined, that is, the optimal reactions were 4 g SPI, 50% Glycidyl methacrylate (by SPI weight), 3 h of reaction time and 80 °C reaction temperature. Through the physical and mechanical properties of composite, the results showed that when a small number of modified SPI (3–5 phr) as reinforcement agent was used, the mechanical properties were improved. KH-550 had good effect on enhancing the overall properties of the composites.     

Incorporation of nano-sized mesoporous MCM-41 material used as fillers in natural rubber composite

The nano-sized mesoporous MCM-41 (without template), and the modification of MCM-41 (without template) were used to prepare natural rubber (NR) composites. The effects of coupling agents γ-aminopropyltriethoxysilane (KH-550), γ-methacryloxypropyltrimethoxysilane (KH-570), bis-(γ-triethoxysilylpropyl)-tetrasulfide (Si-69), isopropyl tri-(dioctylpyrophosphate)titanate (NDZ-201) on the mechanical properties of the composites were also investigated. The results showed that the tensile properties of Natural rubber/mesoporous MCM-41 nanocomposite were improved as compared with those of NR compound. KH-570 had good effect on enhancing the overall properties of the composites. Scanning electron microscopy (SEM) observations revealed that the modified nano-sized MCM-41 material was well dispersed in the polymer matrix and the enhancement of the interface between the matrix and fillers was obtained.     

液晶聚酯/氮化铝复合基板材料制备中偶联剂的应用

本文研究了在液晶聚酯/氮化铝复合基板材料的制备中偶联剂(KH-550和NDZ-101) 对复合材料的加工性能和复合材料的强度, 导热系数和介电性能的影响。     

Influence of interfacial modification on the thermal conductivity of polymer composites

In this study, the influence of modifying ZnO filler with surface-treating agents on the thermal conductivity of the ethylene-vinyl acetate copolymer (EVA) composites was reported. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were applied to analyze the surface modification of ZnO filler and the fractured surface morphology of the EVA–ZnO composites. The test results indicated that surface-treating ZnO filler with the valid modifying agents (stearic acid, OL-AT16, KH-560, or NDZ-132) at right dosage and treating temperature, the thermal conductivity of the EVA–ZnO composites can be enhanced effectively on account of reducing the interfacial phonon scattering; while the dosage of modifying agents exceed a right amount, the thermal conductivity of EVA–ZnO composites modified with the small-molecule treating agents (F-1, n-Octylic acid, or stearic acid) descend more evidently with the dosage increase.     

偶联剂对炭黑导电涂料导电性能的影响

研究了三种钛酸酯偶联剂NTC 4 0 1、CT 136、JSC ,两种硅烷偶联剂KH 5 5 0、KH 5 70对炭黑导电涂料导电性能的影响。结果表明加入NTC 4 0 1、CT 136、JSC后体系的电阻升高 ,而KH 5 5 0、KH 5 70降低了体系的电阻值 ,其中以加入质量分数为 2 5 %的KH 5 5 0效果最好。利用SEM分析了加入KH 5 5 0对炭黑与树脂的界面状态的影响 ,并研究了偶联剂的使用方法对导电性的影响。     

界面层结构对填充聚丙烯力学性能及流变行为的影响

本文采用各类偶联剂处理填充改性聚丙烯的无机填料。实验结果表明,硅烷类 KH-550偶联剂在界面层形成刚性架的有机硅烷膜复盖层结构,使填充聚丙烯屈服强度明显提高,断裂面形貌为界面结合较好的脆性断裂。TSC,NDZ-201,OLT-671和 DL-411等酯类偶联剂在界面形成线型柔性链的单分子层结构,使填充聚丙烯冲击强度、断裂仲长率提高,加工流动性能明显改善。     

低碳钢表面硅烷化处理对聚乙烯涂层结合强度的影响

利用硅烷偶联剂(KH-550,KH-560,KBM-7103)对低碳钢表面进行预处理,制备了聚乙烯(PE)涂层,通过对涂层的结合强度、抗热震性能等实验,研究了硅烷化处理对涂层性能的影响.结果表明:KH-560处理法能显著提高PE涂层的结合强度,比砂纸打磨、喷砂处理分别提高了40.3%,13.2%,而KH-550,KBM-7103不能显著提高PE涂层的结合强度;对于PE涂层的硅烷化处理,适宜的KH-560的浓度为5%(体积分数),水解时间为48h;"喷砂 KH-560"处理法抗热震实验后涂层的结合强度仅降低了10.9%,远低于其他处理方法热震后的下降幅度.     

Effects of coupling agent on the preparation and dielectric properties of novel polymer–ceramic composites for embedded passive applications

The study was carried out to investigate the effects of silane coupling agent, γ-aminopropyl triethoxy silane (KH-550), on the preparation and dielectric properties of Barium titanate (BaTiO₃)/Bisphenol-A dicyanate (2,2′-bis (4-cyanatophenyl) isopropylidene)(BADCy) composites for embedded passive implications. It was found that KH-550 accelerated the polymerization of BADCy and was beneficial to improve the compatibility between BaTiO₃ particles and BADCy matrix. The dielectric constant (ε) and dielectric loss (tanδ) both increased at first and then decreased with the increase of the KH-550 content. With the increase of the frequency, the variation ranges of the dielectric constant and dielectric loss of these composites were not obvious since the dielectric properties of cyanate ester were stable at various frequencies.     

Mechanical properties of a diamond–copper composite with high thermal conductivity

Using pressureless infiltration of copper into a bed of coarse (180 μm) diamond particles pre-coated with tungsten, a composite with a thermal conductivity of 720 W/(m K) was prepared. The bending strength and compression strength of the composite were measured as 380 MPa. As measured by sound velocity, the Young's modulus of the composite was 310 GPa. Model calculations of the thermal conductivity, the strength and elastic constants of the copper–diamond composite were carried out, depending on the size and volume fraction of filler particles. The coincidence of the values of bending strength and compressive strength and the relatively high deformation at failure (a few percent) characterize the fabricated diamond–copper composite as ductile. The properties of the composite are compared to the known analogues — metal matrix composites with a high thermal conductivity having a high content of filler particles (~ 60 vol.%). In strength and ductility our composite is superior to diamond–metal composites with a coarse filler; in thermal conductivity it surpasses composites of SiC–Al, W–Cu and WC–Cu, and dispersion-strengthened copper.     

Pressure infiltration casting process and thermophysical properties of high volume fraction SiCp/Al metal matrix composites

Abstract

SiC_p/Al composites containing high volume fraction SiC particles were fabricated using a pressure infiltration casting process, and their thermophysical properties, such as thermal conductivity and coefficient of thermal expansion (CTE), were characterised. High volume fraction SiC particulate preforms containing 50–70 vol.-%SiC particles were fabricated by ball milling and a pressing process, controlling the size of SiC particles and contents of an inorganic binder. 50–70 vol.-%SiC_p/Al composites were fabricated by high pressure infiltration casting an Al melt into the SiC particulate preforms. Complete infiltration of the Al melt into SiC preform was successfully achieved through the optimisation of process parameters, such as temperature of Al melt, preheat temperature of preform, and infiltration pressure and infiltration time after pouring. Microstructures of 50–70 vol.-%SiC_p/Al composites showed that pores resided preferentially at interfaces between the SiC particles and Al matrix with increasing volume fraction of SiC particles. The measured coefficients of thermal expansion of SiC_p/Al composites were in good agreement with the estimated values based on Turner's model. The measured thermal conductivity of SiC_p/Al composites agreed well with estimated values based on the 'rule of mixture' up to 70 vol.-% of SiC particles, while they were lower than the estimated values above 70 vol.-% of SiC particles, mainly due to the residual pores at SiC/Al interfaces. The high volume fraction SiC_p/Al composite is a good candidate material to substitute for conventional thermal management materials in advanced electronic packages due to their tailorable thermophysical properties.     

Processing of Al/SiC composites in continuous solid–liquid co-existent state by SPS and their thermal properties

Silicon carbide (SiC)-particle-dispersed-aluminum (Al) matrix composites were fabricated in a unique fabrication method, where the powder mixture of SiC, pure Al and Al–5mass% Si alloy was uniquely designed to form continuous solid–liquid co-existent state during spark plasma sintering (SPS) process. Composites fabricated in such a way can be well consolidated by heating during SPS processing in a temperature range between 798 K and 876 K for a heating duration of 1.56 ks. Microstructures of the composites thus fabricated were examined by scanning electron microscopy and no reaction was detected at the interface between the SiC particle and the Al matrix. The relative packing density of the Al–matrix composite containing SiC was higher than 99% in a volume fraction range of SiC between 40% and 55%. Thermal conductivity of the composite increased with increasing the SiC content in the composite at a SiC fraction range between 40 vol.% and 50 vol.%. The highest thermal conductivity was obtained for Al–50 vol.% SiC composite and reached 252 W/mK. The coefficient of thermal expansion of the composites falls in the upper line of Kerner’s model, indicating strong bonding between the SiC particle and the Al matrix in the composite.     

Carbon fiber polymer–matrix structural composites exhibiting greatly enhanced through-thickness thermoelectric figure of merit

The through-thickness thermoelectric behavior of continuous carbon fiber epoxy-matrix composites is greatly improved by adding tellurium particles (13 vol.%), bismuth telluride particles (2 vol.%) and carbon black (2 vol.%). The thermoelectric power is increased from 8 to 163 μV/K, the electrical resistivity is decreased from 0.17 to 0.02.Ω.cm, the thermal conductivity is decreased from 1.31 to 0.51 W/m.K, and the dimensionless thermoelectric figure of merit ZT at 70 °C is increased from 9 × 10⁻⁶ to 9 × 10⁻². Tellurium increases the thermoelectric power greatly. Bismuth telluride decreases the electrical resistivity and thermal conductivity. Carbon black decreases the electrical resistivity.     

放电等离子烧结制备Diamond/Al复合材料

采用放电等离子烧结法（SPS）制备了Diamond/Al复合材料,研究了金刚石粒径、成分配比、工艺参数等对复合材料的导热性能的影响。结果表明,SPS可以得到导热性能较好的Diamond/Al复合材料,致密度是影响该材料导热性能的最重要因素。在实验确定的金刚石体积分数50%,金刚石粒径70 μm,温度550℃、压力30 MPa的工艺条件下,所制备的材料致密度较高,热导率为182 W/(m·K),比相同条件下纯铝粉烧结体的热导率提高了34.8%,表明金刚石的添加对烧结铝基材料导热性能有明显的改善作用。      

SiC颗粒-SiC晶须混杂填料/双马来酰亚胺树脂导热复合材料的制备与性能

以双马来酰亚胺树脂(BMI)为树脂基体,二烯丙基双酚A(DABA)为增韧剂,γ-缩水甘油醚氧丙基三甲氧基硅烷(KH-560)表面改性的SiC颗粒-SiC晶须(SiCP-SiCW)为复配导热填料,浇注成型制备SiC_P-SiC_W/BMI导热复合材料,分析研究SiC形状、用量、质量比及表面改性对SiC_P-SiC_W/BMI导热复合材料的导热性能、介电性能、力学性能和热性能的影响。结果表明,当改性SiC_P-SiC_W用量为40wt%且SiC_P∶SiC_W质量比为1∶3时,SiC_P-SiC_W/BMI导热复合材料具有最佳的综合性能,导热系数λ为1.125W(m·K)~(-1),介电常数ε为4.12,5%热失重温度为427℃。     

Fabrication of Al-Si controlled expansion alloys by unique combination of pressureless sintering and hot forging

The present work reports the synthesis of Al-X wt.% Si (X = 20, 30, 40 and 50) alloys by a unique combination of pressureless sintering (PLS) and hot forging at 800 and 1000 MPa forging pressures with 37.5 and 50% deformation, respectively, in a specially designed die. The effect of hot forging parameters on densification, hardness, compressive strength and microstructures of the alloys was studied as well as suitably compared with the conventional PLS alloys. The ‘PLS + forged’ alloys, specifically 50% deformed at 1000 MPa, yielded excellent densification and subsequent very good mechanical properties. The combination of hot forging pressure and temperature enabled the high densification due to pore collapse, fracturing of Si particles leading to Al flow between the fractured Si particles and better interfacial diffusion between Si and Al. Moreover, the alloys showed excellent electrical conductivity (~67% of that of pure Al), low coefficient of thermal expansion (CTE) and high thermal conductivity (TC) at par with the same alloys prepared with other methods, like spark plasma sintering, hot pressing and Osprey techniques.     

碳纳米管的偶联剂修饰及其在环氧树脂复合材料中的应用

为了在环氧树脂( EP) 复合材料中改善碳纳米管(CNTs) 的分散性和获得优良的界面特性, 利用Fenton 试剂对CNTs 进行了羟基化处理, 然后分别利用硅烷偶联剂KH550、KH560、KH570 和钛酸酯偶联剂NDZ201对羟基化CNTs 进行表面修饰, 通过SEM、TGA、DSC 和阻抗分析仪研究偶联剂修饰对CNTs/ EP 复合材料性能的影响。实验结果表明: Fenton 试剂和4 种偶联剂修饰都能显著改善CNTs 在复合材料中的分散性, 提高EP的玻璃化温度(T_g) 和热稳定性, 其中偶联剂修饰比Fenton 试剂处理更有效; 然而这些改性却大幅度降低了复合材料的导电性能、介电常数以及介电损耗。4 种偶联剂中, KH560 对应的复合材料的T_g最高, 热稳定性和导电性能最好, 同时具有较高的介电常数和较低的介电损耗。      

Modeling the thermal conductivity of diamond reinforced aluminium matrix composites with inhomogeneous interfacial conductance

A reasonable model for describing the thermal conductivity of diamond reinforced aluminium matrix composites behaving a distinctive character of inhomogeneous distribution of interfacial thermal conductance on diamond surfaces is proposed in terms of an equivalent diameter approach combined with a double effective-medium approximation scheme. Theoretical analyses for the thermal conductivity of diamond reinforced Al (Si) composites prepared by different infiltration techniques (squeeze casting (SQ), gas pressure infiltration (GPI)) are given for rediscovering the existing experimental results considering inhomogeneous conductance behavior. Numerical results using present model agree reasonably well with the experimental observations and explore new findings, i.e. the diffusion bonding also occurs at Al–diamond {1 1 1} interfaces of GPIed composites; the interconnected particles is possibly existed in GPIed Al/diamond composites.     

Effect of copper content on the thermal conductivity and thermal expansion of Al–Cu/diamond composites

Al–Cu matrix composites reinforced with diamond particles (Al–Cu/diamond composites) have been produced by a squeeze casting method. Cu content added to Al matrix was varied from 0 to 3.0 wt.% to detect the effect on thermal conductivity and thermal expansion behavior of the resultant Al–Cu/diamond composites. The measured thermal conductivity for the Al–Cu/diamond composites increased from 210 to 330 W/m/K with increasing Cu content from 0 to 3.0 wt.%. Accordingly, the coefficient of thermal expansion (CTE) was tailored from 13 × 10⁻⁶ to 6 × 10⁻⁶/K, which is compatible with the CTE of semiconductors in electronic packaging applications. The enhanced thermal conductivity and reduced coefficient of thermal expansion were ascribed to strong interface bonding in the Al–Cu/diamond composites. Cu addition has lowered the melting point and resulted in the formation of Al₂Cu phase in Al matrix. This is the underlying mechanism responsible for the strengthening of Al–Cu/diamond interface. The results show that Cu alloying is an effective approach to promoting interface bonding between Al and diamond.     

电沉积锌镍掺杂硅烷复合膜的耐蚀性能

单纯的锌镍镀层和KH-560硅烷膜的耐蚀性均为不佳。以KH-560作硅烷偶联剂、锌镍作掺杂颗粒,在碳钢表面沉积含有锌镍颗粒的KH-560复合膜。通过Tafel极化曲线、电化学阻抗谱及中性盐雾腐蚀表征了该复合膜的耐腐蚀性能,并将其与磷化膜、锌镍镀层及KH-560膜进行了比较;通过红外光谱和EDS能谱分析了复合膜的化学成分,通过SEM表征了其微观结构。结果显示:掺杂有锌镍颗粒的KH-560复合膜比其他膜都具有致密的结构和优异的耐腐蚀性能。     

Microstructures and thermal properties of A356/SiCp composites fabricated by liquid pressing method

A356/45vol.%SiCp composites with a uniform distribution of SiC particles have been fabricated by a liquid pressing method. Increasing the melt temperature, holding time and pre-treatment of SiCp by thermal oxidation improves the soundness of composites for the liquid pressing method. The sound composites exhibited low coefficient of thermal expansion (8 ppm/K) and high thermal conductivity (155 W/m K). The measured values for coefficient of thermal expansion agree well with the predicted values based on Turner’s model irrespective of porosity. The measured values for thermal conductivity decrease with porosity, and the effect of pore on the thermal conductivity has been evaluated based on the modified Hasselman–Johnson model.