Studies on Preparation and Property Researches of EP/SiC Thermal Conductivity Composites

The epoxy resin/silicon carbide thermal conductivity composites were prepared via casting method. The content of SiC and coupling reagents effecting on the thermal conductivity, mechanical and thermal properties of composites were investigated. Results revealed that the thermal conductivity properties of the composites were improved with the increasing mass fraction of SiC, and the thermal conductivity coefficient λ was 0.7152 W/mk with 50% mass fraction of SiC, being over 3 times of that of native epoxy resin. The flexural strength and impact strength of the EP/SiC composites increased firstly, but decreased with excessive addition of SiC, and the properties of EP/SiC composites were maximum with 10 wt% SiC. DSC and TGA analysis showed that the glass transition temperature (Tg) of composites decreased, but the heat resistance increased with the addition of SiC. SEM observation of impact fracture revealed that the impact strength had the relationships of large or small fracturing ability and the fracturing extended ability and the resin elasticity deformation.     

SiO2/丁酮分散液的制备及其在环氧复合材料中的应用

通过机械球磨与偶联剂表面处理结合,制备得到高浓度含量、低黏度、分散稳定的SiO2/丁酮分散液。将分散液与环氧树脂混合、固化,制备得到环氧树脂/SiO2复合材料。研究了偶联剂GPTMS对SiO2/丁酮分散液的分散性能的影响。研究表明:加入质量分数为1%的偶联剂GPTMS,极大地提高了SiO2/丁酮分散液的分散性能及环氧树脂/SiO2复合材料的界面粘接性能。高含量SiO2的加入有效降低了复合材料的热膨胀系数,材料的玻璃化转变温度也有了一定的提高。     

Enhanced Thermal Conductivity of Epoxy Composites with MWCNTs/AlN Hybrid Filler

To further improve the thermal conductivity of epoxy resin, the multi-walled carbon nanotube/aluminum nitride (MWCNTs/AlN) hybrid filler was employed to prepare thermal conductivity MWCNTs/AlN/epoxy composite by casting process, and the silane coupling reagent of γ-glycidoxy propyl trimethoxy silane(KH-560) was also used to functionalize the surface of MWCNTs and/or AlN. Results revealed that, the thermal conductivity of epoxy resin was improved remarkably with the addition of MWCNTs/AlN hybrid filler, a higher thermal conductivity of 1.04 W/mK could be achieved with 29 wt% MWCNTs/AlN hybrid filler (4 wt% MWCNTs +25 wt% AlN), about 5 times higher than that of native epoxy resin. And the epoxy composite with 29 wt% MWCNTs/AlN hybrid filler possessed better thermal conductivity and mechanical properties than those of single 5 wt% MWCNTs or 40 wt% AlN. The thermal decomposition temperature of MWCNTs/AlN/epoxy composite was increased with the addition of MWCNTs/AlN hybrid filler. For given filler loading, surface treatment of MWCNTs and/or AlN by KH-560 exhibited a positive effect on the thermal conductivity of epoxy composite.     

聚酰胺固化环氧树脂的热分解动力学研究

利用热重分析(TG)采用不同升温速率(10,15,20,25℃/min)分别在空气和氮气气氛下对聚酰胺固化环氧树脂热稳定性进行了研究.采用Coats-Redfem和Ozawa热分析处理动力学数据的方法,计算了环氧树脂热分解反应活化能E、反应级数n及频率因子A.求得空气气氛下5%～30%的失重率下反应表观活化能在70.3...     

环氧树脂基导热复合材料的研究

概述了国内外近年来环氧树脂导热复合材料的研究进展,简要分析了复合材料研究中存在的问题,并对其未来发展方向进行了展望。     

Studies on the Preparation of Polystyrene Thermal Conductivity Composites

Various thermally conductive fillers including aluminum oxide(Al₂O₃), magnesium oxide(MgO), β-silicon carbide particle(β-SiCp) and β-silicon carbide whisker(β-SiCw) were used to prepare polystyrene thermal conductivity composites. Experimental results showed that, for given filler loading, the thermal conductivity of the composites was higher for PS flake than that of PS particle, and the thermal conductivity was optimal by powder blending method. The SiCw filler was more favorable to improve the thermal conductivity of the composites; a much higher thermal conductivity of 1.18 W/mK could be achieved for the composite with 40 vol% SiCw, about six times higher than that of native polystyrene. The experimental thermal conductivity values were in agreement with those predicted by lower bound of Maxwell-Eueken model. For given SiC loading, the thermal conductivity increased with the increasing shape parameter of n. The SiCw was much easier to form the thermal conductivity chains and network than that of SiCp.     

电子封装用液态环氧树脂中陶瓷填料的改性研究

选用氮化硼(BN)、氮化铝(AlN)、氧化铝(Al2O 3)、氮化硅(Si3N4)、二氧化硅(SiO2)添加到液态环氧树脂中制备复合材料,并对其进行黏度、热导率、热膨胀系数和介电常数的测试.结果表明:层片状的BN添加到液态环氧树脂中后,复合材料获得了较好的综合性能,即在体积分数为35%时,具有较高的热导率(2.12 W/m·K)、较低的热膨胀系数(38.13×10-6 K-1)、较低的介电常数(4.01,1 MHz).     

环氧树脂多孔复合材料的制备及性能

以环氧树脂为基体、蓖麻油酸(RA)或二聚蓖麻油酸(DRA)改性的四乙烯五胺(TEPA)(RATEPA/DRATEPA)作为固化剂、水为致孔剂、釉粉为无机填料,通过树脂-水-填料悬浮乳液复合体系聚合法,在室温下合成了环氧树脂多孔材料,采用SEM、压汞仪、电子万能试验机、TGA对多孔材料的形貌、孔径分布、孔隙率、机械性能及热性能进行了表征和测试。结果表明:随着水相质量分数和填料粒径的增大,多孔材料的孔径和孔隙率增大,压缩强度减小;随着固化剂分子量的增大,多孔材料的孔径和孔隙率减小,压缩强度增大。当填料粒径为40μm,固化剂为RATEPA,m(水相)∶m(树脂相)=2∶1时,多孔材料的综合性能最佳,其最可几孔径为3.449μm,孔隙率为21.8%,压缩强度为26.89 MPa。TGA和DTG测试结果表明:环氧树脂多孔材料的热稳定良好,具有耐高温性能,可以在高温条件下应用。     

SCRIMP用原位分相增韧中温环氧树脂体系制备及复合材料性能

针对复合材料真空辅助树脂浸渍模塑技术(SCRIMP)对树脂体系要求进行配方设计及性能测试。采用动态差示扫描量热(DSC)法,运用Kissinger动力学方程研究了基础树脂的固化反应动力学。通过添加QS-VA-3型原位分相型增韧剂,改善了基础树脂脆性,依据力学性能测试结果确定最佳添加量。对增韧环氧树脂体系进行等温/非等温黏度特性研究,确定了SCRIM P灌注成型过程的适用期,并使用该技术成型了增韧环氧树脂体系/单向玻璃纤维布复合材料试样,发现与玻璃纤维复合后具有强度高、界面性能好及低电压绝缘性能良好特点,但牺牲了高电压环境下绝缘性能。     

Cure Kinetics and Thermal Property of Bisphenol-S Epoxy Resin and Phthalic Anhydride

Abstract

The cure kinetics of bisphenol-S epoxy resin (BPSER) and curing agent phthalic anhydride, with N,N-dimethyl phenzylamine as an accelerator, were studied by means of differential scanning calorimetry (DSC). Analysis of DSC data indicated that an autocatalytic behavior showed in the first stages of the cure. The autocatalytic behavior was well described by the model proposed by Kamal including two rate constants, k1 and k2, and two reaction orders, m and n. The overall reaction order, m + n, is in the range 2～3. The activation energies for k1 and k2 were 111.69 and 80.47 KJ/mol, respectively. Diffusion control was incorporated to describe the cure in the latter stages. The glass transition temperatures (T_gS) of the BPSER/anhydride samples isothermally cured partially were determined by means of torsional braid analysis (TBA). and the results showed that the reaction rate increased with increasing T_g in terms of the rate constant, but decreased with increasing conversion. The T_g of completely cured BPSER/anhydride system is about 40 K higher than that of BPAER. The thermal degradation kinetics of this system was investigated by thermogravimetric analysis (TGA). It illustrated that the thermal degradation of the BPSER/phthalic anhydride has n-order reaction kinetics.     

环氧树脂/有机蒙脱土复合材料的制备与力学性能研究

利用插层聚合法制备了环氧树脂/有机蒙脱土(EP/OMMT)复合材料.采用XRD对复合材料进行了表征,并研究了复合材料力学性能.实验表明:环氧树脂/有机蒙脱土形成了剥离型的纳米复合材料结构;环氧树脂中加入适量的有机蒙脱土,可以提高环氧树脂的拉伸强度和冲击强度.当经过改性的OMMT质量分数为5%时,EP/钛酸酯偶联剂(Coupler)-OMMT复合材料的拉伸强度达到51.21 MPa,提高了40.26%;当OMMT质量分数为3%时,EP/Coupler-OMMT复合材料冲击强度达25.31 kJ/m2,提高了34.56%.     

氨基硅烷活化绢云母改性环氧树脂的固化反应动力学研究

采用氨基硅烷偶联剂(KH550)活化绢云母,在甲基四氢邻苯二甲酸酐(MeTHPA)作用下制备活化绢云母改性环氧树脂.设定不同的升温速率,分别对活化绢云母/环氧树脂/MeTHPA体系进行DSC测定,并采用Kissinger法和Ozawa法处理数据,研究了其固化反应动力学.结果表明,添加活化绢云母前后环氧树脂/MeTHPA...     

ABS/石墨/NBR导热复合材料性能的研究

采用熔融共混法制备丙烯腈-丁二烯-苯乙烯共聚物(ABS)/石墨/丁腈橡胶(NBR)导热复合材料,通过热常数分析仪、同步热分析仪、扫描电子显微镜、力学性能测试等手段研究了NBR、ABS高胶粉及石墨(G)的添加量对ABS复合材料导热性能及力学性能的影响。结果表明,ABS高胶粉和NBR均能明显提高ABS的热导率和缺口冲击强度,但是丁腈胶粉的改性效果优于高胶粉。以NBR作为ABS复合材料的增韧剂,随着石墨含量的增大,增韧效果下降,ABS复合材料的热导率提高到纯ABS的5倍,热分解温度提高40℃左右,热膨胀系数下降。当ABS/G/NBR复合材料的质量比为60/15/25时,其热导率为纯ABS的2倍,缺口冲击强度达21.8 kJ/m2,明显高于纯ABS(2.6kJ/m2)。     

超细膨润土/环氧树脂复合材料的结构与热性能

采用TG-DTA、IR、SEM、马丁耐热和Daniel流动点测定等方法,研究了有机胺改性超细膨润土与环氧树脂的固化体系的结构及其性能。结果表明,有机胺改性膨润土与环氧树脂固化复合后,可形成由层问固化与层外固化相结合的结构,所得复合材料的耐热性能、分散性均有提高,其中活化有机膨润土／环氧树脂复合体系的分散效果和马丁耐热特性改善更加显著。     

环氧树脂/AlN复合材料中气孔的形成与控制

采用不同粒径的氮化铝(AlN)粉末为填料,通过超声波分散及机械搅拌分散相结合的方式制备了环氧树脂/AlN复合材料.运用 SEM 对填料及气孔在基体中的分布情况进行表征分析,同时讨论超声波分散、真空脱泡及分散剂在材料成型过程中的消泡效果.结果表明:超声分散的应用不利于气孔率的减少,真空脱泡及消泡剂的添加能有效地减少材料中的气孔分布,提升材料的导热性能.     

碳纳米管/环氧树脂复合材料的研究进展

介绍了碳纳米管与环氧树脂复合材料的力学性能、电性能、摩擦性能及吸波性能等;并结合国内外研究现状,探讨了该复合材料制备中存在的问题及发展的方向。     

氮化铝/氧化石墨烯对环氧树脂胶黏剂导热性能的影响

使用硅烷偶联剂KH-560对氮化铝进行了表面改性,并以其为导热填料,环氧树脂为基体,制备了氮化铝/环氧树脂导热胶黏剂。采用FTIR、SEM、TG、热常数分析仪对导热胶黏剂进行了表征。结果表明:改性后硅烷偶联剂分子成功接枝在氮化铝表面。改性后,氮化铝与环氧树脂的界面粘结力增强,热稳定性和导热性均得到明显改善。当氮化铝质量为导热胶黏剂质量的70%时,改性氮化铝/环氧树脂热胶黏剂的导热系数为2.24W/(m·K),而未改性氮化铝/环氧树脂的导热系数仅为1.73W/(m·K)。为进一步提高其导热性能,制备了改性氮化铝/氧化石墨烯/环氧树脂导热胶黏剂,当改性氮化铝和氧化石墨烯的质量分数分别为50%和3%时,导热胶黏剂导热系数为3.05 W/(m·K)。     

环氧树脂/凹凸棒土纳米复合材料的制备与表征

采用共混法制备了凹凸棒土(AT)质量分数分别为1%、3%、5%、10%的环氧树脂(EP)/AT纳米复合材料,通过拉伸测试、SEM、DMA、TGA等测试方法对该纳米复合材料的形态结构和性能进行了研究。结果表明,AT在EP基体中基本达到均匀分散,与纯EP树脂相比,不同AT用量的纳米复合材料的拉伸强度和断裂伸长率均有所提高,表现出较好的韧性。此外,加入AT后,EP树脂的玻璃化转变温度有一定程度的增大,热分解温度有所提高。     

固化剂对环氧包封料性能的影响

研究了以甲基四氢苯酐和间苯二胺作固化剂时 ,环氧树脂包封料的固化放热现象 ,测定了不同固化剂体系的包封料力学性能、电性能、密度和吸水性。结果表明 ,间苯二胺的活性大于酸酐固化剂的活性 ,但填料的加入使胺固化的放热降低 ,酸酐固化的升高。胺固化的冲击强度较高 ,加入填料可提高拉伸强度。胺固化的介电常数 ,介电损耗角较高 ,但体积电阻率较低 ,其吸水性较高     

球形二氧化硅/环氧树脂复合材料制备与性能表征

以普通角形二氧化硅为原料,采用氧-乙炔火焰法制备出球形二氧化硅。将环氧树脂(E-51)、固化剂(906)、固化促进剂(DMP-30)和球形化前后二氧化硅按照不同的比例经机械搅拌混合、超声分散和升温固化(100℃、2h和150℃、2h)后制备出二氧化硅/环氧树脂复合材料。研究对比球形化前后二氧化硅对环氧树脂浇注体系热学和力学性能的影响。结果表明:球形二氧化硅的加入,提高了环氧树脂的热稳定性,添加量30%时热分解温度达到最大值340℃,球形化后二氧化硅/环氧树脂复合材料热膨胀系数和初始黏度较球形化前明显降低,力学性能得到提高。