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.     

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。     

The Preparation and Cure Kinetics Researches of Thermal Conductivity Epoxy/AlN Composites

The aluminum nitride (AlN) was employed to prepare epoxy/AlN composites by blending-casting moulding method, two different coupling agents were used to functionalize the surface of AlN. The thermal conductivity and mechanical properties of the composites were investigated. And the cure kinetics of the EP/AlN composites was studied by means of isothermal DSC. Results revealed that the thermal conductivity of EP improved remarkably with the addition of AlN, a higher thermal conductivity of 1.05 W/mK can be achieved with 42 vol% AlN, about 5 times higher than that of native epoxy resin. And the flexural and impact strength of the EP/AlN composites were optimal with 3.3 vol% AlN. The curing process of the EP/AlN composites contained autocatalytic mechanism, the whole process was according with the Kamal model. The presence of AlN did not change the cure reaction mechanism, and had little effecting on the activation energy, but decreased the rate constants k_l and k₂.     

导热PA6复合材料导热性能的研究

将氮化硼和氧化铝等助剂混合后,经过平行双螺杆挤出机制备了导热PA6复合材料,研究了将不同粒径的氮化硼和氧化铝复配对尼龙6复合材料导热系数的影响。结果表明:采用不同粒径的氮化硼和氧化铝复配,添加60%的含量可得到导热系数为1.869的导热PA6复合材料。     

炭纤维/树脂复合材料导热性能的数值模拟

采用有限元方法对炭纤维/树脂复合材料的导热性能进行了数值模拟,分别建立一维结构和二维结构炭纤维/树脂复合材料计算分析模型,研究炭纤维含量、界面接触热阻、以及炭纤维直径对复合材料有效热导率的影响。研究结果表明炭纤维作为复合材料增强相,其含量越高复合材料的热导率越高;界面的接触热阻在10-3~10-5(m2 K)/W范围内对复合材料有效热导率有较大的影响,超出范围之后改变接触热阻对材料热导率的影响可以忽略;接触热阻比较大时,炭纤维的直径对复合材料的热导率有较大的的影响,当接触热阻比较小时,炭纤维的直径对于复合材料热导率的影响非常小。     

聚苯乙烯的热裂解研究

废旧高分子材料的处理已成为环境污染治理的重要课题之一。本文详细调查了聚苯乙烯的裂解反应,表征了聚苯乙烯的裂解产物,探讨了裂解介质,等,获得了优化的裂解工艺参数。     

颗粒填充聚合物复合材料导热系数公式的初步验证

应用颗粒填充聚合物复合材料等效导热系数公式,估算了酚醛/铝粉和酚醛/石墨复合材料的等效导热系数,并与相关材料体系的实验测量数据相比较,结果表明,等效导热系数的理论计算值和实测值较为接近。     

聚苯乙烯/氧化石墨烯复合建材的制备与保温性能研究

通过聚苯乙烯(PS)与氧化石墨烯(GO)共混,制备聚苯乙烯/氧化石墨烯(PS/GO)保温建筑材料,并对PS/GO阻燃性能以及保温性能进行研究。结果表明:GO含量为6%时,4号样品的综合性能最好。4号样品的LOI值为33.4%,阻燃等级达到V-1,热释放速率峰值(pHRR)为525.76 kW/m²,总产烟量(TSP)为629.37 m²。此外,4号样品具有较低的导热系数0.034 2 W/(m·K),并且吸水率以及水蒸气透过系数均满足标准值,说明其可以有效应用于建筑保温材料。     

ZnO/EP复合材料的制备及其导热性能

采用溶胶-凝胶法制备纤锌矿型氧化锌(zinc oxide,ZnO)粉体,考察了煅烧温度对ZnO粉体质量的影响;将不同煅烧温度获得的ZnO填充于环氧树脂(epoxy resin,EP)得到系列ZnO/EP复合材料,采用红外光谱仪(Fourier transform infrared spectroscopy,FTIR)和...     

Thermal Conductivity Coefficients of Unidirectional Fiber Composites Defined by the Concept of Interphase

In this paper, the thermal conductivity coefficients of unidirectional composites have been estimated. In the present analysis, a model which takes into account the influence of the boundary interphase has been proposed. The thermal conductivity coefficients of the composite were calculated by using this concept to determine the role of the interphase which mainly depends on the quality of adhesion between fibers and matrix. The interphase matter is the part of the polymer matrix lying on the close vicinity of the fiber bounding surface. It has been primarily assumed that the interphase is inhomogeneous with thermophysical properties varying from the fiber surface to the matrix. Five laws of variation have been taken into consideration in order to derive closed form expressions for the thermal conductivity coefficients in which the role of the interphase layer occurs, possessing properties different from those of the constituent phases. A thermal analysis method known in the literature has been adopted in order to find the extent of the interphase layer. According to this viewpoint, theoretical expressions in order to calculate the thermal conductivity coefficients of the glass fiber reinforced composite materials were derived taking into consideration the interphase layer.     

聚苯乙烯热分解反应动力学研究

采用热重法对聚苯乙烯(PS进)行了热分解动力学研究。结果表明:PS呈两段热解,主要发生在340~520℃区间,在该范围内,PS在400~444℃达到最大热解速率;随着升温速率的增加,其最大热解速率对应的峰温有所升高,热解起始、终止温度也相应提高,但最终质量分数基本一致,为4.4%~4.8%。采用等转化率法和比较法求解得到PS热解过程的动力学三因子,其活化能为136.76kJ/mol,指前因子lnA为26~28,动力学机理函数的积分形式为。用反应模型对实验数据进行了模拟,模拟准确度很高,标准偏差为0.048。     

Review Article: Recycling of Polystyrene

Recycling of polystyrene can be done by mechanical, chemical, and thermal methods. High impact polystyrene is a promising material for mechanical recycling since its properties are not extremely affected even after multiple processing of upto nine cycles. Production of liquid products and gaseous products are highly dependent on the reaction condition. The catalysts used are highly selective for the production of liquid as well as gaseous products. In this article we have reviewed the various types of methods followed so far for recycling of polystyrene.     

聚丙烯/石墨烯微片/碳化硅复合材料微观形态与导电导热性能研究

采用熔融共混法制备聚丙烯/石墨烯微片/碳化硅(PP/GNP/SiC)复合材料,研究了SiC用量对PP/GNP/SiC复合材料的微观形态、结晶度和导电导热性能的影响。SEM与XRD测试结果表明,SiC粒子有助于提高拉伸力场对GNP的剥离效果以及GNP在PP基体中的分散程度,随着SiC粒子用量的增加,GNP的片径尺寸和片层厚度均减小,并与SiC粒子相互搭接。导电导热分析结果表明,随着SiC粒子用量的增加,PP/GNP/SiC复合材料的电导率先升高后降低,热导率逐渐提高。SiC用量为5%时,复合材料的电导率最高;SiC用量为20%时,复合材料的热导率最高。     

热塑性聚酰亚胺复合材料导热性能研究

采用稳态热板法测定铜粉（Cu）填充热塑性聚酰亚胺（TPI）复合材料的热导率，研究了Cu填充量对复合材料的力学性能和导热性能的影响，初步探讨了温度与复合材料热导率的关系。通过扫描电子显微镜观察了复合材料的微观形态。在此基础上，理论计算复合材料热导率。研究表明，Cu填充TPI可有效提高复合材料力学性能和导热性能。当Cu体积分数提高到26％时，填料聚集形成导热链，Cu／TPI复合材料的热导率是纯TPI树脂的3．5倍；当填料含量低于10％时，Maxwell—Eucken模型适合预测复合材料热导率；基于导热链考虑的Y．Agan模型可较好地反映复合材料热导率随填料含量的变化情况；随着温度的升高，Cu／TPI复合材料热导率先增大后趋于平缓。     

Thermal Conductivity of Platelet-Filled Polymer Composites

Platelet-shaped particles of similar size and shape were investigated as fillers for improving the thermal conductivity of polymer–ceramic composite materials. The conductivities of composites filled with hard, stiff ceramic particles exceeded 3.5 W·(m·K)⁻¹, or >20 times the conductivity of the polymer matrix, and were shown to be almost independent of the intrinsic filler conductivity range of 33–300 W·(m·K)⁻¹. In contrast, the thermal conductivity of composites filled with soft, platelet-shaped BN fillers reached over 13 W·(m·K)⁻¹. A mechanism is proposed whereby deformation of the soft filler particles provides improved particle-to-particle connectivity and allows greater packing density, resulting in the ability to achieve much higher conductivity than is possible for hard and stiff particles of similar initial morphology. Experimental results are discussed in light of various thermal conductivity prediction models in the literature.     

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.     

建筑用聚苯乙烯泡沫塑料的绝热保温性能测试和分析

对聚苯乙烯泡沫塑料在建筑上的应用的优异性能进行了简述,测定并分析了材料的导热系数和密度的关系。     

高分子复合材料导热性能研究

以Al2O3、MgO和BN三种无机填料作为尼龙6(PA6)的导热填料,研究填料的种类、填充量、粒径大小和粒径配比等对复合材料热导率的影响。结果表明:PA6基复合材料的热导率随导热填料填充量的增加而增大,随导热系数大的填料填充量的增加增大较快;导热系数大的填料的粒径对复合材料的导热系数的影响比较明显;导热系数大的填料,不同粒径的复配可以显著提高复合材料的导热系。     

预测聚合物基复合材料导热系数方法综述

由聚合物与高导热填料共混制得的导热聚合物基复合材料,被应用于防腐和节能要求较高的换热场合,符合换热设备新材料的要求;而聚合物基复合材料的等效导热系数预测比较复杂。总结了预测聚合物基复合材料等效导热系数的多种方法,包括最小热阻力法、热阻网络法、傅里叶定律法、均匀化方法和逾渗理论方法,归纳了这些模型和方法的特点,对应用这些模型和方法提出了建议。     

纳米银颗粒包覆氧化铝的制备及其硅胶复合材料热导率

用化学方法在微米级球形氧化铝上包覆纳米银颗粒,包覆层可在空气中稳定存在。银包覆层明显提高了氧化铝/硅胶复合材料的热导率。复合材料断面形貌图显示纳米银包覆层改善了氧化铝与硅胶之间的界面结合,并且银颗粒起到桥梁作用连接起相邻的氧化铝。