Al(OH)_3填充EPDM基复合材料动态力学性能的研究

本文用动态力学分析仪（ＤＭＡ）研究了Ａｌ（ＯＨ）_３。填充ＥＰＤＭ基复合材料的动态力学性能。研究结果表明,Ａｌ（ＯＨ）_３的体积分数和粒径对ＥＰＤＭ的玻璃转变过程和复合材料动态力学性能的影响很大。复合材料在玻璃态时的动态模量随Ａｌ（ＯＨ）_３体积分数的增加而增大,力学损耗随Ａｌ（ＯＨ）_３体积分数的增加而减小。     

Al（OH）3填充EPDM基复合材料动态力学性能的研究

本文用动态力学分析仪（ＤＭＡ）研究了Ａｌ（ＯＨ）３填充ＥＰＤＭ基复合的动态力学性能。研究结果表明,Ａｌ（ＯＨ）３的体积分数和粒径对ＥＰＤＭ的玻璃转变过程和复合材料动态力学性能的影响很大,复合材料在玻璃态时的动态模量随Ａｌ（ＯＨ）体积分数的增加而增大,力学损耗随Ａｌ（ＯＨ）３体积分数的增加而减小。     

填料对复合材料电导率影响的研究

评述了现有计算聚合物基复合材料电导率的公式, 并指出各自的适用范围。研究了填料的体积份数、粒径和表面状态对复合材料电导率的影响, 并讨论了复合材料电导率的机理。提出了填料粒子效应的导电物理模型, 推出的复合材料电导率随Ａｌ（ＯＨ）３ 填料体积份数变化的Ｓ形规律与试验结果相吻合。     

Al(OH)_3颗粒分散状态对EPDM/Al(OH)_3复合材料电导率影响的研究

本文用扫描电子显微镜（SEM）观察了无机填料Al（OH）3颗粒在EPDM基体中的分散状态，并根据Maxwell理论和Yamada推导的方程计算了Al（OH）3颗粒的分散因子，研究了Al（OH）3颗粒的分散状态对复合材料电导率的影响。     

三元乙丙橡胶聚集态结构对其复合材料动态力学性能的影响

采用动态力学分析技术分别研究了两种不同聚集态结构三元乙丙橡胶(EPDM)对EPDM／Al(OH)2复合材料动态力学性能的影响。研究结果表明，在玻璃化转变过程中，结品性EPDM比非结晶的动态模量(E')大，而介质损耗因素(tanδ)、动态粘度(n’)值则小，且峰温移向高温；当Al(OH)2填料浓度相同时，结品性EPDM与Al(OH)3复合材料的E’大、tanδ峰值小，但在结晶性EPDM与Al(OH)3复合材料中Al(OH)3粒子与EPDM两相间的作用参数(B)较小。     

Al（OH）3颗粒分散状态对EPDM／Al（OH）3复合材料电导率影响的研究

本文用扫描电子显微镜（ＳＥＭ）观察了无机填料Ａｌ（ＯＨ）３颗粒在ＥＰＤＭ基体中的分散状态，并根据Ｍｘｗｅｌｌ理论和Ｙａｍａｄａ推导的方法计算了Ａｌ（ＯＨ）３颗粒的分散因子，研究了Ａｌ（ＯＨ）３颗粒的分散状态对复合材料电导率的影响。     

环氧/碳化硅复合材料的制备和导热性能研究

碳化硅纳米线(SiCNWs)具有导热系数高、热稳定性好、力学性能及耐腐蚀性优异等优点,是提高环氧树脂复合材料导热性能的理想填料。通过对SiCNWs高温氧化使纳米线表面形成二氧化硅(SiO_2)的壳层得到核壳结构的碳化硅纳米线(SiC@SiO_2NWs),对比研究了SiCNWs和SiC@SiO_2NWs对环氧(Epoxy)复合材料热性能的影响。结果表明:Epoxy/SiC@SiO_2NWs复合材料的导热系数达到0.391W/(m·K),相比纯环氧提高了79.4%,同时提高了其热稳定性。     

聚酰胺酸低黏化制备导热BN/PI复合薄膜

为解决填料在高黏度聚酰胺酸（PAA）中易团聚、分散性差的问题，本研究以3,3′,4,4′-联苯四甲酸二酐（BPDA）和对苯二胺（PDA）为原料，采用酸酐水解法在较高固含量下合成了低黏度的聚酰胺酸溶液。在此基础上，通过填料的液相法超声分散预处理和高效球磨混合工艺，制备了氮化硼质量分数为0～40%的氮化硼/聚酰亚胺（BN/PI）复合薄膜，系统考察了填料的分散性以及复合薄膜的力学、耐热、导热等性能。结果表明：聚酰胺酸的低黏化及填料混合分散工艺赋予了填料良好的分散性，并对BN/PI复合薄膜的性能产生重要影响。当填料质量分数为40%时，复合薄膜的力学强度约为140 MPa，玻璃化转变温度为385.2℃，导热系数高达0.741 W/(m·K)，相比无填料添加的纯PI膜提高了338%。     

导热绝缘高分子复合材料的研究进展

近年来,随着微电子行业的快速发展,通过添加导热绝缘填料制备导热绝缘高分子复合材料受到广泛关注。本文综述了导热绝缘复合材料的导热绝缘机理,详细介绍了导热绝缘高分子复合材料的影响因素,主要涉及导热绝缘填料及其几何尺寸、填料在基体中的分散状态以及填料表面改性等,并概述了导热绝缘高分子复合材料的应用现状,最后对未来导热绝缘高分子复合材料的研究方向提出了建议与展望。     

高强度导热三元乙丙橡胶复合材料的性能研究

通过多尺度氧化铝、纳米氧化锌单一填料填充以及两者复合填充三元乙丙橡胶,研究导热填料对三元乙丙橡胶复合材料拉伸强度和导热系数的影响,制备具有较高力学性能的三元乙丙橡胶导热复合材料,并测试了其绝缘性能.结果表明:使用多尺度氧化铝、纳米氧化锌复配填充,且两者的填充量均为200份时,得到的复合材料导热系数达1.16 W/(m·K),拉伸强度达5.01 MPa,撕裂强度达21.12 N/mm.     

碳纳米管填充的高介电常数聚合物基复合电介质材料

介绍了碳纳米管电性能及其功能化改性、以及利用碳纳米管掺杂聚合物制备柔性高介电常数复合材料的研究现状,发现化学气相沉积法得到的多壁碳纳米管(MWNT)在化学处理前后形成的聚合物基复合材料具有明显不同的分散特性和介电性能.相对于微米级球形导电颗粒填充的复合材料,一维尺度碳纳米管填充的复合材料具有明显低得多的渗流阈值,低渗流阈值可以明显保持聚合物基体优良的机械性能.期望在这一领域从工程电介质的角度做深入的研究工作,以发现碳纳米管在聚合物基复合材料领域所表现出的新特性、新现象.     

真空下环氧复合材料耐脉冲电流烧蚀性能

在脉冲功率装置中,由于沿面闪络引起绝缘破坏的现象极其常见,因而有必要研制具有高耐烧蚀强度的绝缘材料来延长脉冲功率装置的使用寿命。本文通过向环氧基体中添加微/纳米氢氧化铝,微/纳米氧化铝,以真空闪络一定次数后试样表面形貌和质量损失的变化为烧蚀性能的评价方法,研究了无机填料对环氧耐烧蚀性能的影响。试验结果表明:无机填料对环氧耐烧蚀性能有所提高,氢氧化铝的效果比氧化铝明显;纳米氢氧化铝要好于同质量分数的微米氢氧化铝,而微/纳米氧化铝之间的效果差别刚好相反。     

Low loss flexible SrTiO<Subscript>3</Subscript>/POE dielectric composites for microwave application

Flexible, high dielectric constant and low dielectric loss composites for microwave application fabricated with SrTiO₃ (STO) ceramic filler dispersed inside a thermoplastic polyolefin elastomer (POE) polymer matrix have been studied in this paper. The dielectric property and the mechanical property of STO/POE composites filled with different volume fraction of ceramic filler were investigated. The results indicated that with the increase volume fraction of ceramic filler, both the permittivity and the dielectric loss of composites increased. Good frequency stability within a wide range was observed in all the samples. For the composites containing 40 vol% STO, the composites has a tensile strength of 2.75 MPa with an elongation of about 90% at break value. The permittivity and the dielectric loss of the composites were 11.0 and 0.01 in microwave frequency, respectively. A microstrip transmission line on the composites containing 40 vol% STO as a microwave substrate is designed and measured after bending at different angles, meanwhile the transmission coefficients of the microstrip transmission line were unchanged when bending angle is less than 60°. This indicates that the STO/POE composites have the promising characteristics for potential applications in microwave substrate, flexible dielectric waveguide and related flexible microwave devices.     

Influence of filler on the curing and thermal aging of epoxide compounds

An experimental investigation of the filler sort and dispersity influence on inner mechanical stress in UP5–162 epoxide compound during thermal aging was carried out. It was found that the size of filler particles has a dominant influence on a value of the inner mechanical stress, while filler thermophysical properties, such as thermal conductivity and heat capacity, are more important during thermal aging. The backgrounds for maintaining of high mechanical properties of a compound are the filler particle distribution homogeneity over a compound volume, as well as a narrow dispersion distribution.     

废印刷电路板再资源化技术研究

本文研究了废旧线路板湿法回收处理工艺,将废印刷线路板进行湿法粉碎,分选,实现金属粉和非金属粉的分离。以回收得到的非金属粉作为填料,分别与不同的粘结剂采用熔融共混方法制备模塑复合材料,并与木材的机械及耐水性能进行了对比试验。试验结果表明:模塑复合材的各种性能都接近或优于各种常用木材,可替代木材用于制造湿环境中的产品等,达到了减少环境污染、实现资源再利用的目的。     

FEATURE ARTICLE Conducting Polymer Composites

Conducting polymer composites become increasingly important for technical applications. In this article, the resulting electrical properties of such materials are illustrated by a variety of experimental examples. It is shown that the combined mechanical, thermal and electrical interaction between the filler particles via their electrical contacts and the surrounding polymer host matrix are responsible for the properties of the composite material. A short review is given of the theoretical background for the understanding of the electrical transport in such materials. The arrangement of the filler particles and the resulting conductivity can be described either by percolation or by effective medium theories. It can also be related to different types of charge carrier transport processes depending on the internal composite structure. Special emphasis is given to the microstructure of the filler particles such as size, hardness, shape and their electrical and thermal conductivities. A detailed analysis of the physics of the contact spots and the temperature development during current flow at the contact is given. It is shown that the polymer matrix has a strong influence on the electrical conductivity due to its elastic properties and the response to external thermal and mechanical stimulation. Strong changes in the electrical conductivity of conducting polymer composites can be realized either by thermal stimuli, leading to a positive and negative temperature coefficient in resistivity, or by applying mechanical stress. By using nonlinear fillers an additional degree of functionality can be achieved with conducting polymers.     

Ti02/环氧复合材料脉冲真空沿面闪络特性

为了揭示微米TiO2填料对环氧复合材料真空快脉冲作用下的沿面闪络特性的影响,并探讨相关影响因素的作用机理,制备了6种不同填料含量的TiO2/环氧复合材料,测试了各种试样在30 ns(脉冲前沿)/200ns(半高宽)脉冲作用下的真空沿面闪络电压,并测量了介电频谱和热刺激去极化电流(TSDC)。结果显示,TiO2质量分数(wt%)的变化对Ti02/环氧复合材料的闪络电压有显著影响,但两者之间并不是线性关系;随着填料质量分数的增加,复合材料的介电常数和电导率都逐渐增加;所有实验材料都存在深、浅两种不同的陷阱能级,深陷阱电荷量和浅陷阱电荷量随填料质量分数的变化呈现出不同的变化规律。分析认为,Ti02/环氧复合材料的真空快脉冲沿面闪络特性不能由介电常数和电导率等影响因素的变化趋势单独解释,而针对闪络的深浅陷阱共同作用模型可以很好地解释闪络电压的实验结果。同时,根据实验结果对闪络的深浅陷阱共同作用模型进行完善,提出了当填料质量分数较低时,浅陷阱将显著降低材料的闪络强度,而当填料质量分数较高时,深陷阱对闪络强度的增强作用更为明显。     

基于动态力学参数研究环氧云母绝缘材料的老化特征

基于动态力学参数研究了环氧云母绝缘材料在电热条件和冷热循环条件下的老化特征。推导了其玻璃化转变活化能的计算公式 ,并计算了不同老化阶段环氧云母复合绝缘材料的玻璃化转变表观活化能。提出了用动态力学参数表征环氧云母绝缘材料老化特征的新方法。     

The Shielding Effectiveness of Composite Media - a Parametric Analysis Supporting an Engineering Perspective

This paper is presented as an example of a parametric approach that may be applied to engineering the radio and microwave properties of composite materials in the context of providing electromagnetic shielding capability. In this case, the composites are formed by a conductive filler component embedded within an insulating material. The effective electromagnetic (permittivity) properties of the composite are modeled under the quasistatic approximation using the McLachlan general effective medium model, which enables the impact of the percolation (insulator-conductor) transition to be explored. Composites within the transition region exhibit a power-law nature to their effective material properties. The power-law exponents may take a range of values above a limiting value set by the dimensionality of the filler particle network within the composite and with the assumption of a perfectly random distribution of filler particles. In practice, the values of the power-law exponents depend on the chemical interactions between the constituents, the processing conditions and the nature of the inter-particle charge transport. The paper demonstrates the implications of different values of power-law exponent in the context of the trade-off between shielding effectiveness and composite thickness.