碳纤维发热织物的电热性能研究

研究了以碳纤维为基质材料的发热织物的电热性能,通过改变碳纤维的排列以及外界的电学条件,观察发热织物的电阻、温度和发热时间等电热性能的变化情况。经过试验探索得到:碳纤维以交叉的方式排列、电源的功率为5 W时,可在较短的时间内使其织物表面温度达到53.7℃,持续发热6.8 h。通过试验还发现:碳纤维织物的通电时间长短以及断电的次数对碳纤维织物的电阻影响很微弱。     

不饱和聚酯树脂/炭黑/碳纤维复合材料的导电性能研究

本文研究了由炭黑、短切碳纤维填充的不饱和聚酯树脂复合材料的导电性能,得到了乙炔炭黑、短切碳纤维用量与复合材料电阻率的关系,对其导电机理进行了分析.     

碳纤维/炭黑/丁腈橡胶复合材料导电性能的研究

研究碳纤维/炭黑/丁腈橡胶复合材料的物理性能和导电性能。结果表明：随着碳纤维用量的增大,复合材料的硬度和撕裂强度增大,拉伸强度、定伸应力和拉断伸长率先增大后减小;加入碳纤维后复合材料的导电性能明显提高,碳纤维长度对导电性能影响不大;经浓硝酸处理后的碳纤维与基体材料结合更紧密。     

新型碳纤维复合导电材料的制备以及性能研究

研究了新型碳纤维复合导电材料的制备方法及其导电性能,提出了基于电气相沉积(CVD)法和热解法的新型碳纤维复合导电材料制备方法。采用电化学调节方法和稳态控制方法,进行碳纤维复合导电材料的光生电荷的分离;采用热解法对碳纤维复合导电材料进行热解分离及衍射谱分解;将羧甲基纤维素盐加入到碳纤维复合导电材料的溶解质中,确保制备过程中碳纤维复合导电材料的导电性。对性能进行研究时,通过分析碳纤维复合导电材料的电磁特征,对导电材料的电阻率、材料制备成本、功率损耗及效率进行分析。研究得知,制备的新型碳纤维复合导电材料的导电性能较好,输出稳态性较强。     

碳纤维炭黑导电混凝土的接地特性研究

选取碳纤维和炭黑作为导电相制备导电混凝土,对导电混凝土的导电性能、导电稳定性及力学性能等基本接地特性进行了研究,同时制备导电混凝土接地模块,并研究了其并联接地的降阻效果.研究结果表明:当碳纤维和炭黑掺量均为0.1％、电极面积为10％时,导电混凝土具有良好的导电性能;混凝土电阻率随龄期增长趋于稳定,稳定值为530 Ω·cm左右,电阻率在-40～ 50℃范围内的变化幅度小于5％,导电性能稳定;导电混凝土28 d抗压强度达到35 MPa,抗折强度达到6 MPa,满足接地材料的力学性能要求;采用并联接地的形式敷设导电混凝土接地模块对接地电阻存在集合效应,当敷设间距为30～60 cm时,集合系数小于1.5,并联接地的降阻效果较好.     

导电炭黑和沥青基短切碳纤维对丁腈橡胶性能的影响

研究导电炭黑及其与沥青基短切碳纤维(PCF)并用对丁腈橡胶(NBR)物理、导电和导热性能的影响。结果表明:随着导电炭黑用量增大,导电炭黑/NBR硫化胶的拉伸强度、撕裂强度和热导率均呈增大趋势,而体积电阻率呈阶梯形减小趋势;随着导电炭黑用量减小和PCF用量增大,导电炭黑/PCF/NBR硫化胶的拉伸强度和撕裂强度均明显减小,体积电阻率略有降低,而热导率呈线性增大趋势。     

硅钼棒特种功能导电陶瓷电热元件设计应用

系统地阐述了硅钼棒电热元件工作原理、使用寿命与失效理论、基础应用数据资料，设计公式，安装方法，控制系统配套原理，并与瑞典硅钼棒对比，提出国产元件的特点，根据实验和现场应用数据统计，重新提出了电热体的工作温度范围，该文是现有国产ＧＭ－１７００、ＧＭ－１８００硅钼棒系统的设计应用资料。     

橡胶/碳纤维层压复合导电发热板的电学性能研究

研究了橡胶／碳纤维层压复合导电面状发热板的电学性能。结果表明,硫化过程对导电发热板的电阻有直接影响,不同规格导电发热板的电阻下降率不同;导电发热板具有较发的热循环稳定性,数次热循环后,室温电阻可保持恒定;其伏－安特性、表面温度－功率密度均呈现良好的线性关系;在长期通电使用下,能保持其功率的稳定性。     

多层石墨烯/钢纤维复合砂浆导电性能研究

制备了多层石墨烯(MG)/钢纤维(SF)复合砂浆.利用四电极法测试复合砂浆的电阻率,研究了测试时间、MG和SF掺量、养护龄期和含水量对砂浆电阻率的影响,并通过扫描电镜观察多层石墨烯在砂浆中的微观形貌.结果表明:砂浆外通电流后,内部产生的极化效应导致测试电阻率随导电时间增长而增大,导电填料抗氧化性越强,极化效应越小;砂浆的电阻率随MG和SF掺量的变化出现了渗流现象,运用GEM理论拟合了单掺MG和SF砂浆的电导率与其掺量的关系;MG和SF的协同作用可以增加导电链条、提高导电能力,其中复掺SM比单掺MG电阻率降低21.7％～41.8％;养护龄期越长,砂浆导电能力越差;砂浆干燥状态下的电阻率比湿润状态增加了29％～199％,复掺不同导电填料或增加导电填料含量,都能降低含水量对电阻率的影响.     

复合炭系电热涂料的制备及电热性能研究

为开发出电热性能优良、适用范围较宽、性能稳定的电热涂料,以炭黑、碳纤维、石墨烯为导电填料,丙烯酸乳胶为粘结剂,制备了水性炭系电热涂料.分析了3种导电填料对涂层电热性能的影响,并对涂层的表面温度、体积电阻率、升温速率、附着力、耐热性以及表面形貌进行了测试.结果 表明:在24V电压下,涂层尺寸为60 cm×30 cm,厚度...     

导电炭黑及与沥青基碳纤维并用对NBR导电、导热性能的影响

研究了导电炭黑(VXC72)用量及与沥青基短切碳纤维(CF)并用对丁腈橡胶(NBR)的力学性能及导电、导热性能的影响;并用扫描电镜(SEM)观察填料的分散状态,同时考察了双辊开炼机对CF长径比的剪切破破坏程度。结果表明,随VXC72用量的增加,NBR/VXC72硫化胶的拉伸强度、撕裂强度和导热系数基本呈线性增加;体积电阻率呈阶梯形下降,逾渗阈值为25 phr。随VXC72/CF并用比的增大,NBR硫化胶的拉伸强度和撕裂强度明显降低,体积电阻率略有减小,而导热系数有一定程度的增加。填充20 phr CF时,NBR的导热系数较填充VXC72时提高了约30%。混炼使CF的长径比L/D剧烈降低,由原来的600降低到10-20,这也许是CF对NBR体积电阻率降低幅度不大的主要原因。     

Influence of carbon fiber surface treatments on the structure and properties of conductive carbon fiber/polyethylene films

Effects of carbon fiber (CF) surface modification on the crystalline structure and both electrical and mechanical properties of conductive CF/high‐density polyethylene (HDPE) films were studied. Three different types of surface‐treated CF, epoxy‐sized, unsized, and sized but thermally treated, were considered. It was found that the uniformity of the transcrystalline zone around CF and the overall crystallinity of the polyethylene matrix decreased when epoxy‐sized CF was used. Epoxy‐sized CF caused a significant reduction not only in electrical resistivity and temperature coefficient of resistivity (TCR) but also tensile strength and coefficient of linear thermal expansion (CLTE) of composite films compared with that of unsized or sized CF that was thermally treated. We observed the systematic changes of TCR and CLTE values in accordance with CF surface modification and CF content in composite films. It was concluded that thermal expansion of the polymer matrix is the main reason for the positive TCR of CF/HDPE films. As the most probable reasons for decreased resistivity and strength of the CF/HDPE films with epoxy‐sized CF, the diffusion of epoxy sizing agent into the polyethylene matrix and the formation of loosened semiconductive interphase structure in the film are considered. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2040–2048, 2002; DOI 10.1002/app.10500     

纤维级碳黑导电母粒研究进展

介绍了纤维级碳黑(CB)导电母粒的制备方法,分析了偶联剂用量、分散剂用量、共混体系组成、螺 杆转数和混合时间等对纤维级CB导电母粒导电性的影响。指出提高CB的分散性,降低导电母粒的电阻 值,提高导电母粒的可纺性是开发高品质纤维级CB导电母粒的关键。     

Effect of axial stretching on electrical resistivity of short carbon fibre and carbon black filled conductive rubber composites

The variation of electrical resistivity of carbon black and short carbon fibre (SCF) filled rubber composites was studied against the degree of strain at constant strain rate. It was found that both the degree of strain and strain rate affect the electrical resistivity of the composites. The change in resistivity against the strain and strain rate depends both on the concentration and the type of conductive filler. The incorporation of short carbon fibres (SCF) imparts higher conductivity to the composite than carbon black at the same level of loading. Composites filled with carbon black exhibit better mechanical properties than SCF filled composites. Electrical setting, ie a permanent change in electrical resistivity, was observed during extension–retraction cycles. A good correlation was found between the mechanical response and the electrical response towards strain sensitivity. The results of different experiments are discussed in the light of breakdown and formation of conductive networks in the filled rubber composites. © 2002 Society of Chemical Industry     

EPDM/PP TPV与导电炭黑复合材料导电性的研究

探讨EPDM/PP动态硫化热塑性硫化胶与导电炭黑复合材料导电性的影响因素。结果表明 ,导电炭黑用量(小于 15份 )增大 ,复合材料的体积电阻率显著减小 ,EPDM/PP共混比为 70 /3 0的复合材料减小趋势较缓 ;EPDM/PP共混比从 3 0 /70增大到 5 0 /5 0 ,复合材料的体积电阻率减小 ;EPDM/PP共混比大于 5 0 /5 0后 ,随着共混比增大 ,复合材料的体积电阻率呈增大趋势 ;导电炭黑用量达到 10份后复合材料热老化前后体积电阻率变化不大 ;复合材料具有明显的NTC效应 ,在 180℃的半熔融状态下体积电阻率几乎不变     

An electrical approach to monitor wire and cable thermal oxidation aging condition based on carbon black filled conductive polymer composite

Polymeric materials are widely used as insulation and jacketing materials in wire and cable. When such materials are used for long‐term applications, they undergo thermal oxidation aging in the environment. It is necessary to develop an in situ and nondestructive condition monitoring (CM) method to follow the aging of cable materials. The main objective of this work was to investigate low‐density polyethylene/carbon black (LDPE/CB) conductive polymer composites as potential sensor materials for this purpose. LDPE/CB composites with a carbon black loading below the percolation threshold underwent accelerated thermal oxidation aging experiments. The results indicated that the substantial resistivity decreases of the LDPE/CB composites could be directly related to the increases in volume fraction of the conductive carbon black, which was mainly caused by the mass loss of polymer matrix and sample shrinkage during the thermal oxidation aging process. Compared to existing CM method based on density change, the electrical resistivity is more explicit regarding its absolute changes throughout the thermal oxidation aging. The change in resistivity spanned over four orders of magnitude, whereas the composite density only increased 10%. The results offer strong evidence that resistivity measurements, which reflect property changes under thermal aging conditions, could represent a very useful and nondestructive CM approach as well as a more sensitive method than density CM approach. Crystallinity changes in materials investigated by modulated DSC and TGA measurements indicated deterioration of crystalline regions in polymer during the thermal oxidation aging. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 513–520, 2004     

碳纤维面状发热材料的性能研究

本文研究了碳纤维面状发热材料在热压过程中的电性能变化以及在通电使用过程中电阻变化规律,结果表明：热压过程中,压力,温度及绝缘树脂的固化等对碳纤维面状发热体的电阻性能会产生影响,具有“压实搭接”的特性,压力对电阻起很重要的作用,其次是树脂的熔融固化过程,压制过程中导电纸电阻呈下降趋势,随通电时间的增加,碳纤维面状发热体的电阻趋于稳态化,具有恒功率的特征。碳纤维面状发热板具有远红外辐射特性,其波长在８     

2种导电炭黑复合橡胶体系的导热性能研究

研究了2种导电炭黑复合天然橡胶材料的导热性能随着温度和填料用量的变化规律。结果表明,温度对于导电炭黑复合体系导热性能的影响不大。乙炔黑复合体系具有极高的导热性能,随着炭黑用量的增加,其导热性能优势越加明显。据透射电镜观察填料的微观形态,乙炔黑链枝状结构丰富,聚集体之间以面接触为主,这是其复合橡胶导热性能优异的原因,乙炔黑复合材料的热导率与炭黑体积分数呈线性关系。40B2复合体系的热导率与炭黑体积分数呈现逾渗规律,逾渗阈值在炭黑体积分数8.30%至13.63%之间。据扫描电镜观察复合材料的微观结构,逾渗现象与炭黑在基体内的分布密切相关。为更精确地描述填料用量与复合体系热导率的关系,对2种复合体系的热导率与炭黑的体积分数进行了回归。     

碳纤维增强酚醛树脂/石墨双极板复合材料性能及其界面结合

以碳纤维、酚醛树脂以及石墨为原料通过热模压成型得到一种质子交换膜燃料电池双极板材料。研究了碳纤维的处理方式、含量以及长度对复合材料导电性能与弯曲强度的影响,以及复合材料的界面结合。结果表明经过液相处理10 h的碳纤维能有效引进羟基等官能团,改善材料间的界面结合,增强效果较为明显;复合材料的性能随碳纤维含量的增加,出现先增大后减小的趋势;随着碳纤维长度的增大,复合材料性能出现最大值时的碳纤维含量有下降的趋势;利用经过液相处理10 h,含量为3%、长度为10~15 mm碳纤维对复合材料进行增强时,复合材料的弯曲强度与电导率最佳,其值分别为63.6 MPa1、75.4 S/cm。     

镀银玻璃微珠/硅橡胶导电复合材料导电性能的影响因素

研究镀银玻璃微珠的用量、粒径、表面改性工艺以及导电硅橡胶硫化程度等对镀银玻璃微珠/硅橡胶复合材料导电性能的影响.结果表明,镀银玻璃微珠的粒径越大,复合材料的导电性能越好;湿法预处理和原位改性-分散工艺制得复合材料的导电性能和导电稳定性优于直接干混工艺;导电硅橡胶硫化程度的提高有利于提高材料的导电性能;Payne效应的大小与导电硅橡胶的体积电阻率有很强的相关性.