炭黑/十四醇基低居里温度PTC复合材料的热控性能  

Thermal Control Performances of Carbon Black/Tetradecanol-Based PTC Composites with Low Curie Temperatures

作　　者：董畅 刘欢欢 李杰 王跃毅 徐玲 雷军[1] 李忠明[1] 鄢定祥[1,2] DONG Chang;LIU Huanhuan;LI Jie;WANG Yueyi;XU Ling;LEI Jun;LI Zhongming;YAN Dingxiang(State Key Laboratory of Polymer Materials Engineering,School of Polymer Science and Engineering,Sichuan University,Chengdu 610045,China;Sichuan Key Laboratory of Robotic Satellites,School of Air and Space Science and Engineering,Sichuan University,Chengdu 610045,China)

机构地区：[1]四川大学高分子科学与工程学院,高分子材料工程国家重点实验室,四川成都610045 [2]四川大学空天科学与工程学院,机器人卫星四川省重点实验室,四川成都610045

出　　处：《塑料工业》2024年第9期45-51,共7页China Plastics Industry

摘　　要：具有正温度系数(PTC)的导电高分子复合材料组成的自控温热敏电阻,可代替普通电阻用于加热器件,在电子设备主动控温方面具有很大优势。然而,现有PTC复合材料的居里温度(>60℃)普遍较高,在常温段工作电子设备的控温方面应用受到限制。基于此,本文以低相变温度的十四醇为相变基体,炭黑(CB)为导电粒子,乙烯-醋酸乙烯酯共聚物(EVA)为骨架,通过熔融共混和模压成型方法制备了具有低居里温度(35℃)的PTC复合材料,探究了CB质量分数对复合材料电性能和PTC性能的影响。结果显示,当CB质量分数为12%时,复合材料室温电阻率为0.5Ω·m,PTC强度高达7.0,且未出现负温度系数(NTC)效应。通过扫描电子显微镜观察了复合材料微观结构,并将复合材料电性能变化与微观结构相关联,解释了复合材料获得优异PTC性能的内在机理。此外,研究了PTC复合材料的热控行为,发现与普通电阻加热器相比,PTC复合材料作为电阻加热器具有自适应控温能力,无需外部控制系统条件下可将受控器件温度控制在常温段温度范围内并保持平衡。Self-regulating thermistors composed of conductive polymer composites exhibiting positive temperature coefficients(PTC)could replace resistors in heating devices and provide significant advantages in the active temperature control of electronic devices.However,the Curie temperatures(>60℃)of existing PTC composites are generally high,limiting their applications in the temperature control for electronic devices operating at room temperature.This study prepared PTC composites with a low Curie temperature(35℃)by the melt blending and molding methods.Tetradecanol with a low phase transition temperature was used as the phase transition matrix,carbon black(CB)was used as the conductive particles,and ethylene vinyl acetate copolymer(EVA)was used as the backbone.The effects of CB mass fractions on the electrical and PTC properties of the composites were investigated.The results indicate that the composite with a CB mass fraction of 12%exhibits a room temperature electrical resistivity of 0.5Ω·m,a PTC strength of 7.0,and the negative temperature coefficient(NTC)effect is not observed.The microstructures of the composites were analyzed using scanning electron microscopy.The changes in electrical properties were correlated with the microstructures,explaining the intrinsic mechanisms behind the composite excellent PTC properties.Additionally,the thermal control behaviors of the PTC composites were investigated.The results indicate that,compared with the ordinary resistance heaters,the PTC composites possess a self-adaptive temperature control capability.The temperature of the controlled device could be maintained within the room temperature range and kept in equilibrium without an external control system.

关 键 词：正温度系数复合材料 居里温度 室温电阻率 正温度系数性能 自适应控温能力 乙烯-醋酸乙烯酯 

分 类 号：TQ325.5[化学工程—合成树脂塑料工业]