新型PTC材料的阻温特性及其热控性能的研究

Study on the Temperature-Resistivity Characteristics and Thermal Control Behavior of Novel PTC Materials

正温度系数(Positive temperature coefficient, PTC)材料是一种电阻随温度变化的热控功能材料,然而,传统的PTC材料由于高室温电阻率以及负温度系数效应而限制了其在电子设备热控领域的应用。本文基于石蜡/乙烯–醋酸乙烯酯共聚物混合基体,利用多壁碳纳米管和炭黑杂化填料的协同效应制备得到具有室温居里点、低室温电阻率和优异电阻正温度效应的新型PTC材料。研究了基体配比、填料含量对室温电阻率和PTC性能的影响,并采用羧甲基纤维素对其负温度系数效应现象进行改善。此外,对新型PTC材料的自适应热控性能进行了研究和分析。研究发现:与普通的电阻加热器相比,PTC加热器具有自适应控温能力,并且在没有任何外部控制系统的条件下可以将被控设备的温度控制在正常工作温度范围内。

Positive temperature coefficient(PTC) material is a kind of thermal control functional material whose resistance changes rapidly with temperature. However, traditional PTC materials have limited their application in the thermal control of electronic equipment due to the high room-temperature resistivity and negative temperature coefficient effect. In this paper, based on the paraffin/ethylene-vinyl acetate copolymer mixed matrix, a new PTC material with room-temperature Curie point, low room-temperature resistivity and excellent PTC effect is prepared based on the synergistic effect of multi-walled carbon nanotubes and carbon black hybrid filler. The effects of matrix ratio and filler content on room temperature resistivity and PTC performance were studied, and the NTC phenomenon was improved by adding carboxy-methyl cellulose. In addition, the adaptive thermal control performance of the new PTC material is researched and analyzed. The results show that, compared with ordinary resistor, PTC heaters have the ability of adaptive temperature control.It can control the temperature of the controlled equipment within the normal operating temperature range without any external control method.