decreasing and increasing electrical resistivity of materials by increasing temperature named Negative thermal coefficient (NTC) and positive thermal coefficient (PTC), respectively, are two critical properties for thermistor materials. In this research, the PTC/NTC behavior of conductive adhesive are investigated by performing two tests: Hall Effect and Joule heating tests. In Hall Effect, the temperature increases by the heating element, while in Joule Heating, the ohmic resistance of adhesive leads to increasing the temperature. The adhesives are made of polyvinyl acetate as binder and 40, 50, 60, and 70 wt.% Graphite (G) as filler. Characterizations include the lap-shear strength, electrical conductivity, and Archimedes porosimetry tests, as well as Fourier-transform infrared spectroscopy, Raman spectroscopy, and Scanning Electron Microscopy analysis to investigate the change of chemical composition and crystallinity of carbon adhesives before and after the Joule Heating test. There are little information about the physical mechanisms of NTC/PTC behavior in literature. NTC behavior of carbon adhesives is interpreted by two physical mechanisms. The first is based on increasing temperature on the regions named hot spots, thereby decomposing polymer to amorphous Carbon (validate by experimental analyses) and the second, decreasing polymer viscosity and, consequently, s rotating and aligning the G particles, validated by mathematical modeling.

通过分别升高温度（称为负热系数（NTC）和正热系数（PTC））来降低和增加材料的电阻率是热敏电阻材料的两个关键特性。在这项研究中，通过执行两个测试来研究导电胶的PTC / NTC行为：霍尔效应测试和焦耳热测试。在霍尔效应中，温度通过加热元件升高，而在焦耳加热中，粘合剂的欧姆电阻导致温度升高。该粘合剂由聚乙酸乙烯酯作为粘合剂和40、50、60和70重量％的石墨（G）作为填料制成。表征包括搭接剪切强度，电导率和阿基米德孔隙率测试，以及傅立叶变换红外光谱，拉曼光谱，和扫描电子显微镜分析来研究焦耳加热测试前后碳粘合剂的化学成分和结晶度的变化。文献中关于NTC / PTC行为的物理机制的信息很少。碳粘合剂的NTC行为可以通过两种物理机制来解释。第一种是基于升高的热点区域的温度，从而将聚合物分解为无定形碳（通过实验分析验证），第二种是降低聚合物粘度，从而旋转和排列G粒子，并通过数学建模进行了验证。文献中关于NTC / PTC行为的物理机制的信息很少。碳粘合剂的NTC行为可以通过两种物理机制来解释。第一种是基于升高的热点区域温度，从而将聚合物分解为无定形碳（通过实验分析验证），第二种是降低聚合物粘度，从而旋转和排列G颗粒，并通过数学建模进行了验证。文献中关于NTC / PTC行为的物理机制的信息很少。碳粘合剂的NTC行为可以通过两种物理机制来解释。第一种是基于升高的热点区域温度，从而将聚合物分解为无定形碳（通过实验分析验证），第二种是降低聚合物粘度，从而旋转和排列G颗粒，并通过数学建模进行了验证。