热塑性聚酰亚胺复合材料导热性能研究

Research on Thermal Conductivity of Thermoplastic Polyimide Composites

采用稳态热板法测定铜粉(Cu)填充热塑性聚酰亚胺(TPI)复合材料的热导率,研究了Cu填充量对复合材料的力学性能和导热性能的影响,初步探讨了温度与复合材料热导率的关系。通过扫描电子显微镜观察了复合材料的微观形态。在此基础上,理论计算复合材料热导率。研究表明,Cu填充TPI可有效提高复合材料力学性能和导热性能。当Cu体积分数提高到26%时,填料聚集形成导热链,Cu/TPI复合材料的热导率是纯TPI树脂的3．5倍；当填料含量低于10%时,Maxwell-Eucken模型适合预测复合材料热导率；基于导热链考虑的Y．Agari模型可较好地反映复合材料热导率随填料含量的变化情况；随着温度的升高,Cu/TPI复合材料热导率先增大后趋于平缓。

The thermal conductivity of Cu powder modified thermoplastic polyimide （TPI） was measured via stable thermal plate method. The effects of filler content on the mechanical properties and thermal conductivity has been investigated, the relation between temperature and thermal conductivity of Cu/TPI composites was discussed. The micro morphology of composite was observed using SEM, and its thermal conductivity was calculated followed the models. It was indicated that the filling of polyimide with Cu could obviously improve the mechanical properties and thermal conductivity of the modified composites. Its conductivity reached 3.5 times that of neat PI while filling 26 % Cu and thermal conductive chain was developed effectively. It was also found that the Maxwell-Eucken model was only suitable for composite with low content of Cu. Considering the thermal conductivity chain, Y. Agari model can reflect the change of the thermal conductivity with filler content increase favorably. The thermal conductivity of the composite increased with elevating temperature, and leveled off at some point.