膨胀石墨“开口封装”聚乙二醇构筑连续导热相的热界面材料研究  

Thermal interface material with continuous thermal conductive phase constructed by expanded graphite“open encapsulation”polyethylene glycol

作　　者：刘长青 于伟[3] 李一凡[3] 范俊辉 袁文华 曹炳阳 LIU ChangQing;YU Wei;LI YiFan;FAN JunHui;YUAN WenHua;CAO BingYang(School of Mechanical and Energy Engineering,Shaoyang University,Shaoyang 422000,China;Key Laboratory of Hunan Province for Efficient Power System and Intelligent Manufacturing,Shaoyang University,Shaoyang 422000,China;School of Energy and Materials,Shanghai Polytechnic University,Shanghai 201209,China;Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Department of Engineering Mechanics,Tsinghua University,Beijing 100084,China)

机构地区：[1]邵阳学院机械与能源工程学院,邵阳422000 [2]邵阳学院高效动力系统及智能制造湖南省重点实验室,邵阳422000 [3]上海第二工业大学能源与材料学院,上海201209 [4]清华大学工程力学系热科学与动力工程教育部重点实验室,北京100084

出　　处：《中国科学:技术科学》2025年第2期233-244,共12页Scientia Sinica(Technologica)

基　　金：国家自然科学基金(批准号:52276074,52076141);上海浦东产学研合作科技发展基金(编号:PKX2023-W04);湖南省自然科学基金(编号:2023JJ50040);湖南省教育厅重点项目(编号:23A0540)资助。

摘　　要：相变型热界面材料是强化高功率器件散热的一个重要研究方向,但其面临防止泄漏和降低接触热阻共存的一对矛盾问题.针对该问题,本文提出高导热的多孔状膨胀石墨“开口封装”聚乙二醇的新方法.基于膨胀石墨的高导热能力和多孔结构特性,添加少量的膨胀石墨可以有效防止聚乙二醇的泄漏,并保持低接触热阻(TCR),同时容易实现首尾相连构筑连续导热相而显著提高热导率.本文系统研究了复合热界面材料的热性能,结果表明:膨胀石墨/聚乙二醇热界面材料的热导率随膨胀石墨填充质量增大而提高,当膨胀石墨质量分数为3.23 wt%时,复合热界面材料热导率高达3.24 W/(m K),提高了575%;TCR随温度升高而降低,当温度达到聚乙二醇的相变点时,发生急剧降低(从1.5×10^(−3)~2.5×10^(−3)℃m^(2)/W降低至约1.0×10^(-5)℃m^(2)/W);复合相变材料应用于定温加热板散热过程,表面温度变化结果证实接触面处温升诱导其逐渐转变为熔融态,导致接触热阻发生显著降低.该方法为推进兼具高导热、形状稳定和低接触热阻相变型热界面材料的实际应用提供了一种方案.Phase change thermal interface materials are an important research object for enhancing the heat dissipation of high-power devices,but they suffer a contradictory challenge of how to prevent leakage and reduce thermal contact resistance(TCR).In response to this issue,this paper proposes a new method for“open encapsulation”of polyethylene glycol by means of the high-thermal-conductivity porous expanded graphite.Based on the high thermal conductivity and porous structure characteristics,adding a small amount of expanded graphite can effectively prevent the leakage of polyethylene glycol,maintain low TCR,and easily achieve end-to-end connection to build a continuous thermal conductive phase,notably improving thermal conductivity.The thermal properties of composite thermal interface materials are systematically studied.The results demonstrate that the thermal conductivity of the expanded graphite/polyethylene glycol thermal interface material increases with the filling mass of expanded graphite.When the mass fraction of expanded graphite is 3.23 wt%,the thermal conductivity of the composite thermal interface material is increased 575%and reaches 3.24 W/(m K).TCR decreases with increasing temperature,with a sharp decrease(from 1.5×10^(−3)–2.5×10^(−3)℃m^(2)/W to~1.0×10^(−5)℃m^(2)/W)occurring when the temperature reaches the phase transition point of polyethylene glycol.The use of composite phase change materials in the heat dissipation process of a constant temperature heating plate confirms that temperature rise at the contact surface gradually induces to transform into a molten state,notably decreasing TCR.This method provides a solution for facilitating the practical application of phase change thermal interface materials that combine high thermal conductivity,shape stability,and low TCR.

关 键 词：热界面材料 接触热阻 开口封装 相变材料 连续导热相 

分 类 号：TB34[一般工业技术—材料科学与工程]