氧化铝/聚氨酯导热胶的动态流变行为与性能  

Dynamic Rheological Behavior and Properties of Al_(2)O_(3)/Polyurethane Thermally Conductive Adhesives

作　　者：王志凯 朱友志 朱芸 王贵友[1] WANG Zhikai;ZHU Youzhi;ZHU Yun;WANG Guiyou(Shanghai Key Laboratory of Advanced Polymeric Materials,School of Materials Science and Engineering,East China University of Science and Technology,Shanghai 200237,China)

机构地区：[1]华东理工大学材料科学与工程学院,上海市先进聚合物材料重点实验室,上海200237

出　　处：《功能高分子学报》2024年第6期481-490,共10页Journal of Functional Polymers

基　　金：镇江贝斯特新材料股份有限公司资助项目。

摘　　要：制备了不同氧化铝载荷(w(Al_(2)O_(3)))和粒径的氧化铝/蓖麻油(Al_(2)O_(3)/Castor oil)悬浮液、氧化铝/聚氨酯(Al_(2)O_(3)/PU)预聚体悬浮液和氧化铝/聚氨酯(Al_(2)O_(3)/PU)导热胶。对两种悬浮液动态流变行为进行了研究,并采用两相模型对线性黏弹数据进行拟合和定量分析;同时考察了Al_(2)O_(3)载荷和粒径变化对导热胶搭接剪切强度和导热性能的影响,探究了流变性能-结构-性能三者之间的关联。结果表明:当Al_(2)O_(3)载荷为80%以上时,悬浮液的储能模量(G′)-频率(ω)曲线出现第二平台区,对应逾渗网络的形成;应变放大因子和黏弹贡献因子均随Al_(2)O_(3)体积分数(φ)的增加而增大,凝胶点随φ增加向低频区移动;固定Al_(2)O_(3)载荷为80%,Al_(2)O_(3)粒径越小对悬浮液的黏弹性贡献越大。当Al_(2)O_(3)粒径为70μm、载荷为80%时,Al_(2)O_(3)/PU导热胶对铝合金和不锈钢的搭接剪切强度分别达到了21.38、25.85 MPa,热导率最高为1.38 W/(m·K),这与Al_(2)O_(3)-PU相界面的减小和导热逾渗网络的形成有关。Al_(2)O_(3)/Castor oil,Al_(2)O_(3)/polyurethane(PU)prepolymer suspensions,and Al_(2)O_(3)/PU thermally conductive adhesives with different loadings(w(Al_(2)O_(3)))and particle sizes of Al_(2)O_(3) were prepared.The dynamic rheological behavior of the suspensions was characterized,and the linear viscoelastic data were fitted and quantitatively analyzed by using a two-phase model.At the same time,the effects of the loading and particle size of Al_(2)O_(3) on the lap shear strength and thermal conductivity of the thermally conductive adhesives were investigated.The correlation among rheological property,structure and property was explored.Results show that when w(Al_(2)O_(3))is more than 80%,the second plateau region appears in the storage modulus(G')versus frequency(ω)curve,which corresponds to the formation of the percolation network.The strain amplification factor and the viscoelastic contribution factor increase,while the gel point moves towards the low-frequency region with the increase of volume fraction of Al_(2)O_(3)(φ).With a fixed loading of 80%,the viscoelastic contribution to the suspension increases as the Al_(2)O_(3) particle size decrease With a particle size of 70μm and 80%loading of Al_(2)O_(3),the lap shear strength of Al_(2)O_(3)/PU thermally conductive adhesives on aluminum alloy and stainless steel reaches 21.38 MPa and 25.85 MPa,respectively,and the thermal conductivity is the highest at 1.38 W/(m·K),which is related to the decreased Al_(2)O_(3)-PU phase interface and the formation of thermally conductive percolation network.

关 键 词：聚氨酯 氧化铝 动态流变行为 两相模型 搭接剪切强度 热导率 

分 类 号：TQ436[化学工程]