One-step exfoliation and deprotonation of ANF/BNNS suspension for constructing 3D vertically aligned skeleton in epoxy-based thermal management composites  

作　　者：HAN GaoJie XUE PeiWen CAI ZhengHao FENG YueZhan LIU ChunTai SHEN ChangYu 

机构地区：[1]Key Laboratory of Materials Processing and Mold Ministry of Education,National Engineering Research Center for Advanced Polymer Processing Technology,Zhengzhou University,Zhengzhou450002,China

出　　处：《Science China(Technological Sciences)》2022年第11期2675-2686,共12页中国科学（技术科学英文版）

基　　金：supported by the National Key R&D Program of China(Grant No. 2019YFA0706802);the National Natural Science Foundation of China (Grant Nos. 51903223 and 12072325);the Natural Science Foundation of Henan Province (Grant No. 222300420541);the Key Technologies R&D Program of Henan Province (Grant No. 212102210302);。

摘　　要：Two-dimensional(2D)boron nitride nanosheet(BNNS)is promising in polymer-based thermal management materials(TMMs)by pre-constructing three-dimensional(3D)thermally conductive skeleton,but it yet suffers from the challenges of higheffective exfoliation and affinitive compatibility with matrix.In this work,we developed a one-step exfoliation and deprotonation approach by the high-effective ball milling technique to prepare aramid nanofiber(ANF)/BNNS suspension.Under the strong collision/shear effect of ball-milling,micron-level h BN sheets were exfoliated into smaller and thinner BNNS with edge functional groups,meanwhile,poly-p-phenylene terephthalamide(PPTA)fibers were split into ANF by dissociating the intermolecular hydrogen bonds.More importantly,both the exfoliation and deprotonation could be accelerated by each other to achieve a 100%yield of ANF/BNNS suspension with strong hydrogen/covalent bonding interactions between them.Subsequently,the prepared ANF/BNNS suspension was used to construct 3D vertically aligned ANF/BNNS skeleton by the unidirectional freezing method.The obtained epoxy-based composite(EP/ANF/BNNS)revealed excellent thermal conductivity of 2.41 W m^(-1)K^(-1) at 14.9 vol%BNNS loading due to the vertically oriented heat conduction paths and low interfacial thermal resistance in the skeleton.Moreover,EP/ANF/BNNS composite showed high thermal stability and extraordinary fire retardancy with dramatically decreased heat release rate(265 W g^(-1)) and total heat release(20.6 kJ g^(-1)).Therefore,this work demonstrates a high-efficient one-step ball-milling exfoliation and deprotonation technique for preparing ANF/BNNS suspension,which reveals an enormous potential in preparing advanced TMMs by constructing 3D thermally conductive skeletons.

关 键 词：boron nitride nanosheet aramid nanofiber ball milling EXFOLIATION thermal management composites 

分 类 号：TB332[一般工业技术—材料科学与工程]