Fabrication of highly thermal conductive epoxy/graphite@La2O3 composite coating with anti‐erosion and mechanical flexibility

Abstract

AbstractHighly thermal conductive polymer coating is delivered from blending thermal conductive fillers, yet sacrificing the mechanical properties, e.g. anti‐erosion, and mechanical flexibility. In this work, highly thermal conductive, mechanical flexible and anti‐erosion epoxy resin (EP)/graphite@La2O3 composite coating was developed via chemically modification. Polydopamine (PDA), γ‐methacryloxypropyltrimethoxysilane and n‐octyltrichlorosilane were used to graft La2O3 particles onto graphite (graphite@La2O3) to enhance interfacial compatibility. Graphite@La2O3 homogeneously dispersed in epoxy forming more thermal conductive pathways and layered structure. In‐plane and cross‐plane thermal conductivity of EP/graphite@La2O3 coating was 2.06 and 1.7 W/(m K), respectively. The temperature of EP/graphite@La2O3 composite coating increased from room temperature to 107.2°C in 60 s while the temperature of EP/graphite coating increased to 59.9°C within 60 s. Furthermore, dispersing graphite@La2O3 into epoxy significantly decreased the weight loss percentage from 0.17 to 0.05 mg/g while the hardness increased from around 7.0–16.77 HV, respectively. The fracture stress and strain of EP/graphite@La2O3 coating was 25 MPa and 6.0%, respectively, which is two times of EP/graphite coating. This is attributed to the chemically grafting La2O3 particles enhanced the interfacial compatibility, homogeneous dispersion and the formation of layered structures in epoxy. This study provides an effective approach to prepare thermal conductive epoxy coatings with multifunctional mechanical properties.Highlights La2O3 nanoparticles grafted on graphite successfully. Mechanical flexibility and anti‐erosion were improved by chemical grafting. Chemical modification improves the interfacial compatibility. The utilization of La2O3 nanoparticles induced the formation of layer structure. Layered structure offsets the stress improving thermal and mechanical property.