Enhanced thermally conductive and thermomechanical properties of polymethyl methacrylate (PMMA)/graphene nanoplatelets (GNPs) nanocomposites for radiator of electronic components

In this work, multi-layer hot pressing (MLHP) method was used to prepare the graphene nanoplatelets (GNPs) filled polymethyl methacrylate (PMMA) composites. Effect of GNP content on the viscoelastic behavior and thermomechanical properties of composites was studied via rheometer, scanning electron microscope (SEM), infrared thermal imaging (ITI) and dynamic mechanical thermal analysis (DMTA), etc. According to dynamical rheological testing, thermorheological complexity was clearly displayed at elevated GNP content, based upon flow activation energy (Ea) and time-temperature superposition (TTS) principle. The infrared thermal imaging (ITI) indicated that a filler conductive network was gradually formed with increasing filler content. The average heating rate of the samples increased from 0.74 to 0.92 ◦C/s. The Agari model was found to fairly interpret the variation of thermal conductivity as a function of GNP loading, which agreed well with SEM observation and indicative of the formation of a GNP network structure. Dynamic thermomechanical properties of the composites were heavily influenced by the temperature distributions within the samples. The addition of GNP increased the glass transition temperature of PMMA from 116.7 to 125.9 ◦C, which favored enhanced thermophysical properties of PMMA. The prepared composites in this work showed wonderful mechanical properties even at relatively high temperatures (e.g., having storage modulus of 1.3–1.9 GPa and yielding strength more than 58.0 MPa at 50 ◦C). The current work is practically significant for further expanding the application range of PMMA/GNP nanocomposites.

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