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 (E_a) 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.

在这项工作中，多层热压（MLHP）方法用于制备石墨烯纳米片（GNPs）填充的聚甲基丙烯酸甲酯（PMMA）复合材料。通过流变仪、扫描电子显微镜（SEM）、红外热成像（ITI）和动态机械热分析（DMTA）等研究了GNP含量对复合材料粘弹性行为和热力学性能的影响。 根据动态流变测试，热流变复杂基于流动活化能 ( E _a) 和时间-温度叠加 (TTS) 原理。红外热成像（ITI）表明，随着填料含量的增加，填料导电网络逐渐形成。样品的平均加热速率从 0.74°C/s 增加到 0.92°C/s。该Agari发现模型将热导率的变化合理地解释为 GNP 负载的函数，这与 SEM 观察非常吻合，并表明 GNP 网络结构的形成。复合材料的动态热机械性能受样品内温度分布的影响很大。GNP 的加入使 PMMA 的玻璃化转变温度从 116.7 °C 增加到 125.9 °C，这有利于增强 PMMA 的热物理性能。这项工作中制备的复合材料即使在相对较高的温度下也表现出出色的机械性能（例如，在 50°C 下具有 1.3-1.9 GPa 的储能模量和超过 58.0 MPa 的屈服强度）。目前的工作对于进一步扩大PMMA/GNP纳米复合材料的应用范围具有重要的现实意义。