Micro-quartz-reinforced - polyethylene glycol (PEG) composites were fabricated by a simple liquid method. This study reveals the thermomechanical properties of the PEG/quartz composites around its melting transition temperature. The quartz microparticles were prepared from natural silica sand collected from Tanah Laut Pelaihari, South Kalimantan, by magnetic separation, HCl immersion, and water cleaning. Then, quartz powders were heated in various temperatures, i.e., at 500, 1000, and 1200 °C where we found quartz particle sizes of 168, 217, and 249 nm, respectively. PEG/quartz composites with 10 wt% of these sizes were synthesized and a pure PEG sample was also prepared for comparison. The Fourier-transform infra-red spectroscopy (FTIR) and x-ray diffraction (XRD) data showed that there was no additional peak in composite patterns which verified the successful synthesis of the PEG/micro-quartz composites. Meanwhile, the dynamic mechanical analysis (DMA) data and analysis revealed that the maximum storage moduli (G’) and melting transition temperature (T m ) exhibited by the composite with quartz heated at 500 °C, i.e., 610.78 MPa and 53.4 °C, respectively. This value is almost six times of that of pure PEG. In general, quartz particle size shifted the G’and T m to the higher values.