Khadim Mboup

This study presents the development of polylactide (PLA)-based biocomposites reinforced with 5, 10, and 15 wt.% polymethylsilsesquioxane (PMSQ) microparticles. The materials were prepared by melt blending followed by injection molding to evaluate the effect of PMSQ content on the morphological, thermal, mechanical, thermomechanical, rheological, and thermal conductivity properties of polylactic acid (PLA). Scanning electron microscopy (SEM) revealed a relatively uniform dispersion of PMSQ particles, especially at low filler content (up to 5 wt.%). Differential scanning calorimetry (DSC) showed that PMSQ incorporation did not significantly affect the melting temperature of PLA, while the cold crystallization temperature decreased by 14 °C combined with a higher crystallinity level. Thermogravimetric analysis (TGA) showed a slight improvement in thermal stability, with higher residual mass as PMSQ content increased. Mechanical tests showed a 7.4% reduction in Young's modulus and a 20% loss of tensile strength for the biocomposite containing 15 wt.% PMSQ due to limited interfacial stress transfer and particle agglomeration. However, dynamic mechanical analysis showed that low PMSQ concentration (5 wt.%) increased the storage modulus by 15% at 35 °C and slightly increased the glass transition temperature by up to 2 °C. Rheological analyses revealed higher storage modulus, loss modulus, and complex viscosity with increasing PMSQ content. Additionally, the presence of PMSQ enhanced the thermal conductivity of PLA by up to 23% at 75 °C. Overall, PLA/PMSQ biocomposites, especially at low PMSQ content, showed improved thermomechanical stability and thermal conductivity, suggesting their potential use in thermoforming applications.

This study investigates the development of polypropylene (PP) composites reinforced with polymethylsilsesquioxane (PMSQ) microparticles at varying concentrations (0, 5, 10, and 15 wt%). The composites were produced via melt blending to evaluate the effect of PMSQ on their thermal, thermo-mechanical, and electrical properties. Differential scanning calorimetry (DSC) revealed slight changes in melting temperature, crystallization temperature, and crystallinity level with PMSQ addition. Thermogravimetric analysis (TGA) showed improved thermal stability, with residual mass increasing proportionally to PMSQ content. Dynamic mechanical analysis (DMA) indicated enhanced stiffness, as showed by a 32% increasing in storage modulus at 15 wt% PMSQ. However, the glass transition temperature remained unchanged. The thermal conductivity was improved by 20% with 10 wt% PMSQ, coupled with a tenfold increase in electrical resistivity. These results suggest that PP/PMSQ composites are promising candidates for applications requiring efficient heat dissipation and high electrical insulation, such as in electrical and electronic systems.