Influence of branched or un-branched alkyl substitutes of POSS on morphology, thermal and mechanical properties of polyethylene

Organic-inorganic hybrids comprising octakis(dimethylsiloxy)octasilsesquioxanes with linear (POSSl) and branched C5 substitutes (POSSb) and low density polyethylene (PE) were prepared by a melt mixing method. The influence of both structure and concentration of POSSs on the morphological, thermal and mechanical characteristics of PE/POSSs nanocomposites was investigated. QNM analysis showed a similar distribution of POSS fillers regardless their structure. XRD and DSC results indicated that the addition of POSS does not induce changes in the crystal structure of PE but influences the amorphous peak characteristics and crystallinity degree. TGA analysis revealed that the presence of POSS strongly improves the thermo-oxidative stability of PE, the thermal stabilization effect being nearly the same for both POSS types. Mechanical characterization showed significant improvement of tensile strength and elongation properties of PE/POSS nanocomposites as compared to neat PE, the enhancement of mechanical properties being more pronounced for nanocomposite containing POSSb.