Polymer nanocomposites are gaining considerable industrial interest with applications in consumer products, transportation and aerospace, pharmaceutical, and construction industries. Of particular interest is a group of nanosized inorganic-organic hybrid materials known as Polyhedral Oligomeric Silsesquioxanes (POSS). Recently, POSS have been exploited as nanoparticle fillers for polymers due to their low cost, chemical stability, compatibility and ease of functionality. When chemically or physically blended with a variety of polymers, POSS molecules can enhance the physical and mechanical properties of the host polymer. Cubic POSS molecules, having the nomenclature (RSiO3/2)8, are frequently employed as nanoparticle fillers where a silicon-oxygen cubic cage core can be octafunctionalised with pendant R groups attached at the corners of the cube. The pendant groups are often hydrocarbon chains or other similar organic derivatives which allows compatiblisation with the polymer matrix. We have synthesised a series of unique polyethylene‒polyhedral oligomeric silsesquioxanes (PE-POSS) nanocomposite blends where the POSS pendant groups are long linear alkyl-chains, ranging from C8 to C18. Time-resolved Small- and Wide-Angle X-Ray scattering (SAXS/WAXS), microscopy and thermal techniques were used to elucidate the affect that POSS and its pendant groups have on the dispersal and crystallization kinetics of the host polymer. Depending on the chemical structure of the POSS molecules, their miscibility and dispersal in the host polymer is seen to increase with the increasing alkyl-chain length of the pendant groups. This suggests increased compatibility and interaction with the host polymer chains. Some POSS molecules are found to act as nucleating agents increasing the crystallinity, crystallization kinetics and influencing the final lamellar morphology, but do not compromise the melting and crystallization temperatures of the host polymer.

Investigating the crystallization kinetics and structure development of hybrid polymer-nanocomposite materials using SAXS/WAXS and thermal techniques

249th National Meeting (2015)

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