title: The stability of polysiloxanes incorporating nano-scale physical property modifiers.
abstract: Reported here is the synthesis and subsequent characterization of the physical and chemical properties of novel polysiloxane elastomers modified with a series of polyhedraloligomericsilsequioxane (POSS) molecular silicas. The physical properties of the formulated nanocomposite systems have been characterized with a combination of dynamic mechanical analysis (DMA), broadband dielectric spectroscopy (BDS) and confocal Raman microscopy. The results of the physical property characterization demonstrate that the incorporation of low levels (1-4% by wt.) of POSS particles into the polysiloxane network leads to significant improvements in the mechanical properties of the elastomer and significantly alters the motional chain dynamics of the system as a whole. The results of studies performed to assess the long-term stability of these novel nanocomposite systems have demonstrated that POSS physical property modifiers can significantly alter the thermal stability of polysiloxane elastomers. Physically dispersed POSS has also been shown in some cases to be both mobile and disruptive within the polysiloxane networks, agglomerating into domains on a micron scale and migrating to the surface of the elastomers. This work demonstrates both the potential of POSS nanoparticles as physical property modifiers and describes the effects of POSS on the physical and chemical stability of polysiloxane systems.
authors.affiliation: Deptartment of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G11XL, UK.
authors.forename: James P
authors.initials: JP
authors.lastname: Lewicki
authors.affiliation: Materials Science and Research Division, Atomic Weapons Establishment, Aldermaston, Reading RG7 4PR, UK.
authors.forename: Mogon
authors.initials: M
authors.lastname: Patel
authors.affiliation: Materials Science and Research Division, Atomic Weapons Establishment, Aldermaston, Reading RG7 4PR, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Morrell
authors.affiliation: Deptartment of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G11XL, UK.
authors.forename: John
authors.initials: J
authors.lastname: Liggat
authors.affiliation: Materials Science and Research Division, Atomic Weapons Establishment, Aldermaston, Reading RG7 4PR, UK.
authors.forename: Julian
authors.initials: J
authors.lastname: Murphy
authors.affiliation: Deptartment of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G11XL, UK.
authors.forename: Richard
authors.initials: R
authors.lastname: Pethrick
keywords: POSS; dimethylsiloxane; nanocomposite; physical property modifiers