title: The role of polyhedral oligomeric silsesquioxane on the thermo-mechanical properties of polyoxymethylene copolymer based nanocomposites.
abstract: Hybrid nanocomposites formed with polyoxymethylene copolymer (POM) and different types of polyhedral oligomeric silsesquioxane (POSS) nanoparticles have been investigated. Four types of POSS have been studied in contents of 2.5% and 5% wt. The POSS were incorporated by direct melt-mixing. Traditionally copolymerization has been the preferred approach used to form polymer-POSS nanocomposites because the possibility of immiscibility with the polymer matrix is reduced. However, melt-blended POSS nanoparticles can also improve the thermo-mechanical properties of some polymers. Different morphologies were obtained depending on the type of POSS used. GI-POSS and O-POSS exhibit sub-micron or micron-sized inclusions which size increased with increasing percentages of POSS added. On the other hand, both G-POSS and T-POSS appeared to be uniformly dispersed in the POM matrix probably at a molecular level. This is a clear indication of miscibility between these systems and also that POSS solubility in POM is higher than 5 wt%. G-POSS improved the thermal stability of the systems. However, the melting temperature and the modulus of elasticity were found to slightly decrease. On the other hand, the O-POSS produced the opposite effect in the matrix. Finally T-POSS filled systems do not yield important variations in regard to polymethylene oxide properties although interaction between T-POSS and the matrix was detected.
authors.affiliation: Centre Català del Plastic, Universitat Politècnica de Catalunya, C/Colom 114, 08222 Terrassa, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Illescas
authors.forename: A
authors.initials: A
authors.lastname: Arostegui
authors.forename: D A
authors.initials: DA
authors.lastname: Schiraldi
authors.forename: M S
authors.initials: MS
authors.lastname: Sánchez-Soto
authors.forename: J I
authors.initials: JI
authors.lastname: Velasco