Titre du document / Document title
Crystallization and morphology study of polyhedral oligomeric silsesquioxane (POSS)/polysiloxane elastomer composites prepared by melt blending
Auteur(s) / Author(s)
LING LIU (1) ;
MING TIAN (1) ;
WEI ZHANG (1) ;
LIQUN ZHANG (1) ;
MARK James E. (2) ;
Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)
(1) The Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, CHINE
(2) Department of Chemistry and Polymer Research Center, The University of Cincinnati, Cincinnati, OH 45221, ETATS-UNIS
Résumé / Abstract
Composites of poly(methylvinylsiloxane) ("silicone") elastomers with polyhedral oligomeric silsesquioxane (POSS) were prepared by melt blending. One goal was to establish conditions that would lead to morphologies different from that of a simple filler dispersed in a polymer matrix for the purposes of reinforcement. To this end, the study focused on the dispersion and state of POSS in silicone rubber blends as determined by X-ray diffraction (XRD), polarizing optical microscopy (POM), scanning electron microscopy (SEM), and analysis using a rubber processing analyzer (RPA). Of particular interest were the thermal stability of POSS macromers, and the effects of mixing temperature and subsequent vulcanization of the polysiloxane. The results showed that highly crystalline POSS macromers could undergo condensation reactions at 230 °C in air, leading to partially amorphous structures. Also, POSS crystals apparently dissolved in the polysiloxane at high temperatures and POSS crystals with hexahedral or flake-like structures recrystallized out upon cooling. Both crystallites and POSS molecules co-existed in these blends, with the amount of dispersed molecular POSS being increased at higher temperatures. The POSS molecules exhibited some physical interactions with the polysiloxane uncross-linked chains, but phase separation was induced by the process of cross-linking. In this curing process, POSS molecules could react with the polysiloxane, resulting in decreases in cross-link density. The original POSS crystals could also be dissolved in the polysiloxane during the initial curing stages, but recrystallization upon cooling gave regenerated crystals that were roughly spherical.
Revue / Journal Title
Polymer
ISSN
0032-3861
CODEN POLMAG
Source / Source
2007, vol. 48, n
o11, pp. 3201-3212 [12 page(s) (article)] (33 ref.)
Langue / Language
Anglais
Editeur / Publisher
Elsevier, Kidlington, ROYAUME-UNI
(1960)
(Revue)
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Localisation / Location
INIST-CNRS, Cote INIST : 11463, 35400016221344.0200
Nº notice refdoc (ud4) : 18753085
