The Influence of Polyhedral Oligomeric Silsequioxanes on Domain Microstructure in Polyurethane Elastomers

Autor: Krzysztof Pielichowski, Brian P. Mayer, Albert Loui, James P. Lewicki, Bartlomiej Janowski, Robert S. Maxwell, Stephen J. Harley
Rok vydání: 2013
Předmět:
Zdroj: Silicon. 5:205-212
ISSN: 1876-9918
1876-990X
DOI: 10.1007/s12633-013-9147-1
Popis: The influence of polyhedral oligomeric silsequioxanes (POSS) as covalently bound hybrid physical property modifiers on the segmental dynamics and morphology of segmented polyurethane elastomers has been studied by solid-state magic sandwich echo nuclear magnetic resonance (MSE-NMR), differential scanning calorimetry (DSC) and atomic force microscopy (AFM). A model system has been synthesized which incorporates diol functionalized POSS over a range of loadings into the hard-block of a methylene di-isocyanate - butane diol - poly(tetramethylene glycol) (MDI-BDO-PTMG) segmented PU elastomer. MSE-NMR has been employed to probe the segmental dynamics of the PU system as a function of POSS loading and it has been demonstrated that low levels of POSS as a substitute chain extender, both rigidify the hard-block phase of the PU and significantly alter both the phase morphology, mixing and structure of the inter-phase domains. These observations are supported by more classical AFM and DSC morphological characterization of the POSS-PU hybrid systems which show significant re-structuring of the phase domain structure of the PU and ordering of the crystalline hard-block domains. This work demonstrates the application of a multi-scaled experimental approach towards understanding the effects of three-dimensional, nano-scale cage moieties on the already complex phase structure of segmented polyurethanes. Through these efforts, new insight has been gained into the mechanisms by which low levels of a nano-material such as a cubic sesquioxane, can impact the phase separation and segmental dynamics of block ter-polymer polyurethanes.
Databáze: OpenAIRE
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