Covalent and Non-Covalently Coupled Polyester-Inorganic Composite Materials
Document Type
Article
Publication Date
11-1-2002
Department
Polymers and High Performance Materials
Abstract
Two types of organic/inorganic materials were synthesized via sol-gel reactions for tetraethylorthosilicate (TEOS) and organoalkoxsilane monomers in the presence of poly(epsilon-caprolactone) (PCL): (1) non-covalent hybrids, in which PCL and silicate, and PCL and organically modified silicate (ORMOSIL), phases are coupled by non-bonded interactions; (2) covalent hybrids in which triethoxysilane-telechelic PCL molecules form chemical bonds with a sol-gel-derived silicate phase. Chemical structures were verified using FTIR and C-13 NMR spectroscopies and MALDI-TOF mass spectrometry. The constant PCL phase T-g for the silicate-PCL hybrids of (1) implies poor organic/inorganic mixing, but dual-melting endotherms varied with silicate content. TGA revealed significant elevation of degradation onset temperature (T-d) of (1) and suppression of the low temperature chain scission process. No PCL glass transition is seen for ORMOSIL-PCL hybrids where diethoxydimethylsilane is the co-monomer and melting occurs in one step, and there are significant increases in T-d. Likewise, no glass transition is seen when acetoxypropyltrimethoxylsilane is the semi-organic co-monomer, but there are dual-melting endotherms. Triethoxysilane-endcapped PCL was synthesized and its microstructure verified by GPC, MALDI-TOF mass spectrometry, FTIR and NMR spectroscopies. T-g for this telechelic PCL that was reacted with a small fraction of TEOS increases relative to hydroxy-telechelic PCL due to formation of phase-linking Si-O-Si bonds through end groups. The temperature/magnitude of the melting transition decreased upon inorganic modification. TGA showed appreciable increase in T-d relative to PCL and both the high and low temperature degradation processes were hindered. Silane-telechelic PCL films have oxygen permeability values less than that of pure PCL, which is totally attributed to a decrease in diffusion coefficient. (C) 2002 Published by Elsevier Science Ltd.
Publication Title
Polymer
Volume
43
Issue
23
First Page
6101
Last Page
6114
Recommended Citation
Young, S.,
Gemeinhardt, G. C.,
Sherman, J.,
Storey, R. F.,
Mauritz, K.,
Schiraldi, D. A.,
Polyakova, A.,
Hiltner, A.,
Baer, E.
(2002). Covalent and Non-Covalently Coupled Polyester-Inorganic Composite Materials. Polymer, 43(23), 6101-6114.
Available at: https://aquila.usm.edu/fac_pubs/3469