Naslov
Influence of Epoxy-Amine Ratio on Degradation of Epoxy-Silica Hybrid Materials

Autori
Macan, Jelena ; Ivanković, Marica

Vrsta, podvrsta i kategorija rada
Poglavlja u knjigama, znanstveni

Knjiga
Progress in Polymer Degradation and Stability Research

Urednik/ci
Moeller, Herbert W.

Izdavač
Nova Science Publishers

Grad
Haupauge (NY)

Godina
2008

Raspon stranica
209-231

ISBN
1-60021-828-8

Ključne riječi
epoxy, organic-inorganic hybrid materials, degradation

Sažetak
Organic-inorganic hybrid materials are nanostructured materials whose inorganic phase is synthesised by sol-gel process. Polymer based hybrid materials contain inorganic phase dispersed in polymer matrix on a nanometric level. Sol-gel process is particularly suitable for preparation of these materials since the inorganic phase is formed at low temperatures, preserving polymeric matrix from degradation during synthesis. Similarly to other polymeric nanocomposites, organic-inorganic hybrid materials show improved thermal stability compared to unmodified polymeric materials. This can be ascribed to poorer diffusion of degradation products through the stable inorganic phase, and also to stabilising effect of silicon. Organic-inorganic hybrid materials based on diglycidyl ether of bisphenol A (DGEBA) and 3-glycidyloxypropyltrimethoxysilane (GLYMO) were prepared, with a poly(oxypropylene) diamine, Jeffamine D230, as a crosslinking agent. Previous research on these hybrid materials has shown that epoxy groups of GLYMO are able to react only with primary hydrogen atoms in amine groups of D230. Therefore two sets of hybrids were prepared, one with stoichiometric quantity of amine (1 mole of amine groups per 2 moles of epoxy groups) and the other with doubled quantity of amine in relation to epoxy groups of GLYMO. Thermal degradation of all prepared hybrid materials, as well as unmodified epoxy resin, was investigated by combined differential thermal analysis and thermogravimetric analysis (DTA-TGA) in inert atmosphere of nitrogen and oxidative atmosphere of air. It was determined that although increased content of amine improves conversion of epoxy groups and therefore degree of organic crosslinking in the hybrid materials, their overall thermal stability is decreased. Hybrid materials with increased amine content have lower degradation onset temperatures and lower residue at 1000 °C. This can be attributed to unreacted amine groups that remain in the material, and to lower density of inorganic network. Atmosphere has very little influence on the main degradation step, which probably proceeds in self-generated atmosphere.

Izvorni jezik
Engleski

Znanstvena područja
Kemijsko inženjerstvo, Temeljne tehničke znanosti

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