Title

Investigation of Pre-Reaction and Cure Temperature on Multiscale Dispersion in POSS-Epoxy Nanocomposites

Document Type

Article

Publication Date

9-1-2012

Department

Polymers and High Performance Materials

Abstract

Dispersion of monoamine-functionalized polyhedral oligomeric silsesquioxane (POSS) in an epoxy network was improved by pre-reacting the POSS with excess epoxide and employing a high-temperature cure. DGEBA/DDS networks were formulated with 2.5 and 10 wt% POSS. In some samples, POSS was pre-reacted with DGEBA. The hybrid materials were characterized via SEM, TEM, and DMA. The microscopy and DMA results evinced a multiscale morphology with POSS-rich glassy domains, nano- and microcrystallites, and crystallite agglomerations. For a loading level of 2.5 wt% POSS, the sample with unmodified POSS cured at 125 degrees C had inorganic crystallites on the order of 1-5 mu m and agglomerations on the order of 10-20 mu m, whereas the sample with pre-reacted POSS cured at 180 degrees C had near-perfect dispersion with no agglomerations and very few POSS crystallites. The 10 wt% POSS epoxies also showed improved dispersion with pre-reaction and increasing cure temperature. The dispersion improvements were attributed to the enhanced miscibility of the pre-reacted POSS and the increased rate of POSS reaction into the growing epoxy network at a higher cure temperature. (C) 2012 Elsevier Ltd. All rights reserved.

Publication Title

Polymer

Volume

53

Issue

21

First Page

4643

Last Page

4651