Improvement of Thermal and Mechanical Properties of a Phenolic Resin Nanocomposite by In Situ Formation of Silsesquioxanes from a Molecular Precursor

Silsesquioxanes are formed in situ during mixing and curing of a phenolic resin and a molecular sil- ane precursor (3-(triethoxysilyl)-1-propaneamine) yielding a nanocomposite. As indicated by a higher onset tempera- ture, a higher characteristic decomposition temperature, and a lower maximum heat flow, the thermal stability of the nanocomposite is significantly improved over the pris- tine resin. Moreover, the bending strength and the strain at break could also be enhanced by 36% and 51%, respec- tively. The nanocomposite was characterized by 29 Si solid- state NMR, STEM/EDS, TGA, DSC, and three point bending tests. The STEM/EDS measurements showed a homogenous distribution of silsesquioxanes in the pheno- lic resin. V C 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 2272-2277, 2010