Epoxy/anhydride networks modified with polyhedral oligomeric silsesquioxanes

Epoxy/anhydride networks were modified, in the presence of benzyldimethylamine as catalyst, with two polyhedral oligomeric silsesquioxanes (POSS), whose inorganic framework had a compact and stable Si-O core and an organic substituent shell. The influence of the content and type of POSS during curing and on the properties of the thermosets was investigated by thermal analysis and infrared spectroscopy. The curing kinetics was analyzed by means of an integral isoconversional nonisothermal procedure. When the POSS modifier was added, the storage modulus in the rubbery plateau increased and the glass transition temperature decreased because of the presence of the flexible organic moieties and the influence in the crosslinking density. The presence of these POSS structures hardly affected the thermodegradation behavior of cured materials. The dispersion of the POSS structures in the epoxy/anhydride matrix was good, but some submicron-sized POSS agglomerates could be observed by transmission electron microscopy. POLYM. COMPOS., 2013. (c) 2012 Society of Plastics Engineers