Crosslinked epoxy microspheres: Preparation, surface-initiated polymerization, and use as macroporous silica porogen

In this article, we report the preparation of crosslinked epoxy microspheres with diameters of 510 m prepared via phase-inverted phase separation induced by polymerization in the thermosetting blend of epoxy and poly(epsilon-caprolactone). The surfaces of the epoxy microspheres were functionalized to bear 2-bromopropionyl groups, which were further used as initiators to obtain poly(glycidyl methacrylate) (PGMA) grafted epoxy microspheres via the surface-initiated atom transfer radical polymerization approach. The PGMA-grafted epoxy microspheres were then employed to react with 3-aminopropyltrimethoxylsilane (APTMS) to obtain the functionalized epoxy microspheres, the surface of which contained a great number of trimethoxysilane groups. A co-solgel process between the APTMS-functionalized epoxy microspheres and tetraethoxysilane was performed, and organicinorganic glassy solids were obtained. The organicinorganic glasses were used as precursors for accessing macroporous silica materials via pyrolysis at elevated temperatures. The hierarchical porosity of the resulting macroporous silica was investigated by means of field emission scanning electronic microscopy, transmission electronic microscopy, and surface-area BrunauerEmmettTeller (BET) measurements. We found that the macroporous silica possessed BET surface areas in the range 183.9235.2 m2/g, depending on the compositions of their precursors. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013