There was investigated the possibility of increasing the apparent specific surface area of polystyrene sorbents by radical-induced post-polymerization reaction using di-tert-butyl peroxide as free radical initiator. It is known that in addition to the activation of vinyl groups, tert-butyl peroxide is also able of abstraction of hydrogen atoms from aliphatic carbons and this way produces active centers for creation of post-polymerization crosslinking. Radical-induced post-polymerization morphology changes were confirmed by detailed morphological examinations of both dry and swollen materials showing distinct reinforcing of the expanded polymer morphology. However, due to the specific character of the post-polymerization reaction, the achieved additional crosslinking was not extensive and only moderate increase to the apparent BET surface area was achieved. (C) 2009 Elsevier Ltd. All rights reserved.