Divinylbenzene (DVB) was used as a comonomer of styrene (St) during the preparation of polypropylene/polystyrene (PP/PS) nanoblends by diffusion and polymerization of St in isotactic PP pellets to make the PS domains crosslinked and further to reduce the coalescence of the PS domains during melt mixing. Different morphologies were obtained after melt mixing with different amounts of the initiator benzoyl peroxide (BPO) and DVB, which was explained by different morphology evolutions during melt mixing with different crosslinked structures of the PS chains. With relatively high amounts of BPO and DVB, the nanosized PS domains almost kept their shape and size, and only simple aggregates of a few PS particles with an average size of 130 nm were observed after melt mixing of the PP/PS blends. It can be concluded that DVB is useful for morphology stabilization of the PP/PS nanoblends during subsequent melt processing. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013