-Methacryloxypropyltrimethoxysilane (MPS) was grafted onto the surface of attapulgite rod to obtain the modified particles AT-MPS. Subsequently

the graft polymerization of methyl methacrylate on the surface of attapulgite was realized by using reversible addition-fragmentation chain transfer (RAFT) radical polymerization method

using cyanopropyl dithiobenzoat (CPDB) as the RAFT chain agent and azodiisobutyronitrile (AIBN) as the initiator

and the grafted particles AT-g-PMMA with a grafting degree of 16.33% were prepared. The modified particles were characterised by FTIR and TGA respectively. The polymerization kinetics and grafting degree of graft polymerization with different amounts of initiator (azodiisobutyronitrile

AIBN) and CPDB were discussed in detail. Experimental results showed that MPS was grafted onto the surface of attapulgite rod crystals

and PMMA was grafted via RAFT polymerization successfully. A longer graft polymerization time and a higher grafting degree were obtained in the presence of RAFT chain transfer agent. Polymerization deviated from linear kinetics behavior due to the premature termination of graft polymerization caused by accelerated bimolecular termination reaction as the AIBN amount increased. The controllability was improved when CPDB was excessive

but polymerization rate and ultimate conversion were decreased obviously. The relatively suitable polymerization conditions are: [MMA]/[CPDB]/[AIBN]=400/1/0.5 and polymerization temperature=70 ℃. Under these conditions

polymerization was living and controllable

and PDI of PMMA in solution was 1.2~1.3. The grafting degree of PMMA decreased with the excessive AIBN or CPDB.