The atom transfer radical polymerization (ATRP) of styrene from poly (dimethylsiloxane) (PDMS) macroinitiators was described．Commercially available difunctional PDMS containing vinylsilyl terminal species was reacted with hydrogen bromide resulting in the PDMS macroinitiators containing alkyl bromide end-groups．The ATRP of styrene was then conducted at 130℃ using the PDMS containing alkyl bromide end-groups as initiators

cuprous chloride (CuCl) as catalyst and 4

4′-di(5-nonyl)-2

2′-bipydine (dNbpy) as ligand to produce block copolymers．Using this technique

copolymers consisting of a PDMS center block and polystyrene terminal blocks were synthesized．Analysis of the copolymers by gel permeation chromatography (GPC) showed that the molecular weight increased linearly with the conversion of monomer

and the polydispersity decreased with the progress of polymerization. The molecular weight increased from 6400 to 17890 and the polydispersity ranged from 1.38～1.26

demonstrating that the reaction was controlled and the polystyrene blocks had low polydispersities typical of radical polymerization by all atom transfer process．IR and 1H-NMR analyses of the PDMS macroinitiators and the copolymers showed that the PDMS macroinitiators containing alkyl bromide end-groups were formed

and the copolymers consisted of polystyrene and PDMS．A DSC analysis confirmed the results．Tg in 100℃ and -120℃ were attributed to polystyrene blocks and PDMS blocks respectively

indicating the copolymer consisted of polystyrene and PDMS

the triblock copolymers polystyrene-b-polysiloxane-b-polystyrene (PSt-b-PDMS-b-PSt) were formed．All these results also demonstrated the effectiveness of ATRP to synthesize a variety of inorganic／organic polymer hybrids．