star-shaped poly(methyl methacrylate) with polyhedral oligomeric silsesquioxane (POSS) as a core was synthesized by atom thansfer radical polymerization (ATRP)

using octa(-chloropropyl) POSS as a initiator and CuCl/2

2-bipyridine as catalyst system-Octa(-chloropropyl) POSS was prepared in methanol through the hydrolysis and condensation of chloropropyltriethoxysilane

and a yield of 28% was obtained.The welldefined structures of POSS and POSS/PMMA composite were fully characterized by FTIR

NMR

GPC and XRD

with results showing POSS molecule was successfully formed

and the mono-dispersion of POSS was achieved by ATRP

meaning that there was only one POSS molecule in a polymer chain.The polydispersity indices (PDI) of POSS/PMMA composite with different polymerization time were 1.20 and 1.14

according to the measurement of GPC.The TGA results indicated the thermal stability of POSS/PMMA composite enhanced from 281℃ to 303℃ with the increase of POSS content

which was due to the incorporation of POSS molecules