Preparation Of Nano-copper/PMMA-b-PSt Composites By Atom Transfer Radical Polymerization

The poly (methyl methacrylate) with single-caped halogen (PMMA-Br) was synthesized by atom transfer radical polymerization (ATRP) method under ultrasonic irradiation, with ethylα-bromopropionate as the initiator and CuBr/2, 2-bipyridine (BPy) as the catalyst and ligand. Then the block copolymer poly (methyl methacrylate)-b-polystyrene was synthesized in cyclohexanone solution containing styrene as comonomer and PMMA-Br as the macromolecular initiator as same as the above synthesis condition Nano-Cu/ poly (methyl methacrylate)-b-polystyrene composites was successfully prepared by NaBH4 as reductant in the polymerization system.The homopolymer and copolymers were characterized by means of Fourier transfer infrared spectrometer (FT-IR), Nuclear magnetic resonance (1H NMR) and Gel permeation chromatography (GPC), the results confirmed the molecular structure of copolymer and shown that the molecular weight of the block copolymer was controlled and the polydispersity index is small. The copolymer chains were self-assembled in acetone solution, the morphology of self-assembled microspheres is PSt chain as core, which not soluble in acetone solution and the PMMA chain as shell. Those microspheres could change morphology to rodlike and reticular as increased of PSt chain.For the Nano-Cu/ poly (methyl methacrylate)-b-polystyrene composites, the results of FT-IR, indicated that there were chemical actions between nano-Cu and copolymer. X-ray photoelectron spectroscopy (XPS) proved that interaction between nano-Cu and the functional group of polymer was formed by coordination between nano-Cu and oxygen of the ester functional group of PMMA-b-PSt. The testing results of TG-DSC showed that the decomposition temperature and glass transition temperature of nano-Cu/ PMMA-b-PSt composites were lower than to present PMMA-b-PSt and the interaction between namo-Cu and copolymer was approved that. The nano-Cu/ PMMA-b-PSt composites were assembled to cyclic morphology when copolymer aggregated to surface of nano-copper in acetone solution. When the nanocomposites were treated with high temperature that is slight above the segment glass translation temperature, the copolymer chain was ordered-assembled within nanocomposites with PMMA chain that was in crystal as the white stripes and PSt chain that was in random as the dark stripes.