Macroinitiator Br-PBA-Br was synthesized via atom transfer radical polymerization with activators regenerated by electron transfer (ARGET ATRP) using the bifunctional initiator and low concentration of complex catalyst composed of inexpensive ligand PMDETA and Cu(Ⅱ)Br2(0.02% molar fraction of monomer).The effects of reaction temperature and catalyst dosage on the polymerization rate and controllability were investigated.Then

PMMA-b-PBA-b-PMMA triblock copolymers with narrow polydispersities were prepared via ARGET ATRP initiated by Br-PBA-Br using CuCl2/PMDETA as catalyst.The residual catalyst was separated with cheap diatomite and the residual concentration of cupric ions was reduced to 0.001% weight fraction to polymer.GPC results showed that the number average molecular weight of the prepared triblock copolymers is in the range of 51000~110000 and the molecular weight distribution is below 1.50.The chemical compositions of triblock copolymer determined by1H-NMR were in good agreement with the GPC results.The glass-transition temperatures (Tg) determined by DSC were around -47℃ and 105℃ corresponding to PBA and PMMA

respectively.AFM

DSC

and DMA confirmed the obvious phase separation in the triblock copolymers.The tensile strength of the copolymer films were among 2.7~11.7 MPa and the elongation at break were among 124%~231%

which showed that the tensile strength and elongation at break of the triblock copolymers were adjustable by changing copolymerization composition.PMMA-b-PBA-b-PMMA triblock copolymer with adjustable properties can be prepared successfully by ARGET-ATRP and the problems of high dosage of catalyst and difficulty in removal are solved.