Synthesis of α-Bromine-Terminated Polystyrene Macroinitiator and Its Initiation of MMA Polymerization by ATRP

In the present paper the synthesis of block copolymers via the transformation from living anionic polymerization （LAP） to atom transfer radical polymerization （ATRP） was described. α-Bromine-terminated polystyrenes（PStBr） in the LAP step was prepared by using n-BuLi as initiator, tetrahydrofuran （THF） as the activator, α-methylstyrene （α-MeSt） as the capping group and liquid bromine （Br2） as the bromating agent. The effects of reaction conditions such as the amounts of α-MeSt, THF, and Br2 as well as molecular weight of polystyrene on the bromating efficiency （BE） and coupling extent （CE） were examined. The present results show that the yield of PStBr obtained was more than 93. 8% and the coupling reaction was substantially absent. PStBr was further used as the macroinitiator in the polymerization of methyl-methacrylate （MMA） in the presence of copper （I ） halogen and 2, 2’ -bipyridine （bpy） complexes. It was found that the molecular weight of the resulted PSt-b-PMMA increased linearly with the increase of the conversion of MMA and the polydispersity was 1. 2-1.6. The structures of PStBr and P（St-b-MMA） were characterized by 1H NMR spectra.

SYNTHESIS OF POLYBUTADIENE MACROINITIATOR AND POLYBUTADIENE/POLYACRYLAMIDE BLOCK COPOLYMERS

An azo-group containing polybutadiene macroinitiator was prepared by Pinner synthesisand characterized by IR, NMR, GPC, viscosity and elemental measurements. Themacroinitiator was further used to polymerize acrylamide (AAm) in benzene to formpolybutadiene/polyacrylamide (PBD/PAAm) block copolymers. High conversion of AAm wasobtained over a wide range of monomer/macroinitiator ratios. The PBD/PAAm blockcopolymers.were found to have excellent solvent resistance.

PREPARATION OF P(MAH-co-VAc)-b-PSt COPOLYMER BY INITIATION OF PRECURSOR CONTAINING ISOPROPYLTHIOXANTHONE RESIDUES AND ITS APPLICATION IN FABRICATING HONEYCOMB STRUCTURED POROUS FILMS

A novel,facile method to prepare copolymers by virtue of the reinitiation of precursor containing isopropylthioxanthone(ITX) residues(ITXH) was reported.Using poly(maleic anhydride-co-vinyl acetate)(P(MAH-co-VAc)) with incorporated ITX residues as a macroinitiator,polymerization of styrene was performed,and poly(maleic anhydride-co-vinyl acetate)-b-polystyrene(P(MAH-co-VAc)-b-PSt) was produced.Applying the resultant copolymer in a breath figure procedure,honeycomb structure films having pore size around ...

Preparation and polymerization mechanism of dihydroxy-capped PCL,poly(CL-b-PEG-b-CL) and poly(DTC-b-CL-b-DTC)

The ring opening polymerization of ε-caprolactone (CL) was initiated by glycol and yttrium tri(2,6-di-tert-butyl-4-methylphenolate)s (Y(OAr)3),preparing dihydroxy-capped poly (ε-caprolactone) (PCL) with controllable molecular weight.1H NMR and SEC analyses indicate that two kinds of active species and corresponding PCL with different structures exist in the system.Increasing the ratio of glycol to Y(OAr)3 benefits the formation of monofunctional active species.However,poly(ethylene glycol) (PEG)/Y(OAr)3 system only contains sole bifunctiona active species to synthesize copolymer of CL with PEG (poly(CL-b-PEG-b-CL)).Dihydroxy capped PCL as macroinitiator can further initiate the polymerization of 2,2-dimethyltrimethylene carbonate (DTC).Thus,triblock copolymer of CL with DTC (poly(DTC-b-CL-b-DTC)) has been prepared.

“Living”/controlled radical copolymerization of N-phenylmaleimide and styrene using Fréchet-type dendritic initiators

Polyarylether dendrons as macroinitiators for the 'living'/controlled free radical copolymerization of N-phenylmaleimide (PhMI) and styrene (St) have been demonstrated. The copolymerization was carried out in bulk or anisole with CuBr/bipy catalyst at 100-130℃. It is found that the resulting copolymers possess predetermined molecular weights and narrower polydispersities (1.18 < Mw / Mn < 1.32). The effects of reaction temperature and monomer feed on the copolymerization kinetics were investigated in detail. By using the Fineman-Ross method, the apparent monomer reactivity ratios for the atom transfer radical copolymerization of PhMI and St were determined to be rPhMI = 0.0207, and rSt = 0.0484, respectively.

Synthesis and Characterization of a New Network Polymer Electrolyte Containing Polyether in the Main Chains and Side Chains

1 Results A new network polymer electrolyte matrix with polyether in the side chains and main chains was synthesized by the azo-macroinitiator method and urethane reaction.The macroinitiator,polymer and network polymer were confirmed by Fourier-transform infrared (FT-IR) spectroscopy and 1H NMR.FT-IR was also used to study the environment of lithium ions doped in these network polymer electrolytes.Three important groups are considered: N-H,carbonyl,and ether groups.The thermal properties of the polymer ...