Synthesis Of Two Functional Polymers By ATRP

In this paper, two polymers with low polydispersion index was synthesized by atom transfer radical polymerization(ATRP) method.First, 8-hydroxyquinoline-end-capped polystyrene was obtained by ATRP. The initiator, 5-chloromethyl-8-acetoxyquinoline was prepared by acetylation of 5-chloromethyl-8-hydrox -yl quinoline with acetic anhydride under reflux. Styrene was polymerized by ATRP with the initiator system consisting of CuCl/5- chloromethyl- 8-acetoxy-quinoline/2,2′-Bipyridine. The end-capped polystyrene with free 8-hydroxyquinoline group was obtained by hydrolysis in aqueous THF with dilute NaOH solution. The purified polymer was coordinated with the ions of Aluminum, to prepare the polymeric complexes. The chemical structure of the polymer and the polymeric complexes were characterized by FT-IR, UV-Vis, RF, GPC and 1HNMR. The thermal performance of the polymers and the polymeric complexes were studied by thermogravimetry analysis. The electroluminescent device using polymeric complex as emitting element have been fabricated. The photoluminescence of the film and the electroluminescence of the device were investigated. The experimental results indicate:(1) 8-hydroxyquinoline-end-capped polystyrene with low polydispersity index(1.26) is obtained. (2) All polymers have excellent thermal stability under nitrogen atmosphere and initial weight-loss temperature higher than 300℃. The polymeric complexes can dissolve in dichloromethane, tetrahydrofuran and other common organic solvent and this dissolubility will facilitate the device-making procedure.(3) Strong fluorescent emission at 512nm was observed of polymeric complexes when the polymeric complexes were irradiated with ultraviolet rays. The polymeric complexes might be potential photoluminescent or electroluminescent materials with excellent film-forming property. (4) The device using polymeric complex as emitting element and PVK as hole transportation materials at the ratio of 1∶4 has the brightness about 280Cd/m~2.In addition, Poly(propargyl methacrylate), containing 2-propynyl side group which can undergo 1,3-dipolar cycloaddition reaction with azides acts as a excellent intermediate in"click"chemistry. But the radical polymerization of propargyl methacrylate always obtained a crosslinked product due to crosslinking reaction of propargyl side group even under low percent conversion of monomer. Thus, it is quite significant to find a suitable polymerization system which can enhance the monomer conversion and molecular weight controllability.In this paper, the effects of reaction conditions on polymerization of propargyl methacrylate(PgMA) by ATRP were studied. Benzyl chloride, tosyl chloride(TsCl), 7-chloroacetoxy-4-methylcoumarin and ethylα-bromoisobutyrate(EBB) was used as initiators, bipyridine as the chelating agent and tetrahydrofuran as solvent. The experiment results indicated that polymerization temperature (60~90℃) has little effect on polymerization, and the prolongation of polymerization time and the increase of monomer concentration will broaden the molecular weight distribution.