Synthesis and characterization of thermo-responsive star shaped $C_{60}$-end capped polymer by atom transfer radical polymerization

Abstract

Part I : Four arm star-shaped poly(N-isopropylacrylamide) (PNIAPM) was prepared from pentaerylthritol by Atom Transfer Radical Polymerization (ATRP) of N-isopropylacrylamide in N,N-dimethylformamide (DMF) and water. The polymerization was carried out under various conditions such as concentration of monomer, catalyst and deactivator, and ratio of DMF to water. The $C_{60}$ molecules were allowed to the ends of the star shaped polymer by Atom Transfer Radical Addition reaction. The covalent bond formation between $C_{60}$ and PNIAPM was confirmed by UV, TGA, and GPC. $C_{60}$ end capped PNIPAM with 4 arms showed aggregate behavior in aqueous solution. Part II : N-phenylated aromatic polyureas were prepared from α,α’- dianilino-p-xylene and aromatic methylenebis(4-phenyl isocyanate) in sulfolane by polycondensation. The amide bond of synthesized polyurea was confirmed by NMR, FTIR analysis. The polyureas were soluble in various organic solvent due to the N-aryl group. The glass transition temperature of the polymers measured by DSC was assigned to $123 ℃. The synthesized polyurea show the ferroelectricity with remanent polymerization of 6.0mC/ ㎡.