Synthesis And Behavioural Study Of Polymer With Fluorescent And Third-order Nonlinear Optical Properties

We designed and synthesized the polycondensate of the benzoguanamine (BGA) and pyromellitic dianhydride(PMDA) and p- Ï€ conjugate polycondensate with differ side chain. On the basis of quantum chemical PM3/CIS method, the geometries of the polyamic acid with different side chain and their monomer are optimized, and their fluorescence spectra and the third-order nonlinear optical susceptibilities have been calculated. The effects of the different side chain on the fluorescence spectra and the third-order nonlinear optical property have been studied. The calculated results are consistent with experimental values on the whole. After p- Ï€ conjugate, the fluorescence intensity and the third-order nonlinear optical property are increased with the length of the side chain alkyl increased. These results give a new method for designing the third-order nonlinear optical polymers with good capability.Atom transfer radical polymerization(ATRP) of styrene(St) and methyl methacrylate(MMA) was conducted at ambient temperature, using 2-Cyano-4'-bromomethy(biphenyl) ( CBP-CH₂Br) as initiator, CuBr as catalyst and N,N,N',N',N'- pentamethyldiethyltriamine(PMDETA) as ligand. The results show that the polymerization is a first order reaction with respect to monomer concentration. The polymerization displayed living character as evidenced by a liner increase of monomer weight with conversion and a relatively narrow distribution(M_n/M_w range from 1.09 to 1.46). The structure of PSt was analyzed by ¹HNMR and the preparation of PSt-b-PMMA block copolymer which proved the polymerization could be controlled. The Effects of reaction temperature , monomer to initiator mole ratio and CuBr to PMDETA mole ratio on the polymerization displayed living character were also discussed in this thesis. The fluorescence intensity of the complex enhances obviously after the macromolecular ligand was coordinated with Ag(â… ) ion.ATRP of St and MMA was also conducted , using (MBPC-CH₂Br) as initiator, CuBr as catalyst and PMDETA as ligand. The results show that the polymerization displayed living character at ambient temperature.The new functionalized monomer 4-(2'-cyano biphenyl) metnyl methacrylate(CBPMMA) is synthesized by CBP-CH₂Br. ATRP of CBPMMA proceeded usingseveral kinds of initiators, CuCl or CuBr as catalyst and PMDETA or BPY as ligand.The results show that the living character and controlled character are obviouslydifferent using different initiators. ATRP of CBPMMA proceeded at quite low temperature(10°C) using ethyl 2-bromoisobutyrate (EB/B) as initiator. And the polymerization displayed good living character(Mn/Mw=1.20). The kinetics study at 15*C shows that the polymerization is a first order reaction with respect to monomer concentration .The polymerization displayed living character as evidenced by a liner increase of monomer weight with conversion and a relatively narrow distribution(Mn/Mw range under 1.39).