Synthesis And Nonlinear Optical Properties Of 6-(4-Formyl Benzoyl) Methacrylate Polymer With Porphyrin Group In Side-chain

Porphyrin(Por)with ?-conjugated system has an inherently fast response time,a broadband spectral response and a large nonlinear absorption coefficient.Therefore,porphyrin and its derivations show excellent optical limiting properties.In this dissertation,firstly,4-(6-hydroxy phenoxy)benzaldehyde(HHBD)was synthesized by reaction of benzaldehyde and 6-bromo-1-hexanol,and 6-(4-formyl benzoyl)methacrylate(MAACE)was synthesized by HHBD and methacryloyl chloride under the condition of ice bath.Then a series of polymers of PMAACE with different molecular weight were obtained using MAACE as monomer by reversible addition fragmentation chain transfer(RAFT)method.Finally,PMAACE-Por was achieved by the post-polymerization modification of PMAACE.Subsequently,FT-IR,UV-Vis,1H NMR,GPC and fluorescence spectroscopy were used to characterize the structure of the products,and the results demonstrated that PMAACE-Por was successfully synthesized.The optical limiting properties of PMAACE-Por were studied by Z-scan.The results showed that PMAACE-Por which was prepared by post-polymerization modification of PMAACE with MAACE(Mn = 2500)has the best nonlinear optical properties,and the nonlinear absorption coefficient was 180×10-10(m/W).Also,it was found that the nonlinear coefficients of PMAACE-Por decreased with the increasing of the molecular weight.This is mainly because that the number of porphyrin in the PMAACE-Por increased with the increase of the molecular weight of PMAACE,which may result in the appearance of more aggregates in the polymer and fluorescence quenching,thus resulting in a decline in the nonlinear absorption coefficient.Obviously,the PMAACE-Por with proper molecular weight can exhibit excellent optical performance.In addition,the PMAACE-Por was mixed with methacrylate(MMA)monomer.After the polymerization of MMA,the PMAACE-Por was incorporated into the PMMA,and the obtained composite materials show absorption coefficient of 150×10-10(m/W).In summary,the obtained PMAACE-Por was a practical optical limiting material.