Preparation And Properties Of Nonlinear Optical Functional Polyacetylenes

Polyacetylenes as well-known conjugated polymers possess excellent time response and electronical conductivity.They also exhibit novel optical,electronic and biological properties when appropriate substituents or pendants are appended to the polyene backbones.Nonlinear optical materials can be both used as frequency conversion material and information processing material,which plays an important role in the solid laser technology and other photoelectric technology.Three novel polyacetylenes with nonlinear optical group were designed and synthesized in this dissertation,and their structures and properties were characterized and evaluated.The content of the dissertation are as follow.1.The development,synthesis method and latest application of functional polyacetylenes were reviewed in detail.2.Three monomer molecules with different conjugation length were designed and synthesized.The homopolymers of them were prepared by solution polymerization using metal as catalyst.The structure of the monomers and homopolymers was characterized by elemental analysis(EA),fourier transform infrared spectoscopy(FT-IR),nuclear magnetic resonance(1H-NMR)technologies.3.The thermal properties of the monomers and homopolymers were measured by differential scanning calorimetry(DSC)and thermo gravimetric analyzer(TGA)technologies.The results show that the thermal stability of homopolymer is better than that of monomer,and the mechanism of stability was discussed in detail.4.The optical properties of monomers and homopolymers were studied by Z-scan,ultraviolet and visible spectroscopy(UV-vis).It can be found out that the peaks of UV absorption and fluorescence emission exhibit redshift with the increase of conjugation length for both monomers and homopolymers.In addition,the UV absorption peaks of homopolymers broadened compared with that of monomers.The results of Z-scan show that the nonlinear optical properties of homopolymers have been improved significantly than that of monomers.Furthermore,the nonlinear optical mechanism was discussed thoroughly.