Synthesis Of Functionalized Poly(Phenylacetylene)s And Their Hybrids With Carbon Nanotubes

Functionalization is the mainstream in the tidal current of the study of polyacetylenes.Polyacetylene derivatives with functions such as fluorescence emission,photoconductivity,photo-pattern,optical limiting,liquid crystal,chiral transfer and amplification,cyto-compatibility,and gas permeability have been designed and synthesized.In our group,a systematic research on the polyphenylacetylene(PPA) derivatives has demonstrated that they have great solvating power to carbon nanotubes(CNTs),and these works have got good peer citation record.CNTs possess unique nano-structure and advanced electronic and mechanical properties,and the PPA derivatives functionalize the CNTs' surface when they dissolve CNTs in organic solvents.Therefore,this is a promising research topic with great scientific value and potential technological applications.In the present thesis,a series of novel PPAs have been designed,synthesized and characterized;the composites of these PPAs and CNTs have been fabricated;and the solvating power of these PPAs to CNTs have been examined;and finally,their potential applications have been explored.Through proper spacers,a series of functional PPAs have been obtained by linking functionalities to polyacetylene backbones.The functionalities include triphenylamine (TPA)(P1),aldehyde-TPA(P2),stilbeniod-TPA(P3),carbazole(P4),fluorene(P5). D-glucose(P6),D-mannose(P7),and D-galactose(P8).Their structures have been characterized with various techniques such as GPC,FTIR,¹H NMR,¹³C NMR, UV-visible and fluorescence spectroscopy.The composites of these polymers and CNTs have been prepared through the routes of solution blending(P1～P5) and in-situ polymerization(P6～P8),and the content of CNTs component in the composites has been quantitatively measured.Spectroscopic methods such as NMR,UV- visible, fluorescence,Raman,and circle dichromism,in combination with morphological observation techniques such as SEM and TEM have been used to investigate the structure and the interactions between PPAs and CNTs.Among the obtained PPAs(P1～P8),P3 showed remarkable solvating power to CNTs.After carefully studying the electronic and photophysical properties of P3,we concluded that the donor-acceptor(D-A) interaction was the reason behind the phenomena.To check the D-A interaction on the effect of salvation CNTs,we synthesized carbazole- and fluorene-containing PPAs.Solubility data and TEM clearly manifested that D-A effect played an important role in the polymer-aided MWNT dispersion in organic solvents.Thus,in addition to the p-p stacking,van der Waals and electrostatic interactions,the D-A interaction offers a new strategy for the design and fabrication of macroscopically processable hybrids of CNTs and polymers.P6～P8 showed water soluble and cyto-philicity.Their hybrids with CNTs can be obtained via in-situ polymerization of corresponding monomers in the presence of CNTs,and they also showed desirable water soluble and cyto-philicity.After solution blending the hybrids with chitosan(CS),CS rods can be fabricated and the mechanical strength of the rods can be effectively improved.According to the experiment data,in comparison with pristine CS rods,the bending strength and modulus of composite CS rods were increased by 18.5～30%and 39～46% respectively.