Novel Poly Synthesis And Properties Of Phenylacetylene Derivatives

This paper summarizes the development of PPV and its derivatives in molecular design and synthesis. On the basis of it, a novel PPV derivative poly(2-pentyloxy-3, 5-dibromine-1, 4-phenylene vinylene) (PPDBPV) carrying on both electron donating group and electron withdrawing group is prepared to improve the electron affinity of PPV. The monomers are polymerized under Gilch dehydrochlorination conditions. It is so hard to get new precursor by the traditional route because of the inactivation on benzene ring causing by electron withdrawing effect. To resolve the problem, a modified route has been prepared. The new route for PPDBPV contains four steps: 1. Williamson reaction. 2. Halogenating reaction on benzene ring. 3. Free radical initiation reaction on benzyl. 4. Polyreaction. The main parameters of every step have been gotten and the relative factors that influence polyreaction have been studied. The monomers and polymer were characterized by 1H-NMR and FT-IR.The fluorescent characteristic of PPDBPV has been studied. The maximum photoluminescence (PL) wavelength of PPDBPV solid appeared at 650nm and gave 20nm red shift comparing with poly(2-methoxy-5-pentyloxy-1,4- phenylene vinyl- ene) (PMPPV). This red shift can be explained from the changes in the molecular structure. The optical absorption band edges of PPDBPV and PMPPV in chloroform solution are located at 475nm and 550nm. The band gap energy values of them are calculated to be 2.62eV and 2.26eV.The weight-average molar mass of PPDBPV is 63364 with the polydispersity 1.93. The heat behavior of PPDBPV is studied by the TGA curve and its heat decomposition temperature is 347℃.