SYNTHESIS OF POLY{N-[2-(4'-BENZYLTHIOACETATE)PROPIONYL]-p-AMINOPHENYLACETYLENE} AND ITS THERMAL STABILITY AND FORMATION OF ORDERED NANOSTRUCTURE

Polymerization of a phenylacetylene monomer containing chiral center and thiolacetate was achieved by using a zwitterionic rhodium complex or Rh+[η-C_6H_5(nbd)B-(C_6H_5)_3] as catalyst.Chemical structure was characterized with infrared(IR),nuclear magnetic resonance(NMR),UV-Vis absorption spectroscopic techniques,and the experimental data confirmed the formation of the expected polymer.The obtained polymer was soluble in common organic solvents such as chloroform,dichloromethane,tetrahydrofurran,and its weight-average molecular weight was about 7.32×104.The polymer was highly thermally stable;it lost 5% of its original weight at a temperature of 336℃,and about 31% residual weight was measured at 900℃.SEM images showed that rod-like ordered entities were observed for the thin film fabricated by casting polymer solution(a concentration of 5.0 mg/mL in chloroform)under ambient condition;while crystallites were observed when dilute polymer solution(a concentration of 0.5 mg/mL in chloroform)was used to film fabrication.As revealed by TEM images,when the evaporation rate was controlled to be slow and the concentration of polymer in chloroform was higher than 1.0 mg/mL,a polymer layer spread on the carbon supporting film on copper micro-grid;when polymer concentration was lower than 0.5 mg/mL,microcrystallites with regular shapes were observed.Based on the macromolecular structure,the improvement of the thermal stability and the formation ordered microstructure can be tentatively ascribed to the role of chiral centers on the side chains of the resulted polyphenylacetylene.