III International Conference

PP-II-311NEW COMPOSITE OF A POLYACETYLENE WITH SINGLE-WALLED CARBONNANOTUBES AND STUDY OF ITS ELECTROCHEMICAL PROPERTIESEfimov O.N., Tkachenko L.I.Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, RussiaE-mail: efimov@icp.ac.ruA new composite material consisting of single-walled carbon nanotubes (SWNT)(2.4 wt %) covered by polyacetylene (PA) has been prepared. PA synthesized directly onsingle-walled carbon nanotubes is a defectless long-chain polymer composed of trans and cisunits with a sufficient length (60 % trans and 40 % cis isomers). The currents of Li +intercalation for composite material near the percolation threshold are 50 times higher ascompared to starting PA.The insertion of electroconducting filler, namely, graphite, SWNT and multi-wallednanotubes (MWNT) into starting PA by mechanical blending sharply enhances conductivityand air stability of the resulting composite. A percolation threshold for PA-SWNT composites[1] is close to 3 v/v.%. A rise in conductivity to 10 -1 –10 0 S cm –1 was explained by the injectionof electrons from the filler particles. The polymerization of propylene carried out directly ongraphite treated by a Ziegler–Natta catalyst yields composites in which the size of graphiteparticles and a distance between them are appreciably decreased compared to those in themechanical mixture [2]. Since in fact SWNTs are bundles of twisted tubes, it is expected thatwith the use of this method, the interface between an SWNT and polyacetylene will increase;as a result, the electrochemical characteristics of the resulting composites will improve.In the present work we synthesized PA directly on SWNT (mass content of nanotubesequal to 80-90 %) in the presence of Ziegler - Natta catalyst, Al(i-C 4 H 9 ) 3 and Ti(OBu) 4 , intoluene ([Al]/[Ti]= 4/1, [Ti] = 3⋅10 -3 mole/l). The monomer pressure was maintained at a levelof 300 mmHg in the course of polymerization.Composite (2.4 wt % SWNT) morphology was characterized using a JEM- 100 CXtransmission electron microscope. The composite was found to consist of SWNT covered by apolyacetylene shell. An average diameter of structural units of the composite was determinedto be ≈ 80 nm. No free polyacetylene was observed between the tubes covered by PA. Thisindicates that polymerization occurs only on SWNT possibly due to the adsorption ofcatalytic centers on an outer surface of SWNT. Such adsorption can be accompanied byseparation of bundles formed by SWNT to single nanotubes. Obviously, the compositevolumes are 2-2.5 times higher than that of PA of the same mass due to loose packing of219