Theoretical prediction of three-dimensionally conjugated novel polymers with excellent mechanical and electric properties: stiffer than diamond!

Summary form only given. Novel polymer crystals with three-dimensionally high elastic moduli have been designed through computer calculations starting from the conventional rigid-rod polymer chains such as poly-p phenylene benzobisoxazole, poly-p-phenytene, polyacetylene, poly-p-phenylene pyromellitimide, etc. These crystals have three-dimensional cross-linking structures in which-the main chains are linked together by the shortest conjugated bonds such as ...-C=C-C=C-... for example. The method of constructing the three-dimensional cross-linking system is quite simple: (1) The polymer chains are arranged in parallel along the chain axis. (2) The hydrogen atoms spreading out of the main chains are replaced by carbon atoms, for example. (3) These carbon atoms are linked together between the neighboring chains by an alternating single and double CC bonds. (4) The thus constructed structure is minimized energetically. (5) The elastic constants are calculated. These calculations were made by using Polygraf (version 3.20, Molecular Simulations, Inc.). The three-dimensional /spl pi/-conjugation structure of these polymer crystals makes us to predict that they should have excellent mechanical and electric properties. In fact, the Young´s moduli predicted for these polymer crystals are in the range of 700 - 1800 GPa, far beyond the modulus of diamond crystal 1030 GPa.