NMR-STUDIES OF POLYDIACETYLENES HAVING ALKYL CHAINS - MOLECULAR MOTIONS OF PRECURSOR MONOMERS AND THE POLYMERS AT VARIOUS STAGES OF THE SOLID-STATE POLYMERIZATION

Polydiacetylenes (PDAs) are synthesized from diacetylenes or more conj ugated acetylenes having long chains with specific structures by the s olid-state polymerization initiated by gamma-ray, UV or thermal activa tion. By using solid-state high-resolution C-13-NMR, we studied the mo lecular motions of the long alkyl chains (n-C14H29) Of the precursor m onomers and the polymers for PDAs of a butadiyne (2A), an octatetrayne (4A), a dodecahexayne (6A) and a p-dibutadiynylbenzene (2A-Bz-2A). It is shown that the yields of the solid-state polymerization are relate d to the molecular motions of the precursor monomers, Since the polyme rs of 4A and 6A have conjugated acetylenic side chains, further reacti ons occurred, and the intramolecular rearrangement were also monitored by C-13-NMR. The changes of the C-13 spectra of the alkyl carbons are considered in detail in this paper. (C) 1998 Elsevier Science B.V.