HIGH-RESOLUTION SOLID-STATE C-13 NMR-STUDIES ON MOLECULAR MOTIONS ANDSOLID-STATE POLYMERIZATION OF OCTATETRAYNES

The effects of monomer alignment on the solid-state polymerizations of five octatetraynes and a butadiyne to produce polydiacetylenes were s tudied. Structural relaxations of the resulting polymers were found to occur over long time intervals. Solid-state high-resolution C-13 NMR spectra were observed for six symmetrical monomers having alkyl chains (C14H29) and side chains containing either urethane or p-toluenesulfo nate and the derived polydiacetylenes (PDA's). The spin-lattice relaxa tion times (T-1) of the PDA's were also measured. The alignment and mo bility of the monomers, which are closely related to the solid-state p olymerizability and structure of the resulting polymers, are reflected in the solid-state C-13 NMR spectra of the monomers. The PDA's with u rethane side chains were found to have slow structural relaxation. Whe n the number of spacer methylenes between the acetylenic carbon and th e urethane moiety is odd, a planar main-chain structure was assumed. I t was found that PDA-4A's having an odd number of spacer methylenes ac hieved a more homogeneous structure after long-term relaxation than a PDA-4A with an even number of spacer methylenes.