A Solid State Carbon-13 NMR Study of the Structure and Mobility of the 1,4-Trans-polybutadiene: Perhydrotriphenylene Matrix System and of the Extracted Polymer.

1,4-Trans-polybutadiene has been studied by high resolution state carbon-13 NMR spectroscopy as its crystalline inclusion compound with perhydrotriphenylene (PHTP). The polymer was formed by sup (60) Co gamma-irradiation of the inclusion compound with monomer butadiene. The chemical shifts and spin-lattice relaxation times (ca. 10 s) of the polymer are consistent with a high degree of chain mobility and a substantial content (about 25%) of the cis (versus skew) conformation at the - CH sub 2 -CH= single bonds. The NMR characteristics are very similar to those of the crystalline polymer in its high temperature modification (Form II). The unusual environment of the PHTP canals prevents interchain interactions while interaction with the matrix is non-specific and permits mobility of the polymer down to very low temperature.