An investigation of the structures and molecular dynamics of natural waxes. III. Montan wax

For pt.II see ibid., vol.21, p.1429 (1988). A detailed NMR investigation, supported by DSC and X-ray diffraction measurements, of montan wax is reported. The solid-state high-resolution 13 C spectrum showed that it has a very high number of carbon atoms occurring in methyl and methylene groups and a relatively low ester, acid and carbonyl content. Laboratory frame spin-lattice relaxation results showed that the methyl groups have a high degree of mobility and that branching of the chains is of minor importance. A reliable value of 34.6+or-2.2 kJ mol -1 was obtained for the activation energy of the reorientational-translational motion of the chains. The temperature at which T 2 , the spin-spin lattice relaxation time, starts to increase with increasing temperature yields tau 0 =(8.7+or-0.6)*10 -14 s for this motion. The average chain length of montan wax is 31 carbon atoms. The chain-end motion as revealed by spin-lattice relaxation measurements in the rotating frame is less hindered in montan wax than in the other natural waxes which have been investigated.