HIGH-TEMPERATURE CRYSTALLINE AND MOLECULAR-STRUCTURES OF THE MAIN-CHAIN THERMOTROPIC POLYESTER POLY[(OXYDODECANEDIOYL)OXY-1,4-PHENYLENE(2-METHYLVINYLENE)-1,4-PHENYLENE] - AN APPLICATION OF THE FIBER WHOLE PATTERN METHOD

The molecular structure of the crystalline phase of the thermotropic main-chain polyester known as C-12-alpha-MS, stable at 175-degrees-C, has been determined by fiber X-ray diffraction using the whole-pattern method. The polymer has a complex polymorphism, and the phase characterized is the one stable just below the transition to the nematic state. The unit cell is monoclinic, P2(1)/a space group with two repeat unit C14H16O2 per cell. Lattice constants are a = 13.83 (1) angstrom, b = 5.28 (1) angstrom, c = 27.3 angstrom, and beta = 138.6-degrees. Due to the strong thermal motion of the carbon and hydrogen atoms of the aliphatic sequence along the molecular chain, the phase has been classified as a disordered crystal of G type.