| Popis: |
The crystal structure of poly[oxy-1,3-(2-cyanophenylene)-oxy-1,3-phenylene] was determined by X-ray diffraction. The structure belongs to the monoclinic system with the space group P 2 1 a , and has unit cell constants of a = 8.62 A , b = 13.07 A , c ( chain axis ) = 9.03 A and β = 99.0° (second setting). There are four monomer units (i.e. four chains) in the unit cell. The molecules in the crystal are constricted by 0.5 A per monomeric unit from the fully extended conformation, and the planes of the adjacent benzene rings lie at an angle of ∼ 90° to each other. The longitudinal elastic modulus of the crystalline component was estimated to be 44 GPa from the X-ray diffraction measurements. Because the polymer is not fully extended, this elastic modulus is not very high. |
