ISSN:
0449-2978
Schlagwort(e):
Physics
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
Crystalline polymers derived from cis- and trans-2-butene oxides were studied by x-ray diffraction methods. X-ray fiber and powder photographs of poly(trans-2-butene oxide) were indexed by an orthorhombic unit cell with the dimensions a = 13.72 A., b = 4.60 A., and c (chain axis) = 6.90 A.; the space group is P212121. The crystal structure of this polymer has been determined in projection. The chain has an erythro-diisotactic structure with -dl, dl- carbon sequences. The polymer has a nonplanar zigzag backbone with carbon and oxygen atoms of alternate monomer units lying nearly in a plane. Two chain molecules pass through the unit cell. The unit cell of poly(cis-2-butene oxide) is orthorhombic with lattice constants a = 11.20 A., b = 10.44 A., c (chain axis) = 7.01 A. The polymer has a threo-diisotactic structure with -dd,dd- or -ll,ll- carbon sequences. Four chain molecules pass through the unit cell. The crystal lattice is body-centered but the space group has not yet been established. The polymer has an almost fully extended zigzag chain configuration. Polymers prepared by either metal halide catalysts (FeCl3, SnCl4) or organometallic catalysts were essentially identical; the latter catalysts did, however, yield more highly crystalline polymers.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/pol.1966.160040110
