The crystal structure of trans polydodecenamer

✍ Scribed by G. Natta; I.W. Bassi

• Book ID: 103069924
• Publisher: Elsevier Science
• Year: 1967
• Tongue: English
• Weight: 644 KB
• Volume: 3
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(67)90082-1

✦ Synopsis

A~traet--The structure of crystalline trans polydodecenamer [--CH------CH--(CH2)~0--]n has been determined from the X-ray diffraction spectra given by hot drawn fibres. The unit cell is monoclinic with one chemical unit per fibre repeat and two chains per unit cell. The unit cell dimensions are: a=7.43 A; b=5.00 A; c=14-85 A (fibre axis); fl=86°30'; space group P21/a.

The c projection of the cell has dimensions similar to those found in odd trans polyalkenamers and in orthorhombic polyethylene. Due to the trans double bonds, the chain conformation deviates from the planar zig-zag conformation of polyethylene. The value of the fl angle of the monoclinic unit cell is correlated to the chain conformation. The chain packing is of the same type of those found for odd trans polyakkenamers and of orthorhombic polyethylene. The even members of the homologous series of trans polyalkenamers have crystal structures very similar to that found for trans polydodecenamer. A different crystalline modification of even trans polyalkenamers has been observed.