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Properties of poly‐β‐hydroxybutyrate. I. General considerations concerning the naturally occurring polymer
Author(s) -
Alper R.,
Lundgren D. G.,
Marchessault R. H.,
Cote W. A.
Publication year - 1963
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360010605
Subject(s) - optical rotatory dispersion , polymer , chemistry , monomer , intrinsic viscosity , wavelength , dispersion (optics) , diffraction , viscosity , optical rotation , crystallography , polymer chemistry , organic chemistry , optics , composite material , materials science , circular dichroism , physics
Poly‐β‐hydroxybutyric acid has been isolated from two bacterial sources by two different procedures. Molecular weight and intrinsic viscosity for the two samples were vastly different. This was blamed on degradation occurring during polymer isolation. An optical rotatory dispersion curve for the high molecular weight sample showed a sharp increase in specific rotation at wavelengths less than 450mμ. From this fact and the reported optical activity of the monomer it is concluded that the polymer is stereo‐regular. X‐ray examination of the “native” and “regenerated” polymer yielded the same crystalline pattern. Electron diffraction and x‐ray data on single crystals of the polymer indicate a fiber repeat of 5.9 A. The value can only be reconciled with some kind of helical conformation in the solid state.