TY - JOUR
T1 - Structures of Mixed-Tacticity Polyhydroxybutyrates
AU - Haslböck, Maria
AU - Klotz, Moritz
AU - Steiner, Lisa
AU - Sperl, Josef
AU - Sieber, Volker
AU - Zollfrank, Cordt
AU - Van Opdenbosch, Daniel
N1 - Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/7/24
Y1 - 2018/7/24
N2 - In order to provide parameters that can be used to tailor the crystalline and supramolecular structures of pure polyhydroxybutyrate, we synthesized polymers with fractions of meso groups in the range 0.5-1. We confirmed the random polymerization of R and S enantiomers by the catalyst. From X-ray diffractograms, the lattice parameters were determined; they remained constant for the observed range of fractions. We also traced the directional crystallite sizes over tacticity, which change significantly for one unit cell direction. The respective crystalline phase atom fractions were quantified by iteratively fitting amorphous phase diffraction patterns. We found that the crystalline contents of small-crystallite polyhydroxybutyrates have so far been underestimated. X-ray diffraction and transmission electron microscopical observations from polymers with meso group fractions of 0.5 are discussed. To facilitate the quantification of crystalline atom fractions, we refined two accessible infrared absorption spectroscopy-based indices. These indices, and the fundamental correlations between chemical and crystallite structuring reported herein, allow to tune structure-dependent properties, e.g., melting point and toughness, of mixed-tacticity polyhydroxybutyrates over wide ranges.
AB - In order to provide parameters that can be used to tailor the crystalline and supramolecular structures of pure polyhydroxybutyrate, we synthesized polymers with fractions of meso groups in the range 0.5-1. We confirmed the random polymerization of R and S enantiomers by the catalyst. From X-ray diffractograms, the lattice parameters were determined; they remained constant for the observed range of fractions. We also traced the directional crystallite sizes over tacticity, which change significantly for one unit cell direction. The respective crystalline phase atom fractions were quantified by iteratively fitting amorphous phase diffraction patterns. We found that the crystalline contents of small-crystallite polyhydroxybutyrates have so far been underestimated. X-ray diffraction and transmission electron microscopical observations from polymers with meso group fractions of 0.5 are discussed. To facilitate the quantification of crystalline atom fractions, we refined two accessible infrared absorption spectroscopy-based indices. These indices, and the fundamental correlations between chemical and crystallite structuring reported herein, allow to tune structure-dependent properties, e.g., melting point and toughness, of mixed-tacticity polyhydroxybutyrates over wide ranges.
UR - http://www.scopus.com/inward/record.url?scp=85050697157&partnerID=8YFLogxK
U2 - 10.1021/acs.macromol.8b01047
DO - 10.1021/acs.macromol.8b01047
M3 - Article
AN - SCOPUS:85050697157
SN - 0024-9297
VL - 51
SP - 5001
EP - 5010
JO - Macromolecules
JF - Macromolecules
IS - 14
ER -