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Gas permeability and side chain structure of poly(γ‐benzyl L ‐glutamate)
Author(s) -
Oohachi Y.,
Hamano H.,
Yoshida T.,
Tsujita Y.,
Takizawa A.
Publication year - 1978
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1978.070220603
Subject(s) - stacking , permeation , solubility , materials science , intermolecular force , crystallography , side chain , differential scanning calorimetry , benzene , chemistry , polymer chemistry , organic chemistry , molecule , polymer , composite material , thermodynamics , biochemistry , physics , membrane
Three structural modifications of poly(γ‐benzyl L ‐glutamate) (PBLG), forms A, B, and C, were prepared by varying the casting solvents and casting temperature. From x‐ray analysis, infrared absorption spectroscopy, differential scanning calorimetry, and viscoelastic measurements, it is concluded that form A of PBLG is characterized by intramolecular stacking between the benzene rings in the side chain, form B exhibits intermolecular stacking, and form C has no stacking. The transition which corresponds to the breakdown of stacking of form A at 135°C is irreversible, while that of form B at 110°C is reversible. The degree of stacking is larger for form A than for form B. These structural features of the side chain region reflect the permeation and sorption behavior of carbon dioxide. Breakdown of stacking between benzene rings causes an abrupt increase in permeability in both form A and form B, and the permeation behavior for form A is not reversible, as is suggested from the irreversibility of the transition. The larger the degree of stacking, the lower is the amount of sorption. Although stacking is considered to affect the sorption site (solubility) and molecular motion, its influence on solubility is more evident in the temperature range up to about 50°C.