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Water transport properties in poly(3‐hydroxybutyrate) and poly(3‐hydroxybutyrate‐ co ‐3‐hydroxyvalerate) biopolymers
Author(s) -
Miguel O.,
Iruin J. J.
Publication year - 1999
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/(sici)1097-4628(19990725)73:4<455::aid-app1>3.0.co;2-y
Subject(s) - gravimetric analysis , sorption , desorption , copolymer , polymer chemistry , polymer , plasticizer , materials science , chemical engineering , diffusion , permeation , thermal diffusivity , chemistry , thermodynamics , organic chemistry , membrane , adsorption , composite material , biochemistry , physics , engineering
Water sorption and diffusion have been investigated in poly(3‐hydroxybutyrate) (PHB) and three poly(3‐hydroxybutyrate‐ co ‐3‐hydroxyvalerate) copolymers [P(HB‐HV)] by means of a Cahn electromicrobalance. Permeability of these samples have been determined using a gravimetric permeation cell. Two experimental setups were used for the gravimetric sorption measurements, under dynamic and static conditions, respectively. The differences observed in the results obtained using these techniques are discussed. The sorption measurements have evidenced the tendency of water molecules to form aggregates or clusters in the polymer. In addition, the static sorption method revealed the potential of PHB and P(HB‐HV) to undergo molecular relaxations, eventually leading to a partial desorption of the previously sorbed water after an induction period. The clustering effect was adequately described by the polycondensation model. On the other hand, the interpretation of the diffusivity in terms of mobility coefficients has revealed a competition between a plasticization effect and clustering. As a whole, water transport properties in PHB and its copolymers can be considered to be very close in magnitude to those of common thermoplastics such as PVC and PET. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 455–468, 1999