Carbon dioxide sorption and diffusion in poly(3-hydroxybutyrate) and poly(3-hydroxybutyrate-CO-3-hydroxyvalerate)

✍ Scribed by O. Miguel; T. A. Barbari; J. J. Iruin

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 192 KB
• Volume: 71
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19990404)71:14<2391::aid-app11>3.0.co;2-q

✦ Synopsis

CO 2 sorption and diffusion in poly(3-hydroxybutyrate) and three poly(3hydroxybutyrate-co-3-hydroxyvalerate) copolymers were investigated gravimetrically at temperatures from 25°to 50°C and pressures up to 1 atm. The sorption behavior proved to be linear for all the copolymers studied. An additional set of measurements performed in a pressure decay apparatus at 35°C showed that the linearity could be extrapolated to pressures up to 25 atm. The sorption results obtained from both techniques were in good agreement. The poly(3-hydroxybutyrate-co-3-hydroxyvalerate) sorption kinetics were increasingly non-Fickian at the higher temperatures, thus preventing the calculation of diffusion coefficients above 35°C. Interestingly, this was not the case for poly(3-hydroxybutyrate), and diffusion coefficients and permeabilities could be calculated at all of the investigated temperatures. The 35°C permeabilities were fairly low, which is attributed to the high degree of crystallinity of this polyester family. Finally, the poly(3-hydroxybutyrate) barrier properties against CO 2 are successfully compared with those of some selected common thermoplastics.