Characterization of polyhydroxyalkanoates synthesized from microbial mixed cultures and of their nanobiocomposites with bacterial cellulose nanowhiskers

Marta Martinez-Sanz, Marianna Villano, Catarina Oliveira, Maria G. E. Albuquerque, Mauro Majone, Maria Reis, Amparo Lopez-Rubio, Jose M. Lagaron

Research output: Contribution to journalArticle

75 Citations (Scopus)

Abstract

The present work reports on the production and characterization of polyhydroxyalkanoates (PHAs) with different valerate contents, which were synthesized from microbial mixed cultures, and the subsequent development of nanocomposites incorporating bacterial cellulose nanowhiskers (BCNW) via solution casting processing. The characterization of the pure biopolyesters showed that the properties of PHAs may be strongly modified by varying the valerate ratio in the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) copolymer, as expected. Increasing the valerate content was seen to greatly decrease the melting temperature and enthalpy of the material, as well as its rigidity and stiffness, resulting in a more ductile behaviour. Additionally, the higher valerate PHA displayed higher permeability to water and oxygen and higher moisture sensitivity. Subsequently, BCNW were incorporated into both PHA grades, achieving a high level of dispersion for a 1 wt.-% loading, whereas some agglomeration took place for 3 wt.-% BCNW. As evidenced by DSC analyses, BCNW presented a nucleating effect on the PHA matrices. BCNW also increased the thermal stability of the polymeric matrices when properly dispersed due to strong matrix-filler interactions. Barrier properties were seen to depend on relative humidity and improved at low nanofiller loadings and low relative humidity.

Original languageEnglish
Pages (from-to)364-376
Number of pages13
JournalNew Biotechnology
Volume31
Issue number4(SI)
DOIs
Publication statusPublished - 25 Jun 2014

Keywords

  • COMONOMER COMPOSITIONAL DISTRIBUTION
  • MECHANICAL-PROPERTIES
  • CRYSTALLIZATION KINETICS
  • POLY(3-HYDROXYBUTYRATE-CO-3-HYDROXYVALERATE)
  • MORPHOLOGY
  • BLENDS
  • POLY(3-HYDROXYBUTYRATE)
  • CRYSTALLINITY
  • BIOSYNTHESIS
  • DEGRADATION

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