title: Biodegradability of Poly-3-hydroxybutyrate/Bacterial Cellulose Composites under Aerobic Conditions, Measured via Evolution of Carbon Dioxide and Spectroscopic and Diffraction Methods.
abstract: Poly-3-hydroxybutyrate (PHB) and bacterial cellulose (BC) are both natural polymeric materials that have the potential to replace traditional, nonrenewable polymers. In particular, the nanofibrillar form of bacterial cellulose makes it an effective reinforcement for PHB. Neat PHB, bacterial cellulose, and a composite of PHB/BC produced with 10 wt % cellulose were composted under accelerated aerobic test conditions, with biodegradability measured by the carbon dioxide evolution method, in conjunction with spectroscopic and diffraction methods to assess crystallinity changes during the biodegradation process. The PHB/BC composite biodegraded at a greater rate and extent than that of PHB alone, reaching 80% degradation after 30 days, whereas PHB did not reach this level of degradation until close to 50 days of composting. The relative crystallinity of PHB and PHB in the PHB/BC composite was found to increase in the initial weeks of degradation, with degradation occurring primarily in the amorphous region of the material and some recrystallization of the amorphous PHB. Small angle X-ray scattering indicates that the change in PHB crystallinity is accompanied by a change in morphology of semicrystalline lamellae. The increased rate of biodegradability suggests that these materials could be applicable to single-use applications and could rapidly biodegrade in compost on disposal.
authors.affiliation: ‡Department of Materials Engineering, Monash University, Clayton, Victoria 3800 Australia.
authors.forename: Dianne R
authors.initials: DR
authors.lastname: Ruka
authors.forename: Parveen
authors.initials: P
authors.lastname: Sangwan
authors.affiliation: §Australian Nuclear Science and Technology Organisation, Kirrawee, New South Wales 2232, Australia.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Garvey
authors.affiliation: ‡Department of Materials Engineering, Monash University, Clayton, Victoria 3800 Australia.
authors.forename: George P
authors.initials: GP
authors.lastname: Simon
authors.affiliation: ‡Department of Materials Engineering, Monash University, Clayton, Victoria 3800 Australia.|∥D3 Consulting Group Pty Ltd., Fitzroy North, Victoria 3068, Australia.
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Dean
mesh_terms: D000332:Aerobiosis; D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D018441:Biofilms; D019149:Bioreactors / Q000382:microbiology; D002245:Carbon Dioxide / Q000032:analysis*; D002482:Cellulose / Q000378:metabolism*; D003460:Crystallization; D006885:Hydroxybutyrates / Q000378:metabolism*; D011091:Polyesters / Q000378:metabolism*; D053838:Scattering, Small Angle; D017550:Spectroscopy, Fourier Transform Infrared; D013997:Time Factors; D014961:X-Ray Diffraction / Q000379:methods*; D000094122:Polyhydroxybutyrates
chemical_list: D002245:Carbon Dioxide; D002482:Cellulose; D006885:Hydroxybutyrates; D011091:Polyesters; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates