Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and wheat straw fibre composites: thermal, mechanical properties and biodegradation behaviour
Tóm tắt
The thermal and mechanical behaviour of a biotechnological polyester (poly(3-hydroxybutyrate-co-hydroxyvalerate) (PHBV) reinforced with wheat straw fibres has been investigated. In order to improve chemico-physical interactions between the components, the reinforcing agent has been previously submitted to a treatment with high temperature steam leading to fibres richer in cellulose and more reactive. The addition of straw fibres has been found to increase the rate of PHBV crystallisation, while it does not affect the crystallinity content. Furthermore, the comparison of the mechanical properties has shown that the composites exhibit higher Young moduli and lower values of both the stress (σB) and strain (∈B) to break than the neat matrix of PHBV. The biodegradability in different environments by means of short and long term tests has been studied. It has been observed that the presence of straw does not affect biodegradation rate evaluated in liquid environment and in long term soil burial tests. In the composting simulation test the rate of biodegradation is reduced for composites with more than 10% of straw content. The morphology of the composites has also been investigated and correlated to the biodegradation process.
Tài liệu tham khảo
S. Y. Lee, Biotechnol. Bioeng. 49 (1996) 1.
J. Anderson and E. A. Dawes, Microbiol. Rev. 54 (1990) 450.
Y. Doi, “Microbial Polyester” ( VCH, New York, 1990).
M. Avella, E. Martuscelli, B. Pascucci, M. Raimo, B. Focher and A. Marzetti, J. Appl. Polym. Sci. 49 (1993) 2091.
B. Focher, A. Marzetti and V. Crescenzi, (eds.), “Steam Explosion Techniques: Fundamentals and Applications” (Gordon and Breach Science Publs., Philadelphia, 1991)
K. E. L. Eriksson, R. A. Blanchette, and P. Ander, (eds.), “Microbial and enzymatic degradation of wood and wood components” (Springer-Verlag, Berlin, 1990).
ASTM (1992). Standard Test Method for Determining the Aerobic Biodegradation of Plastic Materials in the Presence of Municipal Sewage Sludge. ASTM D 5209.
ASTM (1992). Standard Test Method for Determining Aerobic Biodegradation of Plastic Materials under Controlled Composting Conditions. ASTM D 5338.
P. J. Barham, A. Keller, E. L. Otun and P. A. Holmes, J. Mater. Sci. 19 (1984) 2781.
M. Avella, L. Calandrelli, B. Immirzi, M. Malinconico, E. Martuscelli, B. Pascucci and P. Sadocco, J. Environ. Pol. Degrad. 3 (1995) 49.
T. L. Bluhm, G. K. Hamer, R. H. Marchessault, C. A. Fyfe and R. P. Veregin, Macromolecules 19 (1986) 2871.
D. C. Bassett, R. H. Olley and I. A. M. Al raheil, Polymer 29 (1988) 1745.
J. P. Bell and T. J. Murayama, J. Polymer Sci. 7 A-2 (1969) 1059.
T. K. Kirk and R. Farrell, Annu. Rev. Microbiol. 41 (1987) 465.
M. Canetti, M. Urso and P. Sadocco, Polymer 40 (1999) 2587.
J. Tapja and R. Vicuna, Appl. Environ. Microbio'. 61 (1995) 2476.
Y. Kumagai, Y. Kanesawa and Y. Doi, Makrom. Chem. 193 (1992) 53.
G. Tomasi, M. Scandola, B. H. Briese and D. Jendrossek, Macromolecules 29 (1996) 507.