Abstract
Biosynthetic poly[(R)-3-hydroxybutyrate] (PHB) undergoes a deleterious ageing process which has been attributed to progressive crystallisation. In this work an attempt has been made to arrest this crystallisation behaviour by an irradiation treatment which is known to induce cross-linking in many polymers. PHB films were irradiated with different doses of electrons and at different times after the initiation of crystallisation. The degree of crystallinity was subsequently determined as a function of time after irradiation using wide-angle X-ray scattering measurements. In addition, melting endotherms were obtained by differential scanning calorimetry (DSC) and molecular weights by gel permeation chromatography (GPC). Corresponding tensile stress–strain experiments were performed in order to obtain information on the mechanical properties of the sample films. The melting point and molecular weights were found to decrease linearly with radiation dose indicating that higher radiation doses cause degradation due to chain scission. However, lower doses applied to samples still in their amorphous state indicate a high degree of cross-linking, in which a network is formed and the ageing process can be prevented to some extent. The tensile modulus and breaking strain were influenced strongly by the point in time at which the material was irradiated during crystallisation.
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References
Müller HM, Seebach D (1993) Angew Chem Int Ed Engl 32:477
Holmes PA (1988) In: Bassett DC (ed) Developments in crystalline polymers. Elsevier, Amsterdam
Doi Y (1990) Microbial polyesters. VCH, Weinheim
Barham PJ, Keller A (1986) J Polym Sci 24:69
Scandola M, Ceccorulli G, Pizzoli M (1992) Macromolecules 25:6441
Koning GJM, Lemstra PJ (1993) Polymer 19:4089
Koning GJM, Lemstra PJ, Hill DJT, Carswell TG, O’Donnell JH (1992) Polymer 15:3295
Biddlestone F, Harris A, Hay JN, Hammond T (1996) Polym Int 39:221
Mitomo M, Watanabe Y, Ishigaki I, Saito T (1994) Polym Deg Stab 45:11
Yang H, Liu J (2004) Polym Int 53:1677
Luo S, Netravali AN (1999) J Appl Polym Sci 73:1059
Rouxhet L, Legras R (2000) Nucl Instr Meth Phys Res B 171:487
Bergmann A, Owen AJ (2003) Polym Int 52:1145
Acknowledgments
We thank Reinhard Bauer from BGS for his friendly assistance. We are grateful to the FNR (Fachagentur für Nachwachsende Rohstoffe), an organisation of the German Federal Ministry of Consumer Protection, Food and Agriculture, for financial support for this work. Thanks are also due to Professor D. Göritz for helpful advice regarding cross-linking and rubber-like behaviour.
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Bergmann, A., Teßmar, J. & Owen, A. Influence of electron irradiation on the crystallisation, molecular weight and mechanical properties of poly-(R)-3-hydroxybutyrate. J Mater Sci 42, 3732–3738 (2007). https://doi.org/10.1007/s10853-006-1411-y
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DOI: https://doi.org/10.1007/s10853-006-1411-y