caa a22 4500 463233476 CHVBK 20180405153249.0 cr unu---uuuuu 170326e20070601xx s 000 0 eng 10.1007/s10853-006-1411-y doi (NATIONALLICENCE)springer-10.1007/s10853-006-1411-y Influence of electron irradiation on the crystallisation, molecular weight and mechanical properties of poly-( R )-3-hydroxybutyrate [Elektronische Daten] [Antje Bergmann, Jörg Teßmar, Anthony Owen] 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. Springer Science+Business Media, LLC, 2007 Bergmann Antje Institute of Applied Physics, University of Regensburg, 93040, Regensburg, Germany aut Teßmar Jörg Institute of Pharmaceutical Technology, University of Regensburg, 93040, Regensburg, Germany aut Owen Anthony Institute of Applied Physics, University of Regensburg, 93040, Regensburg, Germany aut Journal of Materials Science Kluwer Academic Publishers-Plenum Publishers; http://www.springer-ny.com 42/11(2007-06-01), 3732-3738 0022-2461 42:11<3732 2007 42 10853 https://doi.org/10.1007/s10853-006-1411-y text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10853-006-1411-y text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Bergmann Antje Institute of Applied Physics, University of Regensburg, 93040, Regensburg, Germany aut NATIONALLICENCE 700 1- Teßmar Jörg Institute of Pharmaceutical Technology, University of Regensburg, 93040, Regensburg, Germany aut NATIONALLICENCE 700 1- Owen Anthony Institute of Applied Physics, University of Regensburg, 93040, Regensburg, Germany aut NATIONALLICENCE 773 0- Journal of Materials Science Kluwer Academic Publishers-Plenum Publishers; http://www.springer-ny.com 42/11(2007-06-01), 3732-3738 0022-2461 42:11<3732 2007 42 10853 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer