Effect of 60Co γ-radiation on the properties of poly(hydroxybutyrate-co-hydroxyvalerate)

✍ Scribed by S. Luo; A. N. Netravali

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 248 KB
• Volume: 73
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19990808)73:6<1059::aid-app25>3.0.co;2-q

✦ Synopsis

The effects of 60 Co ␥-radiation on the properties of poly(hydroxybutyrateco-hydroxyvalerate) (PHBV), including the chemical, mechanical, and thermal properties, were investigated. Molecular weight of the irradiated PHBV as measured using a Ubbelohde-type capillary viscometer decreased significantly. Fourier transform infrared-attenuated total reflection (FTIR-ATR) and 1 H nuclear magnetic resonance (NMR) spectra show that chain scission was the predominant reaction in the PHBV irradiated with 10 and 25 MRad doses. The G(S) value for the chain scission was 0.9, and the number of bond cleavages per molecule was 0.22 MRad Ϫ1 . Thermal and tensile properties of control and irradiated PHBV were examined using a differential scanning calorimeter (DSC) and an Instron tensile testing machine, respectively. Results indicate that 60 Co ␥-radiation significantly affected the thermal and tensile properties of PHBV. The melting temperatures of the irradiated PHBV decreased. Tensile strength and fracture strain of the irradiated PHBV decreased dramatically, indicating increased brittleness. The fracture surfaces studied using a scanning electron microscope (SEM) showed some voids and a brittle fracture surface.