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Observation of the degradation due to irradiation of CR 39 polymer by long-term monitoring of mass loss

Faiman, Laurence (2008) Observation of the degradation due to irradiation of CR 39 polymer by long-term monitoring of mass loss. Radiation Physics and Chemistry 77 (5), pp. 669-674. ISSN 0969-806X.

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We γ-irradiated CR 39 of three thicknesses with 51–3311 kGy. Mass loss during irradiation repeated the three-step pattern observed by Li et al. [Li, S.M., Garreau, H., Vert, M., 1990. Structure-property relationships in the case of the degradation of massive aliphatic poly(α-hydroxy acids) in aqueous media. J. Mater. Sci.: Mater. Med. 1, 123–139.] from thick PLA50. Mass loss following irradiation in thin CR 39 repeated the observations of Grizzi et al. [Grizzi, I., Garreau, H., Li, S., Vert, M., 1995. Hydrolytic degradation of devices based on poly(d,l-lactic acid) size-dependence. Biomaterials 16, 305–311.] in thin PLA50, whereas in thicker samples, it followed second-order kinetics. The graph of total mass loss per unit dose against dose absorbed displays the step-wise pattern from ESR spectroscopy [Nara, S., Shimada, S., Kashiwabara, H., Sohma, J., 1968. Relation of the decay of free radicals in irradiated polyethylene to the molecular motion of the polymer and the configuration of the free radicals. J. Polym. Sci., Polym. Phys. Ed. 6, 1435–1449.]. The implications for drug release from γ-irradiated microcapsules is discussed.

Item Type: Article
Keyword(s) / Subject(s): CR 39, sterilization, γ-irradiation, weight loss, bio-resorbable polymers, controlled release, free-radical decays, phase transitions
School or Research Centre: Birkbeck Schools and Research Centres > School of Science > Biological Sciences
Depositing User: Administrator
Date Deposited: 02 Aug 2011 09:50
Last Modified: 17 Apr 2013 12:21

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