Evaluation of thermal and radiation stability of EPDM in the presence of some algal powders
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Evaluation of thermal and radiation stability of EPDM in the presence of some algal powders Traian Zaharescu1 · Carmen Mateescu1 · Andreea Dima1 · Gustavo H. C. Varca2 Received: 30 January 2020 / Accepted: 28 September 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
Abstract In this paper, ecological-friendly materials based on ethylene–propylene–diene terpolymer (EPDM) with improved thermal and radiation stabilities by Chlorella vulgaris (CV) and Spirulina platensis (SP) powders were investigated by complementary procedures: FTIR spectroscopy and isothermal and nonisothermal chemiluminescence (CL). The stabilization potential of microalgae was evaluated at several degrees of γ-radiolysis by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, while the polymer resistances were studied on a large range of algal concentrations (1, 3, 5 and 10 mass%). The carbonyl and hydroxyl indices of all degraded EPDM formulations were found to be two times smaller in the presence of algal powders, if compared to the pristine material. Some dissimilarities between the oxidation development in pristine and modified EPDM appeared, especially in unirradiated samples. The activation energies required for the oxidation of EPDM and the lifetime of these samples at various temperatures between room temperature and 100 °C were calculated. The antioxidant compounds existing in the studied microalgae proved a significant influence on the stability of EPDM, mainly in the presence of SP, which was confirmed by the activation energies calculated from our CL results. The investigation of cycling thermal degradation revealed the obvious contribution of additives towards delaying EPDM ageing. Keywords Chlorella vulgaris · Spirulina platensis · Antioxidants · EPDM · Thermal and radiation stabilization
Introduction The quality of packaging materials is mainly determined by their oxidation resistance, which hinders material degradation and the contamination of foodstuff. The growth of the microbial population and the generation of predominant hazardous oxidation products such as alcohols and ketones from polymeric material packaging are some of the main concerns related to the material degradation that often require the addition of protectors to their compositions. Additionally, the handling of perishable food requires suitable packaging Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10973-020-10319-4) contains supplementary material, which is available to authorized users. * Carmen Mateescu carmen.mateescu@icpe‑ca.ro 1
National Institute for Electrical Engineering, INCDIE ICPE CA, 313 Splaiul Unirii, P. O. Box 149, Bucharest, Romania
IPEN‑CNEN/SP, Cidade Universitaria, Avenida Lineu Prestes, São Paulo 5508‑000, Brazil
2
materials, which are properly stabilized themselves. Concerning the improvement of thermal stability, various alternatives for the protection of polymers have been proposed: synthesis antioxidants [1–3], plant extracts [4–7] or inorganic additives [8, 9]. D
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