Influence of natural ageing on mechanical, thermal and antimicrobial properties of thermoplastic elastomers containing silver nanoparticles and titanium dioxide
- 63 Downloads
The current spread of pathogenic bacteria has brought about an increase in the research for products with antimicrobial properties. Thermoplastic elastomer (TPE) compounds are widely used for personal care objects and sporting goods manufacture and may be produced with the incorporation of antimicrobial additives. TPE compounds (based on styrene–ethylene/butylene–styrene, polypropylene and mineral oil) containing silver nanoparticles (AgNp, 0.05%) and titanium dioxide (TiO2, 4.0%) was exposed to natural ageing; a compound with no antimicrobial additive (Standard) was also tested. Antibacterial activity, mechanical and thermal characteristics of TPE samples was determined after 3, 6 and 9 months of exposure. After 9 months, both Standard and AgNp-loaded samples had a loss of mechanical properties, while the TiO2 sample was more resistant to the action of natural ageing. The infrared and thermal analysis suggested that not only the chain scission, but also the segregation of components that integrate the polymer matrix were one of the causes for mechanical properties loss. Both metal-loaded samples showed a decay of antibacterial efficiency after 9 months of exposure. The decay in antibacterial action can be assigned to the presence of dirt that provides a substrate to microbial proliferation and also avoid contact between the metal-containing surfaces and microorganisms cells.
KeywordsThermoplastic elastomers Antimicrobial Natural ageing TGA DSC
The authors would like to thank FINEP for the financial support (03.13.0280.00) and Softer Brasil Compostos Termoplásticos LTDA for infrastructure support. Special thanks to additive supplier TNS Nanotecnologia Ltda.
Compliance with ethical standards
Conflict of interest
The authors declare no conflicts of interest.
- 1.Shah AA, Hasan F, Hameed A, Ahmed S (2009) Role of microorganisms in biodegradation of plastics: basics and methods in biodegradation of synthetic and natural plastics. VDM Verlag Dr., MüllerGoogle Scholar
- 2.Scott G (1997) Abiotic control of polymer biodegradation. Trends Polym Sci 5:361–368Google Scholar
- 3.Nichols D (2004) Biocides in plastics. Rapra Review Reports, UKGoogle Scholar
- 5.Sudár A, López MJ, Keledi G, Vargas-García MC, Suárez-Estrella F, Moreno J, Burgstaller C, Pukánszky B (2013) Ecotoxicity and fungal deterioration of recycled polypropylene/wood composites: effect of wood content and coupling. Chemosphere 93:408–414. https://doi.org/10.1016/j.chemosphere.2013.05.019 CrossRefGoogle Scholar
- 9.Yang T-C, Noguchi T, Isshiki M, Wu J-H (2014) Effect of titanium dioxide on chemical and molecular changes in PVC sidings during QUV accelerated weathering. Polym Degrad Stab 104:33–39. https://doi.org/10.1016/j.polymdegradstab.2014.03.023 CrossRefGoogle Scholar
- 12.INMET (National Institute of Meteorology, Instituto Nacional de Meteorologia). http://www.inmet.gov.br/sonabra/pg_dspDadosCodigo.php?QTg4NA==. Accessed 18 May 2016
- 13.Gulmine JV, Akcelrud L (2006) FTIR characterization of aged XLPE. Polym Test 25:932–942. https://doi.org/10.1016/j.polymertesting.2006.05.014 CrossRefGoogle Scholar
- 18.Ohlsson B, Hassander H, Tornell B (1996) Blends and thermoplastic interpenetrating polymer networks of polypropylene and polystyrene-block-poly(ethylene-stat-butylene)-block-polystyrene triblock copolymer 1: morphology and structure-related properties. Polym Eng Sci 36(4):501–510CrossRefGoogle Scholar
- 21.Kubacka A, Diez MS, Rojo D, Bargiela R, Ciordia S, Zapico I, Albar JP, Barbas C, Santos VAPM, Fernández-García M, Ferrer M (2014) Understanding the antimicrobial mechanism of TiO2-based nanocomposite films in a pathogenic bacterium. Sci Rep 4:4134–4143. https://doi.org/10.1038/srep04134 CrossRefGoogle Scholar
- 31.Rouillon C, Bussiere P-O, Desnoux E, Collin S, Vial C, Therias S, Gardette J-L (2016) Is carbonyl index a quantitative probe to monitor polypropylene photodegradation? Polym Degrad Stab 128:200–208. https://doi.org/10.1016/j.polymdegradstab.2015.12.011 CrossRefGoogle Scholar
- 32.Lv Y, Huang Y, Yang J, Kong M, Yang H, Zhao J, Li G (2015) Outdoor and accelerated laboratory weathering of polypropylene: a comparison and correlation study. Polym Degrad Stab 112:145–159. https://doi.org/10.1016/j.polymdegradstab.2014.12.023 CrossRefGoogle Scholar
- 34.Billmeyer FW Jr (1984) Polymer structure and physical properties. In: Textbook of polymer, 3rd edn. Wiley, USA, pp 330–355Google Scholar
- 35.Allen NS, Edge M, Ortega A, Sandoval G, Liauw CM, Verran J, Stratton J, McIntyre RB (2004) Degradation and stabilisation of polymers and coatings: nano versus pigmentary titania particles. Polym Degrad Stab 85:927–946. https://doi.org/10.1016/j.polymdegradstab.2003.09.024 CrossRefGoogle Scholar