Microporous polyolefin strands as controlled-release devices for mosquito repellents

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dc.contributor.author Mapossa, António Benjamim
dc.contributor.author Sibanda, Mthokozisi Mayibongwe
dc.contributor.author Sitoe, Alcides
dc.contributor.author Focke, Walter Wilhelm
dc.contributor.author Braack, L.E.O.
dc.contributor.author Ndonyane, Cyril
dc.contributor.author Mouatcho, Joel Claude
dc.contributor.author Smart, Jansie
dc.contributor.author Muaimbo, Herminio
dc.contributor.author Androsch, Rene
dc.contributor.author Loots, Mattheus Theodor
dc.date.accessioned 2019-07-16T14:51:46Z
dc.date.issued 2019-03
dc.description.abstract The main vectors of malaria in Africa, i.e. An. arabiensis, An. gambiae s.s. and An. funestus, are attracted by human foot odour and they tend to bite victims in the ankle area. Hence, affordable mosquito-repellent polymer-foot bracelets with long lasting protection could reduce infective lower limb bites and therefore help to reduce the overall malaria transmission rate. This study investigated the possibility of increasing the duration of repellence activity by incorporating repellents into inexpensive thermoplastic polymers, namely poly(ethylene-co-vinyl acetate) (EVA) and linear low-density polyethylene (LLDPE). Volatile repellents need to be released into the surrounding air to be effective, i.e. they are continuously lost to the atmosphere. This means that the bracelet should also act as a reservoir for relatively large quantities of the active compound. Towards this goal, polymer strands containing mosquito repellent were prepared by twin-screw extrusion compounding. A co-continuous phase structure was achieved by rapid quenching in an ice bath of the homogeneous polymer-repellent melt mixture exiting the extruder. Phase separation occurred through spinodal decomposition that trapped the liquid repellent in the microporous polymer matrix. A skin-like membrane that covered the extruded polymer strands controlled the release rate. Strands that contained up to 30 wt-% of either DEET or Icaridin provided effective protection against mosquito bites even after 12 weeks of ageing at 50 °C. en_ZA
dc.description.department Chemical Engineering en_ZA
dc.description.department Medical Virology en_ZA
dc.description.department Statistics en_ZA
dc.description.embargo 2020-03-15
dc.description.librarian hj2019 en_ZA
dc.description.sponsorship The Deutsche Forschungsgemeinschaft (DFG), Germany, under Grant AN 212/22-1. en_ZA
dc.description.uri http://http://www.elsevier.com/locate/cej en_ZA
dc.identifier.citation Mapossa, A.B., Sibanda, M.M., Sitoe, A. et al. 2019, 'Microporous polyolefin strands as controlled-release devices for mosquito repellents', Chemical Engineering Journal, vol. 360, pp. 435-444. en_ZA
dc.identifier.issn 1385-8947 (print)
dc.identifier.issn 1873-3212 (online)
dc.identifier.other 10.1016/j.cej.2018.11.237
dc.identifier.uri http://hdl.handle.net/2263/70739
dc.language.iso en en_ZA
dc.publisher Elsevier en_ZA
dc.rights © 2018 Elsevier B.V. All rights reserved. Notice : this is the author’s version of a work that was accepted for publication in Chemical Engineering Journal . Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. A definitive version was subsequently published in Chemical Engineering Journal, vol. 360, pp. 435-444, 2019. doi : 10.1016/j.cej.2018.11.237. en_ZA
dc.subject Mosquito repellent en_ZA
dc.subject Controlled release en_ZA
dc.subject Spinodal decomposition en_ZA
dc.subject Icaridin en_ZA
dc.subject DEET en_ZA
dc.subject Host en_ZA
dc.subject Culex en_ZA
dc.subject Diptera en_ZA
dc.subject Induced phase separation en_ZA
dc.subject Anopheles arabiensis en_ZA
dc.subject Membrane formation en_ZA
dc.subject Aedes albopictus en_ZA
dc.subject Microencapsulation en_ZA
dc.subject Behavior en_ZA
dc.subject Efficacy en_ZA
dc.title Microporous polyolefin strands as controlled-release devices for mosquito repellents en_ZA
dc.type Postprint Article en_ZA


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