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Materials 2015, 8(9), 5621-5646;

Influence of Flame Retardants on the Melt Dripping Behaviour of Thermoplastic Polymers

BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, Berlin 12205, Germany
Institute for Materials Research and Innovation, University of Bolton, Deane Road, Bolton BL3 5AB, UK
Author to whom correspondence should be addressed.
Academic Editor: Rodolphe Sonnier
Received: 19 June 2015 / Revised: 14 August 2015 / Accepted: 20 August 2015 / Published: 27 August 2015
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Melt flow and dripping of the pyrolysing polymer melt can be both a benefit and a detriment during a fire. In several small-scale fire tests addressing the ignition of a defined specimen with a small ignition source, well-adjusted melt flow and dripping are usually beneficial to pass the test. The presence of flame retardants often changes the melt viscosity crucially. The influence of certain flame retardants on the dripping behaviour of four commercial polymers, poly(butylene terephthalate) (PBT), polypropylene (PP), polypropylene modified with ethylene-propylene rubber (PP-EP) and polyamide 6 (PA 6), is analysed based on an experimental monitoring of the mass loss due to melt dripping, drop size and drop temperature as a function of the furnace temperature applied to a rod-shaped specimen. Investigating the thermal transition (DSC), thermal and thermo-oxidative decomposition, as well as the viscosity of the polymer and collected drops completes the investigation. Different mechanisms of the flame retardants are associated with their influence on the dripping behaviour in the UL 94 test. Reduction in decomposition temperature and changed viscosity play a major role. A flow limit in flame-retarded PBT, enhanced decomposition of flame-retarded PP and PP-EP and the promotion of dripping in PA 6 are the salient features discussed. View Full-Text
Keywords: fire retardant; viscosity; melt dripping; reaction-to-small-flame; UL 94 fire retardant; viscosity; melt dripping; reaction-to-small-flame; UL 94

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Matzen, M.; Kandola, B.; Huth, C.; Schartel, B. Influence of Flame Retardants on the Melt Dripping Behaviour of Thermoplastic Polymers. Materials 2015, 8, 5621-5646.

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