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Fire Resistance Lower FRs loading with Intumescent materials
Posted on November 22, 2017 by Henri VAHABI
Influence of Flame Retardants on the Melt Dripping Behaviour of Thermoplastic Polymers
Posted on August 31, 2015 by Henri VAHABI
Published: 27 August 2015
Download: pdf
Abstract: 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.
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Influence of clay dispersion on flame retardancy of ABS/PA6/APP blends
Posted on April 8, 2015 by Henri VAHABI
This article was published in Polymer Degradation and Stability, April 2015.
Abstract
Influence of dispersion of clay in acrylonitrile–butadiene–styrene/nylon-6 (ABS/PA6) blends on flame retardancy was investigated. The results of FTIR spectra and transmission electron microscopy (TEM) showed that ammonium polyphosphate (APP) and clay were exclusively dispersed in the PA6 phase. Clay modified with poly (styrene-co-maleic anhydride) (SMA) was selective localization at the interface of blends. Introduction of clay and modified clay to blends caused the dispersion of clay not only in PA6 phase, but also at the interface. The flame retardancy was evaluated by limiting oxygen index (LOI), vertical flammability test, and cone calorimeter tests. For the blends with dispersed PA6 phase, the dispersion of clay only in PA6 phase or at interface had negative effect on flame retardant property. Morphology of residue char characterized by scanning electron microscope (SEM) showed that the inhibition of clay platelets on the expansion of residue char should be responsible for the deterioration of flame retardant properties. When clay dispersed both in PA6 phase and at the interface, the reinforcement of clay platelets on residue char caused the formation of compact and continuous superficial char, resulting in significant improvement of flame retardancy. In blends with continuous PA6 phase, introducing clay to blends caused the formation of compact and continuous superficial char thus improved the flame retardancy no matter where the clay dispersed in blends. The characterization of energy dispersive spectrometry (EDS) revealed that the morphology of char was determined by the dispersion of clay platelets in residue char.
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Adequation between flame retardant solutions and industrial constraints
Posted on February 25, 2015 by Henri VAHABI
4th national conference organized by the Group «Thermal degradation and fire behavior of organic materials» of the Société Chimique de France (SCF)
Adequation between flame retardant solutions and industrial constraints
11th and 12th March 2015
Université de Lorraine
IUT de Moselle-Est
Saint Avold – FRANCE
Program: click here (english version)
(French version)
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Posted on February 23, 2015 by Henri VAHABI
NEWS FROM SP FIRE RESEARCH- N° 51
– New book on Tunnel Fire Dynamics
– Fire safety in wood buildings – A course at Linnaeus University
– Comparison of composition of fire gases from small-scale and
large-scale tests ….
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DOPO-VTS-based coatings in the realm of fire retardants for cotton textile
Posted on February 13, 2015 by Henri VAHABI
This article was published in Journal of Applied Polymer Science, 28 JAN 2015
ABSTRACT
The work elucidates the feasibility of incorporation of phosphorus-silicon containing fire retardant (10-(2-trimethoxysilyl-ethyl)-9-hydro-9-oxa-10-phosphaphenanthrene-10-oxide [DOPO-VTS]) into nanosol coating solutions by cohydrolysis cocondensation reaction of DOPO-VTS with tetraethoxysilane precursor (TEOS). Impregnation of cotton with the organophosphorus silane in a form of nanosol dispersion afforded better fire retardancy of such samples compared to pure DOPO or TEOS-treated cotton indicating synergism between phosphorus and silicon containing species in a condensed phase. The detailed analysis by TGA-MS and SEM pointed to the fact that DOPO-VTS acts as a promoter of cotton degradation which, in turn, results in acceleration of the charring process and formation of compact char in contrast to TEOS-treated samples. Further analysis of the char by XPS confirmed high content of carbonaceous residue in the case of DOPO-VTS-treated samples while mainly siliceous component was left in the char in case of cotton treated with TEOS. Standard flammability test (EN ISO 15025:2008) additionally confirmed the absence of smoldering and better overall fire performance of the DOPO-VTS samples in contrast to TEOS-treated samples.
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Pinfa Newsletter N°48
Posted on January 8, 2015 by Henri VAHABI
Pinfa Newsletter N°48 is now available
Download pdf document : click here
The weblink is http://www.pinfa.eu/media/newsletters/236-non-halogen-fire-safety-solutions-pinfa-newsletter-issue-nd-48.html
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EFRA Newsletter
Posted on December 18, 2014 by Henri VAHABI
The EFRA Newsletter, December 2014 edition, is published. pdf format: click here
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Two PhD dissertations
Posted on December 12, 2014 by Henri VAHABI
THERMAL INSULATION OF POLYMERIC COMPOSITES USING SURFACE TREATMENTS
Flame retardant and dyeing treatment of cellulose fabrics using a combined “grafting from” and PIGP process
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A Green and Renewable Intumescent Flame Retardant System for Ethylene-Vinyl Acetate
Posted on November 25, 2014 by Henri VAHABI
This paper was published in Ind. Eng. Chem. Res. journal:
Chitosan/Phytic Acid Polyelectrolyte Complex: A Green and Renewable Intumescent Flame Retardant System for Ethylene-Vinyl Acetate Copolymer
Abstract
We describe the preparation and characterization of a green and renewable polyelectrolyte complex (PEC) containing phosphorus, nitrogen and carbon elements, based on the ionic complexation between chitosan and phytic acid. Introduction of this PEC to ethylene-vinyl acetate copolymer (EVA) leads to an improvement of the flame retardancy. As for the EVA/PEC composites with 20.0 wt % of PEC (EVA/20PEC), the char residue at 600 oC is 12 wt % higher than that of the pristine EVA under nitrogen atmosphere. Compared to the pristine EVA, the peak heat release rate and total heat release of EVA/20PEC show 249 W g-1 and 5.6 kJ g-1 decreases, respectively. The char residue of EVA/20PEC is full and compact, demonstrating excellent intumescent effect. Introduction of this PEC also contributes to a slight increase of the Young’s modulus while maintains the excellent ductility. This work provides a new approach for the development of environmentally friendly intumescent flame retardant system.
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Flame retardancy of polymers 