  Preparation of fire-resistant poly(styrene-co-acrylonitrile) foams using supercritical CO2 technologyUrbanczyk, Laetitia  ; ; Calberg, Cédric et alin Journal of Materials Chemistry (2010), 20 This work deals with the preparation and characterization of fire-resistant poly(styrene coacrylonitrile) (SAN) foams containing (organo)clays and/or melamine polyphosphate (MPP) as fire retardants using ... [more ▼] This work deals with the preparation and characterization of fire-resistant poly(styrene coacrylonitrile) (SAN) foams containing (organo)clays and/or melamine polyphosphate (MPP) as fire retardants using supercritical CO2 as the foaming agent. The additives dispersion was first characterized with X-ray and transmission electron microscopy (TEM) analyses. Their presence clearly affected the cellular morphology, as observed by scanning electron microscopy (SEM). Then, the peak of heat release rate (PHRR) and total heat evolved (THE) were determined with a cone calorimetry test, performed on each foamed sample as a function of the foam density. Incorporation of clay (3 and 5 wt%) in the exfoliated state into the SAN foam clearly led to a significant decrease of PHRR, while intercalated and aggregated clay had a lower effect. Similar results were obtained with 10 and 20 wt% of MPP. The best results were obtained when exfoliated clay and MPP were combined, with a PHRR drop as large as 75%, thanks to the synergistic action of both additives. The magnitude of PHRR drop, related to the fire resistance, was found to be in direct relationship with the cohesiveness of the protective carbonaceous layer formed at the sample surface during combustion. Clay and MPP, when added together, are thus believed to favour the formation of a highly cohesive protective layer able to act as an efficient shield against the flame, despite the fact that the sample is originally composed of ~90% of voids. [less ▲] Detailed reference viewed: 61 (19 ULg) Morphology and properties of SAN-clay nanocomposites prepared principally by water-assisted extrusion; Urbanczyk, Laetitia ; Calberg, Cédric et alin Polymer Engineering & Science (2010), 50(1), 10-21 An efficient extrusion process involving the injection of water while processing was used to prepare poly(styrene-co-acrylonitrile) (SAN) / clay nanocomposites with a high degree of nanoclay delamination ... [more ▼] An efficient extrusion process involving the injection of water while processing was used to prepare poly(styrene-co-acrylonitrile) (SAN) / clay nanocomposites with a high degree of nanoclay delamination. The usefulness of water-assisted extrusion is highlighted here, in comparison with classical extrusion and roll mill processes. Cloisite® 30B (C30B), a montmorillonite clay organomodified with alkylammonium cations bearing 2-hydroxyethyl chains, and pristine montmorillonite were melt blended with SAN (25wt% AN) in a semi-industrial scale extruder specially designed to allow water injection. XRD analysis, visual and TEM observations were used to evaluate the quality of clay dispersion. The relationship between the nanocomposite morphology and its mechanical and thermal properties was then investigated. The superiority of the SAN/C30B nanocomposite extruded with water has been evidenced by cone calorimetry tests and thermogravimetric measurements (TGA). These analyses showed a substantial improvement of the fire behavior and the thermal properties, while a 20% increase of the Young modulus was recorded. [less ▲] Detailed reference viewed: 99 (6 ULg)Organoclays prepared in supercritical CO2: implication of onium stability on the properties of PA6 nanocompositesNaveau, Elodie ; Calberg, Cédric ; Detrembleur, Christophe et alConference (2009, June 23) The organomodification of layered silicates via our patented supercritical CO2 ion-exchange process, enables the use of a large variety of surfactants, among which phosphonium and ammonium ions of the ... [more ▼] The organomodification of layered silicates via our patented supercritical CO2 ion-exchange process, enables the use of a large variety of surfactants, among which phosphonium and ammonium ions of the very same structure. The as-obtained organoclays were melt blended with PA6 and the morphology as well as the fire properties of the nanocomposites were studied. With the same degree of nanodispersion, longer ignition times were observed with phosphonium-modified clays compared to ammonium-modified clays. [less ▲] Detailed reference viewed: 39 (10 ULg)About the use of PCL/clay nanohybrid masterbatches; ; et al Poster (2008, September 09) Detailed reference viewed: 23 (8 ULg)About the use of PCL/clay nanohybrid masterbatches; ; et al Conference (2008, September 09) Detailed reference viewed: 18 (9 ULg)Thermal behaviour of well-dispersed poly(styrene-co-acrylonitrile)/clay nanocomposites prepared by using supercritical technologyUrbanczyk, Laetitia ; Alexandre, Michaël ; et alPoster (2008, September 08) Detailed reference viewed: 7 (1 ULg)Effect of the addition of nanoclay on the extrusion foaming of poly(styrene-co-acrylonitrile) with supercritical carbon dioxideUrbanczyk, Laetitia ; Calberg, Cédric ; et alConference (2008, May 22) Detailed reference viewed: 12 (5 ULg) |
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