Polymer/layered silicate nanocomposites: a review from preparation to processing

A review on polymer–layered silicate nanocomposites

BiVO4 photocatalysts for O2 evolution, which work under visible light irradiation, were prepared by an aqueous process. The BiVO4 photocatalysts were obtained by the reaction of layered potassium vanadate powder (KV3O8 and K3V5O14) with Bi(NO3)3 for 3 days in aqueous media at room temperature. Highly crystalline monoclinic and tetragonal BiVO4 were selectively synthesized by changing the ratio of vanadium to bismuth in the starting materials. X-ray diffraction and scanning electron microscopy measurements showed that the monoclinic BiVO4 was formed via a tetragonal BiVO4 intermediate. Tetragonal BiVO4 with a 2.9 eV band gap mainly possessed an ultraviolet absorption band while monoclinic BiVO4 with a 2.4 eV band gap had a characteristic visible light absorption band in addition to the UV band. The UV bands observed in the tetragonal and monoclinic BiVO4 were assigned to the band transition from O2p to V3d whereas the visible light absorption was due to the transition from a valence band formed by Bi6s or ...

A Novel Aqueous Process for Preparation of Crystal Form-Controlled and Highly Crystalline BiVO4 Powder from Layered Vanadates at Room Temperature and Its Photocatalytic and Photophysical Properties

Production, properties and potential of graphene

Structural engineering of polyurethane coatings for high performance applications

Summary: This paper reviews recent approaches for making intumescent systems The mechanisms of action involving intumescence are described and commented on Synergistic aspects using zeolites and organoclays are also considered and discussed New strategies are examined on the basis of the mechanism of intumescence The approach of using char forming polymers as additives (blend technology) is also fully discussed This consists of substituting classical polyols (char forming agents) with char forming polymers (polyamides and thermoplastic polyurethane) It will be shown that the advantages of this concept are to obtain flame-retarded (FR) polymer blends with improved mechanical properties in comparison with polymers loaded with classical formulations, and the avoidance of problems due to the water solubility of the polyols and their migration The “nanocomposite approach” enhances the performance of intumescent systems by using a nanostructured char forming polymer It will be shown that this combination of intumescence via the blending approach and nanocomposites enhances both flame retardancy and mechanical properties, and allows many specifications to be produced (for example, the design of EVA-based materials for flame retarded low voltage cables and wire) This appears to be one of the most promising ways for designing new efficient intumescent materials

Intumescent residue after LOI test of an intumescent poly(propylene)

Recent Advances for Intumescent Polymers

This work deals with new flame retardant (FR) intumescent formulations for ethylene-vinyl acetate copolymers (EVA) using charring polymers polyamide-6 (PA-6) and polyamide-6 clay nanocomposite hybrid (PA-6-nano) as carbonization agents. Use of PA-6 nano improved both the mechanical and fire properties of FR EVA-based materials. The part played by the clay in the improvement of the FR performance was studied using FTIR and solid state NMR. It is shown that the clay allowed the thermal stabilization of a phosphorocarbonaceous structure in the intumescent char which increased the efficiency of the shield and, in addition, the formation of a ‘ceramic’ which can act as a protective barrier. Copyright © 2000 John Wiley & Sons, Ltd.

PA-6 clay nanocomposite hybrid as char forming agent in intumescent formulations

Carbonization mechanisms resulting from intumescence-part II. Association with an ethylene terpolymer and the ammonium polyphosphate-pentaerythritol fire retardant system

4A zeolite synergistic agent in new flame retardant intumescent formulations of polyethylenic polymers — study of the effect of the constituent monomers

Michel Le Bras

Papers

Recent Advances for Intumescent Polymers

PA-6 clay nanocomposite hybrid as char forming agent in intumescent formulations

Carbonization mechanisms resulting from intumescence-part II. Association with an ethylene terpolymer and the ammonium polyphosphate-pentaerythritol fire retardant system

4A zeolite synergistic agent in new flame retardant intumescent formulations of polyethylenic polymers — study of the effect of the constituent monomers

Recent advances in the use of zinc borates in flame retardancy of EVA