Improving fire retardancy nanoparticles

Nanoparticles added to thermoplastic polymers improve the mechanical properties, increase Tg and enhance fire retardancy. Nanoparticles in UPRs bring similar effects [217]. Montmorillonite (MMT) was used to obtain polymer nanocomposites [218]. That general approach was applied to the UPR-layered MMT nanocomposites. The structure of the nanocomposites was investigated by XRD and TEM. Organophilic MMT was applied dodecylammonium-bromide treated MMT was used. A UPR synthesized... 

This chapter develops at first the more frequent combinations of nanoparticles that concern layered silicates associated with phosphorus compounds, as well as metallic hydroxides and halogen compounds. The association of natural layered silicates with intumescent FR (IFR) systems represents one of the main contributions of the combined use of nanoparticles and FRs. Moreover, combinations of layered silicates with other phosphorus compounds have been studied and have led to significant improvements for fire retardancy. 

The use of nanoparticles in combination with additional materials has been widely studied, with the aim to improve the fire retardancy of nanocomposites. 

Based on the size, fillers can be broadly classified into two categories, micro and nano sized fillers. Lighter, thinner, stronger and cheaper structures are the goals of material science and engineering applications today. Nanoparticles satisfy these requirements. The use of nanofillers improves mechanical and physical polymer properties. The added cost of the nanofilled matrix can be low due to the small amounts of filler necessary for a significant improvement. Nanofillers can significantly improve or adjust the properties of the materials into which they are incorporated, such as optical, electrical, mechanical, thermal or fire-retardant properties. 

Nowadays a variety of nanoparticles have been used to fabricate fire retardant nanocomposites with improved mechanical and functional properties. The common... 

Composites prepared using different types of nanoparticles can show superior properties compared to pure PU and have a wide range of applications in structural and biomedical fields. The surface morphology of nanocomposites is affected by the nature and amount of the nanoparticles embedded in polymer matrix. Different shapes and sizes of the nanoparticles play a significant role in enhancement of the mechanical, rheological, thermal, and fire retardant properties of the PU nanocomposites. Considerable improvements in antibacterial properties have been reported using nanocomposites compared to pure PU. Incorporation of the different kinds of nanoparticles in PU matrix alters the biocompatible nature of the composites, suggesting that PU composites may have use in biomaterial applications. 

A. Laachachi, E. Leroy, M. Cochez, M. Ferriol, and J. M. Lopez-Cuesta, Use of oxide nanoparticles and organoclays to improve thermal stability and fire retardancy of poly(methyl methacrylate). Polymer Degradation and Stability, 89 (2005), 344-52. 

In conclusion, although their appears to be no general improvement in fire performance when nanoclays are added to conventionally flame-retarded resins, there is evidence that in certain formulations, such as those containing APP and ATH, some benefits are observed, and this opens opportunities for favorable introduction of nanoclays and other nanoparticles in flame retardant resin formulations for use in reinforced composites that have improved fire properties. 

In case of immiscible polymer pairs the ternary mixture is more stable thermodynamically (their adsorption on the surface of solid particle is more preferred than that of a miscible polymer pair). This is the basis of the nanocompatibilization (i.e. compatibilization with the aid of nanoparticles). Performance fire retardant system of polypropylene (PP) and phosphorylated epoxy resin (PEP) was reported to improve when montmorillonite nanoclay was introduced. Without nanoclay the distribution of epoxy in PP matrix was inhomogenous, while homogeneous nanodispersion could be achieved after attachment of PEP to clay nanoparticles as interlayer. (8). 

Z. Wang, E. Han, and W. Ke, Effect of nanoparticles on the improvement in fire-resistant and anti-ageing properties of flame-retardant coating, Surf. Coat. Technol., 2006, 200 5706-5716. 

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