Flame Retardants

The present chapter deals with a brief account on various types topics in flame retardant of polymer nanocomposites. This chapter discussed with different topics such as flame retardancy of polymer nanocomposite, recent developments in different techniques used for the flame retardancy, recent development of phosphorus flame retardants in thermoplastic blends and nanocomposites, non-halogen flame retardants in epoxy-based composites and nanocomposites, flame retardant/resistant based nanocomposites in textile, flame retardants in bitumens and nanocomposites, fire retardant for phase change material, flame retardant finishing for textiles, flame retardant of cellulosic materials and their composites.

Nanofillers such as carbon nanotubes and clay are attractive materials, because addition of small amount of nanofillers can improve mechanical, thermal and electrical properties of plastics without changing processability. However, nanofillers themselves do not show excellent fire retardancy such as self-extinguish properties. Nanofillers should be combined with other fire retardants. Some combination showed positive synergy effect in fire retardancy, but some case showed negative synergy. It is important to know fire retardant mechanism of nanofiller to develop more efficient fire-retardant nanocomposites. In this chapter, we’ll show the fire retardant mechanism of nanofillers. Then, effective combination of nanofiller and conventional fire retardant is introduced reviewing lots of papers.

To improve the flame retardancy of polymer blends, composites and nanocomposites for extending their application, recent developments in different techniques used for the flame retardancy are reviewed in this chapter. We introduce the fundamentals of experimental methods such as cone calorimetry and UL 94 used to describe fire behavior. Also the pyrolysis process of condensed phrase is presented to prevent further pyrolysis of polymeric materials. Additionally, the combustion process of polymeric materials is described for selecting feasible flame retardants to reduce the amount of flammable volatiles emitted during combustion. At the same time, the smoke formation is discussed during fire for reduce smoke to protect environments and human’s health. Finally, the future trends of different techniques utilized for the flame retardancy are introduced such as nanotechnology, catalysis reaction, vapor phase flame retardant and flame retardant synergy.

With the increasing use of thermoplastics and thermosetting polymers on a large scale for applications in buildings, transportation, electrical engineering and electronics, as well as the high fires safety standards which polymer resins should meet, a large variety of flame retardant products have been developed over the past 40 years. Restrictions on the use of polybrominated diphenyl ethers (PBDE) have resulted in the increased use of alternate flame retardant chemicals, such as phosphorus flame retardants (PFR). PFR contains a wide group of different organic and inorganic compounds, with a great variation in their physico-chemical properties. They are non-flammable, non-explosive and odorless substances listed as High Production Volume Chemicals (HPV). Non-halogen, phosphorus-containing flame retardants such as ammonium polyphosphate and red phosphorus are shown to be very effective in thermoset resins. Phosphate esters significantly lower the heat distortion temperature and impact properties of PC/ABS blends while increasing melt flow in so called antiplasticization process. Resorcinol diphosphate (RDP) was the first material developed for PC/ABS and it is a liquid additive with 9 % P content and good efficacy as a flame retardant. Bisphenol A bisphosphate (BADP) is another liquid with properties similar to RDP. Polymer–clay nanocomposites have attracted a great deal of interest due to their improved mechanical, thermal and biodegradability properties. Nano “sponge” structures produced from cyclodextrins have been tested with flame retardants ammonium polyphosphate (APP) and triethylphopshate. The PFRs can be enclosed in the nano sugar sponge structure, improving mixing with plastic polymers and enabling high flame retardant loadings without deteriorating polymer mechanical performance. Fire performance tests using the nano sugar sponge—PFR combination (heat release, heat of combustion, mass loss, smoke) showed that the combination was effective for environmentally friendly structures polypropylene, linear low density polyethylene and polyamide 6.

Since more environmental regulations restricted to the use of halogen-based flame retardants are issued the halogen-free flame retardants have been gradually increased in demand at electronics applications. Several DOPO derivatives and recently developed phosphorus containing flame retardants are introduced into the market as a counterpart of tetrabromobisphenol A (TBBA). This short review paper focuses on their flame retardancy and material properties in epoxy resins. The inclusions of inorgano-metallic compounds and nanoparticles are also briefly reviewed for their potential opportunities in the epoxy composites.

Due to the increasing consideration in nanotechnology during the past decade, numerous studies were undertaken in improving the flame retardancy properties of natural, artificial and synthetic fibers as well as fabrics by applying nanocomposite approach. This chapter considers key issues concerning traditional and novel approaches or processes to develop nanocomposites coating, nanocoatings on textile as well as the incorporation of nanoparticles into fibers. The incorporation of nanocomposite to form flame retardant coatings onto the surface of textiles or to functionalize fibers by melt spinning which can be subsequently woven or knitted are mainly related for application fields required high performance such as automotive, protective clothing, etc.

To realize the flame retardant of bitumens correctly is of great significance for academicians and technicians. This chapter begins by introducing the types and properties of conventional flame retardants modified bitumen. It then based on exist disadvantages of conventional flame retardants modified bitumen, further introduces environmental friendly flame retardants using in bitumen and bitumen/flame retardants nanocomposites. The chapter finally outlines a short commentary on likely future trends and provides some sources of further information and advice.

Fire-retarded form-stable phase change material (PCM) products consisting of paraffin (RT21) (or propyl ester), high density polyethylene (HDPE) and fire retardants were prepared using the Brabender Plastograph. The properties of the form-stable PCM, containing different types of fire retardants such as magnesium hydroxide, aluminium hydroxide, expanded graphite (EG), ammonium polyphosphate (APP), pentaerythritol (PER) and treated montmorillonite (MMT) were classified using vertical burning test, thermogravimetry analysis (TGA) and differential scanning calorimeter (DSC). The results from the vertical burning test have shown that the form-stable PCM which contained APP + PER + MMT and APP + EG showed the best improvement in fire retardancy since it can self-extinguish by forming a large residue. The TGA graphs showed that addition of fire retardants has increased thermal stability of material by increasing the amount or residues formed, which was also supported by the Con Calorimeter testing, while DSC results showed that adding fire retardants to PCM did not change its thermal properties significantly.

State of the art and perspectives on chemicals and techniques which have been developed in textile finishing for conferring flame retardant properties to natural and synthetic fibres are discussed in this review. An overview on the mechanism of combustion and fire retardancy is reported as well as the chemistry of flame retardants action, the different available types and their uses. The chemistry of molecules used to improve fire retardancy is discussed along with their thermal stabilities and flame-retardant properties. Simplified assumptions about the gas and condensed phase processes of flaming combustion provide relationships between the chemical structure of polymers and fire behaviour, which can be used to design fire-resistant textile materials. Moreover, an overview of currently accepted test methods on textile fabrics to quantify burning behaviour is reported. Finally, as a consequence of increasing commercial demands in terms of cost-effectiveness coupled with increasing concerns about the environmental and general toxicological character of flame retardant additives, some consideration is also given to both the novel approaches of the chemistry of antimony-free and halogen-free flame retardants and to attempts at increasing the efficiency of known chemistry to enhance char formation by intumescent action.

Three main topics are described in this chapter, namely (i) physical and chemical structural of cellulosic materials, (ii) fire and flame retardancy finishing of cellulosic materials, and (iii) fire and flame retardancy finishing of cellulosic materials and its composite. The first subject describes in detail different cellulose sources and their chemical and physical structures. Furthermore, the types, structure, and chemical composition of different fibers (cotton, linen, jute, bamboo, hemp, and wood) and their blend have been described in detail. The second subject contains the uses of flame retardant fabrics, and describes the deference in the definition of retardant/resistant terms; in addition, the theory of combustion or burning process, and the mechanism of fire and flame retardant action are explained in detail. Also, different phosphorous flame retardant synergism, types of flame resistant finishes, and their classification based on durability and nature have been mentioned. By the end of this chapter, different Flammability Tests for Textile are described in detail. The last section of the chapter shows the finishing of cellulosic materials and their composites in detail.