New developments in flame retardancy of styrene thermoplastics and foams (original) (raw)
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Molecules
Polystyrene, despite its high flammability, is widely used as a thermal insulation material for buildings, for food packaging, in electrical and automotive industries, etc. A number of modification routes have been explored to improve the fire retardance and boost the thermal stability of commercially important styrene-based polymeric products. The earlier strategies mostly involved the use of halogenated fire retardants. Nowadays, these compounds are considered to be persistent pollutants that are hazardous to public and environmental health. Many well-known halogen-based fire retardants, regardless of their chemical structures and modes of action, have been withdrawn from built environments in the European Union, USA, and Canada. This had triggered a growing research interest in, and an industrial demand for, halogen-free alternatives, which not only will reduce the flammability but also address toxicity and bioaccumulation issues. Among the possible options, phosphorus-containing...
Advancements in traditional and nanosized flame retardants for polymers—A review
Journal of Applied Polymer Science, 2020
Synthetic polymers are ubiquitous materials widely used in construction, automotive, electronics, and countless commercial products. With the growing trend of polymer applications in everyday life, upholding the rigorous fire safety regulations has become a matter of concern. In this regard, numerous studies have been conducted for improving the fire retardancy of polymers, mainly through incorporating a diverse group of fire‐retardant compounds into polymer‐based composites. This review article aims to present a comprehensive overview of recent advances in the fire‐retardant categories for polymeric materials especially emphasizing the nanosized fire retardants. Along with an attempt to focus attention on the consumption of conventional and possibly harmful fire retardants, potential eco‐friendly alternatives are represented. A detailed discussion on the flame retardation mechanisms and conventional fire characterization techniques are also discussed.
The Flame Retardancy of Polyethylene Composites: From Fundamental Concepts to Nanocomposites
Molecules, 2020
Polyethylene (PE) is one the most used plastics worldwide for a wide range of applications due to its good mechanical and chemical resistance, low density, cost efficiency, ease of processability, non-reactivity, low toxicity, good electric insulation, and good functionality. However, its high flammability and rapid flame spread pose dangers for certain applications. Therefore, different flame-retardant (FR) additives are incorporated into PE to increase its flame retardancy. In this review article, research papers from the past 10 years on the flame retardancy of PE systems are comprehensively reviewed and classified based on the additive sources. The FR additives are classified in well-known FR families, including phosphorous, melamine, nitrogen, inorganic hydroxides, boron, and silicon. The mechanism of fire retardance in each family is pinpointed. In addition to the efficiency of each FR in increasing the flame retardancy, its impact on the mechanical properties of the PE system...
Fire and Materials, 2013
1 Low-melting glass has been synthesized in the system PbO-ZnO-B 2 O 3 and Na 2 O-P 2 O 5 -MoO3 and its composition has been developed. The effect of the glass chemical composition on the softening temperature and the change of appearance during the heating have been established. Polypropylene-based composite with different content of glass powder as a filler was obtained. Thermophysical properties of the composites were determined. Introduction of glass powder to the polypropylene composition damaged the material structure homogeneity. Using DTA method it was established that the developed filler shifts the temperature of polymer complete combustion toward higher temperature by above 40 K.
Polymer Degradation and Stability, 2012
Organophosphorus compounds have a long history as effective flame retardants for polymeric materials. There is increasing interest in developing new phosphorus flame retardants as a consequence of the increasing worldwide regulatory pressure on the use of organohalogen flame retardants which are persistant in the environment, tend to bioaccumulate, and pose potential health risks for the human population. It has been widely suggested that the flame retardant activity of phosphorus compounds may be enhanced by the presence of nitrogen, sulfur, silicon and a few other elements. This has been tested by examining the flamability behavior of copolymers derived from styrene monomers containing phosphorus moieties in comparison to those containing similar monomers in which both phosphorus and nitrogen are present.
Flame and fire retardancy of polymer-based composites
Materials Research Innovations, 2020
In this article, the recent development concerning the flame and fire-retardant characteristics of polymer-based composites has been discussed. The process of polymer combustion and its inhibition, and the chemistry behind the fire retardancy are mentioned in the background. Focussed are given on mainly inorganic hydroxide, halogen, phosphorus, nitrogen, silicon, boron, clay-layered silicates, metal hydroxides, and carbons based flame retardants as the use of these different nanofiller additives designed the polymer for enhancing flame retardancy. Emphases are given on how these nanofillers are beneficial to retard the flame from spreading during the development of fire. The usefulness to incorporate the conventional flame retardants in nanocomposites is also discussed. Finally, the mechanism of flame retardancy for clay-and carbon-based nanocomposites is reported.
Halogen-free flame retardants for polymeric foams
Polymer Degradation and Stability, 2002
The effectiveness of some mixtures of halogen-free flame retardants (i.e. expandable graphite, triethylphosphate and red phosphorus) in flame retardancy of polyisocyanurate-polyurethane (PIR-PUR) foams, blown with n-pentane, has been investigated by means of DIN 4102-B2 and oxygen index tests. The thermal stability and mechanical properties of PIR-PUR filled foams have also been considered. The results showed that the introduction of increasing amounts of expandable graphite, into foams containing triethylphosphate or red phosphorus, causes a significant worsening of physical-mechanical properties. The fire behaviour characterisation has demonstrated that the introduction of such flame retardants as fillers leads to a great improvement particularly for foams filled with expandable graphite and triethylphosphate. Also significant improvement has been observed in thermal stability due to the presence of flame retardants.
Polymers in Fire Protection, 2023
In this entry, fire protection of polymeric materials has been discussed with respect to flameretardant polymers as well as additives employed. Flame retardants for polymer and their potential suitability for use in fire applications have been reviewed. Five principle types of flame retardants were discussed for inclusion in polymers, namely halogen, phosphorus, nitrogen, silicon, and organic flame retardants. In this regard, the choice of polymer matrix, additive, processing techniques and characterization method is important for the formulation of high-performance nonflammable system. The influence of polymers and modified flame retardant addition on flame retardation and smoke suppression features have been investigated using cone calorimetric methods, limiting oxygen index measurement, and thermogravimetric analysis. Consequently, it was observed that with increasing flame retardant content, significant enhancement in flame retardancy features may occur.
Combustion and fire retardance in polymeric materials
Le Journal de Physique IV, 1993
The use of organic polymeric materials is limited in many applications because of fire hazard. Fire retardant systems have been found which reduce this hazard below acceptable levels. The development of more efficient systems is constantly pursued to meet the demand for ever safer materials. This involves the difficult problems of the testing methods and of the mechanistic approach which should supply information for progressing in this task. Examples of mechanistic studies on halogen based or intumescent fire retardant are illustrated.