Reactive Modification of Thermoplastic and Thermoset Polymers using Flame Retardants: An Overview

Abstract

Flame retardants are the chemicals used in thermoplastics, thermosets, textiles and coatings to arrest the spread of fire. There are basically two ways to improve flame retardancy, namely additive and reactive. It was observed that the reactive modification enhances flame retardancy of polymer to the greater extent than the additive route. Hence in this review, more emphasis is given to the reactive approach. Following review depicts various flame retardants that can be incorporated to thermoplastic and thermosetting polymers, their mechanism of action and their combined effect on flame retardant properties of polymer system in which they are incorporated in.

Synergistic Flame-Retardant Mechanism of Dicyclohexenyl Aluminum Hypophosphite and Nano-Silica

“…The combustion process can release more heat, which radiates to the unburnt material and continues to promote pyrolysis and combustion until the heat/fuel/oxygen runs out. To effectively inhibit or delay the burning of the substrate and reduce the risk of fire, a flame retardant is generally required in the polymer [1,2,3].…”

Phosphorus-Containing Flame Retardants from Biobased Chemicals and Their Application in Polyesters and Epoxy Resins

“…Many research groups have tried to find a new, renewable raw material for epoxy resins [118], but also intrinsic flame retardant, biobased epoxy resins are developed based on eugenol [40,119], daidzein [120] components of soybeans [121], furan derivatives [40], itaconic acid [45,122] or pentaerythritol [123]. Another approach is incorporating flame-retardant silicon- [124] or phosphorus- [45] containing groups into the backbone as substituents in epoxy resins or curing agents [48]. Flame retardant epoxy resins are typically synthesized by:incorporation of phosphorus-containing groups into an epoxide component orincorporation of phosphorus-containing groups into a molecule with a following epoxidation of unsaturated side chains.…”

Effect of the flame-retardant 3-hydroxyphenylphosphinyl-propanoic acid on the mechanical, thermal, and flammability properties of poly(ethylene terephthalate) nanofiber mats

“…8 Many kinds of FRs such as phosphorous FR and halogenated FR have been added during polymerization or by blending to improve the flame retardancy of PET. 9,10 Nowadays, the phosphorous FRs are primarily used to produce the FR PET. 11 The mechanism of phosphorus compounds as FRs in combustion conditions is that the phosphorus units are converted by thermal decomposition to phosphoric acid, which, in the condensed phase, extracts water from the pyrolyzing substrate, causing it to char.…”

“…8 Many kinds of FRs such as phosphorous FR and halogenated FR have been added during polymerization or by blending to improve the flame retardancy of PET. 9,10 Nowadays, the phosphorous FRs are primarily used to produce the FR PET. 11…”