Flame retardant selection for thermoplastics

Thermoplastics have huge applications in many sectors, but theflammability of both commodity and engineering plastics remains a constraint of their use, which additionally threatens our lives and environment. Therefore, research on flame retardancy of thermoplastics has already become an important challenge, along with a critical demand for widening thermoplastics performance window. The mainly consumed thermoplastics involve polyolefins, polyvinyl chloride (PVC), polyesters, and linear aliphatic polyamides, and some formulations with flame retardants (FRs) have already been used for these polymers through melt-blending, melt-spinning, or copolymerization methods in industry. For example, brominated additives and inorganic fillers such as magnesium hydroxide (MDH) and aluminum hydroxide (ATH) are efficient FRs for polyethylene and polypropylene, which are widely used with their synergists in industry. Inorganic FRs are considered as good options to achieve flame retardancy and smoke suppression for PVC systems. The intumescent flame retardants (IFRs) can solve the flame retardancy and melt dripping, thus are common FRs of polyethylene terephthalate, polybutylene terephthalate. For polyamide-6 and polyamide-66, nitrogen and phosphorus-based FRs are effective ways to reach a sufficient result, and reactive flame-retardant method can also achieve the same level of flame retardancy at lower loading levels. Meanwhile, legal compliance and ecological trends are driving the increased preparation and usage of novel high-performance formulations via decreasing or eliminating the content of hazardous elements. It is a complex iteration process for the industrialization of new FRs, such that FRs, and the selection of FR for thermoplasticsdepends on technical requirement, economic consideration, and regulatory compliance.