Hyperbranched Polymer Flame Retardant

Polymeric flame retardants, especially hyperbranched polymers, are promising, promoting the development of halogen-free flame retardants. Alfa Chemistry is committed to the continuous innovation and research of flame retardants (FRs), providing a variety of hyperbranched polymer flame retardants (HBFR). If the HBFR you are interested in is not found in our product list, please contact us to customize an HBFR that meets your specific needs.

Typical Products

Various hyperbranched polymers include polyamides, polyamidoamines, polyureas, polyurethanes, polyesters, polycarbosilanes, polycarbosiloxanes, polycarbosilazanes, perfluoro derivatives of many previous polymers, and so on.

Structure

Hyperbranched polymers (HBPs) are highly branched three-dimensional (3D) macromolecules. Their unique structures, such as spherical and dendritic structures, give them unique properties. The comparison of HBP with linear polymers and dendrimers is summarized in the figure below. [1]

Features

• With hyperbranched structure
• Excellent char formation
• Multifunctional properties such as toughening agent to improve mechanical properties of materials
• Rich functional groups
• Intramolecular cavity
• Low viscosity
• High solubility

Flame Retardant Mechanism

Taking phosphorus-containing HBFR as an example, during the combustion process, DOPO in HBFR is pyrolyzed into PO·, PO2·, and polyphosphoric acid, which can not only inhibit the chain free radical reaction and reduce the release of combustible gas, but also catalyze the dehydration and cyclization of epoxy matrix to form dense and continuous carbon layer. The carbon layer protects the underlying polymer substrate from heat and oxygen while preventing the release of flammable gases. In addition, PO· and PO2· quenched the active radicals, and a large amount of non-combustible gas diluted the combustible gas, thus inhibiting the combustion process of the gas phase.

Schematic diagram of possible flame retardant mechanism of HBFR modified resin [2]

Applications

• HBFR is used in polyolefin, polystyrene resin (ABS and HIPS, etc.), PBT, PET, nylon, epoxy resin, unsaturated resin, polyurethane, polycarbonate, acrylic resin, elastomer and other occasions.
• HBFR can be compounded with amine polyphosphate, melamine polyphosphate, red phosphorus, inorganic hypophosphite and organic hypophosphite to form a compound intumescent flame retardant system (IFR).

Research Information

HBFR with rigid backbone structure

NaTeng et al. synthesized a hyperbranched flame retardant (HBFR) with a rigid backbone structure and used it for epoxy resin modification. In this work, not only the flame retardancy of epoxy resin is improved, but its toughness, flexural strength and modulus are also significantly increased due to the enlarged free volume, rigid backbone structure and high crosslink density of the hyperbranched structure. [2]

The synthetic route and chemical structure of HBFR [2]

References

1. Yaochen Zheng, et al. (2015). "Hyperbranched polymers: advances from synthesis to applications," Chem. Soc. Rev. 44, 4091-4130.
2. Na Teng, et al. (2021). "Hyperbranched flame retardant for epoxy resin modification: Simultaneously improved flame retardancy, toughness and strength as well as glass transition temperature," Chemical Engineering Journal 428, 131226.