Flame Retardance and Char Analysis of an Eco-Friendly Polyurethane Hyperbranched Hybrid Using the Sol–Gel Method

Abstract

This study used the sol–gel method to synthesize a non-halogenated, hyperbranched flame retardant containing nitrogen, phosphorus, and silicon (HBNPSi), which was then added to a polyurethane (PU) matrix to form an organic–inorganic hybrid material. Using 29Si nuclear magnetic resonance, energy-dispersive X-ray spectroscopy of P- and Si-mapping, scanning electron microscopy, and X-ray photoelectron spectroscopy, this study determined the organic and inorganic dispersity, morphology, and flame retardance mechanism of the hybrid material. The condensation density of the hybrid material PU/HBNPSi was found to be 74.4%. High condensation density indicates a dense network structure of the material. The P- and Si-mapping showed that adding inorganic additives in quantities of either 20% or 40% results in homogeneous dispersion of the inorganic fillers in the polymer matrix without agglomeration, indicating that the organic and inorganic phases had excellent compatibility. In the burning test, adding HBNPSi to PU made the material pass the UL-94 test at the V2 level, unlike the pristine PU, which did not meet the standard. The results demonstrate that after non-halogenated flame retardant was added to PU, the material’s flammability and dripping were lower, thereby proving that flame retardants containing elements such as nitrogen, phosphorus, and silicon exert an excellent flame-retardant synergistic effect.

Flame retarded polymer systems based on the sol-gel approach: recent advances and future perspectives

“…The same phosphaphenanthrene derivative (DOPO-HQ) was adopted by Shen et al [27], who synthesized a hyperbranched organic-inorganic hybrid material containing Si, N and P, aimed at improving the flame retardancy of a polyolbased polyurethane. The sol-gel procedure employed DOPO-HQ and 3-isocyanatopropyltriethoxysilane (IPTS) through two polycondensation steps, the second following the addition of triglycidyl isocyanurate (TGIC).…”

Phosphorus-Containing Flame-Retardant Benzocyclobutylene Composites with High Thermal Stability and Low CTE

“…Therefore, OPFRs have great development potential and space. In order to meet the needs of certain specific applications, − they have received continuous attention from flame retardant researchers at home and abroad. For example, the representative of OPFRs are 9,10-dihydro-9-oxa-10-phosphazephenanthrene-10-oxide and its derivatives, which are characterized by the rigid structure of the benzene ring, high rigidity, high heat resistance, good flame retardancy, and low toxicity, which are widely used in the CCL field to improve their flame retardance …”

Combustion and Thermal Properties of Flame Retardant Polyurethane Foam With Ammonium Polyphosphate Synergized by Phosphomolybdic Acid

“…Therefore, it is of great significance to study the flame retardant performance of polyurethane enhanced by flame retardants. The common method is to introduce additive flame retardants and reactive flame retardants into polyurethane to improve its flame retardancy (Jia et al, 2019;Li et al, 2020;Shen et al, 2021;Çalışkan et al, 2021).…”