The Flame Retardant and Mechanical Properties of the Epoxy Modified by an Efficient DOPO-Based Flame Retardant

• Published in: Polymers Vol. 16; no. 5; p. 631
• Main Authors: Li, Pengyu, Wang, Jihui, Wang, Changzeng, Xu, Chengxin, Ni, Aiqing
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 26.02.2024; MDPI
• Subjects: Analysis; Bioaccumulation; Bisphenol A; Carbon; Chemical synthesis; Cone calorimeters; Environmental impact; Epoxy resins; Fire resistance; Fireproofing agents; Flame retardants; Hydroxyl groups; Mechanical properties; Methods; Nitrogen; NMR; Nuclear magnetic resonance; Phosphate esters; Phosphorus; Phosphorus compounds; Phosphorus content; Polycyclic aromatic hydrocarbons; Polymers; Raw materials; Spectrum analysis; Structure; Synthesis; Thermal properties; X ray photoelectron spectroscopy; China; United States > US; Germany; high efficiency; epoxy resin; DOPO; flame retardancy; phosphorus
• ISSN: 2073-4360; 2073-4360
• DOI: 10.3390/polym16050631

Currently, the mechanical performance reduction caused by excessive phosphorus content in the halogen-free flame-retardant EP has been an obstacle to its extensive application. This study presents the effective synthesis of a novel flame-retardant BDD with great efficiency, achieving an optimum phosphorus level of merely 0.25 wt %. The structure of BDD was verified by FTIR, 1H NMR, 31P NMR and XPS spectra. To investigate the flame-retardant properties of BDD, several EPs with various phosphorus levels were synthesized. The addition of phosphorus to the EP significantly increases its LOI value from 25.8% to 33.4% at a phosphorus level of 0.25 wt%. Additionally, the resin achieves a V-0 grade in the UL 94 test. The P-HRR and THR of the modified resin measured by the cone calorimeter are also significantly reduced. At the same time, the addition of a modest quantity of BDD has a minimal impact on the mechanical properties of epoxy resin. This study shows that the removal of hydroxyl groups significantly enhances the fire resistance of phosphate-based flame retardants, thereby providing a novel approach to synthesizing efficient flame retardants.