A novel flame retardant of spirocyclic pentaerythritol bisphosphorate for epoxy resins

Abstract

A novel flame retardant for epoxy resins, bisdiglycol spirocyclic pentaerythritol bisphosphorate (BDSPBP) was synthesized from the reaction of diglycol with spirocyclic pentaerythritol bisphosphorate diphosphoryl chloride, which was obtained from the reaction of phosphoryl chloride with pentaerythritol. Flammability of the cured epoxy resin systems consisted of diglycidyl ether of bisphenol A (DGEBA), low-molecular-weight polyamide and BDSPBP are investigated by vertical burning test (UL-94) and limiting oxygen index test (LOI). The results indicate that BDSPBP has good flame retardance on epoxy. The thermogravimetric analysis (TGA) shows that the epoxy resin containing BDSPBP has a high yield of residual char at high temperatures, indicating that BDSPBP is an effective charring agent. From the SEM observations of the residues of the flame retardant systems burned, the compact charred layers can be seen, which form protective shields to protect effectively internal structure, and inhibit the transmission of heat and heat diffusion during contacting fire.

Flame-retarding behaviors of novel spirocyclic organo-phosphorus compounds based on pentaerythritol

“…At the same time, one observe the compact charred layers which can exert as protective layers to inhibite the transmission and diffusion of heat during contacting fire. 44,45 Furthermore, the char layers show many swollen bubbles which remain unbroken on the surface. These foam structures produced from instumescent decomposition of polymer/FR mixtures would be expected to provide an effective insulating barrier between the substrate and heat source.…”

The synthesis of a novel flame retardant and its synergistic efficiency in polypropylene/ammonium polyphosphate system

“…The characterization of Si-E SPDPC has high reactivity and is prone to react with amine, alcohols, and phenols; it has often been applied in the preparation of SPDPC copolymers. [17][18][19] The NMR characterization of Si-E has been shown in Figs 1 and 2. H-a was the characteristic peak of methyl connecting to Si-O-Si.…”

Synthesis of charring agent and its derivatives of dipentaerythritol polycyclicphosphonates flame retardants

“…It represents the lowest environmental oxygen volume content for sustaining flame. The oxygen index test is used to evaluate the flammability of fibers, because the test is a convenient method to obtain a single numerical value of relative flammability of polymeric fibers (Akoval and Giündogan 1990; Chen, Yang, and Wang 2006).…”

“…And the mechanical properties and flammability of IFR-PS were not satisfactory . Consequently, bisdiglycol spirocyclic pentaerythritol bisphosphorate (BDSPBP) was synthesized with SPDPC and diglycol, which improved the flame retardancy of cured epoxy resins effectively (Chen, Yang, and Wang 2006).…”