Synthesis of biobased phosphate flame retardants

Abstract

An approach to prepare some biobased flame retardant (FR) compounds is presented. The adopted strategy consists in functionalizing an aromatic biobased phenolic compound, the phloroglucinol, with different phosphate groups in order to promote a charring effect. Different chlorophosphates were grafted onto phloroglucinol hydroxy groups and the functionalization of the hydroxy groups was quantitative. The synthesized biobased FR were incorporated into an epoxy matrix as additive to estimate their flame retardant properties. The influence of different parameters was studied such as the phosphorus content of the thermoset or the nature of the R group of the used phosphate P-O-R. MEB/EDX observations proved the influence of this R group on the compatibility between the FR and the matrix and its importance to obtain homogeneous thermoset. Thermogravimetric analyses of the phosphorus-containing thermosets showed a small decrease in thermal stability accompanied by a char yield almost tripled for a 3 % w P-containing thermoset compared to that of the thermoset without any FR. Pyrolysis combustion flow calorimetry was also used to evaluate the flammability of the modified epoxy thermoset. A significant decrease in peak of heat release rate and total heat released was observed compared to thermoset without FR. These results demonstrate the good flame retardant properties of these biobased phosphates in an epoxy matrix. In addition these results show the potential of the biobased phenolic compounds as raw material for flame retardants syntheses.

From a bio-based phosphorus-containing epoxy monomer to fully bio-based flame-retardant thermosets

“…DGEBA, cured by isophorone diamine (IPDA). 22 During early stages of curing, viscosity of the system decreases and may allow sedimentation or creaming of segregated phases. That is why DGEBA is widely used, especially in the production of coatings or high performance composites.…”

“…5 shows the thermograms of the DGEBA-IPDA thermosets series. 22,25 This loss of thermal stability appears to be a function of the phosphorus content. 5).…”

“…The most actual trends of green solutions for ame retardancy have been gathered in a recent book. 21 In a recent paper, 22 our team reported the synthesis of several bio-based phosphoruscontaining additive ame retardants by graing phosphate functions onto hydroxyl groups of phloroglucinol, a bio-based phenolic molecule found in the bark of fruit trees. 10 Once again, various fractions of the biomass have been considered in the literature to promote biobased FR.…”

Preparation of 4‐(4‐hydroxyphenoxy)phenol diglycidyl ether with improved toughness behavior

“…Epoxy resins, an important class of thermoset materials, have been widely used as structural adhesives, coatings, electron insulating materials, and advanced composites because of their good adhesion and chemical stability, as well as excellent thermal and electrical properties . In the world nowadays, bisphenol‐A diglycidyl ether (DGEBA) has possessed more than 90% market share of the universal epoxy resin, which is suitable for the applications in the aerospace and electronic industries.…”

Phosphonated homopolymers and copolymers via ring opening metathesis polymerization: T g tuning, flame resistance, and photolithography

“…Biologically, polyphosphate backbone upholds nucleic acids and insures inheritance of human beings . In industry, PCPs are very promising as halogen‐free flame retardants . They are also very good adhesives to bind metals due to potentially strong complexation abilities, which also found applications in dental and bone tissue engineering .…”