Synthesis, characterization, and polymerization of brominated benzoxazine monomers and thermal stability/flame retardance of the polymers generated

Abstract

Novel monofunctional brominated benzoxazine 3-(2,4,6-tribromophenyl)-3,4-dihydro-2H-1,3-benzoxazine (P-bra) and bifunctional brominated benzoxazine 6,6 0 -bis(3-(2,4,6-tribromophenyl)-3,4-dihydro-2H-1,3-benzoxazinyl) isopropane (B-bra) were prepared and highly thermally stable polybenzoxazines were obtained by the thermal cure of the corresponding benzoxazines monomers. The chemical structures of these novel monomers were confirmed by FITR, 1 H-NMR and elemental analysis. FTIR spectra and differential scanning calorimetry (DSC) suggested that the polymerization was thermally initiated and occurred via ring-opening of the monomer in each case. Thermogravimetric analysis (TGA) indicated that brominatation could have a profound effect on increasing char yield and on thermal degradation temperatures. The results of UL-94 burn test showed that the polybenzoxazines prepared from P-bra and B-bra had good flame retardance.

Preparation and properties of cardanol‐based polybenzoxazine/SiO2 hybrids by sol‐gel technique

“…As shown in Figure 1, cardanol‐based benzoxazine monomer containing a hydroxyl group (CBZ) was synthesized by a solventless process adapted from earlier work 18. Freshly distilled cardanol (0.4 g, 0.1 mol) and 6 g (0.2 mol) paraformaldehyde were weighed in a round bottom flask and placed over a magnetic stirrer.…”

Synthesis of borosiloxane/polybenzoxazine hybrids as highly efficient and environmentally friendly flame retardant materials

“…1 H NMR (300 MHz, acetone‐d 6 , δ , ppm): 7.14–7.73 (Si—C 6 H 5 ). C NMR (125 MHz, THF—D 2 O, δ , ppm): 127.60–134.34. B NMR (128 MHz, THF—D 2 O, δ , ppm): 19.42.…”

“…One is the incorporation of halogens into PBZs. For example, Li et al synthesized bromine‐containing benzoxazine monomer via Mannich reaction using 2,4,6‐tribromoaniline as the starting material . The cured product achieved a V‐0 grade in the UL‐94 flame testing.…”

Comparison of two bisbenzoxazines containing carboxylic groups and their thermal polymerization

“…In our previous studies [18][19][20][21], we synthesized various benzoxazines to enhance the properties of PBZ. In this work, a new bisbenzoxazine monomer containing carboxylic groups based on phenolphthalein (named as BPA) was designed and expected that incorporation of the carboxylic moieties into benzoxazine could lower the curing temperature and improve the properties of the corresponding PBZ.…”