Synthesis and characterization of cage structured flame resistant melamine and pentaerythritol based polymer networks

In this study, a Schiff base 2,4,6-tris(4-hidroksibenzimino)-1,3,5-triazine (HT) was synthesized from condensation reaction of 4-hydroxybenzaldehyde and melamine. Subsequently, various imine or ether bond cage polymers were synthesized using 2,4,6-tris(4-hydroxybenzimino)-1,3,5-triazine (HT), pentaerythritol (PT), 1,5-dibromopentane (DP), and p-xylylene dibromide (DX) in DMF. The structures of the compounds were characterized using FT-IR, 1 H, 13C-NMR and TGA measurements. The surface morphologies, particle ratious and the glass transition temperatures of polymers were found from SEM, DLS and DSC measurements, respectively. The melamine-based polymers PHTDX and PHTDP were synthesized from the monomer HT. Pentaerythritol-based PPTDX and PPTDP polymers were synthesized from the monomer PT. Melamine (M) and pentaerythritol are used in many applications, such as fire-resistant coatings and flame-retardant plastics. Thermally stable polymers were prepared with melamine and pentaerythritol. Based on SEM images, the polymers were found to have a porous structure. These pores make the polymers flame retardant by trapping combustible gases during thermal degradation. The limiting oxygen index values of PHTDX, PHTDP, PPTDX, and PPTDP at 1000 °C were reported to be 43.96, 40.42, 31.35 and 23.11, respectively, in TGA measurements.