Synthesis and characterization of a cyclic 9,9-bis(4-hydroxyphenyl)fluorine (phenylene phosphonate) oligomer and its flame retardancy application

摘要: A novel solid flame retardant cyclic 9,9-bis(4-hydroxyphenyl)fluorine (phenylene phosphonate) (CPFP) oligomer was synthesized in high yields by the reaction of phenylphosphonic dichloride with under pseudo-high-dilution conditions via polycondensation. Detailed structural characterizations this were conducted matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), 1H NMR, 31P NMR and FTIR. Furthermore, flame-retardant efficiency polybutylene terephthalate (PBT) studied using limiting oxygen index (LOI) UL-94 tests. After addition CPFP, LOI increased V-0 rating achieved. The occurrence an interaction between CPFP PBT elucidated thermogravimetric analysis (TGA), FTIR pyrolysis/GC/MS. results showed that could change degradation path improves char formation PBT/CPFP system. residual morphologies residues PBT/CPFP25% system investigated scanning electron microscopy (SEM). SEM investigations revealed chars contained polyphosphoric or phosphoric acid, which plays important role process carbonization.