Flame-retardant in situ reinforced PBT via a DOPO-based phosphorus-containing thermoliquid crystal copolyester

p-TLCP was synthesized using 2-(6-oxid-6 H -dibenzo[ c , e ][1,2]oxaphosphorin-6-yl)-1,4-benzenediol (DOPO-HQ), terephthalic acid (TPA), p -hydroxybenzoic acid ( p -HBA), and dimethyl terephthalate (DMT) as monomers in a molar ratio of 3 : 3 : 2 : 2.