SYNTHESIS AND PROPERTIES OF PHOSPHORUS-CONTAINING PET AND PEN (I)

2-(6-Oxido-6H-dibenz [c,e][1,2] oxaphosphorin-6-yl) dimethyl itaconate (ODOP-DI) was prepared by the addition reaction between 9,10-dihydro- 9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and dimethyl itaconate wh ile DOPO was synthesized through multistep reaction from o-phenylpheno l and phosphorus trichloride. The compound (ODOP-DI) was used as a rea ctive flame retardant in polyethylene 1,4-terephthalate (PET) and poly ethylene 2,6-naphthalate (PEN) for film, fiber, and electronic applica tions. The thermal properties of the resulted copolyesters were invest igated by differential scanning calorimetry (DSC) and thermal gravimet ric analysis (TGA). Owing to the incorporation of the rigid structure of DOPO and pendant P groups, the resulted phosphorus containing copol yesters exhibited better flame retardancy, higher char yield, and ther mal stability than homopolymers of PET and PEN. UL 94-VO rating could be achieved with a phosphorus content of as low as 0.75% for PET, 0.5% for PEN, and no fume and toxic gas emission were observed. (C) 1998 J ohn Wiley & Sons, Inc.