A novel phosphorus-containing polymer as a highly effective flame retardant

A novel phosphorus-containing polymeric retardant, WLA-3, was synthesized from phenylphosphonic dichloride (PPD) and 2-(6-oxido-6H-dibenz<c,e><1,2>oxaphosphorin-6-yl) 1, 4-benzenediol (ODOPB). The flame-retardant element, phosphorus, was bonded both in the main chains and in the pendant chains of flame-retardant polymer molecules, and reached a content of 13.8%. The high phosphorus content and rich aryl group structures of WLA-3 contribute an excellent flame retardancy to poly(ethylene terephthalate) (PET) without a considerable decrease of mechanical properties. WLA-3 is also very effective in improving flame retardancy of epoxy resin and unsaturated polyester.