Patent ID: 6984716

Claim:
A phosphorus-containing compound represented by formula (I): wherein R 1 is selected from the group consisting of —OH, —COOH, —NH 2 , —CHO, —SH, —SO 3 H, —CONH 2 , —NHCOOR 4 , and anhydride; R 4 is hydrogen or an alkyl group; and Ar 1 and Ar 2 are independently selected from: wherein R 2 is selected from the group consisting of hydrogen, alkyl group, alkoxyl group, nitro group, halogen, and aryl group; R 3 is a chemical bond or an alkylene group; R 5 is selected from the group consisting of a chemical bond, —CR 2 R 4 —, —O—, —CO—, —S—, —SO—, and —SO 2 —; R 1 and R 4 are defined as above; a and b are independently an integer from 0 to 6, and a+b≦6; c and d are independently an integer from 0 to 4, and c+d≦4; and z is an integer from 1 to 20.