Polymers derived from 4-bis(carbalkoxyethyl)-phosphinoxy-2,2,6,6-tetramethylpiperidine

A composition of matter represented by formula (I):

• ##STR8## wherein R represents hydrogen, C.sub.1 -C.sub.18 alkyl, or benzyl;
• R.sup.1, R.sup.2, and R.sup.3 independently represent hydrogen C.sub.1 -C.sub.6 alkyl, benzyl, or phenethyl, or R.sub.2 and R.sub.3 together with the carbon to which they are attached form a C.sub.5 -C.sub.10 cycloalkyl;
• R.sup.4 is hydrogen, C.sub.1 -C.sub.6 alkyl, hydroxyl, or oxyl;
• R.sup.5 is hydrogen, C.sub.1 -C.sub.6 alkyl, or ##STR9## wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4 are as previously defined;
• X is C.sub.2 -C.sub.12 alkylene optionally interrupted by an oxy, thio, or ##STR10## radical;
• or X is C.sub.5 -C.sub.10 cycloalkylene, ##STR11## C.sub.6 -C.sub.12 arylene, or C.sub.8 -C.sub.14 aralkylene;
• and, n is an integer greater than 1.