The invention relates to poly(vinylalcohol)-co-poly(vinylamine) copolymers represented as formula (I), where B is greater than or equal to 1, L is independently of each other a chemical linking group which is --NH--, --N.dbd., >N--, >N.sup.++<, --O-- or --CO--, COPOLYMER is derived from a prepolymer of the formula (II) where R.sub.1 and R.sub.3 are independently H; 3-propionic acid or C.sub.1,-C.sub.6 alkyl ester thereof; or is 2-methyl-3-propionic acid or C.sub.1-C.sub.6 alkyl ester thereof, R.sub.2 and R.sub.4 are independently H or C.sub.1,-C.sub.6 alkyl, x+y+z is between about 3 and about 50 mole percent and q, n and m together make up the remainder of the mole percent, the indices x, y, z, n, m -and q independently may be 0, if q is not 0, b may also be 0. ##STR00001##