water - soluble , biodegradable polymeric materials are provided for skin , hair and cosmetic use comprising the formula : ## str1 ## wherein a is a water soluble , biodegradable polymeric material containing a radical selected from the group consisting of hydroxy , amino , imino , thio and carboxy ; x is ## str2 ## r 1 is h , -- oh , -- cn , halogen or c 1 - c 4 alkyl ; r 2 is a saturated or unsaturated , at least bivalent hydrocarbon radical optionally substituted with one or more substituents selected from the group consisting of hydroxy -, amino -, c 1 - c 8 alkyl -, c 1 - c 8 alkoxy - and hydroxyalkyl groups which may be optionally substituted with one or more moieties selected from the group consisting of -- co --, -- o -- c -- o --, -- c -- o --, -- o --, -- o -- c --, -- s --, -- nr 4 --, -- nh -- c -- and -- nh -- c -- nh --; y is a connecting link to the main chain of the hydrocolloid a selected from the group consisting of -- o --, -- o -- c --, -- c -- o --, -- nh -- c -- and -- c -- nh ; r 3 and r 4 are independently h or alkyl ; and n is 0 to 5 .