A composition contains a silylated polysaccharide, where the silylated polysaccharide is characterized by: (a) having linked fructose, galactose, anhydrogalactose, or glucose saccharide units provided that glycosidic linkages of glucose are alpha linkages and that the silylated polysaccharide is other than a silylated starch; and (b) on average 1 to 100 mole-percent of the hydroxyl groups on the polysaccharide have been silylated with a silyl group having the structure —SiR3 linked to the polysaccharide through a C—O—Si bond where each R is independently selected from hydrocarbyl radicals having from one to 12 carbon atoms, provided that on average at least one R per polysaccharide has a terminally unsaturated carbon-carbon double bond.