Abstract: The invention provides waterproof sunscreen compositions which include polymers of isoprene, butadiene and/or styrene, particularity conjugated dienes which may be subject to some degree of hydrogenation. A copolymer of two different conjugated dienes is preferred. The polymers may be selectively hydrogenated to produce polymers which have highly controlled amounts of unsaturation, thereby improving water resistancy.

Abstract: The invention provides dispersants and dispersant viscosity index improvers which include polymers of conjugated dienes which have been hydrogenated, functionalized, optionally modified, and post treated. The dispersant substances include a copolymer of two different conjugated dienes, such as butadiene-isoprene-butadiene. The polymers are selectively hydrogenated to produce polymers which have highly controlled amounts of unsaturation, permitting highly selective functionalization. Also provided are lubricant fluids, such as mineral and synthetic oils, which have been modified in their dispersancy and/or viscometric properties by means of the dispersant substances of the invention. Also provided are methods of modifying the dispersancy and/or viscometric properties of lubricating fluids such as mineral and synthetic lubricating oils. The dispersant substances may also include a carrier fluid to provide dispersant concentrates.