The styrenic elastoplastics resist water, alcohols, and dilute alkalies and acids. They are soluble in, or are swelled by, strong acids, chlorinated solvents, esters, and ketones. Applications for the styrene-butadiene block copolymers include disposable medical products, food packaging, tubing, sheet, belting, mallet heads, and shoe soles. These materials are also used as sealants, hot-melt adhesives, coatings, and for wire and cable insulation. They are uncured or have low levels of crosslinking.
Material cost is mid-range among the elastoplastics.
The TPOs have good resistance to some acids, most bases, many organic materials, butyl alcohol, ethyl acetate, formaldehyde, and nitrobenzene. They are attacked by chlorinated hydrocarbon solvents. Compounds rated V-0 by UL 94 methods are available. Thermoplastic vulcanizates are essentially a fine dispersion of highly vulcanized rubber in a continuous phase of a polyolefin. Critical to the properties of a TPV are the degree of vulcanization of the rubber and the fineness of its dispersion.