Abstract: Alcohol catalysts are utilized to effect ambient temperature cure of urethane prepolymers or polymers with a methylenedianiline (MDA) salt complex. The alcohol catalysts are generally quasi polar such as a polyester polyol, a polyether polyol, an aliphatic polyol, or an aliphatic or an aryloxypoly(oxyalkylene) alcohol.

Abstract: Sulfur-curable, carbon black reinforced material rubber compounds having improved processing properties in the uncured state and improved strength and dynamic properties in the cured state are obtained by the addition of from about 0.2 to about 15 parts by weight per 100 parts by weight of natural rubber of a zinc dimethacrylate having a surface area of from about 3.7 to about 5.4 m.sup.2 /g or more to the compounds. The addition of the zinc dimethacrylate to the compounds permits the use of lower quantities of carbon black than would ordinarily be employed in the absence of the zinc dimethacrylate while still providing for the improved properties.