Abstract: Improved fiber-reinforced metallic composite material includes as a matrix a metal or alloy of aluminum, magnesium, copper, nickel or titanium and as a reinforcing material an inorganic fiber of 15 to 70% by volume, which is characteristic in that the metal alloy composing the matrix contains 0.05 to 10% by weight of lead or a combination of 0.05 to 10% by weight of lead and 0.01 to 5% by weight of one or more metals selected from the group consisting of sodium, potassium, calcium, strontium, cesium, barium and radium. The composite material has improved mechanical strength, particularly tensile strength, and is useful as a material for various parts and devices in various industrial fields such as the aerospace, atomic power and automobile industries.

Abstract: Synthetic resins, particularly polyolefins, are markedly improved in their resistances to heat and oxidation by the incorporation of a 2-methyl-4-t-butyl-5-hydroxyphenylalkanoic acid ester alone or in combination with a thioether-type antioxidant represented by the general formula ##STR1## wherein R represents an alkyl group of 12 to 20 carbon atoms, or by the general formula ##STR2## wherein R represents an alkyl group of 4 to 20 carbon atoms.