Abstract: Improved reinforcing fibers such as carbon fibers are provided which may be employed in composites to improve the impact resistance thereof. The fibers disclosed are coated with a sizing composition comprised of a blend of an epoxy resin and a organophosphazene elastomer.

Abstract: A curable composition, and composites comprising (A) an epoxy resin and (B) a heterocyclic compound prepared by reacting at least one aromatic or aliphatic polyamine compound having at least two amine groups, which are separated by no more than one carbon atom, with at least one carbonyl-containing compound selected from the group consisting of aldehydes and ketones.

Abstract: There is provided a method of increasing the toughness of a fibre-reinforced composite material. The fibre and matrix material are so selected that, upon development in the matrix of a crack bridged by a fibre, the grip of the matrix on the fibre due to matrix shrinkage will be small enough to allow the fibre, while stretching, to progressively shrink away from the matrix beginning at the crack, but large enough to cause the fibre to break when the progressive fibre shrinkage reaches a major flaw in the fibre. This is effectively accomplished by making the fibre Poisson's shrinkage at breaking stress substantially the same as the matrix contraction strain. The latter can be adjusted by mixing with the basic matrix material a selected quantity of an additional substance, such as spiro polymer or an inert particulate material.

Abstract: The present invention relates to an epichlorohydrin elastomer composition having an improved ageing resistance.This composition comprises 100 parts by weight of epichlorohydrin homopolymer or copolymer, 0.5 to 20 parts by weight of a plasticizer such as stearic acid, 1 to 150 parts by weight of a reinforcing filler constituted by a slightly agglomerated, medium structure carbon black having an average particle size of 200 to 280 microns and 0.5 to 7.5 parts by weight of a first acid acceptor constituted e.g. by zinc or calcium stearate, 0.5 to 7.5 parts by weight of a second acid acceptor constituted e.g. by lead oxide Pb.sub.3 O.sub.4, 0.5 to 5.5 parts by weight of at least one protection agent constituted by an organic compound with conjugated aromatic cycles containing amine or phenol functions and/or by an alkyl or aryl dithiocarbamate metal salt and 0.5 to 5.5 parts by weight of a vulcanizing agent preferably constituted by hexamethylene diamine carbamate.

Abstract: High temperature-resistant thermobarriers have a filler therein. The filler can be an opaque thermobarrier material, a fabric or cloth such that a laminated thermobarrier is formed, or preformed bubbles of glass, ceramic or plastic such that a syntactic foam thermobarrier is formed. The thermobarrier contains a boroxine compound therein as well as epoxy resins and various phosphorus compounds and/or aromatic alcohols. Generally, the syntactic foam thermobarriers give the best heat protection.

Abstract: Liquid polyglycidyl compounds, diethyltoluylenediamine, a curing accelerator and optionally further additives form a liquid matrix system with which fibres and fibre shapes are impregnated by known techniques, particularly by filament winding, pultrusion and injection processes. The components thus produced are for example tubes capable of withstanding pressure and torsional stress.

Abstract: A catalyst for forming ambient temperature stable diamino-diphenyl sulfone-epoxy composition comprises the half-salt of a strong aromatic sulfonic acid such as toluene sulfonic acid and an imidazole, preferably an alkylated imidazole such as 2-ethyl-4-methylimidazole. The composition fully cures at moderate temperature to form a humidity resistant resin having a high heat distortion temperature and can be impregnated onto reinforcing fibers such as graphite to form composites.

Abstract: A two-package solventless rust preventive material comprises (A) a sprayable component essentially containing a liquid epoxy resin and a liquid polycarboxylic acid anhydride and (B) a sprayable component essentially containing a liquid primary or secondary amino compound and a curing accelerator, at least one of said components (A) and (B) essentially comprising a non-reactive epoxy resin diluent having a molecular weight of 300 to 4,000 and an electrically conductive powder.