Abstract: Crimped acrylic fibers with a small diameter, a minimum aspect ratio in the 20-50 range, and having a crimp of greater than about 10% so as to enhance the viscosity of polymers, resistance to gravity-induced slumping when applied to vertical surfaces, and mix stability, as well as provide matrix reinforcement and toughness, are adapted to act as improved physical thixotropes in adhesives, sealants, coatings, paints, grouts, building materials and the like.

Abstract: Crimped acrylic fibers with a small diameter, a minimum aspect ratio in the 20-50 range, and having a crimp of greater than about 10% so as to enhance the viscosity of polymers, resistance to gravity-induced slumping when applied to vertical surfaces, and mix stability, as well as provide matrix reinforcement and toughness, are adapted to act as improved physical thixotropes in adhesives, sealants, coatings, paints, grouts, building materials and the like.

Abstract: Heat curable compositions of reinforcing fibers (filaments), a thermosetting prepolymer or prepolymers and an effective amount of a curing agent or agents in which the fibers have been precoated with a fiber- and matrix resin-reactive elastomer are described. The compositions are useful to form composites of high fracture toughness and compressive strength which, in turn, can be formed into structural members such as aircraft parts. Processes for applying an elastomer coating to fiber tapes, fabrics and rovings are also described.

Abstract: Acrylic fibers of a fiber-forming first acrylonitrile polymer containing at least 50% acrylonitrile, a flame retardant amount of a halogen-containing vinyl monomer, and any balance of a halogen-free vinyl monomer having heterogeneously dispersed therein a small amount of an incompatible, halogen-free, second acrylonitrile polymer containing at least 70% acrylonitrile and one or more halogen-free vinyl monomers. The fibers are prepared by wet-spinning an intimate mixture of the polymers separately dissolved in aqueous inorganic solutions of the same salt following conventional procedures but including a hot-wet relaxation of the stretched wet-gel filaments prior to drying.

Abstract: Aqueous solutions containing at least 30% sodium thiocyanate and 2 to 25% dipropylene glycol are solvents for acrylonitrile polymers containing 55 to 80% acrylonitrile and 15 to 40% vinyl chloride, vinyl bromide, vinylidene chloride, vinylidene chlorobromide, and/or vinylidene bromide useful in forming solutions of 8 to 15% of such polymers for wet-spinning into fibers.