Abstract: A thixotropic gel composition comprising an .alpha.-cyanoacrylate monomer, stabilizer, plasticizer and free radical scavenger is improved with the addition of fibers, spheres or mixtures of the same of certain materials which are insoluble in and inert to the .alpha.-cyanoacrylate monomer. The fibers or spheres composed of such materials as polyolefins, polyesters or polyamides enhance the physical and chemical characteristics of the thixotropic gel.

Abstract: The present invention is directed to mineral filled .alpha.-amino acid polymer composite materials. The composite materials are prepared by the in situ polymerization of an .alpha.-amino acid N-carboxyanhydride in the presence of mineral fillers which are optionally surface-modified with a partially hydrolyzed polyoxazoline prior to said polymerization. Composite materials prepared in this manner consist of an intimate mixture of polymer and mineral filler which may be optionally blended with a crosslinking agent and then molded to produce smooth, hard homogeneous materials that are water and oil resistant and have good heat distortion properties.

Abstract: A polymer composite is produced by polymerizing an olefine monomer in the presence of a catalyst system obtained by treating a filler material with (a) an organic magnesium compound which contains halogen or (b) an organic magnesium compound and thereafter with a halogen-containing compound; and then with a transition metal compound, which is preferably titanium tetrachloride, adding an organic metal activator compound and continuing the polymerization to obtain a composite containing desired proportions of polymer and filler. The filler may be carbon, an aluminosilicate such as mica or talc, or glass-fibre. Homogeneous composites, in respect of the distribution of filler in various size fractions, can be obtained. Composites having good flow characteristics may be obtained. The composites may be formed directly into shaped articles by suitable shaping techniques. Alternatively, the composite may be blended with a polymeric material.

Abstract: An inorganic filler component for use in resin-based direct dental filling materials comprises fumed or submicron silica which has been silane treated and coated with a thin coating of an active polymerizable monomer of the type used as the binder in making the composition. The use of such a submicron material permits the total filler loading of the composition to be increased substantially, thereby increasing both the compressive and diametrical tensile strength of the cured material as well as improving its polishability and resistance to wear, and reducing its susceptibility to water absorption.

Abstract: The invention is concerned with the preparation of polyurethane compositions in which the deleterious effect of gaseous by-products formed in the reaction is minimized. This is achieved by the use of coupling reagents which incorporate a steric hindrance function. The latter does not interfere with the normal coupling reactions between the coupling agent and polymer matrix and filler material but it does prevent such reaction between the coupling agent and filler material as would cause release of low molecular weight compounds occluded by the filler. Since the release of low molecular weight compounds is avoided, the formation or evolution of gases which give rise to unwanted cellularity of the cured composition is at least minimized.

Abstract: The invention relates to the use of agglomerates of silicic acid having an average agglomerate size of 0.5 to 50 .mu.m, containing primary particles of silicic acid having an average particle size of 1 to 100 nm and serving as filler in dental materials on the basis of ethylenically unsaturated polymerizable monomers. This reinforcing filler is practically colorless and can be blended in considerable quantity into the polymerizable monomer material especially mono-functional and di-functional as well as polyfunctional esters of the acrylic acid and the methacrylic acid and yields a satisfactorily processable plastically deformable paste. If necessary, the agglomerated silicic acid is used together with non-agglomerated micro-fine silicic acid of an average particle size of 1 to 100 nm.

Abstract: Physical properties particularly including tensile modulus and heat-distortion temperature of high nitrile copolymer resins are improved by including therein a processing aid, such as tetra chloro phthalic anhydride, and a filler material, such as clay.

Abstract: Process for preparing platinum catalyzed SiH-olefin silicone compositions using hydroperoxy-containing inhibitors.