Abstract: A filled polyester molding composition which, based on the weight of the total composition, comprises (a) from about 5 to about 40 weight percent of a polyester resin; (b) from about 60 to about 95 percent of tungsten metal filler; and (c) from 0 to 20 weight percent of an impact modifier with a specific gravity greater than about 3.0 g./cc.

Abstract: This invention relates to a process of forming a composite material comprising a polymer matrix comprising a polymeric material and dispersed particles selected from the group consisting of platelet or fibrillar particles having average thicknesses of less than 50 and a maximum thickness of less than about 100 and fibrils having an average diameter equal to or less than about 200 and a maximum diameter of about 200 and having an organo metallic residue species covalently to said particles organo metallic species having a moiety which is compatible with a polymer species in the polymer matrix, or said species having a moiety which is covalently bonded to a polymer species in the polymer matrix or a combination thereof, said dispersed particles being present in an amount less than about 60% by weight of the composite material and to the composite material formed by such process

Abstract: A method for the preparation of a polyimide containing reversible crosslinks comprising the step of curing a monomer having the formula ##STR1## wherein R and R' may be the same or different and each is H or lower alkyl having 1-5 carbon atoms under conditions conducive to the formation of a polyimide and thereby forming a polyimide having the formula ##STR2## R and R' are as defined above and n is an integer from 10 to 100. The polyimide may be converted to a soluble polymer by cleaving the disulfide bond in the presence of a solvent and a reducing agent. The reduced polymer may be reformed into the polymer in an oxidation step or into a modified polyimide in other reaction steps. Copolymerization processes are also disclosed.

Abstract: A method for the preparation of insoluble, infusible epoxy resins containing reversible crosslinks comprising the steps of:(a) forming a reaction mixture of(i) an epoxy compound having two or more epoxy groups, and(ii) a crosslinking agent containing two or more epoxy-reactive groups and further containing a disulfide bond, said crosslinking agent being selected from compounds having the formulaQ--X--S--S--X--Qwhere Q is an epoxy-reactive functional group selected from ##STR1## and X is a divalent aromatic or aliphatic hydrocarbon radical of one to ten carbon atoms, and(b) curing said reaction mixture under conditions conductive to the formation of a crosslinked resin.The epoxy resin can be solubilized by cleavage of the disulfide bond by reduction in the presence of a solvent. The resultant thiol groups can be reoxidized to form the disulfide linkages or can be modified by other reactions.

Abstract: Siloxane-containing polyimides, useful as conformal coatings for electrical devices, can be synthesized via a novel Diels-Alder reaction in which bis-maleimide derivatives are polymerized with siloxane-containing bis-furan derivatives. The Diels-Alder adduct can be aromatized, and applied as a coating to a mineral substrate. The aromatized, polyimide coating can be cured thermally without additional cyclization on the substrate.