Abstract: A polymer having a crosslinked structure made from a polyol and an isocyanate where the crosslinks contain urethane and/or ester bonds made from the reaction of a benzylic hydroxyl group and an isocyanate group.

Abstract: A polymer having a crosslinked structure made from a polyol and an isocyanate where the crosslinks contain urethane and/or ester bonds made from the reaction of a benzylic hydroxyl group and an isocyanate group.

Abstract: A polymer having a crosslinked structure made from a polyol and an isocyanate where the crosslinks contain urethane and/or ester bonds made from the reaction of a benzylic hydroxyl group and an isocyanate group.

Abstract: A polymer having a crosslinked structure made from a polyol and an isocyanate where the crosslinks contain urethane and/or ester bonds made from the reaction of a benzylic hydroxyl group and an isocyanate group.

Abstract: Thermally-reversible polymer compositions are obtained by reacting compounds with isocyanate and labile-hydrogen functionality. Aromatic polyimide, aromatic polycarbonate, polyarylsulfide, aromatic polyester with liquid crystal property, and polyarylimidazolidine oligomers are incorporated into the isocyanate or labile hydrogen compounds to give high-performance characteristics. Such thermally-reversible isocyanate-based polymer compositions with high-performance characteristics are useful, among other things, as finish surface coatings on composite materials such as polypropylene and polyethylene terephthalate. Novel phenolic-hydroxyl terminated polyarylsulfide and polyarylimidazolidine oligomers and their preparation are also described.

Abstract: Thermally-reversible polymer compositions are obtained by reacting compounds with isocyanate and labile-hydrogen functionality. High-performance characteristics are incorporated into the polymer by using aromatic polycarbonate, aromatic polyester, polyarylsulfide, and polyarylimidazolidine oligomers. The compositions are useful as hot-melt adhesives, coatings and especially finish surface coatings on composite materials such as polypropylene and polyethylene terephthalate, moldings and in injection reaction molding applications and composite and laminate fabrication.

Abstract: The present invention is directed to a method for making lactide from aqueous lactic acid. The invention method comprises converting feed aqueous lactic acid to its vapor phase. The feed vapors then are passed through a reactor maintained at elevated temperature and in which optionally is disposed an alumina catalyst. Withdrawn from the reactor is product lactide, water, and unreacted lactic acid which are subjected to separation for recovery of the lactide product. The separated unreacted lactic acid is eligible for readmission to the process for making additional lactide. This cyclic process embodiment of the present invention comprises the steps of passing make-up aqueous lactic acid feed into a vaporization zone along with unreacted aqueous lactic acid filtrate from another step of the process and therein forming aqueous lactic acid feed vapors. The thus-generated vapors that are passed through a vapor phase reaction zone held at elevated temperature for forming lactide therein.

Abstract: Disclosed is a method for producing cyclic esters by the conversion of hydroxy carboxylic acids and their derivatives to their respective cyclic esters. Such cyclic esters, including lactide or glycolide, are particularly useful for producing polymers which can be used to make biodegradable materials, such as biodegradable packaging material. Various methods of cyclic ester production are disclosed, including liquid phase and vapor phase reactions. Also disclosed are various methods for recovering cyclic esters from product-containing streams.

Abstract: The present invention is directed to a method for making L-lactide from aqueous L-lactic acid. Aqueous lactic acid feed for present purposes comprehends an aqueous mixture of one or more of L.sub.1 A, L.sub.2 A, and L.sub.3 A, optionally with LD being present. L-lactic acid is the preferred feed configuration for making L-lactide, and is to be understood even though the configuration symbol is not used throughout this application. Aqueous lactic acid feed is treated for removal of water therefrom until a degree of polymerization (DP) not substantially above about 2 is reached. The treatment then is ceased to produce a crude LD product. LD then is separated from the crude LD product. A preferred treatment involves heating the feed at elevated temperature to remove water. LD can be separated from the crude LD product by a variety of techniques to produce an LD-depleted product.

Abstract: Polyarylimidazolidines with a degree of polymerization of about one to twenty and having phenolic hydroxyl end groups and a novel three-step process for their preparation are described. In the first step of the process, an excess of hydrogen cyanide is reactive with an aryl diisocyanate. The excess hydrogen cyanide promotes polymerization and avoids the reaction of the imino hydrogen on the heterocyclic range with the diisocyanate to form cross linkage and associated gel formation. In the second step, a stoichiometric amount of diisocyanate is added to react with the excess hydrogen cyanide and one hydroxyl of a phenolic dihydroxyl end capping group. In the final third step, the dihydroxyl end capping group is added and the remaining diisocyanate reacts with one of the two phenolic hydroxyls on the end capping group.

Abstract: Thermally-reversible polymer compositions are obtained by reacting compounds with isocyanate and labile-hydrogen functionality. High-performance characteristics are incorporated into the polymer by using polyimide, aromatic polycarbonate, aromatic polyester, polyphenylene sulfide, and poly(parabanic acid) oligomers. Low-temperature flexibility and toughness are imparted to the polymers by using prepolymers such as polycaprolactone diols, polytetramethylene ether glycols and polyaliphatic carbon diols. Ionic bonding and liquid-crystal functionality may also be incorporated into the compositions. The compositions are useful as hot-melt adhesives, coatings, and moldings and in injection reaction molding applications and composite and laminate fabrication.

Abstract: Processes for treating polymeric surfaces to produce smooth, durable, slippery coatings which are able to withstand the rigors of sterilization and, long term exposure to human blood and other bodily fluids without substantial loss of their slipperiness.

Abstract: Epoxy and epoxy novolak resins are impact modified by adding an effective amount of a acrylamide diene nitrile rubber terpolymer to the resin. In a preferred embodiment, the acrylamide diene nitrile rubber includes an acid or ester group attached to the acrylamide portion of the polymer generally through a thiol group. The liquid terpolymer is reacted in the presence of acid catalysts with the resin to provide impact modification.

Abstract: Disclosed is a method for preparing poly(2-hydroxyethyl methacrylate) polymers (PHEMA) by a precipitation/suspension polymerization technique wherein a reaction mixture comprising hydroxyethyl methacrylate monomer (HEMA), solvent, and a free-radical initiator is subjected to heating for a time adequate for said PHEMA to be formed. The improvement in process of the present invention comprises restricting said HEMA to contain less than about 0.5 wt-% polyfunctional acrylate content, incorporating a suspending agent in said reaction mixture, agitating said reaction mixture during said heating, and restricting said solvent to one having a solubility parameter of between about 7.5 and 9, to produce PHEMA polymer particles ranging in size from about 30 to 1,000 microns and having a molecular weight ranging from about 500,000 to 2,000,000.

Abstract: Epoxy and epoxy novolak resins are impact modified by adding an effective amount of an acrylamide diene nitrile rubber terpolymer to the resin. In a preferred embodiment, the acrylamide diene nitrile rubber includes an acid or ester group attached to the acrylamide portion of the polymer generally through a thiol group. The liquid terpolymer is reacted in the presence of acid catalysts with the resin to provide impact modification.

Abstract: A solventless prepolymer which is liquid at room temperature and cures at about 350.degree. F. The novel prepolymer is formed from a rubber monomer; acrylonitrile or methacrylonitrile; and an ether derivative of methylol acrylamide. The ether is formed from methylol acrylamide and an alcohol which boils above the cure temperature of the prepolymer and which preferably is hexyl carbitol. The prepolymer is formed with sufficient chain transfer agent to establish a weight average molecular weight of the prepolymer less than about 25,000. The prepolymer is heat curable to form a solid polymer with excellent compression set, tensile strength, and fuel resistivity. The method of formulating these polymers is also disclosed.

Abstract: A heat curable, solventless liquid prepolymer is prepared from a rubber monomer; a nitrile monomer such as acrylonitrile or methacrylonitrile; and a novel monomer having the following formula: ##STR1## The prepolymer is formed with sufficient chain transfer agent to establish a weight average molecular weight less than about 25,000. This low viscosity prepolymer is heat curable to form a solid rubber polymer suitable for use as a gasket.

Abstract: A solventless prepolymer which is liquid at room temperature and cures at about 350.degree. F. The novel prepolymer is formed from a rubber monomer; acrylonitrile or methacrylonitrile; and an ether derivative of methylol acrylamide. The ether is formed from methylol acrylamide and an alcohol which boils above the cure temperature of the prepolymer and which preferably is hexyl carbitol. The prepolymer is formed with sufficient chain transfer agent to establish a weight average molecular weight of the prepolymer less than about 25,000. The prepolymer is heat curable to form a solid polymer with excellent compression set, tensile strength, and fuel resistivity. The method of formulating these polymers is also disclosed.

Abstract: A heat curable, solventless liquid prepolymer is prepared from a rubber monomer; a nitrile monomer such as acrylonitrile or methacrylonitrile; and a novel monomer having the following formula: ##STR1## The prepolymer is formed with sufficient chain transfer agent to establish a weight average molecular weight less than about 25,000. This low viscosity prepolymer is heat curable to form a solid rubber polymer suitable for use as a gasket.

Abstract: A process for the production of an expandable silicone resin includes reacting a substantial amount of the silanol (SiOH) groups present in the resin to form siloxane bonds and water, and heating the resin to a temperature above the resin's melting point, at which chemical reaction (condensation) of the silanol groups occur. The reaction increases the molecular weight of the resin and decreases the amount of water that must be removed during a subsequent foaming step, thereby controlling the rate and extent of foaming which can occur. The resin is solidified, pulverized and size-reduced to a powder form. The resin powder is blended with a minor amount of a particulate inert filler which is coated with a silicone resin curing catalyst and also with a minor amount of blowing agent (powder). The dry powder blend is then thermally fused for a closely-controlled, short duration, time at a temperature near the lower end of the blowing agent's gas-generating temperature range.