2380 results about "Endcapping" patented technology

Main chain thermotropic liquid crystal esters, ester-imides, and ester-amides were prepared from AA, BB, and AB type monomeric materials and were end-capped with phenylacetylene, phenylmaleimide, or nadimide reactive end-groups. The resulting reactive end-capped liquid crystal oligomers exhibit a variety of improved and preferred physical properties. The end-capped liquid crystal oligomers are thermotropic and have, preferably, molecular weights in the range of approximately 1000-15,000 grams per mole. The end-capped liquid crystal oligomers have broad liquid crystalline melting ranges and exhibit high melt stability and very low melt viscosities at accessible temperatures. The end-capped liquid crystal oligomers are stable for up to an hour in the melt phase. These properties make the end-capped liquid crystal oligomers highly processable by a variety of melt process shape forming and blending techniques including film extrusion, fiber spinning, reactive injection molding (RIM), resin transfer molding (RTM), resin film injection (RFI), powder molding, pultrusion, injection molding, blow molding, plasma spraying and thermo-forming. Once processed and shaped, the end-capped liquid crystal oligomers were heated to further polymerize and form liquid crystalline thermosets (LCT). The fully cured products are rubbers above their glass transition temperatures. The resulting thermosets display many properties that are superior to their non-end-capped high molecular weight analogs.

A thermosetting composition comprises a capped poly(arylene ether), an alkenyl aromatic monomer, and an alkoxylated acryloyl monomer. The composition provides good flow properties and fast curing rates. After curing, the composition exhibits good stiffness, toughness, and heat resistance.

Poly(beta-amino esters) are end-modified to form materials useful in the medical as well as non-medical field. An amine-terminated poly(beta-amino ester) is reacted with an electrophile, or an acrylate-terminated poly(beta-amino ester) is reacted with a nucleophile. The inventive end-modified polymers may be used in any field where polymers have been found useful including the drug delivery arts. The end-modified polymers are particularly useful in delivery nucleic acids such as DNA or RNA. The invention also provides compositions including the inventive end-modified polymers, methods of preparing the inventive polymers, and method of using the inventive polymers.

A copolymer useful as a rigid gas permeable contact lens material is the polymerization product of a monomeric mixture comprising a polysiloxane-containing urethane or urea prepolymer endcapped with polymerizable ethylenically unsaturated radicals.

Disclosed herein is a blocked mercaptosilane selected from the group consisting of[[(ROC(═O))p—(G)j]k—Y—S]r—G—(SiX3)s; and  (1)[(X3Si)q—G]a—[Y—[S—G—SiX3]b]c  (2)whereinY is a polyvalent species (Q)zA(═E) selected from the group consisting of —C(═NR)—; —SC(═NR)—; —SC(═O)—; —OC(═O)—; —S(═O)—; —S(═O)2—; —OS(═O)2—; (—NR)S(═O)2—; —SS(═O)—; —OS(═O)—; (—NR)S(═O)—; —SS(═O)2—; (—S)2P(═O)—; —(—S)P(═O)—; —P(═O)(—)2; (—S)2P(═S)—; —(—S)P(═S)—; —P(═S)(—)2; (—NR)2P(═O)—; (—NR)(—S)P(═O)—; (—O)(—NR)P(═O)—; (—O)(—S)P(═O)—; (—O)2P(═O)—; —(—O)P(═O)—; —(—NR)P(═O)—; (—NR)2P(═S)—; (—NR)(—S)P(═S)—; (—O)(—NR)P(═S)—; (—O)(—S)P(═S)—; (—O)2P(═S)—; —(—O)P(═S)—; and —(—NR)P(═S)—; wherein the atom A attached to unsaturated heteroatom E is attached to the sulfur which in turn is linked via a group G to the silicon atom;each R is chosen independently from hydrogen, straight, cyclic, or branched alkyl that may or may not contain unsaturation, alkenyl groups, aryl groups, and aralkyl groups, with each R containing from 1 to 18 carbon atoms;each G is independently a monovalent or polyvalent group derived by substitution of alkyl, alkenyl, aryl, or aralkyl, wherein G can contain from 1 to 18 carbon atoms, with the proviso that G is not such that the blocked mercaptosilane would contain an α,β-unsaturated carbonyl that can undergo polymerization reactions, and if G is univalent, G can be a hydrogen atom;X is independently selected from the group consisting of —Cl, —Br, RO—, RC(═O)O—, R2C═NO—, R2NO—, R2N—, —R, and —(OSiR2)t(OSiR3) wherein each R is as above and at least one X is not —R;p is 0 to 5; r is 1 to 3; z is 0 to 2; q is 0 to 6; a is 0 to 7; b is 1 to 3; j is 0 to 1, but it may be 0 only if p is 1; c is 1 to 6; t is 0 to 5; s is 1 to 3; k is 1 to 2; with the provisos that (I) if A is carbon, sulfur or sulfonyl, then (i) a+b is 2 and (ii) k is 1; (II) if A is phosphorus, then a+b is 3 unless both (i) c is greater than 1 and (ii) b is 1, in which case a is c+1; and (III) if A is phosphorus, then k is 2.

A method for end-capping polycarbonate resins, comprising the step of processing a mixture comprising a polycarbonate having free hydroxyl-end groups and an end-capping reagent in a melt transesterification reaction to produce a polycarbonate resin, wherein the end-capping reagent comprises a mixture of: (a) at least one species of a symmetrical activated aromatic carbonate, and (b) at least one species of an optionally-substituted phenol, whereby said end-capping reagent reacts with at least some of the free hydroxyl end-groups of the polycarbonate to produce an end-capped polycarbonate resin.