E.i. Dupont De Nemours and Company

Wesley Memeger, Jr

Young H Kim

Stephan Claude De La Veaux

James E Geary, Jr

Roland T Brierre

Michael L Trancynger

Bruce E Smart

Anthony J Arduengo, Iii

Disclosed herein are cyclic oligomers comprising substituted or unsubstituted m-phenylene isophthalamide, complexes of these oligomers with selected metal salts, novel methods for their preparation, and polymerization of the cyclic oligomers to linear aramids. The aramids are useful, for example, as fibers for fire resistant clothing. Amino-functional cyclic oligomers may be reacted with polyfunctional acyl halides to produce polyamides.

Cyclic oligomers comprising m-phenylene isophthalamide and polymers

Composite materials made wholly from aromatic polyamides are prepared, which have the advantage of better performance and less delamination than composites composed of chemically distinct components. The foam matrix for such composites is prepared using N,N'-dialkylated aromatic polyamide. Both fiber reinforced foam structural forms and foam/felt laminates are prepared.

PPD-T structural composites

Disclosed herein are cyclic oligomers comprising substituted or unsubstituted m-phenylene isophthalamide, complexes of these oligomers with selected metal salts, novel methods for their preparation, and polymerization of the cyclic oligomers to linear aramids. The aramids are useful, for example, as fibers for fire resistant clothing. Amino-finctional cyclic oligomers may be reacted with polyfunctional acyl halides to produce polyamides.

Disclosed is a process for preparing polyether ketones comprising reacting one or more bihaloaryl ketones in the presence of a catalyst, co-catalyst and solvent.

Process for preparing polyether ketones

Process for the ring opening polymerization of lactams to higher molecular weight polyamide polymers utilizing non-ionic polymerization catalyst base with a pKa of equal to or greater than 30, particularly certain strong, nitrogen and phosphorus containing non-ionic bases.

Strong non-ionic base catalyzed ring opening polymerization of lactams

This invention concerns cyclic aromatic amide oligomer compositions and a process for preparing such cyclic oligomers.

Cyclic aromatic amide oligomers

A method for producing para-aramid pulp includes forming a liquid, actively-polymerizing solution and subjecting the solution to orienting flow which produces an optically anisotropic liquid solution with polymer chains oriented in the direction of the flow. When the solution has a viscosity sufficient to maintain the orientation of the polymer chains, the solution is incubated until it gels. The gel is cut transversely at intervals and para-aramid pulp is isolated from the gel. Para-aramid pulp produced by the process can be used similarly to pulp produced from spun fiber.

Method and apparatus for producing para-aramid pulp and pulp produced

Method for producing para-aramid pulp

Coherent expanded nonwoven sheets having a density of less than 0.16 g/mL are comprised of fibrids of a wholly synthetic polymer, preferably not melting below 130.degree. C., and optionally containing up to 80% by weight floc. The sheet is comprised of a plurality of paper-like membranous layers which join and separate at random throughout the thickness of the sheet to form expanded cells. The expanded nonwoven sheets are prepared by rapid vaporization of water in a wet, never-dried sheet of fibrids containing at least 60% by weight water. Rapid vaporization of the water preferably is induced by dielectric heating. Embossing may be used before or during expansion to produce a sheet which is expanded only in selected areas.

Low density nonwoven sheets

Aromatic polyamide foams having a density of 0.025 to 0.7 g./cm..sup.3 are prepared by heating N-alkyl aromatic polyamides having at least one .beta. hydrogen atom on the alkyl groups, a plasticizer and an aromatic sulfonic acid catalyst at 250.degree. to 340.degree. C. for a length of time sufficient to remove substantially all of the N-alkyl groups.

Wholly aromatic polyamide foam

Aromatic polyamide foams having a density of 0.025 to 0.7 g./cm..sup.3 are prepared by heating N,N'-dialkyl aromatic polyamides having at least one .beta. hydrogen atom on the alkyl groups, a plasticizer and an aromatic sulfonic acid catalyst at 250.degree. to 340.degree. C. for a length of time sufficient to remove substantially all of the N-alkyl groups.

Growing community of inventors

Wilmington, DE, United States of America

Wesley Memeger, Jr