The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 19, 1989
Filed:
Dec. 19, 1988
Michael S Sennett, Maynard, MA (US);
The United States of America as represented by the Secretary of the Army, Washington, DC (US);
Abstract
The invention is a continuous polymerization process for producing high molecular weight linear poly(dichlorophosphazene) polymers in dilute solution. Substantially pure cyclic oligomers represented by the formula (NPCl.sub.2).sub.n are polymerized in dilute solution in an inert solvent at a temperature in the range from 150 degrees Celsius to 300 degrees Celsius for a period of time sufficient to convert a predetermined percentage of oligomer to polymer. The polymer solution may be added to a fresh solution of oligomer, solvent and catalyst to obtain polymers of greater molecular weight. This step may be repeated as many times as necessary to obtain a particular molecular weight. This invention provides a significant improvement in the attainable molecular weight in dilute solution polymerization, with a very high conversion rate of oligomer. The viscosity of the solution during the continuous reaction process is maintained at a level which may be easily handled.