Chemistry of inorganic compounds – Phosphorus or compound thereof – Halogen containing
Patent
1988-12-19
1989-09-19
Doll, John
Chemistry of inorganic compounds
Phosphorus or compound thereof
Halogen containing
C01B 2510
Patent
active
048679577
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.
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Doll John
Donahue Richard J.
Elbaum Saul
Goldberg Mark
Langel Wayne A.
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