Process for controlling the molecular weight of polycarbonates using ammonia or ammonia compounds
AssigneeThe Dow Chemical Company
InventorJoseph McClendon Baggett
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Abstract
Process for the preparation of aromatic polycarbonates by the interfacial technique wherein the molecular weight is controlled by adding an effective amount of ammonia or ammonium compounds to the polymerization reaction. Examples of suitable compounds effective to control the molecular weight are ammonia, ammonium hydroxide, ammonium sulfite and other ammonium salts.
Claims5
A process for controlling the molecular weight of thermoplastic aromatic polycarbonates which comprises reacting under interfacial polycarbonate-forming conditions
- 1. a carbonyl halide,
- 2. a dihydric phenol or mixtures of dihydric phenols,
- 3. a catalyst useful to form polycarbonates, and
- 4. a chain terminating amount of a compound selected from the group consisting of ammonia or an ammonium compound which liberates ammonia under the conditions of the reaction.
A process for controlling the molecular weight of thermoplastic polycarbonates which comprises reacting under interfacial polycarbonate-forming conditions
- 1. a carbonyl halide,
- 2. a dihydric phenol or mixtures of dihydric phenols,
- 3. a catalyst useful to form polycarbonates, and
- 4. a chain terminating amount of a compound having one of the formulas
- a. NH.sub.3,
- b. NH.sub.4 Z, or
- c. (NH.sub.4).sub.2 Z.sub.2
- wherein Z is a monovalent inorganic anion, and Z.sub.2 is a divalent inorganic anion.
Dependencies are inferred from the claim text.