Flame retardant thermoplastic polymer composition, method of manufacture, and articles formed therefrom

A sheet having a thickness of less than or equal to 3 mm, comprising a thermoplastic polymer composition, wherein the thermoplastic polymer composition comprises:

• a branched cyanophenyl endcapped polycarbonate having:
• repeating structural carbonate units of the formula:
• wherein at least 60 percent of the total number of R1 groups contain aromatic organic groups and the balance thereof are aliphatic, alicyclic, or aromatic groups;
• branching groups derived from reaction with a branching agent;
• and
• cyanophenyl endcapping groups derived from reaction with a cyanophenol;
• 0.01 wt. % to 0.6 wt. % of an aromatic sulphone sulphonate;
• a brominated polycarbonate, in an amount such that the composition comprises 0.26 wt. % to 5.2 wt. % bromine.

A method for the manufacture of a sheet having a thickness of less than or equal to 3 mm, comprising

• extruding a thermoplastic polymer composition, wherein the thermoplastic polymer composition comprises:
• a branched cyanophenyl endcapped polycarbonate having:
• repeating structural carbonate units of the formula:
• wherein at least 60 percent of the total number of R1 groups contain aromatic organic groups and the balance thereof are aliphatic, alicyclic, or aromatic groups;
• branching groups derived from reaction with a branching agent;
• and
• cyanophenyl endcapping groups derived from reaction with a cyanophenol;
• 0.01 wt. % to 0.6 wt. % of an aromatic sulphone sulphonate;
• a brominated polycarbonate, in an amount such that the composition comprises 0.26 wt. % to 5.2 wt. % bromine.