Weatherable, thermostable polymers having improved flow composition

A copolymer composition consisting essentially of:

• a polysiloxane block comprising siloxane units, wherein
• the polysiloxane block is of the formula:
• wherein x is 4 to 50, each R3 is the same or different, and is C1-8 alkyl or C6-13 aryl;
• and D1 is the reaction residue of a dihydroxy aromatic compound;
• or
• the polysiloxane block is of the formula:
• wherein q is 4 to 50;
• each R3 is the same or different, and R4 is a C6-30 hydrocarbylene;
• and
• a polyarylate-polycarbonate block consisting essentially of arylate polyester units and aromatic carbonate units present in an amount of
• 50 to 99 mole percent of arylate polyester units, and
• 1 to 50 mole percent aromatic carbonate units, wherein
• 1 to 30 mole percent of the aromatic carbonate units are resorcinol carbonate units, and
• 0 to 35 mole percent of the aromatic carbonate units are bisphenol carbonate units,
• wherein the sum of the mole percentages of arylate polyester units and aromatic carbonate units in the arylate block is 100 mole percent,
• wherein the polysiloxane blocks are connected to an arylate ester unit, a aromatic carbonate unit, or both an arylate ester unit and a aromatic carbonate unit, and
• wherein the siloxane units of the polysiloxane block are present in an amount of 0.2 to 10 wt % based on the weight of the copolymer composition, and
• wherein a molded article having a thickness of 3.2±0.12 millimeters, and consisting of the copolymer composition, has a percent transmittance of greater than or equal to 70%, according to ASTM D1003-00.

A thermoplastic composition comprising a blend of:

• a first polymer comprising a copolymer composition comprising:
• a polysiloxane block comprising siloxane units, wherein
• the polysiloxane block is of the formula:
• wherein x is 4 to 50, each R3 is the same or different, and is C1-8 alkyl or C6-13 aryl;
• and D1 is the reaction residue of a dihydroxy aromatic compound;
• or
• the polysiloxane block is of the formula:
• wherein q is 4 to 50;
• each R3 is the same or different, and R4 is C6-30 hydrocarbylene;
• and
• a plyarylate-polycarbonate block consisting essentially of arylate polyester units and aromatic carbonate units present in an amount of
• 50 to 99 mole percent of arylate polyester units, and
• 1 to 50 mole percent aromatic carbonate units, wherein
• 1 to 30 mole percent of the aromatic carbonate unit are resorcinol carbonate units, and
• 0 to 35 mole percent of the aromatic carbonate units are bisphenol carbonate units,
• wherein the sum of the mole percentages of arylate polyester units and aromatic carbonate units in the arylate block is 100 mole percent,
• wherein the polysiloxane blocks are connected to an arylate ester unit, a aromatic carbonate unit, or both an arylate ester unit and a aromatic carbonate unit, and
• wherein the siloxane units of the polysiloxane block are present in and amount of 0.2 to 10 wt % based on the weight of the copolymer composition;
• and
• a second polymer,
• wherein the first and second polymers are not identical, and
• wherein a molded article having a thickness of 3.2±0.12 millimeters, and consisting of the thermoplastic composition, has a percent transmittance of greater than or equal to 70%, according to ASTM D1003-00.