Polycarbonate with high refractive index

1. An aromatic polycarbonate comprising a first monomer of Formula (I) and a second monomer of Formula (II):

wherein R 1 -R 16 are each independently selected from hydrogen, halogen, nitro, cyano, C 1 -C 20 alkyl, C 4 -C 20 cycloalkyl, and C 6 -C 20 aryl; and

wherein the molar ratio of the first monomer to the second monomer is from about 45:55 to about 75:25, and wherein the aromatic polycarbonate has a reflective index of at least 1.62.

2. The aromatic polycarbonate of claim 1 , wherein the first monomer is 4,4′-thiodiphenol.

3. The aromatic polycarbonate of claim 1 , wherein the second monomer is 4,4′-dihydroxybiphenyl.

4. The aromatic polycarbonate of claim 1 , wherein the first monomer is 4,4′-thiodiphenol and the second monomer is 4,4′-dihydroxybiphenyl.

5. The aromatic polycarbonate of claim 4 , wherein the molar ratio of the first monomer to the second monomer is about 70:30.

6. The aromatic polycarbonate of claim 1 , further comprising up to 100 molar parts of a third monomer, wherein the sum of the first and second monomers total 100 molar parts; and the third monomer is different from the first and second monomers.

7. The aromatic polycarbonate of claim 6 , wherein the third monomer is a bisphenol of Formula (III):

wherein A is selected from a bond, —O—, —S—, —SO 2 —, C 1 -C 12 alkyl, C 6 -C 20 aromatic, and C 6 -C 20 cycloaliphatic; and R 17 -R 24 are each independently selected from hydrogen, halogen, nitro, cyano, C 1 -C 20 alkyl, C 4 -C 20 cycloalkyl, and C 6 -C 20 aryl.

8. The aromatic polycarbonate of claim 6 , wherein the third monomer is 2,2-bis(4-hydroxyphenyl)propane (bisphenol-A).

9. The aromatic polycarbonate of claim 6 , wherein the third monomer is 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine (PPPBP).

10. The aromatic polycarbonate of claim 1 , having a refractive index of at least 1.67.

11. The aromatic polycarbonate of claim 1 , having a notched Izod impact of greater than 6 foot-lb/inch when measured at 23° C. with 3.18 mm thickness according to ASTM D256.

12. The aromatic polycarbonate of claim 1 , having a haze level of less than 15 when measured at a sheet thickness, according to ASTM D1003-00.

13. The aromatic polycarbonate of claim 1 , having a % T of at least 70 when measured at a thickness of 0.75 millimeter.

14. The aromatic polycarbonate of claim 1 , having a crystallinity of less than 1%.

15. An aromatic polycarbonate, comprising:

45 to 75 molar parts of a first monomer of Formula (I):

25 to 55 molar parts of a second monomer of Formula (II):

0 to 100 molar parts of a third monomer of Formula (III):

wherein R 1 -R 24 are each independently selected from hydrogen, halogen, nitro, cyano, C 1 -C 20 alkyl, C 4 -C 20 cycloalkyl, and C 6 -C 20 aryl; and A is selected from a bond, —O—, —S—, —SO 2 —, C 1 -C 12 alkyl, C 6 -C 20 aromatic, and C 6 -C 20 cycloaliphatic;

wherein the sum of the first and second monomers total 100 molar parts;

wherein the third monomer is different from the first and second monomer, and wherein the aromatic polycarbonate has a refractive index of at least 1.62.

16. The aromatic polycarbonate of claim 11 , having a refractive index of at least 1.670.

17. An article formed from the aromatic polycarbonate of claim 1 .

18. An extruded or molded article formed from the aromatic polycarbonate of claim 11 .

19. An aromatic polycarbonate, comprising:

45 to 75 molar parts of a first monomer of 4,4′-thiodiphenol;

25 to 55 molar parts of a second monomer of 4,4′-dihydroxybiphenyl; and

0 to 100 molar parts of a third monomer of 2,2-bis(4-hydroxyphenyl)propane;

wherein the sum of the first and second monomers total 100 molar parts, and wherein the aromatic polycarbonate has a refractive index of at least 1.62.

20. The aromatic polycarbonate of claim 19 , having a % T of at least 70 when measured at a thickness of 0.75 millimeter, and having a notched Izod impact of greater than 6 foot-lb/inch when measured at 23° C. with 3.18 mm thickness according to ASTM D256.