Methods of making polymers using isosorbide
The present invention is based, in part, on the discovery that the polymeric materials described herein produce polyurethane copolymers with advantageous optical properties. In particular embodiments, polyurethane copolymers comprise repeating units of isosorbide and a difunctional linker where the difunctional linkers can be diisocyanate, diisothiocyanate, dicarboxylic acid, and other monomers. Some of the advantageous optical properties of these polymeric materials include a refractive index of about 1.5 and an Abbe value of at least about 50. Also described are methods for producing these polyurethane copolymers.
1 . A polyurethane copolymer comprising a repeating unit of Formula I:
wherein:
ISO in each repeating unit is independently selected from isosorbide, or a stereoisomer thereof, or an isosorbide adduct thereof; and
X in each repeating unit is an independently selected difunctional linker,
wherein X in at least one repeating unit is a difunctional isocyanate linker, and
wherein the polyurethane copolymer has a refractive index of at least about 1.5 and an Abbe value of greater than 65.
2 . The polyurethane copolymer of claim 1 , wherein the stereoisomer is selected from the group consisting of isomannide and isoidide.
3 . The polyurethane copolymer of claim 1 , wherein the difunctional isocyanate linker is a diisocyanate.
4 . The polyurethane copolymer of claim 3 , wherein the diisocyanate is selected from the group consisting of 4, 4′-methylenebis(cyclohexylisocyanate) (H12MDI), methylenebis(phenylisocyanate), hexamethylene diisocyanate, isophorone diisocyanate, cyclohexane diisocyanate, butane diisocyanate, and 1,3-bis(isocyanatomethyl) cyclohexane.
5 . The polyurethane copolymer of claim 1 , wherein the polyurethane copolymer has a light transmittance of at least about 80%.
6 . The polyurethane copolymer of claim 1 , wherein the polyurethane copolymer has a yellow index of lower than about 10.
7 . An optical element made of polyurethane copolymer of claim 1 .
8 . The optical element of claim 7 , wherein the optical element is selected from a ophthalmic lens, a light guide, a fiber optic, a film, a sheet, sunglasses, magnifying glasses, concentrators for solar cells, and microscopic lenses.