**5.2 Synthesis of polyurethanes based on BHETA**

Three types of polyurethanes have been synthesized based on BHETA. In the first case, BHETA is used as ring opening agent in caprolactone polymerization, and then novel biodegradable polyurethane has been synthesized. In the second and third cases, BHTEA is used as chain extender to synthesis of special and high modulus polyurethanes as follows:
