Optically Active Helical Polyurethane−Urea with Single-Handed Conformation for Infrared Low Emissivity

Abstract

Optically active polyurethane−urea (S-PUU) based on S-1,1′-binaphthyl-2′,2-diol (S-BINOL) and polyurethane−urea (PUU) based on racemic 1,1′-binaphthyl-2′,2-diol (BINOL) were synthesized by hydrogen transfer addition polymerization procedure and characterized by Fourier transform infrared spectroscopy (FT-IR), thermal Fourier transform infrared spectroscopy (thermal FT-IR), X-ray diffraction (XRD), circular dichroism (CD) spectroscopy, and vibrational circular dichroism (VCD) spectroscopy. The infrared emissivity values of S-PUU and PUU were investigated at 8−14 μm. S-PUU with single-handed helical conformation possesses prominently interchain hydrogen bonds interactions, which is impactful for the reduction of infrared emissivity value. Thus, the infrared emissivity value of S-PUU is lower than that of PUU. The increasing rate of the infrared emissivity value of S-PUU is affected by hydrogen bonds, while S-PUU is heated up from 25 to 150 °C, and the rate is much higher after disappearance of hydrogen bond...