Preparation of novel graphene oxide crosslinked azo polyurethane composite and its application in thermo-optic switch

A novel graphene oxide/azo polyurethane (GO/CBAPU) composite with 4,4′- bis (4 - dihydroxy-phenylazo)-benzene (BDPB), R(-)-3-chloro-1,2-propanediol and IPDI as comonomers and functionalized with graphene oxide (GO), was prepared by polymerization reaction. The GO/CBAPU composite was characterized by FT-IR, UV-vis spectroscopy, 1H NMR, SEM and TEM. The thermal and mechanical properties of GO/CBAPU composite were measured. Differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA) and mechanical properties of GO/CBAPU composite were investigated. Refractive index (n) of GO/CBAPU composite were measured at different wavelength (532 nm, 650 nm and 850 nm) and temperature by ATR technique; and the transmission loss of GO/CBAPU composite was characterized by CCD digital imaging devices. The results demonstrated that the thermo-optic coefficients (dn/dT) of GO/CBAPU are −19.400 × 10−4 (532 nm), −8.660 × 10−4 (650 nm) and −6.600 × 10−4 (850 nm), and the transmission losses is only 0.1705 dB/cm. The Y-shaped and MZ-typed thermo-optic switches based on GO/CBAPU thermo-optic effect were simulated. The response times of the Y-shaped and MZ-typed thermo-optic switches are 0.2 ms and 0.01 ms, respectively. The conclusion has potential significance to provide an effective and promising method for preparing graphene oxide-based polymer composites.