Synthesis and Characterization of Novel Bisphenol-C-formaldehyde-acrylate-toluene Diisocyanate-PEG-400 Copolyurethanes

Abstract

Bisphenol-C-formaldehyde-acrylate-TDI polyurethane and bisphenol-C-formaldehyde-acrylate-TDI-PEG-400 [0.001 mol (PUA-I), 0.0005 mol (PUA-II), and 0.00025 mol (PUA-III)] copolyurethanes have been synthesized at room temperature. The polyurethane formation is verified by Fourier transform infrared spectroscopy (FTIR). The PUA-I-III are further characterized for their thermo-mechanical and electrical properties and also their chemical resistance against water, 10% each of aqueous NaCl, HCl, HNO₃, H₂SO₄, NaOH, and KOH. Density, tensile strength, and volume resistivity increased, while electric strength decreased with decreasing concentrations of PEG-400. Copolyurethanes possess weight-gain tendency in acidic and alkaline environments and possess excellent hydrolytic stability in harsh acidic, alkaline, and saline environments. In acidic and alkaline environments, the % weight-gain tendency is found to increase with decreasing PEG-400 content. The DSC transitions in conjunction with TG data confirmed multistep decomposition of copolyurethanes. The PEG-400 affected thermal stability to a considerable extent. Copolyurethanes may find applications as good insulators as well as coating materials for harsh environments.

Keywords:

• Copolyurethanes
• Density
• Electric strength
• Tensile strength
• Volume resistivity

ACKNOWLEDGMENTS

We are thankful to the directors of NCPL-Bharuch (for providing TDI); and ERDA-Vadodara and SICART-V.V. Nagar for testing the samples.