Synthesis and Characterization of Waterborne Polyurethanes based on Castor Oil Applied to Wood Protection

Abstract

In this work, bio-based polyurethanes (PUs) were synthesized by reacting castor oil (CO) and polypropylene glycol 2000 (PPG2000) in different ratios (70:30 and 50:50) and isophorone diisocyanate (IPDI). The dispersions obtained were characterized by dynamic light scattering (DLS) and films were prepared for characterization using Fourier transform infrared spectroscopy (FTIR), Buchholz hardness and brightness at 60°. These dispersions were used as impregnants in EUCALYTUS GRANDIS and their behavior against fire has been tested by intermittent flame resistance test. FTIR spectra of the synthesized materials allowed verifying the formation of urethane bonds. The dispersions obtained have particle diameters less than 200 nm. The films showed high brightness values (80 GU) and a Buccholz hardness of 33 units. Preliminary test results on impregnated woods indicated an increase in fire resistance.