Preparation and characterization of biodegradable rigid polyurethane foams from the liquefied eucalyptus and pine woods

In this study, eucalyptus (Eucalyptus camaldulensis L.) and pine (Pinus sylvestris L.) woods were liquefied using the the blended solvents mixture of polyethylene glycol PEG-400/glycerin in the presence of sulfuric acid as a catalyst at 140-160°C for 120 min. The insoluble parts in the liquefied eucalyptus and pine were found as 17.8 and 5.5 wt. %, respectively. The acid and hydroxyl numbers of the liquefied eucalyptus and pine were determined and compared with each other. Polyurethane-type rigid foams (RPUFs) were successfully prepared by a co-polymerization of the liquefied woods (LWs) and polymeric methylene diphenylene diisocyanate (PMDI). The compressive strength (120 to 250 kPa), the modulus of elasticity (1 to 6 MPa), the density (20 to 50 kg.nr-3) and thermal conductivity (0.0352 to 0.0374 W.mK -1) of the RPUFs prepared from the LWs were found to be almost comparable to those of the synthetic foams. Furthermore, the biodegradability of the biomass-based foams was higher than that of the synthetic ones.