Abstract:

The biobased polyol(CG-polyol) was synthesized via one-pot method from crude glycerol(GC), a byproduct of biodiesel production, and the furfural residues(FR) was used as the reinforcing filler, which were blended for the preparation of a type of furfural residues-reinforced biobased polyurethane(PU/FR) foam composite material. The effects of FR size(0.25 mm, 0.09 mm samples FR60 and FR180) and addition amount on the PU/FR foam properties were investigated by characterizing the structure and morphology, thermal stability, foaming time, density and compressive strength of PU/FR foam. The results demonstrated that the CG-polyol synthesized by thermal conversion method had an acid number of 1.9 mg/g, a hydroxyl number of 406 mg/g, and a viscosity of 1 092 mPa·s, enabling it for preparing PU foam. The addition of FR prolonged the foaming time, and the maximum rise time and non-stick time increased from 29 and 31 s to 37 and 39 s, respectively. The cell structure of the foam became more complete, the size of the cell was reduced, and the breakage phenomenon was significantly reduced. When the amount of FR added was ≤5%, the density and compressive strength of the foam could be effectively improved. When the addition amount was the same, FR180 showed the most significant improvement in foam properties. Incorporating 5% FR180 into the preparation of PU/FR180-5 foam composite material resulted in a maximum compressive strength of 0.153 3 MPa, representing a 28.1% increase compared to the foam without FR. At this point, the density was 0.051 0 g/cm³ and the thermal conductivity was 0.032 8 W/(m·K). The overall performance of the composite material was better. Moreover, the addition of FR could moderately enhance the thermal stability of the PU foam material. Compared to the foam without FR, the maximum pyrolysis rate temperature(T_max) of the PU/FR180-5 foam increased from 453 ℃ to 463 ℃.

Key words: furfural residue, crude glycerol, high-value, polyurethane foam