Improved thermal and mechanical properties of water-blown rigid polyurethane foams synthesized with renewable castor oil and toluene diisocyanate-based trifunctional polyols

In this work, glycerol was chemically modified into novel toluene diisocyanate (TDI) based trifunctional polyol (NTP) by a two step process, involving the reaction of TDI with glycerol to form an isocyanate-terminated pre-polymer, followed by the reaction with glycol. A thermal and mechanical property of water-blown rigid polyurethane foam (WB-PUF) was enhanced by the partial substitution (30 & 50 wt%) of castor oil with glycerol or synthesized NTP. The effects of glycerol content and NTP on the WB-PUF properties were investigated using various characterization techniques including ATR-FTIR, TGA, SEM, compression test, and Shore-A hardness test. Notably, the introduction of NTP substitution into the formulation of WB-PUF foams had beneficial impact on the structure of materials enhancing foam density from 77 kg/m 3 to 117 kg/m 3 and also exhibited superior thermal and mechanical properties compared to those with glycerol and unmodified foams. Shore A hardness and compression strength of those foams ranged from 50 to 69.5 °Sh A and 1.88-3.28 MPa, respectively. These findings suggest potential applications of the modified WB-PUF in areas such as rigid tissue engineering.