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Abstract
A series of bio-based polyurethane flexible foams were synthesized by substituting polyether polyol with castor oil and polyethylene glycol (PEG). The influence of the castor oil component in the prepolymers on the structure and properties of the castor oil-based polyurethane flexible foams were investigated and compared. FTIR (Fourier transform infrared spectroscopy) results confirmed that bio-based polyurethane was successfully synthesized by castor oil, PEG and MDI (diphenyl methane diisocyanate), and its urethane group content decreased as the castor oil content increased from 40 to 60 wt.%. TG (thermogravimetry) and DTG (derivative thermogravimetry) results showed that the thermal degradation of the bio-based polyurethane flexible foams occurred at about 150, 320 and 420 °C. The Young's modulus improved from 0.196 to 1.235 KPa and the compression resilience improved from 97.76 to 99.65 % with increased content of castor oil. Moreover, these bio-based foams exhibited lower water absorption and higher contact angle with increased castor oil content.