Design of biobased non-isocyanate polyurethane (NIPU) foams blown with water and/or ethanol

A promising process to design non-isocyanate polyurethane (NIPU) foams has been developed. The transurethane polycondensation reaction between fatty biscarbamates, fatty diols, and diamines was used to synthesize a biobased aminotelechelic NIPU oligomer. The prepared oligomer (hard phase) was mixed with an amino-telechelic polydimethylsiloxane (PDMS, soft phase) and then reacted with a biosourced tri-epoxide molecule as crosslinking agent, in the presence of water/ethanol mixtures as physical blowing agents. The crosslinking reaction was followed by Fourier transform infrared spectroscopy (FTIR) and rheometry. The foams can be obtained in less than 2 hours at 95 & DEG;C. The prepared foams exhibited cell diameters ranging from 130 to 3090 & mu;m, as well as densities ranging from 55 to 950 kg/m3. Their thermal stability thresholds were above 300 & DEG;C. They displayed glass transition temperature values ranging from -20 to -18 & DEG;C, and low values of the Young modulus ranging from 2.0 & BULL;103 to 5.7 & BULL;103 Pa. The hysteresis loss, the recovery time, and the firmness of these foams were dependent on the PDMS content and/or the morphological parameters.