Effect of Natural Oil Based Polyols on the Properties of Flexible Polyurethane Foams Blown by Distilled Water

Generally, the flexible polyurethane foams were synthesized by mainly petroleum-based polyols. In this present study, Caradol SA34-05 (petroleum-based polyol) was replaced by Emerox® 14001 (natural oil-based polyol) with 0-50 wt% replacement to prepare flexible polyurethane foam by one shot method. The NCO index (NCO equivalent/OH equivalent) was fixed at 1.00. The characteristic times such as cream time, gel time, rise time and tack free time were followed during cup test. The physical properties were characterized and studied by Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and foam density. The tensile and compression properties were investigated by UTM machine. The results show that the foam density decreased with increasing Emerox® 14001 contents up to 20 wt% replacement and then decreased. This trandency was similar to tensile modulus, compressive modulus and compressive strength results. The cell size of foams was important parameter to control their properties. However, tensile strength and elongation at break were enhanced by the addition of Emerox® 14001 at 20 wt% contents replacement and then decreased at higher content. Both parameters rely on balance between urethane linkages and urea microdomain and/or polyurea ball contents(urea aggregate), which were rapidly generated by isocyanate group and water. The increased Emerox® 14001 contents required more isocyanate. As a result, more urea microdomain were produced leading to the decreasing of tensile strength and elongation at break. Moreover, the compression set of the foams was dependent upon amount of urea linkages which was generated from the reaction of isocyanate group and water.