Production of polyols and new biphasic mono-component materials from soy hulls by oxypropylation

• Oxypropylation of soybean hulls was successful.
• Two products were obtained in a single reaction step.
• Viscous polyol formed has adequate characteristics to prepare polyurethanes.
• Superficial modified soybean hull may be employed in self-reinforced composite preparation.

The present study is aimed at oxypropylating soybean hulls (SH) to obtain two products in a single reaction: a viscous polyol (SHP) and a solid fibrous residue of soybean hulls modified on the surface (SHBM) by a layer of thermoplastic polymer poly (propylene oxide). The oxypropylation reaction was conducted by polymerizing propylene oxide in the presence of the SH in a reaction catalysed by KOH at 150 °C. The chemical composition of the SH was determined. The samples before (SH) and after oxypropylation (SHP and SHBM) were characterized by Fourier Transform Infrared Spectroscopy and thermogravimetric analysis. The SH and SHBM were also characterized by scanning electron microscopy and X-ray diffraction. The SHP was characterized with respect to its hydroxyl index value (IOH), intrinsic viscosity [η] and with respect to the amount of poly (propylene oxide) homopolymer (PPO) formed. These characterizations were carried out in order to assess the effectiveness of the process and verify the applicability of both products: (i) for producing polymer derivatives such as polyurethane foams in the case of polyol; and (ii) to prepare biphasic monocomponent composites in the case of the superficially oxypropylated residue.