Elastomers from Renewable Metathesized Palm Oil Polyols

Polyurethane (PU) elastomers were prepared from 1-butene metathesized palm oil (PMTAG) polyols in order to study the effect of their molecular structure on the properties of polyurethanes. The chemical structure, thermal degradation, thermal properties, and tensile strength of the PUs were determined using Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and texture analysis, respectively. Depending on the cross-linking density, which increases with increasing hydroxyl values of the polyols, the polyurethanes produced behave as rigid plastic or elastomeric rubbers. The highest hydroxyl polyol (OH value: 184 mg KOH/g) produced polyurethanes displaying a tensile strength of ∼18 MPa and displayed characteristics of a rigid plastic. On the other hand, the polyurethane prepared from the low hydroxyl polyol (OH value: 83 mg KOH/g) displayed more elastomeric characteristics with a lower tensile strength of ∼4.2 MPa and ∼120% elongation at break. All of the PUs prepared in this study display high thermal stability (T_on of degradation of ∼280 °C), comparable to commercial PUs. The thermal transition behavior of the PUs from DSC and DMA indicates that the glass transition temperature of the PUs increased with an increase in OH value of the polyols. Polyurethanes prepared from metathesized palm oil polyols display superior performance when compared with more expensive bio based PUs derived from canola and soybean oils and represent potential for replacing current commercially available petrochemically derived polyols.