Effect of Liquefied Lignin Content on Synthesis of Bio-based Polyurethane Foam for Oil Adsorption Application

The present study focused on synthesizing polyurethane foams with different contents of liquefied lignin. To fulfill that, the weight ratios of liquefied lignin to polypropylene glycol triol (PPG as chain extender) were altered from 25 to 100%. The lignin based polyurethane foams (LPUFs) were characterized by Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), dynamic mechanical thermal analysis (DMTA), scanning electron microscopy (SEM), and compression strength test. The experimental results revealed that LPUFs structures became more disorganized and their density diminished while their heat stability increased with increasing lignin polyol content. Moreover, the specific compressive properties of LPUFs grew from 1.35 to 35.23 kPa Kg(-1) m(3) and their glass transition temperature elevated from 38.5 to 90 degrees C with an increase in lignin polyol due to the three-dimensional lignin structure. Finally, the oil adsorption behavior of LPUFs was studied with Langmuir, Freundlich and Redlich-Peterson isotherms. It was observed that oil adsorption properties enhanced for LPUFs with higher contents of lignin polyol. The current work demonstrated that lignin polyol in polyurethane formulation even up to high concentrations, can be appropriately used in the production of soft and rigid bio based foams for different applications such as bio-friendly oil absorbent.