Synthesis of waterborne polyurethane nanocomposite adhesives of bio‐based polyol from rapeseed cake residual and cellulose nanowhisker

Abstract

AbstractIn this research work, we synthesize a series of waterborne polyurethane (WPU) bio‐nanocomposite adhesives from bio‐based polyols, extracted from rapeseed cake residual (RCR) by oxypropylation procedure, and cellulose nanowhisker (CNW). The hydroxyl‐ (OH) number of the polyols, as the first variable parameter, is controlled through tuning oxypropylation degree by changing propylene oxide (PO) to RCR ratio. From the four prepared polyols, WPU of Polyol‐2 (WPU2) shows the most significant shear strength for wood and glass adhesion substrates. Polyurethane nanocomposites of CNW, with three different weight contents of 0.25, 0.50, and 1.0%, are prepared from WPU2, as the optimum WPU, and the WPU2 nanocomposite of WPU2‐0.50 wt% show the highest shear strength for all types of the substrates. For the WPU2 and WPU2‐0.50 wt% adhesives, the wood‐wood substrate show a high shear strength of 12.8 and 15.1 MPa, respectively. This work revealed that the shear strength of the adhesives and their failure mechanisms are affected by the structural parameters, OH‐number, and CNW content.