نبذة مختصرة : Bio-based adhesives have been largely applied on several applications in many industrial areas, includingautomotive and laminated food packaging. Polyurethanes (PU) occupy a leading position among the mostused bio-based polymers due to their large range of properties and application versatility. Recent works reportedthat PU obtained from castor oil and Kraft lignin as polyol developed high mechanical properties andblend miscibility. In spite of its well-known mechanical behavior, additional investigations might support theapplication of this bio-based PU as adhesive. In this context, our work investigated the effect of adhesive(bondline) thickness variation (size effect) on shear modulus of a bio-based polyurethane under finite deformationand related shear stress distribution. Polyurethane was obtained using a blend of Kraft lignin and castoroil as polyol (20 wt% of Kraft lignin) and applied as adhesive for metal bonding, in which adhesive thicknesschanged from tens of micrometers up to 220 micrometers. Steel plates were used as substrates and adhesiveshear modulus was evaluated using substrates with large thickness (4.76 mm), which minimized the effectof substrate deformation on shear modulus measurement. Single lap joints were uniaxial loaded in orderto generate the shear stress on adhesive bondline. Additionally, shear modulus changes were simulated byfinite element analysis (FEA), analytical models and compared to experimental data. Results revealed thesize effect and pointed to high shear modulus of the PU bondline, justifying its use as an adhesive for structuralapplications.Keywords: bio-based polyurethane, Kraft lignin, finite element analysis, adhesive.
Processing Request
No Comments.