Polyurethane Wood Adhesives Prepared from Modified Polysaccharides.

Area of Science:

• Polymer Chemistry
• Materials Science
• Sustainable Adhesives

Background:

• Polyurethane adhesives are widely used but often rely on petroleum-based components.
• Developing sustainable alternatives from renewable resources like wheat starch is crucial.

Purpose of the Study:

• To investigate the performance of polyurethane adhesives incorporating modified wheat starch (MS).
• To evaluate the impact of MS on thermal properties, rheology, and mechanical strength.

Main Methods:

• Synthesis of polyurethane adhesives using modified wheat starch (MS), native wheat starch (NS), polyols (1,3-propanediol (PD) and glycerol (Gly)), and 4,4'-diphenylmethane diisocyanate (pMDI).
• Analysis of thermal behavior (DSC), rheological performance, and lap shear strength.
• Comparison with control adhesives made with NS and pMDI.

Main Results:

• Addition of MS reduced curing temperature and heat, slightly enhancing thermal stability.
• Adhesives with MS exhibited significantly increased viscosity.
• Tensile shear strength of wood veneers was substantially improved with MS, even under wet conditions.

Conclusions:

• Modified wheat starch (MS) effectively enhances the performance of polyurethane adhesives.
• MS-based adhesives offer improved thermal and mechanical properties, comparable to conventional pMDI controls.
• This research highlights the potential of bio-based wheat starch in developing high-performance, sustainable adhesives.