Glyoxal Cross-Linked Polyvinyl Alcohol- Microcrystalline Cellulose Blend as a Wood Adhesive with Enhanced Mechanical, Thermal and Performance Properties
Unknown authors
Abstract
Toxicity and limited availability of petrochemicals for wood adhesive have opened research for alternative materials that are sustainable and renewable. Cellulose is one such material that is incorporated in other matrices for reinforcing and enhancing properties. This work investigates the properties of wood adhesive prepared by blending polyvinyl alcohol (PVA) and microcrystalline cellulose (MCC) in water. The blend is further modified by cross-linking with a dialdehyde, glyoxal at 0.1 wt. % and 0.2 wt. % for enhancing properties. Cross-linking occurs by the acetal bond formation with free hydroxyl groups of MCC and PVA. The effect of cross-linking was studied by various tests, including viscosity and pH measurements, Fourier-transform infrared (FTIR) spectroscopy, and contact angle measurement. Enhancement of mechanical property and thermal property of cross-linked blends were evidenced from pencil hardness of the films, improvement in storage modulus by dynamic mechanical analysis (DMA), and increase in glass transition temperature by differential scanning calorimetry (DSC). The performance property of cross-linked wood adhesive was measured by wet tack analysis and tensile lap shear test with a canarium wood substrates after 6 hr. and 24 hr. of bonding showed excellent results. Glyoxal cross-linked blends show enhancements in adhesion with improved thermo-mechanical properties.