Properties of Wood Adhesives

Polarity
Wood is a polar substance with partially unsaturated polar groups on its surface; adhesives must also possess polar groups to enable the mutual attraction of opposite polarities, thereby creating a strong bond with the wood surface.
Wettability
This refers to the ability of the adhesive to adhere to and spread across surfaces such as wood. Wettability is influenced by surface tension and cohesive force; lower surface tension and cohesive force result in greater adhesion and spreading, while higher values ​​result in less. However, excessive wettability can lead to the adhesive being absorbed by the wood, causing "starved joints" (insufficient adhesive) and excessive consumption. Appropriate concentration and viscosity levels should be selected based on the specific materials being bonded.
pH Value
Adhesives that are strongly acidic or strongly alkaline can impair the mechanical properties of wood, with strong acidity having a particularly detrimental effect.
Molecular Weight Distribution
Adjusting (or designing) the required molecular weight range and distribution to suit the specific application of the adhesive can enhance bonding strength and accelerate curing.