Systematic assessment of wheat extenders in condensation resins for plywood production: Part I-physico-chemical adhesive properties

The use of additives for resins modification is common practice in wood-based panel industry and wheat flour has been one of the most widely used extenders for decades. The amount of wheat flour to be added is determined through a sense of proportion, mainly based on experience, as systematic scientific studies on the effect of its individual components are limited. In this study, we added wheat flour, wheat starch and wheat protein as extenders in various quantities to urea (UF) and phenol formaldehyde (PF) resins and analysed their structure, pH value and buffer capacity through closely examining their interaction with the resins as well as their effect on viscosity and bonding strength development. As a result, wheat protein proved to be the most effective on both resins. Despite influencing adhesive properties in uncured state, no effect on the curing behaviour of the resins could be observed.

Automated summary

This study found that wheat protein is the most effective additive for both urea formaldehyde and phenol formaldehyde resins. The addition of wheat flour, wheat starch, and wheat protein had an impact on the structure, pH value, and buffer capacity of the resins, but did not affect the curing behavior of the resins.