# Investigating Cell Wall Diffusion in Wood Modified with Phenol Urea Formaldehyde Resin in Different Length Scales

## TL;DR

This study examines how phenol urea formaldehyde resin diffuses into wood cell walls at different scales to improve wood durability and stability.

## Contribution

The study reveals how cell wall diffusion optimization enhances wood modification using thermosetting resins.

## Key findings

- Facilitated diffusion improved dimensional stability in antiswelling efficiency tests.
- Enabled diffusion more effectively excluded bound water from the cell wall.
- Resin migration locations in the cell wall were influenced by diffusion and drying conditions.

## Abstract

Wood modification using low molecular weight thermosetting
resins
improves the biological durability and dimensional stability of wood
while avoiding increasingly regulated biocides. During the modification
process, resin monomers diffuse from the cell lumen to the cell wall,
occupying micropore spaces before in situ curing
at 150 °C. This study investigated the mechanism of cell wall
diffusion at multiple scales, comparing two test groups where diffusion
was either facilitated or restricted. Antiswelling efficiency tests
demonstrated improved dimensional stability when diffusion was facilitated.
Differential scanning calorimetry showed that bound water was excluded
more effectively from the cell wall if cell wall diffusion was enabled.
Solid-state NMR spectroscopy (1H MAS and 13C
MAS) with relaxation time analysis indicated that resin migrated to
distinct locations within the cell wall, influenced by diffusion and
drying conditions. These findings highlight how optimizing cell wall
diffusion can significantly improve the performance of wood modification
processes using thermosetting resins.