Cell Wall Bulking by Maleic Anhydride for Wood Durability Improvement

Mingming He,Jilong Fan,Shihan Gui,Zaixin He,Xiaohan Dai,Dandan Xu,Yuzhen Ma,Xiya Pan,Yongfeng Li,Xiaoying Dong,Changgui Li

doi:10.3390/f11040367

Abstract

Wood is susceptible to swelling deformation and decay fungi due to moisture adsorption that originates from the dynamic nanopores of the cell wall and the abundant hydroxyl groups in wood components. This study employed as a modifier maleic anhydride (MAn), with the help of acetone as solvent, to diffuse into the wood cell wall, bulk nanopores, and further chemically bond to the hydroxyl groups of wood components, reducing the numbers of free hydroxyl groups and weakening the diffusion of water molecules into the wood cell wall. The derived MAn-bulked wood, compared to the control wood, presented a reduction in water absorptivity (RWA) of ~23% as well as an anti-swelling efficiency (ASE) of ~39% after immersion in water for 228 h, and showed an improvement in decay resistance of 81.42% against white-rot fungus and 69.79% against brown-rot fungus, respectively. The method of combined cell wall bulking and hydroxyl group bonding could effectively improve the dimensional stability and decay resistance with lower doses of modifier, providing a new strategy for wood durability improvement.

Highlights

As a renewable resource material, wood has been widely used in construction, transportation, and furniture
Polyethylene glycol [35], maleic anhydride [36], and silicon compounds [37] have been explored for diffusion into the wood cell wall to fill the dynamic nanopores or bond to the hydroxyl group, preventing water from penetrating into the cell wall and improving the dimensional stability and even the decay resistance of wood
maleic anhydride (MAn) is a small-molecule and polar cyclic anhydride compound. It can diffuse into the the dynamic nanopores due to its small volume and high polarity in order to bulk the cell wall, dynamic nanopores due to its small volume and high polarity in order to bulk the cell wall, occupying the space that the water molecule could originally take up and chemically bonding occupying the space that the water molecule could originally take up and chemically bonding the the hydroxyl group by its active anhydride to prevent the wood cell wall from adsorbing moisture hydroxyl group by its active anhydride to prevent the wood cell wall from adsorbing moisture (Figure 1a,b) [34,47]

Summary

Introduction

As a renewable resource material, wood has been widely used in construction, transportation, and furniture. The explored modification methods include filling wood cell lumen by physical or chemical means, such as physical filling with poly (glycidyl methacrylate) [27] or phenolic resin [28], physical or chemical filling with polyacrylic resin [29,30,31], or physical or chemical filling with inorganic silica compounds [32] This strategy implies the use of large amounts of filler, resulting in high cost. Polyethylene glycol [35], maleic anhydride [36], and silicon compounds [37] have been explored for diffusion into the wood cell wall to fill the dynamic nanopores or bond to the hydroxyl group, preventing water from penetrating into the cell wall and improving the dimensional stability and even the decay resistance of wood. Such treatment could be inspired to design MAn containing a functional system to bulk cell wall for wood durability improvement

Experiment Materials

Preparation of Modified Wood

Characterization and Properties Evaluation of the Modified Wood

Experimental Results and Discussion

Conclusions