Determination of Moisture Content and Shrinkage Strain during Wood Water Loss with Electrochemical Method.

Zongying Fu,Jingpeng Li,Hui Wang,Yun Lu

doi:10.3390/polym14040778

Abstract

Moisture content and shrinkage strain are essential parameters during the wood drying process. The accurate detection of these parameters has very important significance for controlling the drying process and minimizing drying defects. The presented study describes an electrochemical method to determine wood moisture content and shrinkage strain during drying, and the accuracy of this method is also evaluated. According to the results, the electrical resistance of the samples increased with the decrease in wood moisture content. As the moisture content changed from 42% to 12%, the resistance increased from 1.0 × 107 Ω to 1.2 × 108 Ω. A polynomial fitting curve was fitted with a determination coefficient of 0.937 to describe the relationship between moisture content and electrical resistance. In addition, both the shrinkage strain and resistance change rate increased with the decrease in wood moisture content, especially for the moisture content range of 23% to 8%, where the shrinkage strain and resistance change rate increased by 4% and 30%, respectively. The shrinkage strain increased exponentially with the increase in the resistance change rate; thereby, an exponential regression equation was proposed with a determination coefficient of 0.985, expressing the correlation between the two. This demonstrates the feasibility of the electrochemical method for measuring wood moisture content and shrinkage strain.

Highlights

Wood drying is an essential step in wood processing, and it is the most energyand time-demanding step
When the drying quality of wood is ensured, the reduction in time and energy consumption can result in economic benefits. This enhancement requires persistent improvements of the process to obtain the best trade-off between the drying rate and quality, which can be facilitated by a greater understanding of the drying process, especially for moisture content (MC) and shrinkage strain
Where R is the resistance change rate for shrinkage strain measurement specimens, Ri is wthheeirnei∆tiaRl irsesthisetarnesciestaatntcheecMhaCnogfe4r2a%te afonrdsRhriisnkthaegeresstirsatainncmeeaatsduirfefmereenntt sMpCecsi.mens, Ri is the initial resistance at the MC of 42% and R is the resistance at different MCs

Summary

Introduction

Wood drying is an essential step in wood processing, and it is the most energyand time-demanding step. Shrinkage strain is another characteristic of significant interest that can be used as an indicator to evaluate the wood drying process. No previous research discusses the feasibility of electrochemical workstations in measuring shrinkage strain during wood drying.

Results

Conclusion