High Permeability of Boron along the Transverse Direction of Wood under High-Voltage Electrostatic Field (HVEF) Treatment Daiyuan Zhang 1 , Qian He 2 , Baocong Du 2 , Junbao Yu 2,3 , Xudong Zhu 3 , Dingyi Yang 2 , Shengcai Li 2 , Tianyi Zhan 1 , Liming Shen 1,* , Zhiqiang Wang 1,* and Xiaoning Lu 1 1 College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, 210037, China 2 College of Civil Science and Engineering, Yangzhou University, Yangzhou, 225127, China 3 Yangzhou Polytechnic Institute, Yangzhou, 225100, China * Corresponding Authors: Liming Shen. Email: shenlm@njfu.edu.cn; Zhiqiang Wang. Email: wangzhiqiang@njfu.edu.cn Received: 26 March 2021 Accepted: 29 April 2021 ABSTRACT Permeability of wood preservative is one of the most significant factors for protection of wood construction. Ani- sotropic flow permeability was involved in different directions of wood with higher flow resistance in the trans- verse and lower longitudinal directions. In this study, boron acid solution was brushed onto the tangential section of air-dried wood cubes and boron penetration along wood transverse direction was investigated under free dif- fusion, vacuum and HVEF treatments. Multi-scale boron distribution, FTIR measurement, leaching property, mechanical properties and fungistatic characteristic were investigated for free diffusion, vacuum and HVEF trea- ted samples respectively. The results revealed that boron exhibited high permeability along the transverse direc- tion with the penetration depth of ≈35 mm for HVEF treated samples and ≈1 mm for free diffusion and vacuum treated samples. For HVEF treated samples, no significant decrease of hardness, compression modulus of elasti- city and strength were found in the treated samples. Better fungistatic characteristic was showcased in HVEF trea- ted samples exposed to white rot fungi. Thus, HVEF treatment has a positive effect on boron permeability and the improvement of penetration depth of preservatives hence playing a significant role in wood protection and prolonging the service life of wood construction. KEYWORDS Wood permeability; boron distribution; transverse direction; HVEF treatment; mechanical property; fungistatic property 1 Introduction Wood, as a renewable and eco-friendly material, has been increasingly utilized in constructions and architecture with advantages of simplicity and speed for fabrication [1]. However, wood is easy to be decayed by rot fungi when placed in a moist environment. This will lead to significant decrease in the mechanical properties of wood material and further limit the scope and service life of wood application [2]. Various preservatives have been utilized for protection of wood and their penetration behavior in wood micro-structure plays a significant role in the anti-fungal properties of wood which has been a topic of investigation for a long time [3,4]. This work is licensed under a Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. DOI: 10.32604/jrm.2022.016793 ARTICLE ech T Press Science