Effects of Biological and Chemical Degradation on the Properties of Scots Pine Wood—Part I: Chemical Composition and Microstructure of the Cell Wall

Broda, Magdalena; Popescu, Carmen-Mihaela; Curling, Simon F.; Ilie Timpu, Daniel; Ormondroyd, Graham A.

Abstract

Research on new conservation treatment for archaeological wood requires large amounts of wooden material. For this purpose, artificial wood degradation (biological—using brown-rot fungus Coniophora puteana, and chemical—using NaOH solution) under laboratory conditions was conducted to obtain an abundance of similar samples that mimic naturally degraded wood and can serve for comparative studies. However, knowledge about its properties is necessary to use this material for further study. In this study, the chemical composition and microstructure of degraded cell walls were investigated using FT-IR, XRD, helium pycnometry and nitrogen absorption methods. The results show that biological degradation caused the loss of hemicelluloses and celluloses, including the reduction in cellulose crystallinity, and led to lignin modification, while chemical degradation mainly depleted the amount of hemicelluloses and lignin, but also affected crystalline cellulose. These changes affected the cell wall microstructure, increasing both surface area and total pore volume. However, the chemical degradation produced a greater number of mesopores of smaller size compared to fungal decomposition. Both degradation processes weakened the cell wall’s mechanical strength, resulting in high shrinkage of degraded wood during air-drying. The results of the study suggest that degraded wood obtained under laboratory conditions can be a useful material for studies on new consolidants for archaeological wood.

Citation

Broda, M., Popescu, C., Curling, S. F., Ilie Timpu, D., & Ormondroyd, G. A. (2022). Effects of Biological and Chemical Degradation on the Properties of Scots Pine Wood—Part I: Chemical Composition and Microstructure of the Cell Wall. Materials, 15(7), Article 2348. https://doi.org/10.3390/ma15072348

• Journal Article Type: Article
• Acceptance Date: Mar 19, 2022
• Online Publication Date: Mar 22, 2022
• Publication Date: 2022
• Deposit Date: May 9, 2022
• Publicly Available Date: May 9, 2022
• Publisher: MDPI
• Peer Reviewed: Peer Reviewed
• Volume: 15
• Issue: 7
• Article Number: 2348
• DOI: https://doi.org/10.3390/ma15072348
• Keywords: degraded wood; decayed wood; wood microstructure; surface area; porosity; cellulose crystallinity; chemical degradation; decay; wood polymers; wood properties
• Public URL: http://researchrepository.napier.ac.uk/Output/2870523