Properties of leucaena leucocephala Lam. Bark as lignin adhesive and particleboard
Bark from trees is considered a worthless raw material. However, this resource could be economically beneficial if utilized efficiently due to its rich chemical compounds. Employing bark particles without mixing other fibres minimised formaldehyde emissions from the particleboards meanwhile lignin e...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2023
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| Subjects: | |
| Online Access: | https://eprints.ums.edu.my/id/eprint/39041/1/24%20PAGES.pdf https://eprints.ums.edu.my/id/eprint/39041/2/FULLTEXT.pdf |
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| Summary: | Bark from trees is considered a worthless raw material. However, this resource could be economically beneficial if utilized efficiently due to its rich chemical compounds. Employing bark particles without mixing other fibres minimised formaldehyde emissions from the particleboards meanwhile lignin extracted from bark used as an adhesive in bark particleboard can maximize the use of biomass waste, be cost effective, and be environmentally friendly. Utilizing appropriate particle sizes could improve the physical and mechanical qualities bark particleboard. In this study, Leucaena leucocephala stem bark that was eleven years old was examined for its chemical composition and usage. The chemical compositions (extractive, cellulose, and lignin) were analysis using FTIR spectroscopy. In the second section, the properties of particleboards made from coarse (2.5 to 12.0 mm), medium (1.0 to 2.5 mm), and fine (0.2 to 1.0 mm) Leucaena leucocephala bark particles bonded with urea formaldehyde adhesives were evaluated and in the final stage, lignin extracted from bark was used as an adhesive in bark particleboard at different particle sizes. The results found that the bark of L. leucocephala has a pH value of 6.04 and that the solubility of the bark in 1% NaOH alkali is the highest (41.36%) compared to the solubility in hot water (14.45%) and cold water (14.36%), while the chemical composition of the bark of L. leucocephala was ash (15.76%); extractives (8.39%); cellulose (29.19%) and lignin (38.24%). Results from FTIR analysis revealed that aromatic functional groups were mainly found in the extractive, while water, carbonyl and ether were the dominant groups in cellulose, and methyl, methylene, carbonyl, and carboxyl groups were enriched in lignin. The varying particle sizes had a significant impact on bark particleboard bonded with Urea formaldehyde (UF) adhesives which fine particles (0.2 to 1.0 mm) offered excellent physical properties for moisture content and dimensional stability, while coarse particles possessed good mechanical properties such as density, modulus of elasticity (MOE), modulus of rupture (MOR), and internal bonding (IB). The findings showed that lignin adhesive particleboard works more consistently than UF adhesive particleboard in an air-dry environment, but UF adhesive particleboard exhibits better resistance to water in wet situations. Compared to UF adhesive particleboard, lignin adhesive particleboard is more elastic and ruptures. The thickness swelling decreases in air-dry conditions, but it increases in wet situations as the particle size increases. Bark particleboard has superior strength when the particles used in its production are finer. In MOE, MOR, and IB, fine particles fared best. |
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