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Open AccessArticle

Physical and Mechanical Properties of Ammonia-Treated Black Locust Wood

1
Department of Mechanical Engineering, Faculty of Mechanical Engineering, Transilvania University of Brașov, B-dul Eroilor 29, 500036 Brașov, Romania
2
National Institute of Research and Development for Technical Physics, B-dul Mangeron 47, 700050 Iasi, Romania
3
Faculty of Mining, University of Petrosani, 20 Universității Street, 332006 Petroșani, Romania
4
Technical Sciences Academy of Romania, B-dul Dacia 26, 030167 Bucuresti, Romania
5
Faculty of Forestry, Forest Harvesting, Wood Processing Technologies and Landscape Architecture, Mytishchi Branch of Bauman Moscow State Technical University, 1st Institutskaya street, 141005 Mytischi, Moscow region, Russia
*
Author to whom correspondence should be addressed.
Polymers 2020, 12(2), 377; https://doi.org/10.3390/polym12020377
Received: 3 January 2020 / Revised: 29 January 2020 / Accepted: 30 January 2020 / Published: 7 February 2020
(This article belongs to the Special Issue Advances in Wood Composites II)
Because of the uneven colour of black locust wood, different technologies are used to change the colour, the bestknown being chemical and thermal treatments. Some of them affect the mechanical properties of wood, such as elasticity modulus, strength, durability. This study aims to compare the physical and mechanical properties of black locust wood control samples and treated wood samples with ammonia hydroxide, in terms of density profile, colour values (CIE L*, a*, b*), mechanical properties of samples subjected to static bending, viscous-elastic properties (storage modulus (E’), loss modulus (E”) and damping (tan)).Two types of ammonia-fuming treatment were applied on samples: first treatment T1-5% concentration of ammonia hydroxide for 30 days; second treatment T2-10% concentration for 60 days. The results highlighted the following aspects: the overall colour change in the case of the second treatment is 27% in comparison with 7% recorded for the control samples; the lightness and yellowness values are the most affected by the second ammonia treatment of black locust wood. The density increased with almost 20% due to ammonium fuming (10% concentration/60 days); in case of static bending, the elastic modulus (MOE) tends to decrease with increasing the exposure time to ammonium, but the modulus of rupture (MOR) increases with almost 17% and the breaking force increases too, with almost 41%. In the case of dynamic mechanical analysis, the temperature leads to different viscous-elastic behaviour of each type of samples.
Keywords: black locust wood; ammonia treated wood; colour change; dynamic mechanical analysis black locust wood; ammonia treated wood; colour change; dynamic mechanical analysis
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MDPI and ACS Style

Stanciu, M.D.; Sova, D.; Savin, A.; Ilias, N.; Gorbacheva, G.A. Physical and Mechanical Properties of Ammonia-Treated Black Locust Wood. Polymers 2020, 12, 377.

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