Flame Retarding of Wood by Chemical Modification with Bromate-Bromide Solutions

1997 ◽  
Vol 15 (1) ◽  
pp. 29-51 ◽  
Author(s):  
Menachem Lewin
Keyword(s):  
Mechanical Properties ◽  
Solid State ◽  
Chemical Modification ◽  
Water Absorption ◽  
Dimensional Stability ◽  
Wood Products ◽  
High Yield ◽  
Fungal Attack ◽  
And Storage ◽  
Bromide Solutions

In spite of the extensive and diversified uses of wood and wood products for millenia, there are still a number of basic deficiencies of these pro ducts which limit their use and pose difficult and as yet not satisfactorily solved problems to the engineer and consumer. The most prominent of these problems are: flammability, dimensional stability, and fungal attack. Review of work carried out at the Israel Fiber Institute indicates that treating solid timber and polywood with acidified bromate-bromide solutions is capable of overcoming these deficiencies to a large extent. The treatment is carried out in autoclaves with application of vacuum and pressure. The lignin component of the wood is brominated in the solid state by the treatment solution with a high yield of bromine. The mechanical properties of the treated products are un changed. The treatment is stable to prolonged leaching, aging, and storage. Water absorption and swelling are drastically decreased-dimensional stabi lization. The brominated products are shown not to be attacked by wood fungi.

Mechanical properties and water absorption of surface modified ABS 3D printed by fused deposition modelling

2018 ◽  
Vol 24 (1) ◽  
pp. 195-203 ◽  
Author(s):  
Marco Leite ◽  
André Varanda ◽  
António Relógio Ribeiro ◽  
Arlindo Silva ◽  
Maria Fátima Vaz
Keyword(s):  
Mechanical Properties ◽  
Absorption Coefficient ◽  
Water Absorption ◽  
Dimensional Stability ◽  
Open Porosity ◽  
Fused Deposition Modelling ◽  
Content Type ◽  
Fused Deposition ◽  
Tension Properties ◽  
3D Printed

Purpose The purpose of this paper is to investigate the effect of a sealing protective treatment on the water absorption and mechanical properties of acrylonitrile butadiene styrene (ABS)-printed parts by fused deposition modelling. Protective products include aqueous acetone solutions with different concentrations, polyurethane wood sealer and aqueous acrylic-based varnish. Design/methodology/approach Open porosity was estimated by the absorption coefficient and the total amount of water retained, obtained from water absorption tests. Mechanical characterization was performed by compressive and tensile tests. Different specimens with different build directions and raster angles were used. Findings The treatments with acetone solutions were not effective in reducing the porosity of ABS parts, as the amount of acetone that reduces effectively the porosity will also affect the sample dimensional stability. The polyurethane treatment was found to reduce the absorption coefficient, but the maximum water content and the open porosity remain almost unchanged in comparison with the ones obtained for untreated specimens. The treatment with an acrylic-based varnish was found to preserve the dimensional stability of the specimens, to reduce the open porosity and to maintain the compression and tension properties of the specimens in different build directions and raster angles. Originality/value Surface modification for water tight applications of ABS 3D printing parts enables new designs where both sealing and the preservation of mechanical properties are important. As per the knowledge of the authors, the water absorption and the mechanical behaviour of ABS 3D printed parts, before and after treatment, were not previously investigated.

scholarly journals Influence of Expansive Agent on the Dimensional Stability and Mechanical Properties of Gypsum Plaster

2019 ◽  
Vol 8 (4) ◽  
pp. 928-931
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
Dimensional Stability ◽  
Early Hydration ◽  
Expansive Agent ◽  
Gypsum Plaster ◽  
Hardened State ◽  
Dimensional Variation ◽  
The Stability

Nowadays the use of gypsum plaster has gained momentum due to their economic and eco-friendly nature. The objective of this work was to study the influence of expansive agent such as CaO and MgO on the properties of the gypsum plaster. The effect of expansive agent on the physical, mechanical, water absorption and porosity were analyzed. The dimensional stability of the plaster with various percentages of Cao and MgO were also evaluated. From the results obtained it was confirmed that the addition of expansive agent increased the stability of the gypsum plaster to dimensional variation both during early hydration periods and also at hardened state without affecting the strength of the plaster.

scholarly journals Effects of Resin Content on the Characteristics of Bamboo Oriented Strand Board Prepared from Strands of Betung, Ampel, and Their Mixtures

2021 ◽  
Vol 9 (3) ◽  
pp. 454-465
Author(s):  
Tengku Muhammad Renzy Hariz ◽  
Indra Agus Santosa ◽  
Muhammad Iqbal Maulana ◽  
Marwanto ◽  
Denni Prasetia ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
Dimensional Stability ◽  
Oriented Strand Board ◽  
Physical And Mechanical Properties ◽  
Resin Content ◽  
Thickness Swelling ◽  
Higher Dimensional ◽  
Bambusa Vulgaris ◽  
Dendrocalamus Asper

The objectives of this research were to evaluate bamboo-oriented strand board (BOSB) characteristics made from betung (Dendrocalamus asper), ampel (Bambusa vulgaris), and their mixtures at two different contents (3% and 5%) of methylene diphenyl di-isocyanate (MDI) adhesives. The strands were steam-treated at 126°C for 1 h under the pressure of 0.14 MPa. Three-layered BOSBs with a target density of 0.7 g/cm3 were made with the size of 30 cm x 30 cm x 0.9 cm and a shelling ratio of 1:2:1 (face:core:back layers). The physical and mechanical properties of BOSB were evaluated following JIS A 5908 (2003) standard, and the results were compared with the CSA 0437.0 Grade O-1 standard. The results show that BOSB from the mixtures of betung and ampel bamboo strands has higher dimensional stability as shown by the decrease in water absorption and thickness swelling and higher mechanical properties than single BOSB. All BOSBs with 5% resin content have higher dimensional stability, MOE, and MOR than BOSB with 3% resin content. The physical and mechanical properties of all BOSB manufactured met the CSA 0437.0 Grade O-1 standard. This study proved that BOSBs from the mixture of betung and ampel strands have the potential to be developed due to having better physical and mechanical qualities than a single BOSB. Keywords: ampel (Bambusa vulgaris), bamboo oriented strand board, betung (Dendrocalamus asper), resin content, strand mixtures

scholarly journals Combined Chemical Modification of Bamboo Material Prepared Using Vinyl Acetate and Methyl Methacrylate: Dimensional Stability, Chemical Structure, and Dynamic Mechanical Properties

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1651 ◽  
Author(s):  
Saisai Huang ◽  
Qiufang Jiang ◽  
Bin Yu ◽  
Yujing Nie ◽  
Zhongqing Ma ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Chemical Modification ◽  
Methyl Methacrylate ◽  
Vinyl Acetate ◽  
Dimensional Stability ◽  
Chemical Structure ◽  
In Situ Polymerization ◽  
Dynamic Mechanical Properties

Acetylation and in situ polymerization are two typical chemical modifications that are used to improve the dimensional stability of bamboo. In this work, the combination of chemical modification of vinyl acetate (VA) acetylation and methyl methacrylate (MMA) in situ polymerization of bamboo was employed. Performances of the treated bamboo were evaluated in terms of dimensional stability, wettability, thermal stability, chemical structure, and dynamic mechanical properties. Results show that the performances (dimensional stability, thermal stability, and wettability) of bamboo that was prepared via the combined pretreatment of VA and MMA (VA/MMA-B) were better than those of raw bamboo, VA single-treated bamboo (VA-B), and MMA single-treated bamboo (MMA-B). According to scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analyses, VA and MMA were mainly grafted onto the surface of the cell wall or in the bamboo cell lumen. The antiswelling efficiency and contact angle of VA/MMA-B increased to maximum values of 40.71% and 107.1°, respectively. From thermogravimetric analysis (TG/DTG curves), the highest onset decomposition temperature (277 °C) was observed in VA/MMA-B. From DMA analysis, the storage modulus (E’) of VA/MMA-B increased sharply from 15,057 Pa (untreated bamboo) to 17,909 Pa (single-treated bamboo), and the glass transition temperature was improved from 180 °C (raw bamboo) to 205 °C (single-treated bamboo).

scholarly journals Enhanced Physical and Mechanical Properties of Flake–Shape/Vinyl-ester Nanocomposites Through Surface Modification of Graphene and Glass Flake: A Comparison with Simulated Data

2020 ◽  
Vol 11 (4) ◽  
pp. 11316-11337
Keyword(s):  
Mechanical Properties ◽  
Surface Modification ◽  
Flexural Strength ◽  
Water Absorption ◽  
Storage Modulus ◽  
Vinyl Ester ◽  
Graphene Nanosheets ◽  
Analytical Data ◽  
Physical And Mechanical Properties ◽  
And Storage

: The main goal of this work was to investigate the effects of silane-modified graphene nanosheets (MGNS) and modified nanoglass flakes (MNGF) on the physical and mechanical properties of vinyl-ester resin (VER) composites. The surface modification was evaluated about these composites' physical and mechanical behavior by techniques such as water absorption, tensile, three-point bending, and dynamic mechanical thermal analysis (DMTA). The analytical data revealed that the silane functionalized nanocomposites improved the interface between the nanosheets and vinyl-ester matrix. It was found that surface modification could significantly improve the dispersion and adhesion of GNS and nanoglass flakes (NGF) compared with those of neat vinyl-ester and unmodified composites. The presence functionalization of NGF and graphene nanosheets (GNS) in vinyl-ester formulation did affect the tensile and flexural strength and modulus, water absorption, and storage modulus. GNS/VER exhibited higher tensile and flexural strength and modulus than the original composite. DMTA results also showed incorporation of NGF and GNS decreased glass transition and increased storage modulus relative to neat composites. Nonetheless, the incorporation of functionalized graphene nanosheets and nano glass flakes represent higher Tg and storage modulus.

Study on Properties of Modified Poplar Wood

2014 ◽  
Vol 926-930 ◽  
pp. 242-245
Author(s):  
Yong Wang ◽  
Ze Jun Chen ◽  
La Yun Deng ◽  
You Hua Fan
Keyword(s):  
Mechanical Properties ◽  
Comparative Study ◽  
Water Absorption ◽  
Dimensional Stability ◽  
Physical And Mechanical Properties ◽  
Dry Density ◽  
Poplar Wood ◽  
Absorption Ratio ◽  
Different Levels ◽  
Modified Wood

The paper based on a comparative study between poplar wood and modified poplar wood, concerning dimensional stability, physical and mechanical properties. The result showed that air-dry density and ASE value of modified wood samples were increasing in different levels with change of the modifier concentration, compared with untreated poplar wood. The air-dry density of modified wood reached 0.41 g/cm3 with increase of 5.3% compared to poplar wood. ASE reached 47.8% and the water-absorption ratio decreased by 38% at most when the modifier concentration was 30 wt.%. Moreover, the MOE and MOR of modified poplar wood increased up to 27.4% and 13% respectively when the modifier concentration was 25 wt.%. The SEM spectrum showed some wood rays and the gaps between staggered fibers were filled by modifier.

Chemical Modification of Poplar Wood on the Mechanical Properties

2011 ◽  
Vol 194-196 ◽  
pp. 1815-1818
Author(s):  
Guo Feng Wu ◽  
Qian Lang ◽  
Bin Wang ◽  
Yi Fei Jiang ◽  
Jun Wen Pu
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Compressive Strength ◽  
Chemical Modification ◽  
Water Absorption ◽  
Bending Strength ◽  
Poplar Wood ◽  
Hot Press ◽  
Drying Treatment ◽  
Natural Wood

In this research, the chemical and multilayer hot-press drying was used to modify poplar wood. The timbers were compressed and dried in the multilayer hot-press drying kiln. The combination of chemical modification and hot-press drying can improve the mechanical properties. The influence of chemical and hot-press drying on the compressive strength parallel to grain, the bending strength, the density, the water absorbent and the crystallinity of poplar wood have been investigated in this study. The chemical treated conditions close to real technological regimes selected. The samples were impregnated with three conditions. The samples were dried in a hot-press drying kiln for 130hrs. It was showed that the urea carbamate and hot-press drying treatment increase the properties. The density and mechanical properties increased with increasing urea carbamate, while the water absorption decreased. The crystallinity is 37.03%, 37.11%, 37.78%, separately, compared with the natural wood of 35.09%. The TAG showed the thermal stability increased.

scholarly journals Low viscosity melamine urea formaldehyde resin as a bulking agent in reducing formaldehyde emission of treated wood

BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 2195-2211
Author(s):  
Rabiatol Adawiah Mohd Ali ◽  
Zaidon Ashaari ◽  
Seng Hua Lee ◽  
Mohd Khairun Anwar Uyup ◽  
Edi Suhaimi Bakar ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Dimensional Stability ◽  
Urea Formaldehyde ◽  
Treated Wood ◽  
Physical And Mechanical Properties ◽  
Formaldehyde Emission ◽  
Wood Products ◽  
Formaldehyde Resin ◽  
Low Viscosity ◽  
Resin Impregnation

Melamine urea formaldehyde (MUF) resin impregnation followed by heat compression is a prominent method in improving mechanical properties and dimensional stability of wood. In addition, melamine is reactive to formaldehyde, and therefore able to reduce the free formaldehyde of the treated wood. This study aimed to produce compressed sesenduk (Endospermum diadenum) wood with low formaldehyde emission using low viscosity MUF resin. The effects of treatment efficiency on the physical and mechanical properties of the wood products were evaluated. The experimental design included impregnation of sesenduk strips with 20% and 30% MUF at five different formulations. Then, it was pre-cured at a temperature of 70 °C for 90 min, followed by hot compression at 140 °C with the compression ratio of 80%. The optimum treatment combination was determined through treatability, mechanical strength, dimensional stability, and formaldehyde emission. It was also compared to other treatments, including impregnation without further compression using formulated MUF and commercial MUF. The results revealed that F4 MUF, which consisted of 30% melamine, 50% formaldehyde, and 20% urea, was the optimal MUF formulation that resulted in low formaldehyde emission and acceptable physical and mechanical properties.

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