scholarly journals Improved Water Repellency and Dimensional Stability of Wood via Impregnation with an Epoxidized Linseed Oil and Carnauba Wax Complex Emulsion

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 271
Author(s):  
Jinyu Chen ◽  
Yujiao Wang ◽  
Jinzhen Cao ◽  
Wang Wang
Keyword(s):  
Dimensional Stability ◽  
Linseed Oil ◽  
Average Particle Size ◽  
Water Repellency ◽  
Water Repellent ◽  
Average Particle ◽  
Poplar Wood ◽  
Carnauba Wax ◽  
Natural Wood ◽  
Epoxidized Linseed Oil

Natural wood is susceptible to moisture during its practical use, limiting not only service life but also the range of uses. In this study, plant extracts, specifically linseed oil and carnauba wax (both environmentally friendly and water-repellent substances), were examined as a means to mitigate limitations of natural wood. Stable and homogenous epoxidized linseed oil/carnauba wax emulsions with an average particle size less than 230 nm were used as a modifier to enhance the performance of wood. Weight percentage gain, bulking coefficient, micromorphology, chemical structure, moisture adsorption, contact angle, water repellency, and dimensional stability of treated wood were measured. Using a scanning electron microscope (SEM), it was observed that carnauba wax and epoxidized linseed oil acted as a mechanical barrier and could partially cover or block vessels, pits, and wood rays. Furthermore, the hydrophobicity of wood increased significantly after emulsion impregnation. However, there was no obvious chemical reaction between epoxidized linseed oil and the main components of wood in the Fourier transform infrared spectroscopy (FTIR) results. The combined effect of epoxidized linseed oil and carnauba wax was apparent in both decreased water absorption and dimensional deformation. Poplar wood impregnated with an epoxidized linseed oil/carnauba wax complex emulsion shows potential for improving water-related properties. Thus, the complex emulsion modification can improve the inherent shortcoming of poplar wood effectively.

scholarly journals A comparative study on the effects of linseed oil and shellac treatment on the hygroscopicity, dimensional stability, and color changes of Chinese ash wood

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 8085-8092
Author(s):  
Mihaela Liu ◽  
Xinwei Tu ◽  
Xinyou Liu ◽  
Zhihui Wu ◽  
Jiufang Lv ◽  
...  
Keyword(s):  
Dimensional Stability ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Moisture Absorption ◽  
Linseed Oil ◽  
Morphological Characteristics ◽  
Treated Wood ◽  
Water Repellency ◽  
Wood Products ◽  
Color Changes

Linseed oil and shellac are natural, environmentally friendly materials with good water repellency. They were used to impregnate Chinese ash wood at room temperature (20 °C) using a vacuum-pressure procedure (consisting of three cycles of 0.01 MPa for 1.5 h and atmospheric pressure for 1.5 h) to improve the dimensional stability of wood. The effects of the impregnation treatment on wood color changes, dimensional stability, moisture absorption, and morphological characteristics were evaluated. The linseed oil and shellac treatment improved the dimensional stability of wood. Linseed oil and shellac displayed good permeability in Chinese ash wood, with weight gains of 21.7% and 19.0%, respectively, after impregnation. The swelling coefficients of treated wood in the tangential and radial directions decreased by 15 to 22%, indicating that impregnation improved the dimensional stability of wood. Linseed oil and shellac solidified and occluded the pits within the wood interior to prevent moisture absorption. This method can be used to improve the dimensional stability of a variety of wood products, such as buildings, furniture, and landscape architecture.

Laboratory and outdoor water repellency and dimensional stability of southern pine sapwood treated with a waterborne water repellent made from resin acids

Holzforschung ◽  
2007 ◽  
Vol 61 (3) ◽  
pp. 317-322 ◽  
Author(s):  
Tor P. Schultz ◽  
Darrel D. Nicholas ◽  
Leonard L. Ingram
Keyword(s):  
Dimensional Stability ◽  
Abietic Acid ◽  
Resin Acid ◽  
Water Repellency ◽  
Decay Resistance ◽  
Outdoor Exposure ◽  
Resin Acids ◽  
Water Repellent ◽  
Southern Pine ◽  
Pine Tree

Abstract A major consumer concern regarding lumber in above-ground exposure such as decking is the poor dimensional stability that leads to warping, splitting, and checking. One method to increase dimensional stability is to treat lumber with a water repellent. A waterborne water repellent made from the resin acid abietic acid or a commercial source of resin acids, tall oil rosin or TOR, was tested using southern pine sapwood. In laboratory water-swelling tests, the waterborne abietic acid provided water repellency that was almost equivalent to that provided by wax, while no water repellency was observed with solventborne resin acid. Wood treated with waterborne TOR also provided good water repellency in laboratory tests and fair water repellency at up to 13 months of outdoor exposure, but the laboratory efficacy was partially reduced by a water leach. The dimensional stability (cupping and checking) and mold growth on TOR-treated lumber in above-ground exterior exposure was better than for untreated boards, but not as good as for wax-treated lumber. Analysis of the wood in southern pine tree trunks of 14 or 29 years of age of various diameters and sampled at the bottom, middle and top showed that the resin acid content in southern pine wood is quite variable. This may explain the wide variation in natural water repellency and decay resistance previously observed with untreated southern pine sapwood.

scholarly journals Facile Fabrication of Breathable and Superhydrophobic Fabric Based on Silica Nanoparticles and Amino‐Modified Polydimethylsiloxane

2020 ◽  
Author(s):  
Mahdi Hasanzadeh ◽  
Hossein Shahriyari Far ◽  
Aminoddin Haji ◽  
Giuseppe Rosace
Keyword(s):  
Contact Angle ◽  
Silica Nanoparticles ◽  
Water Contact Angle ◽  
Average Particle Size ◽  
Hydrophobic Surface ◽  
Water Repellency ◽  
Average Particle ◽  
Sliding Angle ◽  
Water Contact ◽  
Fabric Surface

This work attempted to fabricate superhydrophobic fabric via simple immersion technique. Textile fabrics were coated with silica nanoparticles prepared from tetraethoxysilane (TEOS) to obtain sufficient roughness with hydrophobic surface chemistry. Then the coated fabrics were treated with polydimethylsiloxane (PDMS) and aminopropyltriethoxysilane (APTES) to reduce the surface energy. The effects of PDMS concentration on the surface morphology and superhydrophobicity of as-prepared fabric were investigated. The morphology and the composition of superhydrophobic fabric was characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDS) and Fourier transform infrared (FTIR) spectroscopy. The results revealed the formation of spherical silica nanoparticles with average particle size of 250 nm throughout the fabric surface. The possible interactions between silica nanoparticles and APTES, as well as the fabrics were elucidated. Investigating the hydrophobicity of fabrics via water contact angle (WCA) measurement showed that the treated fabric exhibits excellent water repellency with a water contact angle as high as 151° and a very low water sliding angle. It also found that the treated fabric maintained most of its hydrophobicity against repeated washing. The comfort properties of the obtained superhydrophobic fabrics in term of air permeability and bending length did not reveal any significant changes.

scholarly journals Novel hydrophobization of wood by epoxidized linseed oil. Part 1. Process description and anti-swelling efficiency of the treated wood

Holzforschung ◽  
2015 ◽  
Vol 69 (2) ◽  
pp. 173-177 ◽  
Author(s):  
Mohamed Jebrane ◽  
Víctor Fernández-Cano ◽  
Dmitri Panov ◽  
Nasko Terziev ◽  
Geoffrey Daniel
Keyword(s):  
Acetic Acid ◽  
Dimensional Stability ◽  
Linseed Oil ◽  
Treatment Options ◽  
Treated Wood ◽  
Practical Application ◽  
Step Process ◽  
Reference Samples ◽  
Better Than ◽  
Epoxidized Linseed Oil

Abstract The known method of wood modification by epoxidized linseed oil (ELO) has a limiting practical application due to the rapid polymerization of ELO in the presence of acetic acid (AA) needed as a catalyst. The present study was designed to develop an alternative method by means of a two-step process to avoid the rapid polymerization. The treatment options were tested on Scots pine sapwood, with the dimensional stability (DS) of the treated samples in focus. The new method provided an anti-swelling efficiency (ASE) in the range of 40–57%, which was even better than the thermally modified (TM) reference samples with 40% ASE. The developed two-step process is a feasible and practical approach for ELO treatment of wood.

scholarly journals Effect of Water Repellents on Hygroscopicity and Dimensional Stability of Densified Fir and Aspen Woods

2020 ◽  
Vol 71 (1) ◽  
pp. 29-40
Author(s):  
Huseyin Pelit ◽  
Fatih Emiroglu
Keyword(s):  
High Temperature ◽  
Dimensional Stability ◽  
Atmospheric Pressure ◽  
Linseed Oil ◽  
Vacuum Treatment ◽  
Densified Wood ◽  
Water Repellent ◽  
Compression Rate ◽  
Thickness Swelling ◽  
Water Repellents

This study investigated the effect of pre-impregnation with water-repellent agents on the hygroscopicity and dimensional stability of fir (Abies bornmulleriana Mattf.) and aspen (Populus tremula L.) woods. After pre-vacuum treatment, the samples were impregnated at atmospheric pressure with paraffin, linseed oil and styrene, and then densified at compression rates of 20 % and 40 % at 120, 150 and 180 °C. The results showed that water repellents significantly affected the hygroscopicity and dimensional stability of the densified wood samples. Compression recovery rate (CRR), thickness swelling (TS), equilibrium moisture content (EMC), and water absorption (WA) values of the densified samples decreased with impregnation pretreatments. The linseed oil treatment gave more positive CRR and TS results than paraffin. Lower EMC and WA values were found in the paraffin-treated samples. However, the most successful results for all tested properties were determined in the styrene pretreated samples in which hygroscopicity decreased and dimensional stability increased (especially for aspen) due to increases in the compression rate and temperature related to densification conditions. In the styrene pretreated samples, the high temperature (180 °C) and compression rate (40 %) significantly reduced CRR, TS, EMC and WA, total dimensional stability was nearly achieved and the water repellent effectiveness was close to 100 %.

Enhanced catalytic activity of low-Pt content nanocatalysts supported on hollow carbon spheres for the ORR in alkaline media

MRS Advances ◽  
2020 ◽  
Vol 5 (57-58) ◽  
pp. 2961-2972
Author(s):  
P.C. Meléndez-González ◽  
E. Garza-Duran ◽  
J.C. Martínez-Loyola ◽  
P. Quintana-Owen ◽  
I.L. Alonso-Lemus ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Anion Exchange ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Alkaline Media ◽  
High Catalytic Activity ◽  
Average Particle ◽  
Carbon Spheres ◽  
Hollow Carbon ◽  
Hollow Carbon Spheres

In this work, low-Pt content nanocatalysts (≈ 5 wt. %) supported on Hollow Carbon Spheres (HCS) were synthesized by two routes: i) colloidal conventional polyol, and ii) surfactant-free Bromide Anion Exchange (BAE). The nanocatalysts were labelled as Pt/HCS-P and Pt/HCS-B for polyol and BAE, respectively. The physicochemical characterization of the nanocatalysts showed that by following both methods, a good control of chemical composition was achieved, obtaining in addition well dispersed nanoparticles of less than 3 nm TEM average particle size (d) on the HCS. Pt/HCS-B contained more Pt0 species than Pt/HCS-P, an effect of the synthesis method. In addition, the structure of the HCS remains more ordered after BAE synthesis, compared to polyol. Regarding the catalytic activity for the Oxygen Reduction Reaction (ORR) in 0.5 M KOH, Pt/HCS-P and Pt/HCS-B showed a similar performance in terms of current density (j) at 0.9 V vs. RHE than the benchmark commercial 20 wt. % Pt/C. However, Pt/HCS-P and Pt/HCS-B demonstrated a 6 and 5-fold increase in mass catalytic activity compared to Pt/C, respectively. A positive effect of the high specific surface area of the HCS and its interactions with metal nanoparticles and electrolyte, which promoted the mass transfer, increased the performance of Pt/HCS-P and Pt/HCS-B. The high catalytic activity showed by Pt/HCS-B and Pt/HCS-P for the ORR, even with a low-Pt content, make them promising cathode nanocatalysts for Anion Exchange Membrane Fuel Cells (AEMFC).

A New Method for Direct Determination of the Recoilless Fraction with Application to Magnetic Nanoparticles

2002 ◽  
Vol 721 ◽  
Author(s):  
Monica Sorescu
Keyword(s):  
Room Temperature ◽  
Average Particle Size ◽  
Direct Determination ◽  
Average Particle ◽  
Lattice Method ◽  
Recoilless Fraction ◽  
Single Room ◽  
Magnetite Particles ◽  
Physical Mixtures

AbstractWe propose a two-lattice method for direct determination of the recoilless fraction using a single room-temperature transmission Mössbauer measurement. The method is first demonstrated for the case of iron and metallic glass two-foil system and is next generalized for the case of physical mixtures of two powders. We further apply this method to determine the recoilless fraction of hematite and magnetite particles. Finally, we provide direct measurement of the recoilless fraction in nanohematite and nanomagnetite with an average particle size of 19 nm.

Determination of grinding parameters of fenugreek seed

1970 ◽  
Vol 26 (1) ◽  
pp. 16 ◽  
Author(s):  
S Balasubramanian ◽  
Rajkumar Rajkumar ◽  
K K Singh
Keyword(s):  
Particle Size ◽  
Energy Consumption ◽  
Moisture Content ◽  
Specific Energy ◽  
Feed Rate ◽  
Average Particle Size ◽  
Specific Energy Consumption ◽  
Average Particle ◽  
Fenugreek Seeds ◽  
Fenugreek Seed

Experiment to identify ambient grinding conditions and energy consumed was conducted for fenugreek. Fenugreek seeds at three moisture content (5.1%, 11.5% and 17.3%, d.b.) were ground using a micro pulverizer hammer mill with different grinding screen openings (0.5, 1.0 and 1.5 mm) and feed rate (8, 16 and 24 kg h-1) at 3000 rpm. Physical properties of fenugreek seeds were also determined. Specific energy consumptions were found to decrease from 204.67 to 23.09 kJ kg-1 for increasing levels of feed rate and grinder screen openings. On the other hand specific energy consumption increased with increasing moisture content. The highest specific energy consumption was recorded for 17.3% moisture content and 8 kg h-1 feed rate with 0.5 mm screen opening. Average particle size decreased from 1.06 to 0.39 mm with increase of moisture content and grinder screen opening. It has been observed that the average particle size was minimum at 0.5 mm screen opening and 8 kg h-1 feed rate at lower moisture content. Bond’s work index and Kick’s constant were found to increase from 8.97 to 950.92 kWh kg-1 and 0.932 to 78.851 kWh kg-1 with the increase of moisture content, feed rate and grinder screen opening, respectively. Size reduction ratio and grinding effectiveness of fenugreek seed were found to decrease from 4.11 to 1.61 and 0.0118 to 0.0018 with the increase of moisture content, feed rate and grinder screen opening, respectively. The loose and compact bulk densities varied from 219.2 to 719.4 kg m-3 and 137.3 to 736.2 kg m-3, respectively.  

Influence of temperature and humidity on the angle of repose of wood bulk materials

2016 ◽  
Author(s):  
И.В. Бачериков ◽  
Б.М. Локштанов
Keyword(s):  
Field Experiments ◽  
Bulk Material ◽  
Average Particle Size ◽  
Operating Conditions ◽  
Angle Of Repose ◽  
Wood Dust ◽  
Average Particle ◽  
Bulk Materials ◽  
Technical Literature ◽  
The Impact

При проектировании открытых и закрытых хранилищ измельченных сыпучих материалов древесных материалов, таких как щепа и опилки, большое значение имеет угол естественного откоса (статический и динамический) этих материалов. В технической литературе приводятся противоречивые сведения о величине этих углов, что приводит к ошибкам при проектировании складов. В справочных данных не учитываются условия, в которых эксплуатируются емкости для хранения сыпучих материалов, свойства и состояние этих сыпучих материалов. В свою очередь, ошибки при проектировании приводят к проблемам (зависание, сводообразование, «затопление» и т. д.) и авариям при эксплуатации бункеров и силосов на производстве. В статье представлены сведения, посвященные влиянию влажности и температуры на угол естественного откоса сыпучих материалов. На основании лабораторных и натурных экспериментов, проведенных с помощью специально разработанных методик и установок, была скорректирована формула для определения углов естественного откоса (статического и динамического) для измельченных древесных материалов в зависимости от их фракционного и породного состава, влажности (абсолютной и относительной) и температуры. При помощи скорректированной формулы можно определить угол естественного откоса древесных сыпучих материалов со среднегеометрическим размером частицы от 0,5 мм до 15 мм (от древесной пыли до технологической щепы) в различных производственных условиях. Статья может быть полезна проектировщикам при расчете угла наклона граней выпускающей воронки бункеров и силосов предприятий лесной отрасли и целлюлозо-бумажной промышленности. In the design of open and closed storage warehouses chopped wood materials for bulk materials such as wood chips and sawdust, great importance has an angle of repose (static and dynamic) of these materials. In the technical literature are conflicting reports about the magnitude of these angles, which leads to errors in the design of warehouses. In the referencesdoes not take into account the conditions under which operated capacities for storage of bulk materials, and properties and condition of the bulk material. The design errors lead to problems (hanging, arching, «flooding», etc.) and accidents in the operation of hoppers and silos at the mills. The article provides information on the impact of humidity and temperature on the angle of repose of granular materials. On the basis of laboratory and field experiments, conducted with the help of specially developed techniques and facilities has been adjusted formula for determining the angle of repose (static and dynamic) for the shredded wood materials depending on their fractional and species composition, humidity (absolute and relative) and temperature. It is possible, by using the corrected formula, to determine the angle of repose of loose wood materials with average particle size of from 0.5 mm to 15 mm (wood dust to pulpchips) in various operating conditions. The article can be helpful to designers in the calculation of the angle of inclination of the funnel faces produces bunkers and silos forest industries and pulp and paper industry.

Formulating SLN and NLC as Innovative Drug Delivery Systems for Non-Invasive Routes of Drug Administration

2020 ◽  
Vol 27 (22) ◽  
pp. 3623-3656 ◽  
Author(s):  
Bruno Fonseca-Santos ◽  
Patrícia Bento Silva ◽  
Roberta Balansin Rigon ◽  
Mariana Rillo Sato ◽  
Marlus Chorilli
Keyword(s):  
Drug Delivery ◽  
Particle Size ◽  
Drug Release ◽  
Drug Loading ◽  
Average Particle Size ◽  
Delivery Systems ◽  
Average Particle ◽  
Minor Importance ◽  
Routes Of Administration ◽  
Non Invasive

Colloidal carriers diverge depending on their composition, ability to incorporate drugs and applicability, but the common feature is the small average particle size. Among the carriers with the potential nanostructured drug delivery application there are SLN and NLC. These nanostructured systems consist of complex lipids and highly purified mixtures of glycerides having varying particle size. Also, these systems have shown physical stability, protection capacity of unstable drugs, release control ability, excellent tolerability, possibility of vectorization, and no reported production problems related to large-scale. Several production procedures can be applied to achieve high association efficiency between the bioactive and the carrier, depending on the physicochemical properties of both, as well as on the production procedure applied. The whole set of unique advantages such as enhanced drug loading capacity, prevention of drug expulsion, leads to more flexibility for modulation of drug release and makes Lipid-based nanocarriers (LNCs) versatile delivery system for various routes of administration. The route of administration has a significant impact on the therapeutic outcome of a drug. Thus, the non-invasive routes, which were of minor importance as parts of drug delivery in the past, have assumed added importance drugs, proteins, peptides and biopharmaceuticals drug delivery and these include nasal, buccal, vaginal and transdermal routes. The objective of this paper is to present the state of the art concerning the application of the lipid nanocarriers designated for non-invasive routes of administration. In this manner, this review presents an innovative technological platform to develop nanostructured delivery systems with great versatility of application in non-invasive routes of administration and targeting drug release.

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