The Influence of Mechanical and Mechanochemical Activation of Hardwood Wood Waste on Biocomposite Properties

2019 ◽  
Vol 800 ◽  
pp. 200-204
Author(s):  
Jevgenijs Jaunslavietis ◽  
Galia Shulga ◽  
Jurijs Ozolins ◽  
Brigita Neiberte ◽  
Anrijs Verovkins ◽  
...  
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Mechanochemical Activation ◽  
Moisture Sorption ◽  
Wood Waste ◽  
Work Of Adhesion ◽  
Polar Component ◽  
Aspen Wood ◽  
Wood Polymer ◽  
The Impact

As the demand for sustainable environment friendly materials increases, the biocomposites such as wood-polymer composite (WPC) have gained more attention in past years. Wood wastes and by-products like sawdust, chips, bark and wood residues as well as recycled polymers can serve as raw materials for production of WPC. However, there are still many issues obtaining WPCs, mainly a poor compatibility between a hydrophobic polymer matrix and a hydrophilic wood filler. In the present study, mechanical and mechanochemical activation of aspen wood waste were performed to increase their compatibility with recycled polypropylene matrix in the WPC, and the impact of both methods on the biocomposite properties were studied. It was found, that mechanochemical activation (MCA) of aspen wood particles leads to increased hydrophobicity of the obtained WPC compared to the WPC with mechanically activated (MA) particles. Work of adhesion with water was remarkably lower for the WPC modified by MCA which also correlates with moisture sorption results. Surface free energy of the WPC modified by MCA was lower compared to the WPC modified by MA, mostly due to decreased the polar component of surface free energy. The modulus of elasticity (MOE) were competitive for both the WPC formulations, however, MCA led to increased flexural strength of WPC compared to MA.

Hydrophilic-Hydrophobic Characteristics of Wood-Polymer Composites Filled with Modified Wood Particles

2018 ◽  
Vol 762 ◽  
pp. 176-181
Author(s):  
Jevgenijs Jaunslavietis ◽  
Galia Shulga ◽  
Jurijs Ozolins ◽  
Brigita Neiberte ◽  
Anrijs Verovkins ◽  
...  
Keyword(s):  
Free Energy ◽  
Polymer Composites ◽  
Surface Free Energy ◽  
Moisture Sorption ◽  
Contact Angles ◽  
Work Of Adhesion ◽  
Wood Polymer ◽  
Wood Particles ◽  
Wood Polymer Composites ◽  
Modified Wood

In this study, hydrophobic-hydrophilic characteristics, including contact angle and moisture sorption of a modified wood filler and the wood-polymer composites (WPC) containing it was investigated. The wood filler obtained from aspen sawdust was modified by mild acid hydrolysis and by ammoxidation. Contact angles of the wood particles and the WPC samples were measured with Kruss K100M using the Washburn and Wilhelmy methods, respectively. Work of adhesion was calculated using Young-Dupre equation. Surface free energy as well as its dispersive and polar parts were found using Owens-Wendt-Rabel-Kaelble approach. It was found that the hydrolysis and the ammoxidation led to decrease of the hemicelluloses content in the lignocellulosic matrix. Beside this, the ammoxidation favours the formation of amide bonds in the ammoxidised particles. These changes enhanced the contact angles, decreased the work of adhesion, and decreased surface free energy of the WPC samples filled with the modified particles in comparison with the WPC sample that contained the unmodified ones. The treatment of the wood particles decreased the wettability towards water, but increased it towards recycled polypropylene. This positively effects mechanical properties of the samples.

scholarly journals EFFECT OF THE ACIDIC TREATMENT OF DOMESTIC WOOD RESIDUE ON BIOCOMPOSITE WETTABILITY AND MOISTURE SORPTION PROPERTIES

2017 ◽  
Vol 1 ◽  
pp. 129
Author(s):  
Jevgenijs Jaunslavietis ◽  
Galia Shulga ◽  
Jurijs Ozolins ◽  
Brigita Neiberte ◽  
Anrijs Verovkins ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Free Energy ◽  
Dilute Hydrochloric Acid ◽  
Moisture Sorption ◽  
Treatment Temperature ◽  
Aspen Wood ◽  
Wood Residue ◽  
Wood Sawdust ◽  
Wood Polymer ◽  
Wood Polymer Composites

The aim of the work was to evaluate the effect of the acidic treatment temperature of aspen sawdust as a filler on the moisture sorption, wetting and mechanical properties of wood-polymer composites. Aspen wood sawdust was treated with the dilute hydrochloric acid solution at 60oC and 90oC during 5 h. Both the treated particles and the filled composites were studied in terms of moisture sorption and wettability; their surface free energy was calculated using the Owens-Wendt-Rabel-Kaelble (OWRK) approach. The obtained results have shown that the acidic treatment of aspen wood sawdust at 90oC leads to an increase in its hydrophobicity that decreases the wettability and moisture sorption of the obtained composite and increases its mechanical properties.

scholarly journals Evidence for intermolecular forces involved in ladybird beetle tarsal setae adhesion

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Naoe Hosoda ◽  
Mari Nakamoto ◽  
Tadatomo Suga ◽  
Stanislav N. Gorb
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Adhesion Force ◽  
Intermolecular Forces ◽  
Adhesive Force ◽  
Work Of Adhesion ◽  
Polar Component ◽  
Adhesion Mechanism ◽  
Ladybird Beetle ◽  
Ladybird Beetles

AbstractWhy can beetles such as the ladybird beetle Coccinella septempunctata walk vertically or upside-down on a smooth glass plane? Intermolecular and/or capillary forces mediated by a secretion fluid on the hairy footpads have commonly been considered the predominant adhesion mechanism. However, the main contribution of physical phenomena to the resulting overall adhesive force has yet to be experimentally proved, because it is difficult to quantitatively analyse the pad secretion which directly affects the adhesion mechanism. We observed beetle secretion fluid by using inverted optical microscopy and cryo-scanning electron microscopy, which showed the fluid secretion layer and revealed that the contact fluid layer between the footpad and substrate was less than 10–20 nm thick, thus indicating the possibility of contribution of intermolecular forces. If intermolecular force is the main physical phenomenon of adhesion, the force will be proportional to the work of adhesion, which can be described by the sum of the square roots of dispersive and polar parts of surface free energy. We measured adhesion forces of ladybird beetle footpads to flat, smooth substrates with known surface free energies. The adhesive force was proportional to the square-root of the dispersive component of the substrate surface free energy and was not affected by the polar component. Therefore, intermolecular forces are the main adhesive component of the overall adhesion force of the ladybird beetle. The footpads adhere more strongly to surfaces with higher dispersive components, such as wax-covered plant leaves found in the natural habitat of ladybird beetles. Based on the present findings, we assume ladybird beetles have developed this improved performance as an adaptation to the variety of plant species in its habitat.

Interaction at interfaces and induction of surface free energy components

1987 ◽  
Vol 52 (2) ◽  
pp. 271-286 ◽  
Author(s):  
Jan Kloubek
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Organic Liquid ◽  
Interaction Mechanism ◽  
Work Of Adhesion ◽  
Polar Component ◽  
Published Data ◽  
Free Energies ◽  
Dispersion Component ◽  
Mechanism Of Interaction

A set of published data on surface free energy (γ1, γ2) and interfacial energy (γ12) for interfaces mercury-organic liquid, mercury-water, and water-organic liquid (125 pairs altogether) has been critically evaluated. It has been found that the Antonow rule does not hold, that the Neumann equation is suitable for determining the work of adhesion, if γ1 and γ2 are not too different, and that the Fowkes equation can be used to assess the type of interaction at the interface. A hypothesis has been suggested which states that, besides the interaction between dispersion components of the surface free energies of the adjoining phases and the interaction between the non-dispersion components of the same type in bulk, a non-dispersion component of one phase may interact by inducing a component of the same type in the other phase near the interface. Relations concerning the mechanism of interaction at the interface have been derived. Also, the relation between the Girifalco-Good, Neumann and complemented Fowkes equation has been evaluated. For the particular liquids the dispersion portion of their surface free energies and the interaction mechanism at their interface with water and mercury have been estimated. For water, e.g. the polar component of the surface free energy (14.7 mJ m-2) and the hydrogen-bond component (36.3 mJ m-2) have been determined. The introduction of the induced component of the surface free energy is shown, as an example, for water-aromatic hydrocarbons and water-alcohols systems.

MECHANICAL PROPERTIES AND SURFACE FREE ENERGY OF OIL PALM EMPTY FRUIT BUNCHES FIBRE REINFORCED BIOCOMPOSITES AS GLASS FIBRE SUBSTITUTION

2017 ◽  
Vol 79 (4) ◽  
Author(s):  
Gema Sukmawati Suryadi ◽  
Siti Nikmatin ◽  
Sudaryanto Sudaryanto ◽  
Irmansyah Irmansyah
Keyword(s):  
Mechanical Properties ◽  
Free Energy ◽  
Impact Strength ◽  
Surface Free Energy ◽  
Glass Fibre ◽  
Oil Palm ◽  
Short Fibre ◽  
Filler Materials ◽  
Empty Fruit Bunches ◽  
The Impact

Study of the size effect of natural fibre from oil palm empty fruit bunches (OPEFB) as filler, onto the mechanical and physical properties of fibre reinforced biocomposites based on recycled Acrylonitrile Butadiene Styrene (ABS) has been done. The OPEFB fibres were prepared by mechanical milling and sieving to obtain medium-fibre (20 mesh) and short-fibre (100 mesh). The biocomposites have been produced by extrusion using single-screw extruder method. Mechanical properties and S of biocomposites were evaluated and compared with glass fibre (GF) filled composite which is commonly used in plastics industrial applications. The result showed that the impact strength increased with the decreasing of OPEFB fibre size, while the Young’s modulus decreased. Other mechanical properties of biocomposites with short-fibre (RABS/SF) and medium-fibre (RABS/MF) filler were not significantly different at 95% confidence interval. Impact strength of short-fibre filled biocomposite was higher than glass fibre filled composites. The surface free energy of biocomposites lower than glass fibre filled composites, but its dispersive components are higher, indicating more hydrophobic feature of the surface. The fabricated micro-fibre of OPEFB can be used as viable alternative to substitute glass fibre as filler materials of composites.

INFLUENCE OF SURFACE FREE ENERGY ON ADHESION OF CrN THIN FILM DEPOSITED BY AIP METHOD

2012 ◽  
Vol 06 ◽  
pp. 509-514 ◽  
Author(s):  
HIKARU NOUDA ◽  
HIROATSU ODA ◽  
DAISUKE YONEKURA ◽  
RI-ICHI MURAKAMI
Keyword(s):  
Thin Film ◽  
Free Energy ◽  
Surface Free Energy ◽  
High Speed ◽  
Gas Flow ◽  
Sessile Drop ◽  
Ion Bombardment ◽  
Polar Component ◽  
Scratch Testing ◽  
The Relationship

The purpose of this study is to examine the relationship between adhesion of CrN thin film and the surface free energy of substrate. CrN film was deposited on JIS SKH2 high speed tool steel by arc ion plating (AIP) method. The surface free energy of the substrate was measured with/without ion bombardment process using nitrogen and argon gas under various gas flow rate before CrN deposition. The surface free energy was measured by the sessile drop method using distilled water and methylene iodide. The adhesion was evaluated by scratch testing and the relationship between a critical load and the surface free energy in each ion bombardment condition was discussed. As a result, it was found that the adhesion increased with decreasing the surface free energy, in particular the polar component strongly affects the adhesion.

Comparison of Surface Free Energy Calculation Methods

2015 ◽  
Vol 791 ◽  
pp. 259-265 ◽  
Author(s):  
Jacek Domińczuk ◽  
Anna Krawczuk
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Surface Preparation ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Free Energy Calculation ◽  
Boundary Phase ◽  
Polar Component ◽  
Energy Calculation ◽  
Liquid Boundary

The paper presents the main methods of surface free energy calculation of solids based on the contact angle measurement. The basic of splitting the surface free energy into components as well as interactions at the solid-liquid boundary phase considered while developing calculation models were presented. Basing on test results of surface free energy of 0H18N9T stainless steel, the relation between the method of surface preparation and the surface free energy were shown. The analysis focuses on change of the polar part. Differences between methods were indicated and it was pointed that skipping the polar component in analysis of adhesive joints strength results in deterioration of prediction model.

scholarly journals Influence of Low-Pressure RF Plasma Treatment on Aramid Yarns Properties

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3476
Author(s):  
Alicja Nejman ◽  
Irena Kamińska ◽  
Izabela Jasińska ◽  
Grzegorz Celichowski ◽  
Małgorzata Cieślak
Keyword(s):  
Weight Loss ◽  
Free Energy ◽  
Radio Frequency ◽  
Plasma Treatment ◽  
Surface Free Energy ◽  
Low Pressure ◽  
Rf Plasma ◽  
Polar Component ◽  
Specific Strength ◽  
Dispersion Component

The aim of the study was to modify the surface free energy (SFE) of meta- (mAr) and para-aramid (pAr) yarns by their activation in low-pressure air radio frequency (RF) (40 kHz) plasma and assessment of its impact on the properties of the yarns. After 10 and 90 min of activation, the SFE value increased, respectively, by 14% and 37% for mAr, and by 10% and 37% for pAr. The value of the polar component increased, respectively by 22% and 57% for mAr and 20% and 62% for pAr. The value of the dispersion component for mAr and pAr increased respectively by 9% and 25%. The weight loss decreased from 49% to 46% for mAr and 62% to 50% for pAr after 90 min of activation. After 90 min, the specific strength for mAr did not change and for pAr it decreased by 40%. For both yarns, the 10 min activation in plasma is sufficient to prepare their surface for planned nanomodification.

scholarly journals Enhancement of Polyvinyl Acetate (PVAc) Adhesion Performance by SiO2 and TiO2 Nanoparticles

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 707 ◽  
Author(s):  
Gorana Petković ◽  
Marina Vukoje ◽  
Josip Bota ◽  
Suzana Pasanec Preprotić
Keyword(s):  
Free Energy ◽  
Tio2 Nanoparticles ◽  
Surface Free Energy ◽  
Polyvinyl Acetate ◽  
Adhesive Bonding ◽  
Sio2 Nanoparticles ◽  
Work Of Adhesion ◽  
Nanoparticles Concentration ◽  
Adhesion Performance ◽  
End Use

Post press processes include various types of bonding and adhesives, depending upon the nature of adherends, the end use performance requirements and the adhesive bonding processes. Polyvinyl acetate (PVAc) adhesive is a widely used adhesive in the graphic industry for paper, board, leather and cloth. In this study, the enhancement of PVAc adhesion performance by adding different concentrations (1%, 2% and 3%) of silica (SiO2) and titanium dioxide (TiO2) nanoparticles was investigated. The morphology of investigated paper-adhesive samples was analyzed by SEM microscopy and FTIR spectroscopy. In addition, the optimal adhesion at the interface of paper and adhesive was found according to calculated adhesion parameters by contact angle measurements (work of adhesion, surface free energy of interphase, wetting coefficient). According to obtained surface free energy (SFE) results, optimum nanoparticles concentration was 1%. The wettability of the paper-adhesive surface and low SFE of interphase turned out as a key for a good adhesion performance. The end use T-peel resistance test of adhesive joints confirmed enhancement of adhesion performance. The highest strength improvement was achieved with 1% of SiO2 nanoparticles in PVAc adhesive.

Wettability of plasma-polymerized vinyltriethoxysilane film

2009 ◽  
Vol 63 (4) ◽  
Author(s):  
Soňa Lichovníková ◽  
Jan Studýnka ◽  
Vladimír Čech
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Sessile Drop ◽  
Geometric Mean ◽  
Polar Component ◽  
Hydroxyl Groups ◽  
Sessile Drop Technique ◽  
Plasma Polymers ◽  
Drop Technique ◽  
Deposition Conditions

AbstractPlasma-polymerized films of vinyltriethoxysilane were surface characterized using the sessile drop technique. The surface free energy and its components were evaluated using the Owens-Wendt-Kaelble geometric mean method, Wu harmonic mean method, and van Oss, Chaudhury, and Good acid-base theory. Influence of deposition conditions on the surface free energy was demonstrated in the study. Improved wettability of the films was related to the diminished concentration of apolar methyl groups in plasma polymers. An increased concentration of carbonyl and hydroxyl groups resulted in a very small improvement of the polar component.

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