Tag Archives: mechanical properties

434-443 J. Iejavs, M. Podnieks and A. Uzuls
Some physical and mechanical properties of wood of Fast-growing tree species eucalyptus (Eucalyptus grandis) and radiata pine (Pinus radiata D.Don)
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Some physical and mechanical properties of wood of Fast-growing tree species eucalyptus (Eucalyptus grandis) and radiata pine (Pinus radiata D.Don)

J. Iejavs¹*, M. Podnieks² and A. Uzuls³

¹Forest and Wood Products Research and Development Institute, Dobeles iela 41, LV3001 Jelgava, Latvia
²Latvia University of Life Sciences and Technologies, Forest faculty, Department of Wood Processing, Dobeles iela 41, LV3001 Jelgava, Latvia
³Kokpārstrāde 98’ Ltd., ‘Dižkoki’, LV2154 Allažu pagasts, Siguldas novads, Latvia
*Correspondence: janis.iejavs@e–koks.lv

Abstract:

Fast-growing imported plantation tree species have become an available wood resource for Europe’s wood industry in the last decades. This sustainable alternative may reduce the gap between the increasing demand for and decreasing supply of the local tree species. The aim of the study was to determine and compare basic physical and mechanical properties of eucalyptus (Eucalyptus grandis) wood from Uruguay and radiata pine (Pinus radiata D.Don) wood from New Zealand as an alternative for Scots pine (Pinus sylvestris L.) from Latvia, to produce non–structural semi–finished glued laminated timber members for the manufacturing of windows. Such properties as density, swelling, bending strength, bending modulus of elasticity, compression strength and resistance to impact were determined according to ISO 13061 series standards test methods for small clear wood specimens. As the result of this study it was established that there is not significant difference between the majority of radiata pine and Scots pine properties, with the exception of resistance to impact and radial swelling where radiata pine shows significantly higher values. Not surprisingly all the properties of deciduous eucalyptus wood were significantly higher compared to both coniferous tree species. Higher swelling and density properties of eucalyptus compared to radiata pine and Scots pine should be taken into consideration for the design and production of wooden window elements.

Key words:

Eucalyptus grandis, Fast-growing wood, mechanical properties, Pinus radiata D.Don, plantation wood

679–688 P. Alao, M. Tobias, H. Kallakas, T. Poltimäe, J. Kers and D. Goljandin
Development of hemp hurd particleboards from formaldehyde-free resins
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Development of hemp hurd particleboards from formaldehyde-free resins

P. Alao¹, M. Tobias¹, H. Kallakas¹, T. Poltimäe¹, J. Kers¹ and D. Goljandin²

¹Laboratory of Wood Technology, Department of Material and Environmental Technology, Ehitajate tee 5, EE19086 Tallinn, Estonia
²Department of Mechanical and Industrial Engineering, Tallinn University of Technology, Ehitajate tee 5, EE19086 Tallinn, Estonia
*Correspondence: percy.alao@taltech.ee

Abstract:

Low density of hemp hurd (Cannabis Sativa L), better end of life impact, performance comparable to wood chips and low energy requirement for cultivation make it a suitable alternative raw material for particleboards (Pb). However, due to concerns about sustainability and formaldehyde emissions, it is essential to develop the new bio-based resins from renewable resources. In this research, the mechanical and physical properties of Pb produced from hemp hurds (HH) and a variety of resins: Urea-formaldehyde (UF), formaldehyde-free acrylic resin (Acrodur®) and bio-based soy resin (Soyad™) were compared to those of wood particles (WP) bonded with UF. The results indicate that boards from HH are generally lighter than WP with a 5.6% variation between HH+UF and WP+UF. Hemp boards based on soy-resin showed higher tensile performance, with an average of 0.43 MPa compared to the 0.28 MPa and 0.24 MPa of (HH+UF) and (WP+UF) respectively. Nevertheless, thickness swelling (TS) of HH+UF (27%) was the least, while there was no significant difference in the water absorption (WA) compared to HH+Soyad4740, both were still lower than that of WP+UF. The overall outcome shows that bio-based soy resin can be a suitable alternative to UF as a binder in Pb production.

Key words:

Bio-resin, hemp hurd, mechanical properties, particleboard, urea-formaldehyde

980–988 E.O. Samuilova, A.V. Podshivalov, M.I. Fokina, V.S. Chursina, I.E. Strelnikova and M.V. Uspenskaya
Tensile properties of wood plastic composites based on plant-filled polyvinyl chloride/poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) matrices
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Tensile properties of wood plastic composites based on plant-filled polyvinyl chloride/poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) matrices

E.O. Samuilova*, A.V. Podshivalov, M.I. Fokina, V.S. Chursina, I.E. Strelnikova and M.V. Uspenskaya

ITMO University, Faculty of Applied Optics, Kronverkskiy pr., 49, RU197101 Saint Petersburg, Russia,
*Correspondence: samuilova.eo@itmo.ru

Abstract:

The article considers the obtaining and studying of microcomposites based on polyvinyl chloride (PVC)/poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) polymer matrix, filled with a various faction of different natural plant fillers. In work, such plant fillers as wood flour without lignin, spruce flour and rice husk were used. Microcomposites were obtained by melt rolling processing method with subsequent analysis of their morphology and mechanical tensile properties. It is shown that the filler particles were strongly oriented in the direction of the melt rolling process and have a different aspect ratio depending on the filler type. The tensile strength of materials strongly depends on the particle’s aspect ratio. When the aspect ratio of the particles is 4.25, the material has a strength value comparable to a pure PVC/PHBHHx matrix.

Key words:

composites morphology, mechanical properties, polyhydroxyalkanoate, polyvinyl chloride, wood-polymer composites

1517–1531 P.F. Alao, H. Kallakas, T. Poltimäe and J. Kers
Effect of hemp fibre length on the properties of polypropylene composites
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Effect of hemp fibre length on the properties of polypropylene composites

P.F. Alao*, H. Kallakas, T. Poltimäe and J. Kers

Laboratory of Wood Technology, Department of Materials and Environmental Technology, Tallinn University of technology, Ehitajate tee 5, EE19086 Tallinn, Estonia
*Correspondence: percy.alao@taltech.ee

Abstract:

Hemp fibre (HF) is a natural fibre that has gained increased application in interior material for automobile industries (Sanjay, et al., 2016). However, good interfacial bonding between fibre/matrix is necessary to enhance the mechanical properties of the composite (Pickering, et al., 2007). This study focuses on the effect of fibre length, alkali and silane treatments on the mechanical and physical properties of hemp fibre reinforced polypropylene composites. Compression moulding technique was used to produce the composite, fibre lengths of 50, 100 and 150 mm were selected and combined with polypropylene powder at a fibre/PP ratio of 60/40%, a pressure of 1.67 MPa and temperature between 160–200 °C. The results obtained show that longer fibres enhanced mechanical strength. The tensile test result, for instance, shows a 21% increase in flexural strength at 150 mm compared to the fibre length of 50 mm. The modification resulted in a 46% decrease in strength, especially for 150 mm long fibres. This may have been as a result of fibre damage, inadequate modification, less quality fibre or higher initial moisture content in the modified fibres as observed from FTIR spectroscopy. Further investigation of these factors is required to be able to conclusively determine if they may have affected the mechanical performance (Alao, 2018).

Key words:

fibre length, hemp fibre, interfacial bonding, mechanical properties, modification, moisture content., polymer composite, polypropylene

1550–1558 L. Chladek, V. Plachy, P. Vaculik and P. Brany
Evaluation of nutritional and physical values of pellets based on pea and lupine with added yeast in chickens fattening
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Evaluation of nutritional and physical values of pellets based on pea and lupine with added yeast in chickens fattening

L. Chladek¹*, V. Plachy², P. Vaculik¹ and P. Brany¹

¹Czech University of Life Sciences Prague (CULS), Faculty of Engineering, Kamýcká 129, CZ165 21 Prague - Suchdol, Czech Republic
²Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Department of Microbiology, Nutrition and Dietetics, Kamýcká 129, CZ165 21 Prague - Suchdol, Czech Republic
*Correspondence: chladekl@tf.czu.cz

Abstract:

The article is focused on the development of the new type of broiler chicken feed, based on pea (Pisum sativum L.) and blue lupine (Lupinus angustifolius L), enriched with used dried brewer´s yeast. This composition eliminates use of soybean meal (PES) that was yet a traditional component in chicken feed. The main reason for its elimination was the using of genetically modified varieties of soybean and its relatively high price around 0.5 €uro kg^-1 in Czech Republic. For milling of pea or blue lupine was used vertical (hammer) mill type Taurus, supplied by company TAURUS, for drying of used brewer´s yeast had been used drier Memmert UFE 800, final dry matter of the yeast was 88%. For pellets production were used two devices, press type JGE 120-6110 and Testmer. For the determination of physical properties of manufactured pellets (the weight of 1,000 pieces, bulk density, abrasiveness and pellet durability index PDI) were used following laboratory devices, Pellet Tester Holmen NHP and Testmer 200. Experimental activities had shown that the best results were reached using pellets manufactured on base blue lupine enriched by dried brewer´s yeast (6%).

Key words:

000 pellets, abrasiveness, blue lupine (Lupinus angustifolius), broiler chicken, bulk density, feeding, mechanical properties, pea (Pisum sativum), pellet durability index (PDI), pellets, used dried brewery yeast, weight of 1

1116–1122 P. Valášek
Study on impact strength of sisal fibers reinforced epoxy composites using experimental methods
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Study on impact strength of sisal fibers reinforced epoxy composites using experimental methods

P. Valášek

Department of Material Science and Manufacturing Technology, Faculty of Engineering, Czech University of Life Sciences Prague, Kamýcká 129, CZ 165 21 Prague; e-mail: valasekp@tf.czu.cz

Abstract:

Among the advantages of composite materials is their ability to exploit the properties of partial phases that creates the composite. Common materials used as matrix materials include polymeric composites. The properties of these matrices can be optimized by using synthetic or also natural fibers. Natural fibers are inexpensive, ranks among renewable resources and when respecting their biological nature, they can replace synthetic fibers in many applications. This paper describes the impact strength of epoxy resins filled with unordered short sisal fibers with a length of 2–6 mm. From the experimental results it is evident that the presence of fibers of sisal examined as epoxy resins, increases the impact strength, up to 143%. SEM (scanning electron microscopy) was used to assess the failure of mechanism of these composites.

Key words:

Agave Sisalana, fiber composite, mechanical properties, porosity

639-653 H. Kallakas, M.A. Shamim, T. Olutubo, T. Poltimäe, T.M. Süld, A. Krumme and J. Kers
Effect of chemical modification of wood flour on the mechanical properties of wood-plastic composites
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Effect of chemical modification of wood flour on the mechanical properties of wood-plastic composites

H. Kallakas*, M.A. Shamim, T. Olutubo, T. Poltimäe, T.M. Süld, A. Krumme and J. Kers

Department of Polymer Materials, Tallinn University of Technology, Ehitajate tee 5, EE19086 Tallinn, Estonia;
*Correspondence: heikko.kallakas@ttu.ee

Abstract:

The poor compatibility between the highly hydrophilic wood fibres and the hydrophobic polymers is associated with a loss of mechanical properties. Therefore, to improve the interfacial adhesion between the polymer matrix and wood flour (WF), a chemical modification of WF is an appropriate solution. This study analyzes the influence of different chemical modifications of WF on the mechanical properties of wood-plastic composites (WPCs). WPC test samples were prepared from birch (Betula) WF with a mesh size of 0.⁶³ mm as the filler material and polypropylene (PP) as the matrix material. WF was chemically modified by six different methods to increase its adhesion to, and compatibility with, the polymer matrix. The six chemical methods used were: alkaline (NaOH) modification, polyvinyl alcohol (PVA) modification, silane treatment with ³-aminopropyltriethoxysilane (APTES), acetylation with acetic anhydride, cyanoethylation, and wood fibre esterification. The composites were produced using a twin-screw extruder and the test samples were prepared by injection moulding. The composites’ mechanical properties (three-point bending test), Charpy impact strength and thermal properties were tested. In addition, SEM micrographs of WPC surfaces were generated. WF as a filler material enhanced the flexural properties, while impact strength decreased, making the material more rigid and brittle. The test results revealed that the chemical modifications of WF improved the mechanical properties and crystallinity of WPC materials, while the melting temperature decreased. However, the influence of the chemical modification on the mechanical and thermal properties of WPC varied by method.

Key words:

chemical modification, mechanical properties, thermal properties., wood flour, wood-plastic composite

291-298 P. Valášek and M. Müller
EPDM rubber material utilization in epoxy composite systems
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EPDM rubber material utilization in epoxy composite systems

P. Valášek* and M. Müller

¹Department of Material Science and Manufacturing Technology, Faculty of Engineering, Czech University of Life Sciences Prague, Kamýcká 129, Prague; *Correspondence: valasekp@tf.czu.cz

Abstract:

Observing of possibilities for secondary raw materials utilization should rank among the key interests of the society. Nowadays, there are a lot of modern workplaces which are devoted to the possibilities of collecting, processing and using rubber materials. EPDM waste rubber in the form of particles is one of the many products of these workplaces. One of the possibilities for recycling this waste particles material is their interaction with another polymeric material. A reactoplastic which is filled with these particles comes into consideration. This way of utilization of the material is inexpensive and simple. The paper focuses on chosen mechanical qualities of the Epoxy/EPDM waste rubber composite. The waste rubber was gained as one of the outputs of a recycling line of the firm Gumoeko, Ltd., the reactoplastic was represented by a two-component epoxy resin. Distraction of rubber particles in the epoxy matrix was achieved by mechanical mixing without using the technology of vacuum. In the paper, the porosity, tensile strength and shear strength of the composites with various concentrations of EPDM are described. The resulting composite systems may find their application in the field of agriculture – especially during joining and sealing materials of larger units where high quality connections are not required.

Key words:

agriculture., mechanical properties, reactoplastic, waste.