Faculty of Design and Technologies of Furniture and Interior
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Item type:Publication, Water Resistance of Fiberglass Reinforced Plywood during Prolonged Water Exposure.(Faculty of Forestry and Wood Technolgy, University in Zagreb, 2023); Тhe aim of this research is to study the water absorption and thickness swelling of plywood reinforced with fiberglass fabrics pre-impregnated with alcohol-soluble phenol-formaldehyde resin during prolonged water exposure. Four experimental reinforced plywood models were made from peeled beech veneers with thickness of 1.5 mm and 1.85 mm bonded with the same resin used for fabric pre-impregnation. In each model, sheets of pre-impregnated fabric (prepreg) were incorporated in different adhesive layers of the plywood structure. One additional model was made without reinforcements as comparing plywood model. On the basis of the obtained data for the changes of water absorption and thickness swelling of reinforced plywood after immersion in water continuously for a period of 192 days, water resistance of experimental plywood was evaluated. The research results showed that the application of fiberglass prepreg as reinforcement in plywood structure significantly decreases the values of water absorption and thickness swelling. After full water treatment plywood models have good dimensional stability and do not show deformations. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Water absorption and thickness swelling of plywood overlaid with fiberglass prepreg(University of Bihac, Faculty of Technical Engineering, 2023); Water absorption and thickness swelling of experimental eleven-layered beech plywood overlaid with fiberglass prepreg were studied in this research. These properties were tested during exposure to water continuously for period of 192 days. The veneers used in plywood structure had thickness of 1.5 mm and 1.85 mm. The fiberglass prepreg was made form fiberglass fabric that was pre-impregnated with methyl alcohol soluble phenol-formaldehyde resin. The same resin was used for veneer bonding. The test results showed that application of fiberglass prepreg as surface layers lead to decreasing of water absorption and thickness swelling of plywood. After 192 days immersion in water, plywood model has good dimensional stability and does not show deformations. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Bending strength and modulus of elasticity in bending of beech and black pine plywood(Faculty of design and technologies of furniture and interior-Skopje, 2023); The research presented in this paper includes the study of bending properties of plywood made from beech and black pine veneers. For this purpose, four experimental plywood models were made. Two of the models were made from peeled beech veneers and other two models were made from peeled black pine veneers. Water-soluble phenol-formaldehyde resin was used as plywood binder. The bending strength and modulus of elasticity in bending of the experimental plywood were tested in two directions, parallel and perpendicular to the face grain. According to the values of bending strength and modulus of elasticity in bending, plywood models can be used for structural application in construction. Production of plywood with different number of veneers in panel structure, as well as plywood with the same number of the veneers but from different wood specie, gives opportunities for production of panels that can meet different application requirements. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Impact of resin content on water absorption and thickness swelling of composite wood-based panels(Faculty of design and technologies of furniture and interior-Skopje, 2021); ; Mihajlova, JulijaThe aim of the research presented in this paper is to study the impact of resin content on water absorption and thickness swelling of composite wood-based panels. For this purpose three experimental models of composite wood-based panels were made that represent a combination of particleboards and constructive veneers. The core layer of composite panels was made of single-layer particleboard with thickness of 16 mm. Particleboards were overlaid on both sides with beech peeled veneer with thickness of 3,2 mm. Water-soluble phenol-formaldehyde resin with 10 %, 13 % and 16 % dry matters content on dry wood basis was used respectively for production of single-layer particleboard cores of the three composite models. The resin used in all three models was modified with epoxy resin. The veneers were bonded on the particleboard core with the same resin that was used for particle bonding, but without modifier. Tests for the water absorption and thickness swelling after immersion in water for 2 hours and 24 hours, as well as after immersion in boiling water for 2 hours were carried out in controlled laboratory conditions. The results from the research showed that the resin content in particleboard core has significant impact on the values of the tested properties of composite wood-based panels. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Water absorption and thickness swelling of reinforced plywood during prolonged water exposure(Faculty of design and technologies of furniture and interior-Skopje, 2021); Тhe aim of this research is to study the physical properties during prolonged water exposure of experimental plywood reinforced with cotton fabrics pre-impregnated with alcohol-soluble phenol-formaldehyde resin. Plywood composition was consisted of eleven layers of peeled beech veneers with thickness of 1,5 mm and 1,85 mm. The veneers were bonded with alcohol-soluble phenol-formaldehyde resin. The pre-impregnated fabrics were incorporated in each adhesive layer of the plywood panel. On the basis of the obtained data for the changes of the physical properties of reinforced plywood after exposure to prolonged water treatment, water resistance of experimental plywood was evaluated. Tests for the thickness swelling, volume swelling and water absorption were made after immersion in water for prolonged period of 192 days in controlled laboratory conditions. The results from the research showed that the plywood model is characterized by uniform density; it is dimensionally stable during and after prolonged water exposure, without any deformations of the shape of the test specimens - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Janka hardness of plywood reinforced with pre-impregnated cotton fabrics(Faculty of design and technologies of furniture and interior-Skopje, 2021); Higher properties of plywood can be achieved trough applying different non-wood materials in their structure. Тhe aim of this research is to study the Janka hardness of experimental plywood reinforced with cotton fabrics pre-impregnated with alcohol-soluble phenol-formaldehyde resin. Plywood models were made of eleven layers of peeled beech veneers with thickness of 1,5 mm and 1,85 mm. Alcohol-soluble phenol-formaldehyde resin was used as plywood binder. The pre-impregnated fabrics were incorporated as layers in the structure of the plywood panel. Different models of reinforced plywood were made through a change of the position of the reinforcing layers in the structure of the panel. One additional model was made without reinforcements as comparing plywood model. Tests for plywood hardness according to Janka were done on each plywood model. The research results showed that the values of Janka hardness are affected by the use of pre-impregnated fabrics as reinforcements in plywood structure. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Determination of the fiber saturation point of autochthonous and allochtonous wood species(Faculty of design and technologies of furniture and interior-Skopje, 2019); ; The aim of this research is to determine the fiber saturation point of wood from Fagus moesiaca, Quercus sessilis, Quercus conferta, Robinia pseudoacacia, Pinus nigra, Pinus silvestris, Abies alba, Picea excelsa, Pseudotsuga menziesii, Cupressus arizonica, Sequoiadendron giganteum, Pinus strobus and Larix decidua, as a contribution to the utilization of wood. The material used for investigation was collected from twenty-eight methodologically selected localities. The obtained average values of fiber saturation point are based on wood density and volume shrinkage, in accordance with the standard for wood investigation. The results from investigation of fiber saturation point of wood from autochthonous species are within the limits of the up to now empirical and scientific knowledge. The obtained values for the allochthonous species that are subject of our investigation, can significantly impact on further introduction. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Variations of the hardness of Balkan beech wood (Fagus moesiaca cz.)(Faculty of design and technologies of furniture and interior-Skopje, 2019); ; The aim of this research is to determine the significance of the impact of the origin of wood trees (generative or vegetative), height of the cross-section (1,3 and 5,3 m above ground) and relative age of annual rings (distance from pith in radial direction) in which the measurements are made, on the variation of wood hardness, at near same ecological factors. For determination of wood hardness Brinell method is used, and for statistical processing of the data from the measurements, software package SPSS Statistics 21 is used. On the basis of the obtained values form the tests for normal distribution of the hardness and analysis of the homogeneity of the variance, as well as on the basis of multiple comparison for determination of statistical significant differences between average values of wood hardness from different tree trunks, cross-section and age, it is found that the trees from vegetative origin produce wood with significantly higher hardness compare to the trees form generative origin. Among the two cases, the wood hardness of section 1,3 m is significantly higher than the wood hardness of section 5,3 mm. The increment of the relative age of annual rings in trees from vegetative origin in certain interval is followed by increment in wood hardness, whereupon the wood hardness decreases, while in trees from generative origin, first in certain interval the hardness is decreased, whereupon it is increased. The obtained results of these researches, supplemented with the comparative researches of processing of standard (from generative origin) and nonstandard (from vegetative origin) timber should be taken in consideration when choosing the technological process. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Physical properties of plywood during prolonged water exposure(Faculty of design and technologies of furniture and interior-Skopje, 2019); ; Mihajlova, JulijaТhe aim of this research is to study the physical properties of experimental plywood bonded with alcohol-soluble phenol-formaldehyde resin during prolonged water exposure. On the basis of the obtained data for the changes of the physical properties of plywood after exposure to prolonged water treatment of 192 days, water resistance of experimental plywood is evaluated. Tests for the thickness swelling, volume swelling and water absorption are made after immersion in water for prolonged period in controlled laboratory conditions. The measuring of thickness, length, width and mass of plywood test specimens for determination of these properties is made after immersion in water for the period of 1 day (24 hours) to 192 days (4608 hours). Plywood model in this experiment was made from peeled beech veneers bonded with pure alcohol-soluble phenol-formaldehyde resin. The results from the research showed that the plywood model is characterized by uniform density; it is dimensionally stable during and after prolonged water exposure, without any deformations of the shape of the test specimens. The changes of the values of thickness and volume swelling, as well as the values of water absorption in the analyzed period are proportional to change of the duration of the period of water exposure. According to the obtained data from the tests of these properties the plywood model meets the requirements for load-bearing plywood for use in construction. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Bending properties of reinforced plywood with fiberglass pre-impregnated fabrics(Faculty of Forestry, University of Zagreb, 2019-12)One of the methods for achieving higher plywood properties is reinforcing the plywood structure trough applying different non-wood materials in it that will contribute in achieving higher physical and mechanical properties of the end product. The aim of the research presented in this paper is to study the bending properties of plywood reinforced with fiberglass fabrics pre-impregnated with alcohol-soluble phenol-formaldehyde resin. The pre-impregnated fabrics were incorporated as layers in the structure of the plywood panel. Different models of reinforced plywood were made through a change of the position of the reinforcing layers in the structure of the panel. One additional model was made without reinforcements as comparing plywood model. Plywood composition was consisted of eleven layers of peeled beech veneers with thickness of 1.5 mm and 1.85 mm. Alcohol-soluble phenol-formaldehyde resin was used as plywood binder. The bending strength and modulus of elasticity in bending of the plywood panels were tested in two directions: parallel and perpendicular to the face grain. The research results showed that the values of bending strength and modulus of elasticity in bending are significantly affected by the use of pre-impregnated fiberglass fabrics as reinforcements in plywood structure.