The aim of the article was to test new types of rubber-containing particleboards created from waste materials, which positively contributes to environmental protection, saving primary resources and reducing production costs. This article focuses on the study of three-layer particleboards made from wood particles (spruce non-treated beams) and waste rubber granulates (tires, mixture of seals and carpets, internal flammable cables, external non-flammable cables). Urea–formaldehyde glue, melamine–formaldehyde glue, paraffin emulsion, and ammonium nitrate were used as a binders and excipients in the manufacturing of particleboards. In the core layer of each particleboard, 10% of the weight was made up of rubber granulate. Physical properties (density, water absorption, thickness swelling) and mechanical properties (internal bonding strength, modulus of rupture, modulus of elasticity, screw driving torque) were assessed from this perspective using current EN technical standards. According to the findings, the average densities of all particleboards were comparable to each other in a range from 0.692 to 0.704 g·cm⁻³. The lowest average water absorption and thickness swelling reached particleboards containing 10% of waste internal flammable cables, namely 32.79% for water absorption and 13.21% for thickness swelling. The highest average internal bonding strength reached particleboards without rubber filler and particleboards containing 10% of waste external non-flammable cables, namely 0.52 MPa for both types. The highest average modulus of rupture reached particleboards without rubber filler, namely 12.44 MPa. The highest average modulus of elasticity reached particleboards containing 10% of waste internal flammable cables, namely 2206.29 MPa, and the highest screw driving torque reached particleboards without rubber filler, namely 0.46 N·m for seating torque and 1.44 N·m for stripping torque. The results show that particleboards containing waste external non-flammable cables and particleboards containing waste internal flammable cables achieved comparable results to particleboards without rubber filler, which provides a good basis for a new way of utilizing this type of waste in the form of producing new wood–rubber composites.

This study investigated the effects of pilot-hole diameter in medium density fiberboard (MDF) on the characterization of screw-driving torques. The factors investigated were the embedded screw orientation and pilot hole diameter. Based on the curves obtained from screw-driving process, the measurements of the seating torque (SET) and stripping torque (STT) were obtained. The results of statistical analysis indicated that the SET and STT values in MDF were significantly affected by the pilot hole diameter. In the case of driving screws into the side of MDF material, the mean SET ranged from 0.37 to 1.23 N∙m and STT values ranged from 1.18 to 2.68 N∙m whereas for the face specimens, the mean SET ranged from 0.57 to 1.56 N∙m and STT values ranged from 2.89 to 5.41 N∙m.

No literature related to the study of sitting forces on chairs sat on by people who weighed over 136 kg was found. The Business Institutional Furniture Manufactures Association needs force data for development of performance test standards to test chairs for users who weigh up to 181 kg. 20 participants who weighed from 136 to 186 kg completed 6 tasks on an instrumented chair in the sequence of sitting down, remaining seated and rising. Effects of sitting motion, armrest use and seat cushion thickness on vertical sitting forces and centre-of-force were investigated. Results indicated hard sitting down yielded the highest sitting force of 213% in terms of participants’ body weights. Armrest use affected sitting forces of normal sitting down, but not of rising and hard sitting down. Cushion thickness affected sitting forces of normal and hard sitting down and shifting, but not of rising, static seating or stretching backward situations. Practitioner Summary: Results of the sitting force and centre-of-force data obtained for this research can help furniture manufacturers develop new product performance test standards for creating reliable engineering design and manufacturing quality and durable products to meet a niche market need.

The additive effects of the number of staples and gluing on ultimate lateral resistance loads of surface-to-surface, multistaple- and glue-connected joints in oriented strandboards (OSB) were investigated. Experimental results indicated that for a stapled–glued OSB joint with a given configuration of surface-tosurface bonding area of two joint members, its ultimate lateral resistance load and stiffness are governed by the number of staples used and gluing, respectively. Applying glue to multistaple-connected OSB joints can alter the effect of the number of staples used on their ultimate lateral resistance loads. Gluing increases joint lateral resistance loads, but this increase will not be significant when the number of staples used reaches a critical number. Applying glue to a stapled OSB joint improves its stiffness when compared with the stiffness of a stapled-only joint. The differences in ultimate lateral resistance loads of stapled–glued joints among three OSB materials evaluated in this study were not significant when the number of staples was six or less, and the differences became significant when the number of staples increased to eight.

Tr en Özet Çalışmanın amacı: Kontrplağın vida çekme direnci üzerine kılavuz deliğinin, vida tipinin, vidalama yönünün, suda bekletmenin ve yapıştırıcının etkisini araştırmaktır. Materyal ve Yöntem: Çalışmada çapları sırasıyla 3.5 mm ve 4 mm olmak üzere 2 tip vida kullanılmıştır. Temin edilen 18 mm kalınlığındaki kontrplak TS EN 13446 standardına göre 50 mm x 50 mm boyutlarında ebatlandırılmıştır. Kılavuz deliğinin çapı, testlerde kullanılan vida çapının %80’i olacak şekilde delme işlemi yapıldı. Polivinil asetat (PVAc) ve Poliüretan (PÜ) tutkalları kılavuz deliklerine enjekte edildikten sonra örnek yüzeyine ve kenarına vidalama işlemi gerçekleştirildi. Örneklerin yarısı 2 saat süre ile suda bekletildikten sonra vida çekme testleri yapıldı. Testlerin sonuçları istatistik analiz ile yorumlandı. Sonuçlar: Sonuçlar incelendiğinde kılavuz deliği açılmayan örnekler daha yüksek vida çekme direnci göstermiştir. Ayrıca yüzeyden uygulanan vida çekme direncinin kenardan uygulanana göre daha yüksek olduğu tespit edilmiştir. Tutkal uygulanan kılavuz delikli örnekler incelendiğinde Poliüretan (PÜ) uygulananların vida çekme mukavemeti Polivinil asetat (PVAc) uygulananlara göre daha yüksek olduğu belirlenmiştir. Suda bekletilmiş örnekler incelendiğinde daha düşük vida çekme mukavemeti göstermiştir. Ayrıca vida çapı arttıkça vida çekme mukavemetinin arttığı tespit edilmiştir. Araştırma vurguları: Kontrplakta vidalama öncesinde kılavuz deliklerine PÜ uygulanması vida tutma performasını önemli ölçüde etkilemektedir. Aim of study: The purpose of this study is to investigate the effect of the pilot-hole, screw type, screwing direction, water retention and adhesive on the screw pull resistance of the plywood. Material and Methods: Two types of screws, 3.5 mm and 4 mm in diameter, were used in the study. The supplied 18 mm thick plywood is sized to 50 mm x 50 mm according to TS EN 13446 standards. The pilot-holes were drilled so that 80% of the screw diameter would be used. After the polyvinyl acetate (PVAc) and polyurethane (PU) adhesives were injected into the pilot-holes, screwing was carried out perpendicularly and horizontally to the surface of the sample. Half of the samples were immersed in water for 2 hours before the screw withdrawal test. The results of the tests were interpreted by statistical analysis. Main results: When examining the results, all of the pilot-hole drilled samples showed higher screw withdrawal resistance than the pilot-hole drilled samples. It was also found that the screw withdrawal resistance perpendicular to the surface is higher than that parallel to the surface. When the glue applied pilot-hole specimens were examined, the PU specimens showed higher screw withdrawal strength than the PVAc specimens. A lower screw withdrawal strength was determined when samples were immersed in water. It was also found that as the screw diameter increases, the screw withdrawal strength increases. Research highlights: In is concluded that applying PU in pilot-holes before driving screw in significantly affected screw holding performance in plywood.

The growing volume of plastic waste from end-of-life vehicles presents environmental concerns, driving efforts to integrate recycled plastics. This study investigates the possibility of using recycled plastic from automotive parts (painted and unpainted bumpers, fuel tanks) as a 10% filler in the core layer of three-layer particleboards (P) and evaluates its impact on physical properties (water absorption—WA and thickness swelling—TS), mechanical properties (internal bonding strength—IB, modulus of rupture—MOR, modulus of elasticity—MOE and screw driving torque—SDT) and volatile organic compounds—VOC emissions. The boards were produced using conventional hot-pressing technology and analyzed according to applicable standards. Based on the results, the density of the reference (P) was 0.72 g·cm⁻³, while wood–plastic composites ranged from 0.70 g·cm⁻³ to 0.72 g·cm⁻³. After 24 h, WA reached 40% for reference (P) and from 36.9% (for (P) containing unpainted bumpers) to 41.9% (for (P) containing fuel tanks). TS reached 18% for (P) and from 16.8% (for (P) containing unpainted bumpers and fuel tanks) to 18.1% (for (P) containing painted bumpers). Plastic is a hydrophobic material and it is assumed that by increasing the proportion of plastic filler in the particleboards, the WA and TS of prepared boards will decrease. From the point of view of mechanical properties, values for (P) containing plastic filler were slightly lower compared to reference (P). The lowest value of IB (0.39 MPa) were reached for (P) containing painted bumpers. Plastic surface treatment could interfere with adhesion between the plastic and adhesive, weakening the bond in the core layer. For this reason, is preferable to use unpainted fillers, which provide better adhesive properties and higher structural integrity. VOC emissions from wood components consisted primarily of monoterpenes such as α-pinene, 3-carene and limonene. Adding 10% plastic to the particleboard did not increase overall VOC emissions. On the other hand, combining wood and plastic particles resulted in a reduction in overall VOC emissions. The findings confirm that recycled automotive plastics can be effectively incorporated into particleboards, maintaining standard performance while reducing reliance on virgin wood materials, making them a viable and sustainable alternative for furniture and interior applications.