Kernel Ridge Regression with Lagged-Dependent Variable: Applications to Prediction of Internal Bond Strength in a Medium Density Fiberboard Process

Author(s):  
Norman Kim ◽  
Young-Seon Jeong ◽  
Myong-Kee Jeong ◽  
Timothy M. Young
Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 114
Author(s):  
Roberto Magalhães ◽  
Beatriz Nogueira ◽  
Samaritana Costa ◽  
Nádia Paiva ◽  
João M. Ferra ◽  
...  

Wood-based products usually have serious limitations concerning contact with water, both because wood is a hygroscopic material and because the commonly used binder has low moisture resistance. This paper studies the effect of panel moisture content (MC) on the physico-mechanical properties of medium density fiberboards (MDF). Several commercial MDF boards produced in Europe were stored at room temperature and relative humidity (RH) for 9 weeks (approx. range 15–20 °C and 50–85% RH). Every week, a strip of each MDF board was cut out, divided into 5 × 5 cm test pieces and its internal bond strength (IB) was measured. A strong influence of MDF moisture content on internal bond strength was observed and therefore IB test pieces were stored in a climatic chamber (either at 20 °C, 55% RH and at 20 °C, 70% RH). A decreasing linear relation was established between IB and MC. It was found that this effect is reversible: after drying, internal bond strength rises again (following a slight hysteresis). This work reinforces the importance of conditioned storage before board properties analysis, as described in European Standard EN 319.


2019 ◽  
Vol 65 (1) ◽  
Author(s):  
Turgay Akbulut ◽  
Nadir Ayrilmis

Abstract The aim of the study was to develop three-layer medium-density fibreboard (MDF) manufacture by adding the coarse fibres in the middle layer, like three-layer particleboard. The liquid urea–formaldehyde (UF) resin was reduced from 10.5 to 6.5 wt% in the middle layer of the MDFs. The UF resin content was kept constant at 10 wt% in the surface layers of all the MDFs. Moreover, the average density of MDFs was decreased from 730 to 650 kg/m3. The internal bond strength of three-layer MDFs decreased with decreasing UF resin content (10.5 to 8.5 wt%) in the middle layer. However, the decreases in the internal bond strength were statistically not significant. The internal bond strength values of the MDFs having density between 730 and 675 kg/m3 did not show significant differences. The cost savings of the resin were 20% when the amount of resin was reduced from 10.5 to 8.5 wt%. Three-layer MDFs had lower resin consumption at lower densities over traditional single-layer MDFs produced in the same plant with the same material components without decreasing their technological properties. In conclusion, it can be said that three-layer MDF could be produced at a lower cost than traditional single-layer MDF.


Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1435 ◽  
Author(s):  
Hamid R. Taghiyari ◽  
Ayoub Esmailpour ◽  
Roya Majidi ◽  
Jeffrey J. Morrell ◽  
Mohammad Mallaki ◽  
...  

Urea-formaldehyde (UF) resins are primary petroleum-based, increasing their potential environmental footprint. Identifying additives to reduce the total amount of resin needed without adversely affecting the panel properties could reduce these impacts. Wollastonite is a mineral containing calcium and silica that has been used as an additive in a variety of materials and may be useful as a resin extender. Nanoscale wollastonite has been shown to enhance the panel properties but is costly. Micron-scale wollastonite may be a less costly alternative. Medium-density fiberboards were produced by blending a hardwood furnish with UF alone, micron-sized wollastonite alone, or a 9:1 ratio of UF to wollastonite. Panels containing of only wollastonite had poor properties, but the properties of panels with 9:1 UF/wollastonite were similar to the UF-alone panels, except for the internal bond strength. The results suggest that small amounts of micron-sized wollastonite could serve as a resin extender. Further studies are suggested to determine if the micron-sized material has similar positive effects on the resin curing rate.


2020 ◽  
Vol 14 (1) ◽  
pp. 84
Author(s):  
Ragil Widyorini ◽  
Ikhwan Syahri ◽  
Greitta Kusuma Dewi

Bambu memiliki kandungan ekstraktif dengan persentase yang berbeda antar jenis bambu. Penelitian ini bertujuan untuk mengetahui pengaruh perlakuan ekstraksi pada jenis bambu yang berbeda terhadap sifat papan partikel. Dua jenis bambu digunakan yaitu Bambu Petung (Dendrocalamus asper) dan Bambu Wulung (Gigantochloa atroviolacea). Perlakuan ekstraksi digunakan pada partikel bambu sebelum proses pembuatan papan partikel yaitu tanpa ekstraksi, ekstraksi air dingin dan ekstraksi air panas. Papan partikel dibuat dalam ukuran 25 cm x 25 cm x 0,7 cm, target kerapatan 0,9 g/cm3, jumlah asam sitrat 30%, serta kondisi pengempaan suhu 180°C selama 10 menit. Hasil penelitian menunjukkan bahwa interaksi perlakuan ekstraksi dan jenis bambu hanya berpengaruh signifikan pada sifat penyerapan air dan keteguhan rekat internal, sedangkan jenis bambu berpengaruh signifikan pada nilai kadar air, modulus patah dan modulus elastisitas. Semua papan partikel yang dihasilkan memenuhi standar Japanese Industrial Standard (JIS) A 5908 tipe 13. Pada penelitian ini, papan partikel dari bambu wulung tanpa perlakuan ekstraksi mempunyai nilai yang memenuhi standar tipe 18 dan berpotensi sebagai bahan baku untuk produk furnitur eksterior. Perlakuan ekstraksi dapat meningkatkan secara signifikan nilai keteguhan rekat internal papan partikel bambu petung, walaupun secara umum dengan jumlah asam sitrat 30% perlakuan tersebut tidak diperlukan pada papan partikel bambu Properties of Particleboard made from Petung Bamboo (Dendrocalamus asper) and Wulung Bamboo (Gigantochloa atroviolacea) Particles with Extraction TreatmentAbstractBamboo has extractives, which the percentage of extractive was different based on bamboo species. This research aimed to investigate the effect of extraction treatment at different bamboo species on the particleboard properties. Two types of bamboo were used, i.e. Petung bamboo (Dendrocalamus asper) and Wulung bamboo (Gigantochloa atroviolacea). Three extraction treatments were conducted to the bamboo particles before the particleboard manufacture, i.e. unextracted, cold-water extraction, and hot-waterextraction. The particleboard was made in the size of 25 cm x 25 cm x 0.7 cm, target density of 0.9 g/cm³, citric acid content of 30%, and pressing temperature of 180°C for 10 min. The results showed that the interaction between extraction treatment and bamboo species significantly affected on the water absorption and internal bond strength, however bamboo species affected significantly on the moisture content, modulus of rupture, and modulus of elasticity. All of particleboards could met the requirement of the 13 type of Japanese Industrial Standard (JIS) A 5908. In this research, particleboards made from wulung bamboo particles without extraction treatment have properties that met the requirement of the 18 type and the products have potential to be as exterior materials for furniture. In general, an extraction treatment was not an important step on the manufacturing of bamboo particleboard using citric acid 30% as adhesive. However, the extraction treatment could increase significantly the internal bond strength of particleboard made from petung bamboo.


2020 ◽  
Vol 10 (15) ◽  
pp. 5028
Author(s):  
Fidan Aslanova ◽  
Gozen Elkiran ◽  
Salim Hiziroglu ◽  
Serkan Ilseven

The objective of this work was to evaluate some of the mechanical and physical properties of the flooring materials manufactured from panels having magnesia substrate overlaid with oak veneer (Querqus alba) and linoleum sheets. Commercially manufactured panels were used in this work. Bending characteristics, internal bond strength, thickness swelling, and surface quality of the samples were evaluated. The highest modulus of elasticity (MOE) value of 4406 MPa for the sample type-A2 was loaded in the direction of the substrate followed by 3478 MPa for linoleum covered samples which were loaded in the same direction. Internal bond strength values of the panels did not show any significant differences from each other. Dimensional stability of the specimens in the form of thickness swelling for both 2-h and 24-h water soaking tests resulted in values ranging from 0.11 to 0.19%. The surface quality of the samples was not substantially influenced as a function of water exposure. Based on the results in this work magnesium substrate overlaid with oak veneer and linoleum panels could have potential to be used as flooring material with accepted properties.


Fibers ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 46 ◽  
Author(s):  
Jan T. Benthien ◽  
Martin Ohlmeyer

Against the background of the intention to reduce the amount of wood used in the production of particleboard for economic reasons, the associated reduction in panel density and consequently the panel properties, the influence of the alternative use of flat-shaped face layer particles and core layer particles of intentionally greater thickness on the panel properties was investigated. Appropriate particles were made for this purpose, panels with typical (650 kg/m3) and reduced wood usage (500 kg/m3) were produced, and e.g., their bending properties and internal bond strength were determined. Particle size characterization was done with sieve analysis, image analysis (length and width measurement), and manual thickness gauging. It was found that the alternative use of the flat-shaped particle significantly increased the bending properties and thus the level of the reference can be achieved despite the reduced use of wood. The reason for the increased bending properties was assumed to be the higher strength of the particles themselves and the more effective adhesive bond between the particles. The increase in internal bond strength when using alternative particles could be attributed solely the different production history (e.g., use of fresh cutting blades and laboratory scale production).


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