Difficulty of internal bond prediction of particleboard using the density profile

The relationship between density profile and internal bond (IB) of commercial particleboards was investigated. Minimum density was theoretically related to the IB, but the correlation coefficient between them was low at 0.435. The correlation coefficients between core layer densities and IB were also low. These correlation coefficients were approximately 0.460. The IB is influenced not only by density, but also by other factors such as the manufacturing conditions. In addition, commercial particleboards have a narrow density range. This narrow density range results in overfitting, showing a low correlation coefficient. Thus, predicting the IB using density profile was difficult.

SIFAT FISIK DAN MEKANIK PAPAN PARTIKEL AMPAS DAN SERAT KULIT BATANG SAGU (Metroxylon spp) BERDASARKAN KOMPOSISI SUSUNAN PARTIKEL DAN RASIO PEREKAT ASAM SITRAT SUKROSA

The purpose of this study is to analyze the effect of layer composition and the ratio of citric acid-sucrose as well as the interaction of both of them to the optimum quality of the particleboards. Particleboards were made in sizes 30 cm x 30 cm x 1 cm with a target density of 0.7 gr/cm3. Particleboards were prepared by hot pressing at temperature of 160 oC for 20 minutes with a pressure of 25 kg/cm2. Particleboards consists of 3 layers with a composition of layers, namely f/b70: c30, f/b60: c40, and f/b50: c50, with a surface layer (face, back) made form of sago stem bark and core layers made form of pulp sago. Ratio of citric acid-sucrose in this study was varied from 0/100, 25/75, 75/25, and 100/0. Particleboards testing refers to standard JIS A 5908-2003 Type 8. The results showed that the layer composition had a significant effect on density, water absorption, internal bond (IB), and screw holding strenght. Meanwhile ratio of citrid acid-sucrose significantly affected the water content, water absorption, thickness development, MOE, MOR, internal bond (IB), and screw holding strenght. The interaction beetwen the composition layer factor and ratio of citrid acid-sucrose has a significant effect on water content, thickness development, MOE, MOR, and internal bond (IB). The best particleboards is in the treatment with the composition of the layer f/b70: c30 and the ratio of citric acid-sucrose 25/75 with a density value of 0.7675 gr/cm3, a moisture content of 7.5939%, modulus of rupture (MOR) 161.4350 kg/cm2, and the screw holding strength is 66.1930 kg/cm2.Keyword: citrid acid-sucrose, composition of layers, dregs and fibers of sago, particleboardsAbstrakTujuan dari penelitian ini adalah untuk menganalisa pengaruh komposisi lapisan dan perbandingan asam sitrat-sukrosa serta interaksi keduanya terhadap kualitas papan partikel yang optimum. Papan partkel dibuat dengan ukuran 30 cm x 30 cm x 1 cm dengan target kerapatan 0,7 gr/cm3. Papan partikel dikempa panas pada suhu 160 oC selama 20 menit dengan tekanan 25 kg/cm2. Papan partikel terdiri dari 3 lapisan dengan komposisi lapisan yaitu f/b70 : c30, f/b60 : c40, dan f/b50 : c50, dengan lapisan permukaan (face, back) berupa serat kulit batang sagu dan lapisan inti (core) berupa ampas sagu. Rasio asam sitrat-sukrosa dalam penelitian ini bervariasi 0/100, 25/75, 75/25, dan 100/0. Pengujian papan partikel mengacu pada standar JIS A 5908-2003 Type 8. Hasil penelitian menunjukkan faktor komposisi lapisan berpengaruh nyata terhadap kerapatan, daya serap air, keteguhan rekat internal (IB) dan kuat pegang sekrup. Sedangkan faktor rasio perekat asam sitrat sukrosa berpengaruh nyata terhadap kadar air, daya serap air, pengembangan tebal, MOE, MOR, keteguhan rekat internal (IB), dan kuat pegang sekrup. Interaksi antara faktor komposisi lapisan dan rasio asam sitrat-sukrosa berpengaruh nyata terhadap daya serap air, pengembangan tebal, MOE, MOR, dan keteguhan rekat internal (IB). Papan partikel terbaik terdapat pada perlakuan dengan komposisi lapisan f/b70 : c30 dan perbandingan asam sitrat-sukrosa 25/75 dengan nilai kerapatan 0,7675 gr/cm3, kadar air 7,5939 %, keteguhan patah (MOR) 161,4350 kg/cm2, dan kuat pegang sekrup 66,1930 kg/cm2. Kata Kunci : ampas dan serat sagu, asam sitrat-sukrosa, komposisi lapisan, papan partikel

Particleboard from kemenyan wood and belangke bamboo: effect of particle pre-treatment in acidic solution

Dimensional stability is a significant problem in particleboard. This study aims to analyze the effect of immersing particles in an acid solution on particleboard’s physical and mechanical properties made of kemenyan (Styrax sumatrana) wood and belangke (Gigantochloa pruriens) bamboo. The particles were immersed in each acid solution for 24 h, and then dried to reach 9% water content. The particleboard was made with a 25x25 cm2 with a target thickness and density of 1 cm and 0.70 g/cm3, respectively. After being made into sheets, the next step is hot pressing using a hot press machine that has set the temperature, time, and pressure at 160 °C, 5 min, and 30 kg/cm2, respectively. The results showed that immersion in the acid solution can stabilize the dimensions of the resulting particleboard but does not reduce the strength of the board. Several board properties have met the standards, such as density, thickness swelling, modulus of rupture, and internal bond.

The influence of particle soaking in acetic acid and NaOH solutions on the quality of sandwich particleboard from raru wood and belangke bamboo

As a composite product, particleboard has disadvantages related to low dimensional stability. The research purpose was to analyze the effect of immersion in acetic acid and NaOH solution on the quality of the particleboard sandwich. Sandwich particleboard (SPb) was made in a size of 25 cm length and 25 cm width. The target thickness and density are 1 cm and 0.75 g/cm3, respectively. The adhesive used was isocyanate adhesive with a content of 7%. First, The particles, which were in the form of wood shavings and bamboo strands, were soaked in a solution of acetic acid and NaOH at various concentrations (0, 1, 2, and 3%). The moisture content of the particles to be made SPb was set at 7%. After evenly mixing the particles (wood shavings and bamboo strands) and the adhesive, the sheet was created. The board sheets were made into three layers, namely 40% face layer in the form of a bamboo strand, 20% core layer in the form of wood shavings, and 40% back layer in the form of the bamboo strand. The next stage was the hot pressing process at 160 °C for 5 min and 30 kg/cm2 pressure. The following process was conditioning the board for seven days. Testing of quality refers to the standard JIS A5908 (2003). The results showed that the immersion of Raru wood particles in acetic acid and NaOH significantly affected the value of density, water absorption, thickness swelling, modulus of elasticity, modulus of rupture, and internal bond. Except for the moisture content on the AA3 and NA2 boards and the internal bond value on the untreated (control) board, all of the panel properties in this study met the standard.

Dimensional stability and mechanical properties of bio-based composites produced from hydro-thermal treated wheat straw

Bio-composites were produced from untreated (UT) and hydro-thermally treated (HTT) wheat straw (WS) particles and wood, and their dimensional stability and mechanical properties were investigated. The HTT treatment consisted of subjecting the WS particles to a steam explosion process for 8 min at 180 °C. The HTT and UT WS particles were mixed with the wood particles at 10, 20, 30, and 40% ratios. The physical properties, including density, water absorption (WA), and thickness swelling (TS), were determined for the bio-based composites. The mechanical properties evaluated included the modulus of rupture, modulus of elasticity, and internal bond strength. Statistical analyses showed that the hydro-thermal treatment and the WS ratio had significant effects on the dimensional stability and mechanical properties of the bio-composites. The WA of the composites after 2-h and 24-h rose significantly when the HTT WS particle ratio was increased from 10 to 40%. The 2-h and 24-h WA values of HTT-10 were 6.3% and 5.3% lower than those of UT-10, respectively. Improvements in the 2-h TS value were achieved by the HTT WS particles at the 10% ratio, and in the 24-h TS value at the 10 and 40% ratios. The mechanical properties of the composites were higher in the HTT group, but decreased in both the UT and HTT groups as the WS ratio increased.

The influence of particleboard resination on their internal bond strength

The influence of particleboard resination on their internal bond strength. The aim of the project was to investigate the main mechanical and physical properties of particleboards, especially focused on internal bond, in terms of their resination. For the tests, the particleboards have been produced in laboratory conditions with the following glue content: 7, 10, 15, 30 and 50%. Particular attention was paid for examining the mechanical property – tensile strength perpendicular to surfaces (Internal Bond – IB). In addition, there were investigated modulus of elasticity (MOE), modulus of rupture (MOR) density and density profile. In the light of above mentioned tests, there is no positive effect of improvement of tested parameters when raise resination over 30% when producing particleboards. With the resination increase from 7 to 50% a significant change (densification) of panels’ structure, as well as differences between face and core layers density have been found.

Investigation of the use of old railroad ties (Fagus orientalis) and citrus branches (orange tree) in the particleboard industry

Effects of two widely available and underutilized lignocellulosic materials on the mechanical and physical properties of particleboards were investigated in this work. The ratio of mixtures lignocellulosic flakes at four levels (100% aspen wood), (50% aspen wood: 25% citrus: 25% old railroad ties), (50% aspen wood: 50% citrus), and (50% aspen wood: 50% old railroad ties), and the percentage of resin in two levels (8 and 12%) were considered as variable factors. The 100% aspen wood (Populus tremula) was mixed as a control board (100% aspen wood). Then the mechanical and physical properties of the samples including modulus of rupture, modulus of elasticity, internal bond, water absorption, and thickness swelling after 2 h and 24 h of immersion (EN 310-319) and fire resistance (ISO 11925-2) were measured. The results showed that with increasing poplar wood in mixtures, modulus of rupture, modulus of elasticity, internal bond increased, while water absorption and thickness swelling decreased. Also, in comparison with the control boards, the boards that were made by mixing 50% poplar and 50% citrus branches with 12% glue had the highest mechanical strength. The results also showed that increasing the amount of old railroad ties chips in mixing caused a significant decrease in the fire retardancy of the boards.

EFFECTS OF POLYMER ADDITIVES ON SOME MECHANICAL AND PHYSICAL PROPERTIES OF CEMENT BONDED PARTICLEBOARDS

The effects of some polymer additives, also called super plasticizers, on selected physical and mechanical properties of cement bonded particle board were investigated. Two different kinds of poly carboxylic ether (PF300, DX40) and a melamine based polymer (300M) were added to the wood cement mixture. The ratios of polymer additives to the wood cement mixture were 1%, 1.2% and 1.4%. Cement bonded particleboards were manufactured with wood/cement (w/w) ratio of 1:3; target density of 1300 kg.m-3, and CaCl2 content of 5%. The cement bonded particleboards were tested for water absorption (2 and 24 hour), thickness swelling (2 and 24 hour), bending stiffness and strength and internal bond strength. Results of the study showed that most of the polymer addition decreased water absorption and thickness swelling of the boards. Replacement of cement with polymers increased internal bond strength and bending stiffness of the boards while bending strength was slightly reduced. Use of small amount of super plasticizers significantly improves most of the board properties.

Binderless Thermal Insulation Panels Made of Spruce Bark Fibres

Tree bark is a by-product of the timber industry available in large amounts, considering that approximately 10% of the volume of a tree stem is bark. Bark is used primarily for low-value applications such as heat generation or as mulch. To the best of our knowledge, this study is the first one that scrutinises thermal insulation panels made from spruce bark fibres with different densities and fibre lengths manufactured in a wet process. The insulation boards with densities between 160 and 300 kg/m3 were self-bonded. Internal bond, thermal conductivity, and dimensional stability (thickness swelling and water absorption), together with formaldehyde content, were analysed. The thermal properties of the boards were directly correlated with the density and reached about 0.044 W/m*K, while the internal bond was rather influenced by the fibre length and was relatively low (on average 0.07 N/mm2). The water absorption was high (from 55% to 380%), while the thickness swelling remained moderate (up to 23%). The results of this study have shown that widely available bark residues can be successfully utilised as an innovative raw material for efficient eco-friendly thermal insulation products.

Processing parameters optimization of cotton stalk (Gossypium hirsutum L.) particleboards with emulsifiable polymeric isocyanate adhesive

The compaction behavior of cotton stalk particle mats, temperature profile inside the particle mats, and influence of surface particle size were studied relative to the properties of three-layered cotton stalk particleboards. Modulus of rupture (MOR), modulus of elasticity (MOE), internal bond, and thickness swelling were used as a measure for mechanical and physical performance. Two types of cotton stalk particleboard were manufactured. Results indicated that compression stiffness of the particle mat increased with increasing particle size; however, it decreased with increasing mat moisture content and temperature. At mat moisture contents of 12% and 18%, the plateau temperature at the centerline was not significantly different between boards having coarse and fine particles. However, the plateau time of boards with coarse particles was significantly lower than that of boards with fine particles. Additionally, thickness swelling of boards with a surface particle size of 2 mm was significantly lower than that of boards with surface particle size of 4 mm. Boards with a surface particle size of 2 mm had MOR and MOE values 15% and 10% higher, respectively, than boards with surface particle size of 4 mm. Internal bond decreased 6.5% with decreasing surface particle size from 4 mm to 2 mm.