Influence of press temperature on the properties of binderless particleboard made from oil palm trunk

The objective of this investigation was to evaluate the properties of binderless particleboard manufactured from oil palm trunk as a function of press temperature. Particleboard samples were manufactured with a target density of 0.80 g/cm³ using press temperatures of 160 °C, 180 °C and 200 °C. The modulus of rupture, internal bond strength, water absorption and thickness swelling of the boards were determined based on Japanese Industrial Standards (JIS). Thermal gravimetric analysis, Fourier transform infrared spectroscopy and field-emission scanning electron microscopy coupled with energy dispersive X-ray analysis were employed to characterize the properties of the raw materials and the manufactured panels. The moduli of rupture of the samples were observed to increase with increasing press temperature, but they did not meet the standard values. However, the internal bond strength of the samples attained satisfactory values according to the JIS standard for all three temperature levels. Water absorption and thickness swelling of the boards decreased with increasing pressing temperature. Based on the findings in this study, increasing the pressing temperature may be considered a potential way of improving the properties of binderless particleboard.     

Effect of particle geometry on the properties of binderless particleboard manufactured from oil palm trunk

Experimental binderless composite panels were manufactured using fine particles and strands of oil palm (Elaeis guineensis) trunks. Modulus of rupture (MOR), internal bond strength (IB), dimensional stability, and surface roughness of the panels made with a target density of 0.80 g/cm³ were evaluated. Strand type samples had MOR and IB values of 24.95 and 0.95 MPa, respectively. Corresponding values for the fine particle type samples were 4.04 and 0.49 MPa. Panels made from strands met MOR requirement stated in Japanese Industrial Standard (JIS). Enhanced bonding between strands observed by micrographs taken using scanning electron microscopy (SEM) also supported the findings. However, the samples having fine particles had lower MOR values than minimum requirement listed in JIS. Strand type panels had 41.6% thickness swelling which is only 4.6% lower than that of the panels made from fine particles. It appears that dimensional stability of both types of panels exhibited insufficient results according to JIS. Surface roughness quality of the samples made from fine particles had average surface roughness values comparable to those of panels made in past studies. Based on initial results of this work, raw material from oil palm trunks can have some potential to be used to manufacture binderless panels without using any adhesives. This study revealed that mechanical and physical properties of such experimental panels were influenced by the particle geometry. It would be important to consider possible addition of chemical or wax in the particles to improve their dimensional stability in further studies.     

Properties of steam treated binderless particleboard made from oil palm trunks

The objective of this study was to evaluate both physical and mechanical properties of particleboard panels manufactured from steamed material of oil palm trunks without using any adhesives. Experimental panels from fine particles and vascular strands of oil palm were manufactured. Modulus of rupture (MOR), internal bond strength (IB), thickness swelling (TS) and water absorption (WA) of the samples were tested based on Japanese Industrial Standards. Bonding quality of such binderless samples was also evaluated by using scanning electron microscope (SEM). Based on the findings on this work steaming of the raw material enhanced overall mechanical and physical characteristic of the samples. The highest MOR values of 8.12 MPa and 25.84 MPa were found for the samples made from fine particles and strands steamed at a temperature of 130 °C for 30 min, respectively. It appears that mechanical properties of the panels reduced when they exposed to beyond 30 min steaming time.     

Effect of treated particles on the properties of particleboard made from oil palm trunk

The objective of this work was to evaluate the properties of particleboard made from oil palm (Elaeis guineensis) trunks treated with hot water and sodium hydroxide (NaOH). Experimental panels were manufactured from oil palm particles soaked in hot water for 30 min and soaked in NaOH with 2% concentration for the same time span. Urea formaldehyde adhesive was used for both types of particles as binder. Bending, internal bonding strength, thickness swelling and water absorption of the panels were tested. Scanning electron microscopy and fourier transform infrared spectroscopy were employed to analyze the properties of raw materials and manufactured panels. Based on the findings in this study, samples made with raw material treated with hot water resulted in 863.93 MPa modulus of elasticity and 7.09 MPa modulus of rupture which were higher than those of control panels and made from NaOH treated particles. Internal bond strength of the specimens also followed the similar trend. Both treatments improved the dimensional characteristics of the specimens.     

The potential for using walnut (Juglans regia L.) shell as a raw material for wood-based particleboard manufacturing

In this study, the suitability of walnut shell as a renewable agricultural residue for panel manufacturing was investigated. Particleboards containing different walnut shell particle ratios (0%, 10%, 20%, 30%, 40% and 100%) were made using urea–formaldehyde (UF) resin. Some chemical properties of walnut shell (holocellulose, α cellulose, lignin and ash contents, alcohol–benzene solubility, 1% NaOH solubility, hot and cold water solubility), mechanical (modulus of rupture, modulus of elasticity and internal bond strength) and physical properties (thickness swelling and water absorption) of the particleboard were determined. The addition of walnut shell particles greatly improved the water resistance of the panels. However, flexural properties and internal bond strength decreased with increasing walnut shell particle content. The results indicated that panels can be manufactured utilizing walnut shell particles up to 20% without falling below the minimum EN Standard requirements of mechanical properties for general purpose use. Conclusively, walnut shell, an annual residue, could be utilized with mixture of wood particles in the manufacture of particleboard used for outdoor environments due to lower thickness swelling and water absorption.     

The potential for using walnut (Juglans regia L.) shell as a raw material for wood-based particleboard manufacturing

In this study, the suitability of walnut shell as a renewable agricultural residue for panel manufacturing was investigated. Particleboards containing different walnut shell particle ratios (0%, 10%, 20%, 30%, 40% and 100%) were made using urea–formaldehyde (UF) resin. Some chemical properties of walnut shell (holocellulose, α cellulose, lignin and ash contents, alcohol–benzene solubility, 1% NaOH solubility, hot and cold water solubility), mechanical (modulus of rupture, modulus of elasticity and internal bond strength) and physical properties (thickness swelling and water absorption) of the particleboard were determined. The addition of walnut shell particles greatly improved the water resistance of the panels. However, flexural properties and internal bond strength decreased with increasing walnut shell particle content. The results indicated that panels can be manufactured utilizing walnut shell particles up to 20% without falling below the minimum EN Standard requirements of mechanical properties for general purpose use. Conclusively, walnut shell, an annual residue, could be utilized with mixture of wood particles in the manufacture of particleboard used for outdoor environments due to lower thickness swelling and water absorption.     

Properties of binderless particleboard from oil palm trunk with addition of polyhydroxyalkanoates

This study evaluated the properties of binderless particleboard made from oil palm trunk with addition of polyhydroxyalkanoates in the form of freeze dried and pure samples. Modulus of rupture, internal bonding strength, thickness swelling and water absorption of the boards were evaluated based on Japanese Industrial Standards. Modulus of rupture and internal bonding strength increased as the amount of polyhydroxyalkanoates were increased. Thickness swelling and water absorption decreased with increasing percentage of polyhydroxyalkanoates. The surface roughness, gas chromatography, thermogravimetric analyses, Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy and differential scanning calorimetry were also investigated. Based on the findings in this work, it appears that the addition of polyhydroxyalkanoates enhanced overall properties of such binderless panels.     

Properties of particleboard made from rubberwood using modified starch as binder

The objective of the study was to evaluate physical and mechanical properties of experimental particleboard panels made from rubberwood (Hevea brasiliensis) using modified starch as binder. Panels were manufactured using 15% corn starch modified with glutardialdehyde and tested for their properties based on Japanese Standard. The modulus of rupture and the internal bond strength of the panels met the requirement of the specified standard. Based on the findings in this work modified corn starch can have a potential to be used as binder to produce particleboard panels with acceptable properties.     

Using almond (Prunus amygdalus L.) shell as a bio-waste resource in wood based composite

In this research, the suitability of almond shell as a bio-waste resource in wood based composite manufacturing was investigated. Particleboards containing different almond shell particle rations were made using urea–formaldehyde (UF) resin. Some chemical properties of almond shell (holocellulose, α cellulose, lignin and ash contents, alcohol–benzene solubility, 1% NaOH solubility, hot and cold water solubility), mechanical (modulus of rupture, modulus of elasticity and internal bond strength) and physical properties (thickness swelling and water absorption) of the particleboards were determined. The addition of almond shell particles greatly improved the water resistance of the panels. However, flexural properties and internal bond strength decreased with increasing almond shell particle content. The amount of almond shell particles at most should be 30% in the mixture to meet the standard required for mechanical properties. Conclusively, almond shell, an annual agricultural residue, could be utilized with mixture of wood particles in the particleboard manufacturing.     

Particulate composites based on ionic liquid-treated oil palm fiber and thermoplastic starch adhesive

Pretreatment of lignocellulosic materials is a highly essential and critical task for the manufacturing of engineered composite panels. Recently, ionic liquids (ILs) have emerged as a promising green solvent for lignocellulosic biomass disintegration. In this work, the impact of IL pretreatment on the flexural and thermal properties of the thermo-molded biocomposite panels made from oil palm biomass residue and thermoplastic starch biopolymer as binder was studied. Oil palm fiber was pretreated with IL [emim][dep] (1-ethyl-3-methylimidazolium diethyl phosphate) and IL [bmim][Cl] (1-butyl-3-methylimidazolium chloride) prior to mixing with plasticized starch. The compounded mixture was then hot-pressed into composite panels. To understand the effect of IL pretreatment, lignocellulosic characterization, morphology, and thermogravimetric analysis of the untreated and treated fibers were performed. It was found that thermal stability of the oil palm biomass and the biocomposites was improved after IL pretreatment due to partial removal of hemicellulose and lignin from raw fiber. Moreover, pretreated biocomposites exhibited superior strength and modulus as compared to that of untreated sample as evidenced from flexural testing. The study plainly demonstrates that IL-assisted pretreatment could be an extremely attractive and clean technology for the efficient use of agro-based industrial waste in biocomposite field.     

Novel lignocellulosic hybrid particleboard composites made from rice straws and coir fibers

Novel lignocellulosic hybrid particleboard composites with low cost and high performance using the mixture of rice straws and coir fibers were developed in this work. NaOH (sodium hydroxide) aqueous solution was used to remove the wax and silica layer of rice straw surface. The effects of rice straws/coir fibers (R/C) mass ratios on the physical (thickness swelling) and mechanical (modulus of rupture, modulus of elasticity and internal bond strength) properties of particleboard composites were investigated. The results show that NaOH treatment was an effective method for improving wettability of rice straw surface with smaller contact angles and larger diffusivity–permeability constant. The SEM (scanning electron microscope) observation also gave some evidences such as more rough surface and less number of silica cells after NaOH treatment for improving wettability of rice straw surface. The coir fibers content had a significant negative linear effect on the bending properties and thickness swelling, but a significant positive linear effect on the internal bonding strength due to the lower wax and holocellulose content of coir fiber. When no diisocyanate resin applied, the particleboard composites made with only phenol formaldehyde resin at the optimal R/C ratio satisfied the requirements for load-bearing boards used in dry conditions based on Chinese Standard, indicated that the mixture of rice straws and coir fibers to make high quality particleboard composites was a cost-effective and environment friendly approach.     

Evaluation of mechanical and physical properties of industrial particleboard bonded with a corn flour–urea formaldehyde adhesive

The aim of this study was to determine the effect of corn flour content of urea formaldehyde (UF) resin on the panel properties of particleboard. Corn flour was added to UF resin to decrease the free formaldehyde content of particleboard panels. Some physical (thickness swelling and rheological characterization), mechanical (modulus of elasticity, modulus of rupture, internal bond strength and withdrawal of screws) properties and formaldehyde emission of particleboards were evaluated. The results showed that the introduction of small proportions of corn flour (7%, by weight) in UF resins contributes to the improvement of mechanical and physical properties of the boards and reduced their formaldehyde emissions. Hazardous petrochemical UF could be partially substituted in industrial applications by addition of corn flour. To our knowledge, this is the first study on this kind of wood adhesives.     

Properties of laminated panels made from compressed oil palm trunk

This study evaluated physical and mechanical properties of laminated panels made from compressed oil palm trunk (OPT). The OPT were steamed at 130 °C before being compressed and laminated using polyvinyl acetate adhesive at 250 g/m² and 500 g/m² spread rates. The modulus of rupture and compression strength values of laminated panels made from compressed OPT was greater than those of laminated panels made from uncompressed OPT. Surface roughness, water absorption, and thickness swelling of laminated panels made from compressed OPT significantly improved. The findings in this study indicated that compressing of OPT would be considered as an alternative to produce value-added material with enhanced properties.     

The efficiency of tannin as a formaldehyde scavenger chemical in medium density fiberboard

The aim of this study was to determine the effect of tannin content of urea formaldehyde (UF) resin on the panel properties of medium density fiberboard (MDF). Tannin extracted from the bark of white oak (Quercus alba) was added to UF resin at different ratios (based on the resin) to decrease the free formaldehyde content of MDF panels in this study. It was determined that free formaldehyde values of MDF panels decreased when the ratio of tannin content in UF resin increased. However, the modulus of rupture (MOR), modulus of elasticity (MOE), and internal bond strength (IB) of these panels were a little lower, and the thickness swelling (TS) (24 h) and water absorption (WA) (24 h) values were a little higher compared to the control MDF panels.     

The influence of moisture content of raw material on the physical and mechanical properties,surface roughness,wettability, and formaldehyde emission of particleboard composite

The objectives of this research were to investigate surface characteristics, physical (thickness swelling) and mechanical (modulus of rupture, modulus of elasticity and internal bond strength) properties, and formaldehyde emission of particleboard composite, as affected by moisture content of wood. Three-layered particleboard panels manufactured from wood particles at five different moisture contents (20%, 40%, 60%, 80% and 95%). Roughness measurements, average roughness (R_a), mean peak-to-valley height (R_z), and maximum roughness (R_y), were taken from the sanded samples along and across the sandmarks using a fine stylus tracing technique. Contact angle measurements were obtained by using a goniometer connected with a digital camera and computer system. Statistical analysis showed significant differences in the surface roughness, contact angle, formaldehyde emission, physical and mechanical properties of the panels following moisture content. Based on the findings obtained from this study, an increase or decrease in the moisture content of wood beyond a certain limit, before chipping operations, negatively affected the wettability and smoothness of particles, and formaldehyde emission, physical and mechanical properties of particleboards.     

基于玉米醇溶蛋白胶粘剂的刨花板力学性能

为了开发利用玉米淀粉加工残余物(玉米醇溶蛋白)及制备环境友好刨花板,研究了二氯甲烷、玉米醇溶蛋白、制胶时搅拌温度等因素对基于玉米醇溶蛋白胶粘剂的木刨花板力学性能的影响。结果表明,当溶剂中二氯甲烷的体积百分含量在10%～50%范围内增加时,刨花板的静曲强度、弹性模量、抗拉强度及内结合强度等力学性能均呈现先增加后下降的趋势,当二氯甲烷含量为20%时,刨花板的各项力学性能达到最佳;当玉米醇溶蛋白的百分含量在20%～40%范围内增加时,刨花板的各项力学性能也均呈现先增加后下降的趋势,当玉米醇溶蛋白含量为30%时,刨花板的各项力学性能达到最佳;当制胶温度在25℃～65℃范围内增加时,刨花板的各项力学性能均呈现下降趋势,当温度为25℃时,刨花板的各项力学性能最佳。实验室测得玉米醇溶蛋白胶粘剂制备的刨花板力学性能值达到国家标准(GB4897-2003)。     

Some properties of sandwich type composite panels manufactured from eastern redcedar

This study presents some of the properties of sandwich type of panels made from strands of low quality eastern redcedar (Juniperus virginiana L.) logs and Southern pine fibers. Experimental panels were made at three density levels of 0.60 g/cm³, 0.70 g/cm³ and 0.80 g/cm³ using 9% phenol formaldehyde adhesive based on oven dry weight of the raw material. Mechanical properties including modulus of elasticity, modulus of rupture and internal bond strength of three layer panels in addition to their thickness swelling characteristics were evaluated. Both modulus of elasticity and modulus of rupture of the samples improved with increasing panels density. Thickness swelling of the samples for 2-h and 24-h water soaking ranged from 8.33% to 23.90%. Both physical and mechanical properties of the panels showed acceptable and comparable results to those found in past studies used eastern redcedar and other species to manufacture strand type of product. Having fiber layers on the surface of the panels resulted in smooth surface to comparable to that of typical medium density fiberboard with an average roughness value of 6.42 μm. Based on initial findings of this study it appears that eastern redcedar which is an under-utilized invasive resource can have a potential to be used as raw material for sandwich type panel manufacture.     

Some properties of sandwich type composite panels manufactured from eastern redcedar

This study presents some of the properties of sandwich type of panels made from strands of low quality eastern redcedar (Juniperus virginiana L.) logs and Southern pine fibers. Experimental panels were made at three density levels of 0.60 g/cm³, 0.70 g/cm³ and 0.80 g/cm³ using 9% phenol formaldehyde adhesive based on oven dry weight of the raw material. Mechanical properties including modulus of elasticity, modulus of rupture and internal bond strength of three layer panels in addition to their thickness swelling characteristics were evaluated. Both modulus of elasticity and modulus of rupture of the samples improved with increasing panels density. Thickness swelling of the samples for 2-h and 24-h water soaking ranged from 8.33% to 23.90%. Both physical and mechanical properties of the panels showed acceptable and comparable results to those found in past studies used eastern redcedar and other species to manufacture strand type of product. Having fiber layers on the surface of the panels resulted in smooth surface to comparable to that of typical medium density fiberboard with an average roughness value of 6.42 μm. Based on initial findings of this study it appears that eastern redcedar which is an under-utilized invasive resource can have a potential to be used as raw material for sandwich type panel manufacture.     

A new method of making particleboard with a formaldehyde-free soy-based adhesive

A soy-based formaldehyde-free adhesive consisting of soy flour (SF) and a curing agent (CA) has been successfully used for the production of plywood. However, this adhesive cannot be easily sprayed onto wood particles for making particleboard because of its high viscosity. The following new method of using this adhesive was developed and investigated. SF was first mixed with water to form dilute soy slurry that could be easily coated onto wood particles. The soy-coated wood particles were dried to certain moisture content and then further coated with an aqueous curing agent. Effects of particleboard density, adhesive usages for both core and face particles, the solids content of the soy slurry, hot-press time, hot-press temperature, the storage time of the wet soy-coated wood particles, and the SF/CA weight ratio on the internal bond strength (IB), the modulus of rupture (MOR), and the modulus of elasticity (MOE) of particleboard were investigated.     

Fabrication and characterization of gum Arabic bonded Rhizophora spp. particleboards

Gum Arabic (GA) was used as a binder for the fabrication of Rhizophora spp. particleboards. The physical and mechanical properties of the bioadhesive bonded particleboards, including moisture content, internal bond (IB) strength, thickness swelling (TS), water absorption (WA) and field-emission scanning electron microscopy (FESEM) were used to characterize the manufactured particleboards. Three different particle sizes of the Rhizophora spp. with four adhesive levels were utilized. Results revealed that the addition of GA into the particleboards noticeably improved panel overall properties. The GA bonded particleboards resulted in smoother surfaces, more rigid texture and better internal bonding strength compared to binderless particleboards made without using any adhesive. All specimens had internal bond strength of more than the minimum requirement of the Japanese Industrial Standard JIS A-5908 Type-8 of 0.15 N/mm² and were noticed to increase by increasing the adhesive level. However the GA bonded particleboards had higher percentage of WA and the TS compared with the binderless boards. Microscopic study also revealed that particleboards bonded with the gum had better contact compared to the binderless boards. Based on these results, it could be concluded that gum Arabic is an effective natural substance that could be added to manufacture particleboards to improve some of panels’ physical and mechanical properties.