Reducing formaldehyde emission of urea formaldehyde-bonded particleboard by addition of amines as formaldehyde scavenger

Particleboard is one of the building materials that contribute to the emittance of formaldehyde in enclosed area. In order to reduce the formaldehyde emission from particleboard, amines were added into the urea formaldehyde (UF) resin as formaldehyde scavenger. The amines used were methylamine, ethylamine and propylamine. 0.5, 0.7 and 1% of each type of amine were added into UF resin and the mixtures were used to produce particleboard from rubberwood particles. The properties of the UF resin after addition of amines such as gelation time, viscosity, pH, free formaldehyde content and thermal stability were evaluated. The physical, mechanical properties and formaldehyde emission of the produced boards were also assessed. The results revealed that fully cured amine-containing UF resin possesses higher thermal stability compared to control UF resin. Amine-containing UF resin also had longer gelation time due to higher pH value. Nevertheless, both physical and mechanical properties of the resultant particleboard were negatively affected. Particleboard made from amine-containing UF resin had higher thickness swelling and water absorption. In addition, lower bending strength and internal bonding strength were also recorded. Insufficient pressing time for fully cured of resin might be the reason for such phenomenon. Particleboard with F*** emission level (0.5 ≤ x ≤ 1.5 mg/L) as specified in Japanese Industrial Standard (JIS) or European's E0 class equivalent were achieved when ethylamine and propylamine were added, regardless of dosage used. This study showed the feasibility of using amines as formaldehyde scavenger. However, optimisation of processing parameters is needed to enhance the physico-mechanical properties of the particleboard

Physico-mechanical properties and formaldehyde emission of rubberwood particleboard made with UF resin admixed with ammonium and aluminium-based hardeners

In this study, the effects of addition of ammonium and aluminium-based hardeners into urea formaldehyde resin (UF) on the physico-mechanical properties and formaldehyde emission of the rubberwood particleboard were investigated. Four types of hardeners, namely ammonium chloride (AC), ammonium sulphate (AS), aluminium chloride (AlC) and aluminium sulphate (AlS), were added into UF resin. The acidity, gelation time, viscosity and free formaldehyde content of the UF/hardener mixtures were determined. Particleboard made with the UF/hardener mixtures were tested for physico-mechanical properties and formaldehyde emission. The pH values of the resin after addition of aluminium-based hardeners were higher and resulted in higher viscosity and shorter gelation time. Consequently, despite lower formaldehyde emission was recorded, the physico-mechanical properties of the resulted particleboard were inferior compared to that of ammonium-based hardeners. The best quality particleboard in terms of mechanical, physical and formaldehyde emission were obtained from the particleboard made with AS, followed by AC

Phase-Change-Material-Impregnated Wood for Potential Energy-Saving Building Materials

PCMs (phase change materials) are ideal for thermal management solutions in buildings. This is because they release and store thermal energy during melting and freezing. When this material freezes, it releases a lot of energy in the form of latent heat of fusion or crystallization energy. Conversely, when the material melts, it absorbs the same amount of energy from its surroundings as it changes from a solid to a liquid state. In this study, Oriental spruce (Picea orientalis L.) sapwood was impregnated with three different commercial PCMs. The biological properties and the hygroscopic and thermal performance of the PCM-impregnated wood were studied. The morphology of PCMimpregnated wood was characterized through the use of scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). PCM-impregnated wood demonstrated low performance in terms of storing and releasing heat during phase change processes, as confirmed by DSC. The results show that PCMs possess excellent thermal stability at working temperatures, and the most satisfying sample is PCM1W, with a phase change enthalpy of 40.34 J/g and a phase change temperature of 21.49 ◦C. This study revealed that PCMs are resistant to wood-destroying fungi. After the 96 h water absorption test, the water absorption of the wood samples decreased by 28%, and the tangential swelling decreased by 75%. In addition, it has been proven on a laboratory scale that the PCM material used is highly resistant to biological attacks. However, large-scale pilot studies are still needed

Physico-mechanical properties of laminates made from Sematan bamboo and Sesenduk wood derived from Malaysia’s secondary forest

A study was conducted to evaluate the performance of laminated composite made from phenolic resin-treated wood and bamboo strips. Sesenduk (Endospermum diadenum) wood and Sematan bamboo (Gigantochloa scortechinii) strips were impregnated using 30% phenol formaldehyde (PF) resin and assembled in different configurations and orientations prior to compreg nation. The assembled samples were then compressed in a hot press at 150 ± 2 °C for 60 minutes. Dimensional stability, hardness, bending, shear and compression strength of the products were assessed. The results revealed that the properties of the compreg laminates were significantly affected by the treatment variables. Laminated compreg wood had inferior mechanical properties compared to laminated compreg bamboo and bamboo/wood hybrid. However, the dimensional stability of laminated compreg wood is the best among the three types of laminates. Samples assembled parallelly possessed better properties. Mixed application of wood and bamboo had imparted respective advantages to the compreg laminates

Characterization of the properties of buluh madu (gigantochloa albociliata)

Thirteen bamboo species are reported to be in commercial use in Malaysia. However, Buluh madu (Gigantochloa albociliata) did not make to the list. As a species, G. albociliata is cultivated for its delicious bamboo shoot and is demonstrated to possess great potential to produce commercialised products such as laminated bamboo panel. Unlike common bamboo, which has hollow cylindrical culms, G. albociliata has thick culms at the base, with smaller hollow cavities at the top portion. Therefore, it can be easily converted into high-thickness strips, thus improving the processing efficiency of laminated bamboo. To validate this theory, the anatomical, chemical, physical, and mechanical properties of G. albociliata were evaluated. The round bamboo and strips from the top and bottom sections of the bamboo stem were tested. It was found that G. albociliata has a vascular bundle type similar to that of the Gigantochloa genus bamboo. The fibre in G. albociliata is long and strong. The top section of bamboo has longer fibres, a higher density, and a higher specific gravity than the bottom section. As a result, bamboo from the top section has greater bending strength than bamboo from the bottom section. The G. albociliata species was discovered to have high mechanical strength, dimensional stability, and good wettability, making it an ideal material for laminated products

Performance of laminated compreg oil palm wood (Elaies guineensis Jacq.) associated with the diffusion and compression on polymer loading

Treatment of oil palm wood (Elaeis guineensis) with phenol formaldehyde (PF) resin and subsequently compressing at high hot pressure of oil palm wood is one of the potential ways to enhance its dimensional stability and strength properties. Factors such as molecular weight of PF resin, concentration of PF resin, penetration of PF resin as well as thickness of the material and compression ratio (ratio of the final thickness to the initial thickness of wood) need to be considered for efficient treatment. Study was undertaken to determine the effect of diffusion and compression on polymer loading and performance of laminated compreg oil palm wood (OPW) which had been treated with low and medium molecular weight phenol formaldehyde (LmwPF and MmwPF). OPW strips with 80-100% MC were soaked in LmwPF and MmwPF solutions separately for 24 h. Then, the treated strips were wrapped in plastics and left for diffusion for 2, 4, or 6 days, followed by pre-curing them in an oven at 650C for 6 hours. The pre-cured strips were assembled parallel to each other to form three-layer laminated compreg OPW, followed by compressing them under hot press at 150⁰C for 20 min to compression ratios of 55%, 70% and 80%. Laminated untreated OPW bonded with commercial PF resin served as a control. The polymer loading, dimensional stability, mechanical properties and formaldehyde emission of the compreg laminated wood for each treatment condition were determined. The results showed that, the polymer loading, as indicated by weight percent gain (WPG) of the laminated compreg OPW was significantly affected by the diffusion and compression processes. LmwPG-compreg OPW had higher WPG compared to MmwPG-compreg OPW. Compared to the laminated untreated OPW, the compreg products had superior properties where the LmwPF compreg OPW showed better performance than MmwPF compreg OPW. It was also found that density, anti-swelling efficiency (ASE), mechanical properties and formaldehyde emission of laminated compreg OPW were positively correlated with polymer loading, whilst water absorption and thickness swelling were negatively correlated with polymer loading for both laminated compreg OPW. Formaldehyde emission of the LmwPF laminated compreg OPW was relatively higher while formaldeyhde emission for MmwPF laminated compreg OPW was found within the threshold limit between 0.16 mg/l to 2.0 mg/l

Effects of hardeners and amine compounds on formaldehyde emission from rubberwood/urea formaldehyde particleboard

Urea formaldehyde (UF) bonded-particleboard is one of building materials that contribute to the emittance of formaldehyde in enclosed area. Formaldehyde is classified as a type of carcinogen that can cause health problems. Numerous studies have been conducted to reduce formaldehyde emission from particleboard to meet the standard requirement. However, attempts to lower down the formaldehyde emission are always accompany with the reduction of the board performance. In this study, methods to reduce formaldehyde emission while maintaining it or at least lowering the reduction of properties of UF-bonded particleboard were developed through either incorporating amine compounds in the resin system or through post treatment on the surface of particleboard. Amine compounds act as formaldehyde scavenger, meanwhile and ammonium or aluminium-based compound were used as hardeners to speed up the curing of the resin. Homogenous rubberwood particleboards with nominal dimension of 340 mm by 340 mm by 12 mm (thick) with target density of 650 kg/m3 were produced using the formulated resin system. A preliminary study was first conducted to determine the physical properties of UF adhesive admixed with ammonium or aluminium-based hardeners. The pH and gelation time of this adhesive were found to be lower, but the viscosity was higher compared to the values found in the true UF resin. Adhesive with aluminium-based hardener had lower pH and gelation time with significantly higher viscosity than the adhesive with ammonium-based hardener. The addition of the hardeners was also found to reduce the free formaldehyde content in the adhesive. Particleboard bonded with these adhesives were also found to have low formaldehyde emission. In the second phase of the study, amine compounds, methylamine, ethylamine and propylamine (0.5 to 1% w/v based on solid UF resin) were incorporated in the adhesive mixture. It was found that UF adhesive with the presence of amines possessed higher thermal stability, compared to that without amines. Boards fabricated using these resin systems had very low formaldehyde emission. To further improve the performance of the boards, the pressing time was increased from 270 s to 390 s and UF resin concentration was increased from 8 to 12% and, the results revealed that the reduction of formaldehyde improved significantly with the performance of the board successfully met the standard requirement. Post-treatment of particleboard using amine compounds fabricated with 8% UF resin content and were hot-pressed for 270 seconds at 180 C also was carried out to compare the effect with the previous (add-in) method. The compounds were spread on the surface of the fabricated particleboard with a spread rate of 40 g/m2 to 60 g/m2 and show a substantial reduction in formaldehyde emission value from the board. Generally, post treatment application results showed that the formaldehyde emission was successfully reduced without significantly affecting other properties of the particleboard compare to add-in application with the same processing parameters

A study on the efficiency and effectiveness of the Malaysian anti-corruption commission with special reference to the international commission against corruption, Hong Kong / Muhammad Farhan Abd Ghani, Muhammad Aizat Mohd Zaid and Muhammad Hazwan Mohd Hussin

This research analyzed on the different features of the Malaysian Anti-Corruption Commission (MACC) with the Independent Commission Against Corruption (ICAC), Hong Kong. The differences were scrutinized to identify whether such differences of the features contribute to the efficiency and effectiveness of the MACC. Based on the differences identified, some recommendations were made with the intention to improve the efficiency and effectiveness of the MACC. The first chapter goes into the essences and structures of the research. In the second chapter, it focused on the different features of MACC and ICAC, Hong Kong which leads to their efficiency and effectiveness. The third chapter discussed on the special features of anti-corruption agency from other countries like Singapore, New South Wales and Finland. In the fourth chapter, the researchers outlined the findings of the research based on an interview and several emails from respondents. The research was concluded in the last chapter and some recommendations were made to propose on some improvements that can be imposed to the MACC to ensure its efficiency and its effectiveness in handling corruption in Malaysia

Physical and mechanical properties of wood composite from oil palm (Elaeis guineensis Jacq.) fronds

This study involves the production of wood composite from oil palm fronds (OPF). The aim was to determine the wood composite properties fabricated from three different OPF sections, i.e., bottom, middle and top sections bonded with either phenol formaldehyde (PF) or urea formaldehyde (UF). The results showed that regardless of the type of adhesive used, the wood composite fabricated from the bottom section of OPF produced the best quality properties followed by those fabricated at the middle and top sections. The properties of PF-bonded composites were superior compared to UF-bonded composites. The potential use of OPF as an alternative raw material in the wood-based industries is good

Properties enhancement of oil palm trunk plywood against decay and termite for marine applications

Oil palm trunk (OPT) veneers have the potential to be used in the production of plywood for marine applications. However, OPT is not resistant to fungal decay and termites, limiting its use in the production of marine plywood. As a result, in this study, phenolic resin treatment was used to improve the biological durability of OPT and produce marine grade equivalent (MGE) plywood. The OPT veneer was treated with medium molecular weight phenol formaldehyde (MmwPF) resin. The results showed that MmwPF resin with a solid content of 30% resulted in higher weight percent gain and polymer retention. Veneers treated with 30% MmwPF resin were then pressed for more than 10 min at temperatures above 140 °C. Dimensional stability, shear strength, bending strength, fungal decay resistance, and termite resistance were all tested on the plywood produced. The results of this study revealed that MGE plywood has satisfactory bonding quality and excellent biological durability. Good bending strength was recorded for the MGE plywood with modulus of rupture and modulus of elasticity ranged between 31.03 and 38.85 MPa and 4110 and 5120 MPa, respectively. Rubberwood, as a reference sample in this study, is not durable (Class 5) against white rot fungi and is moderately durable (Class III) against subterranean termite attacks. Interestingly, MGE plywood produced in this study was found very durable (Class 1) against white rot fungi. It is also durable (Class II) and very durable (Class I) against termite attacks, depending on the pressing parameters employed. Based on their outstanding bonding quality, bending strength, and biological durability, the study confirmed the feasibility of OPT plywood for marine applications