Dimensional Stability Properties of Medium Density Fibreboard (MDF) from Treated Oil Palm (Elaeis guineensis) Empty Fruit Bunches (EFB) Fibres

The aim of the study was to investigate the effect of pre-treatments by using sodium hydroxide (NaOH) and acetic acid on oil palm Empty Fruit Bunch (EFB) fibres for the production of Medium Density Fibreboard (MDF). The EFB fibres were treated with chemicals in the concentration range of 0.2%, 0.4%, 0.6% and 0.8% prior to refining. Single-homogenous layer MDF with 12 mm thickness and density of 720 kg/m3 was produced. Urea-Formaldehyde (UF) was applied at 10% loading (based on dry weight of dry fibres) as a binder. The physical properties (Water Absorption (WA) and Thickness Swelling (TS)) of the produced panels were tested according to European Standard, EN 622-5:2006. The results show that types of chemical used had greater effects than concentration on the dimensional stability of the MDF. EFB fibres treated with acetic acid produced MDF with better dimensional stability compared to the MDF NaOH treated fibres. High concentration of NaOH produced poor dimensional stability in the panels.

Quantitative study of dimensional stability mechanism and microstructure evolution during precipitation process of 2024Al alloy

In this paper,we were devoted to quantitatively analyzing the dimensional change of 2024 Al alloy during the aging process.Types of precipitates have been defined and the corresponding volume fraction has been measured with Transmission Electron Microscopy(TEM)and Three-Dimensional Atom Probe Tomography(3 D-APT).Guinier-Preston-Bagaryatsky(GPB)zone(0.86 vol.%)was found after aging for 8 h.GPB zone(0.17 vol.%)and S'phase(1.02 vol.%)was found after aging for 24 h.The reduced dimensional change was attributed to the reduction of matrix lattice parameter.Relative to the initial supersaturated solid solution state,the lattice strain of-2.79×10^(-5)and-5.16×10^(-5)was produced after 8 h and 24 h aging respectively.The difference of the lattice parameters between the precipitates and matrix was also considered.A model was established to quantitatively describe the relationship between the precipitation process and dimensional change of 2024 Al alloy.

Influence of Lycra Content and Stitch Length on the Dimensional and Physical Characteristics of Lycra Back Plaited Cotton (LBPC) Single Jersey Fabrics

The physical and dimensional characteristics, i.e. course and wale spacing, stitch density, tightness factor, diameter, porosity, dimensional stability and bursting strength of single jersey knitted items containing lycra yarn with the variations in stitch length and lycra content have been examined and a detail investigation on the lycra filament has been discussed in this study. Six different samples were knitted with identical cotton and lycra yarn but different in lycra contents and stitch length. After conditioning in a controlled environment, all the samples were tested as per the established methods. After analyzing the test results, noticeable effects of variations in stitch length and lycra content on physical and dimensional characteristics of single jersey knitted fabric has been found. As smaller the stitch length and as greater the lycra content, the dimensional stability and bursting strength are better;on the other hand, the air permeability is lower.

Effects of Heat Treatment on Dimension Stability of Larch Pallet Decks

The useful life of wooden pallets is lower because of the defects in lumbers. The quality of lumber can be significantly enhanced by heat treatment. In this paper,the larch pallet decks samples were heat-treated under the conditions of different time and temperatures. The quantity of water uptake has reduced 16. 8% under the condition of 250 ℃ for 150 min. The resistance of water absorption efficiency increases 165. 34% under the condition of 175 ℃ for 90 min. The anti-shrink efficiency increases 72. 08% under the condition of 250 ℃ for 90min. The results showed that the dimension stability of larch panels can be improved by heat treatment. The condition of 250 ℃ for 180 min is the best heat treating condition to improve the dimension stability.

EFFECT OF DIFFERENT DIMENSION STABILIZATION TECHNIQUES ON DIMENSION STABILITY OF SiC_(p)/Al COMPOSITES

The elTcct of different dimension stabilization treatments on the dimension stability of SiC_(p)/Al composites were investigated by the measurement of microyield strength,microcreep properties,dimension,residual stress and analyses of transmission electron microscopy.Results show that the heat cycle dimension stabilization techniques could efficiently decrease the residual stress,stabilize the dimension change,and increase resistance to microplastic deformation.The main reason was that the heat cycle dimension stabilization techniques might form stable dislocation structure in the SiC_(p)/A1 composites.

Characteristics of fast-growing wood impregnated with nanoparticles

Falcataria moluccana or sengon is one of the fast-growing wood species widely grown in Indonesia.However,its wood is low quality with low density,and poor strength,durability,and dimensional stability.This study determined the effects of impregnation with monoethylene glycol(MEG)and nano-SiO2 on the characteristics of sengon wood,including its dimensional stability and density.Impregnation with MEG and nano-SiO2 had a significant effects on dimensional stability in terms of the weight percent gain,anti-swelling efficiency,water uptake,bulking effect,and density.The impregnated wood was examined by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and X-ray diffraction.The results show that MEG and nano-SiO2 were distributed homogeneously into cell walls of wood treated with 0.5%MEGSiO2.

Comparative Study on the Properties of Inorganic Silicate and Organic Phenolic Prepolymer Modified Poplar Wood by Vacuum Cycle Pressurization

To enhance mechanical properties and improve flame retardancy and smoke suppression of fast-growing poplar wood in wood applications,the wood was impregnated and modified.An organic phenolic prepolymer and inorganic sodium silicate was used as contrasting impregnation modifiers and wood samples were impregnated by a bionic“respiration”method with alternating positive and negative pressure.The weight percentage gain,density increase ratio,mechanical properties(bending and compressive strength and hardness),and water absorption rate of inorganic and organic-impregnated modified poplar wood(IIMPW and OIMPW,respectively)were compared and these properties in IIMPW were found to be higher than those of OIMPW with the exception of the water absorption rate which was lower than the OIMPW.This was attributed to the superior absorption of sodium silicate that also improved the impregnation,reinforcement,and dimensional stability in the IIMPW.The chemical structure,crystalline structure,internal morphology,flame retardancy,smoke suppression,and thermal stability of IIMPW and OIMPW were characterized by FT-IR,XRD,SEM,CONE,and TGA.FT-IR and XRD results showed that,although IIMPW cellulose crystallinity reduced the most,more chemical bonds were come into being in IIMPW,which explained the better physical and mechanical properties of IIMPW.Compared with OIMPW,IIMPW had better flame retardant and smoke suppression performance.

Improving the Properties of Fast-Growing Chinese Fir by Vacuum Hot Pressing Treatment

Chinese fir was compressed by vacuum hot pressing and conventional hot pressing at different temperatures(180℃,200℃ and 220℃),respectively.The color parameters of the heat-compressed sample were measured,the relative mechanical properties of the material were tested and changes in the chemistry of fir were investigated using Fourier transform infrared spectroscopy(FTIR)and Xray photoelectron spectroscopy(XPS).The results indicated that the color difference between compressed and untreated wood increased gradually with the increase of temperature.Compared with the conventional hot pressing treatment,the color difference(ΔE*)of the Chinese fir treated by vacuum hot pressing decreased by 43.73%,69.91%,and 77.17%,respectively.The mechanical properties(bending elastic modulus and bending strength)of Chinese fir treated by vacuum hot pressing were significantly improved.The 24-hour water absorption thickness expansion rate of fir treated by vacuum hot pressing is smaller than that of conventional hot pressing.It is implied that vacuum hot pressing treatment is an effective method to produce compressed wood,which can improve the mechanical properties and dimensional stability of wood,and reduce the influence of carbonization on wood color.

具有超高碱性稳定性和尺寸稳定性的聚芳烃N-甲基奎宁基阴离子交换膜

阴离子交换膜水电解槽的阴离子交换膜成本低、无需铂族贵金属催化剂,有望取代高成本的质子交换膜水电解槽.然而,阴离子交换膜的尺寸稳定性差以及在高温、高浓度碱液中的稳定性差,阻碍了阴离子交换膜水电解槽的发展.最近,我们合成了一种具有优异碱性稳定性的聚(三苯基-N-甲基奎宁基)阴离子交换膜,为了进一步提高这种阴离子交换膜的机械强度和尺寸稳定性,在本工作中,我们添加了三氟苯乙酮来制备聚(三苯基-三氟苯乙酮-N-甲基奎宁基)阴离子交换膜.这种共聚阴离子交换膜具有超高的碱性稳定性(在80℃,10 mol L^(-1)的NaOH溶液中浸泡1600小时后OH^(-)电导率和机械强度不发生衰减),优异的尺寸稳定性(30–80℃温度下,纯水中溶胀率不超过7%;10 mol L^(-1)的NaOH溶液中溶胀率不超过2%),高氢氧根电导率(80°C时达134.5 mS cm^(-1))和高机械强度(抗拉伸强度达43.2 MPa).这种阴离子交换膜和镍合金泡沫电极组装的简易水电解槽在80°C下,2.0 V和5 mol L^(-1)的KOH水电解质中具有1780 mA cm^(-2)的优异电流密度,并且具有高耐久性.

Study Situation of Properties and Modification of Masson pine in China

Masson pine(Pinus massoniana) is one of the main pine species in China.It is the most extensively distributed,it is the largest in number,and its use is extensive.This paper deals with the study situation of the property variation of the tree and the effect of external conditions on its properties in China,including pine wood modification(degreasing,mould prevention and improvement of dimensional stability).

Effect of Boron Compounds on Properties of Chinese Fir Wood Treated with PMUF Resin

Plantation Chinese fir wood was modified by low molecular weight phenol melamine urea formaldehyde(PMUF)resin and boron compounds(BB)through a progressive gradual infiltration process.The results showed that the limiting oxygen index(LOI)values,density,dimensional stability and static flexural properties of the PMUF resin treated wood gradually improved with the increase of resin solid content.When boron compounds were additionally introduced into the PMUF resin,the density and the LOI values of the samples of compound modification increased,whereas the anti-swelling efficiency,the modulus of rupture and impact toughness decreased by more than 17.6%,10.1%and 42.9%,respectively.It was demonstrated by X-ray diffraction and Fourier transform infrared spectroscopy that boron compounds could improve the crystallinity of resin modified samples and did not have a chemical reaction with resin or wood.Scanning electron microscope analysis indicated boron compounds made the microstructure of the resin polymers loose,influencing the mechanical properties and dimensional stability of resin modified wood.

Study on Wood Bending Technology

Choosing optimum softening process and exploring the factors affecting dimensional stability and their changing laws can be able to provide technological support for development of curving furniture. The total rubber wood samples were 112 [220 mm (longitudinal) × 17 mm (radial) × 8 mm (tangential)], and they were softened by boiling water and bent through using curved molds in the test. The optimum softening process was selected according to MOR value of the samples. Some affecting factors which influenced the dimensional stability of curving samples were investigated in the optimum softening process, including aging time, final moisture content of the samples, treatment time at a temperature of 100 ℃ and soaking time in water. The results indicate that the optimum softening process is as follows: softening temperature 112 ℃, saturation vapor pressure 0.16 MPa and softening time 3 h. All factors would affect the dimensional stability of curving samples, but the influence of soaking time in water was the most remarkable. When the aging time was 2 h and the final moisture content was 9.8%, the dimensional stability of the curving samples was the best. The chord change of the samples was great in the first 2 hours during heat treating process at a temperature of 100 ℃.

Potential of cellulose-based materials for lithium-ion batteries(LIB)separator membranes

Lithium-ion batteries(LIB)are the dominant power sources for many consumer electronics,and they can also be large-scale power sources/energy storage devices,which can be credited to their advantages:high efficiency,high energy density,long cycling life.The separator membrane is a critical component of LIB.It is an electron insulator between the cathode and anode electrodes in order to prevent electrical short circuits,and it also functions as an ionic conductor to let ions pass freely in the charging and discharging cycles.The critical parameters to meet high quality separator membranes include:high dimensional/thermal/chemical stability,good wettability towards electrolyte,high mechanical strength,appropriate porosity and pore size distribution.Conventionally,plastic materials,such as polyolefin,are the main materials for manufacturing LIB separator membrane.However,polyolefin separator s have a number of drawbacks such as poor thermal stability and wettability.Cellulosic materials have unique properties,and can meet the quality specifications of LIB separator membranes;in addition,they are abundant,low cost,biodegradable,renewable and sustainable.Therefore,cellulose and its related materials can be promising alternatives to replace polyolefin for LIB separator membranes.In this short review,relevant literature on the topic was reviewed and further development/improvement of cellulose-based LIB separator membrane will be discussed.