Accelerated weathering and decay resistance of heat-treated wood reinforced polypropylene composites

The aim of this study was to determine the accelerated weathering and decay resistance of the heattreated wood reinforced polypropylene composites (HT-WPC). Polypropylene (PP) was used as a matrix and the heat-treated wood treated at 180 °C and 220 °C as reinforcement filler. The effect of three filler type, such as 40, 60 and 100 mesh, on the outdoor performance of composites was also investigated. The composites were prepared with twin screw extruder, and the test samples were obtained with compression molding. Lightness index (L*), color changes (ΔE*) and physical changes on the surface of the composites after the accelerated weathering, and decay resistance of the composites were investigated. According to the results, the effects of heat-treated wood on color changes were found to be more than its filler size, and while the filler loadings were increased from 5 % to 20 %, it was determined to increase the color changes of the composites. In scanning electron microscopy (SEM) images, crack formation and deterioration on the surface of the composites were determined. In FTIR spectra, no difference was determined between the composites, and all peaks were similar to each one. The addition of heattreated wood improved the antifungal efficiency of the composite, and the mass losses decreased with the increasing of heat treatment temperature. As a result, adding heat-treated wood to PP was found to improve the outdoor performance of the HT-WPCs.

Download Full-text

Color Stability of Heat-Treated Okan Sapwood during Artificial Weathering

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.197-198.13 ◽

2011 ◽

Vol 197-198 ◽

pp. 13-16

Author(s):

Qiang Shi ◽

Jing Hui Jiang

Keyword(s):

Treated Wood ◽

Untreated Wood ◽

Color Stability ◽

Accelerated Weathering ◽

Experimental Conditions ◽

Color Changes ◽

Heat Treated ◽

Series Of Experiments ◽

Xenon Light ◽

Photo Stability

This study describes experiments of testing the color stability of heat-treated okan sapwood samples. Heat-treatment was done at 160°C,180°C,200°C,220°C during 4 hours, under steam. series of experiments were carried out to investigate the color stability of heat-treated okan sapwood compared to untreated wood during 100 hours xenon light irradiation. Color measurements during accelerated weathering were made at intervals throughout the test period. The results are presented in △E* and L* a* b*coordinates according to the CIE(1976)L*a*b* parameters color system. Better photo-stability in terms of color changes was recorded for heat-treated wood compared to the untreated one. The properties of heat treated wood are involved in the heat-treated wood resistanceagainst xenon light under experimental conditions.

Download Full-text

Comparison of the color and weight change in Paulownia tomentosa and Pinus koraiensis wood heat-treated in hot oil and hot air

BioResources ◽

10.15376/biores.16.3.5574-5585 ◽

2021 ◽

Vol 16 (3) ◽

pp. 5574-5585

Author(s):

Intan Fajar Suri ◽

Jong Ho Kim ◽

Byantara Darsan Purusatama ◽

Go Un Yang ◽

Denni Prasetia ◽

...

Keyword(s):

Heat Treatment ◽

Color Change ◽

Treated Wood ◽

Pinus Koraiensis ◽

Weight Changes ◽

Paulownia Tomentosa ◽

Wood Color ◽

Color Changes ◽

Hot Air ◽

Heat Treated

Color changes were tested and compared for heat-treated Paulownia tomentosa and Pinus koraiensis wood treated with hot oil or hot air for further utilization of these species. Hot oil and hot air treatments were conducted at 180, 200, and 220 °C for 1, 2, and 3 h. Heat-treated wood color changes were determined using the CIE-Lab color system. Weight changes of the wood before and after heat treatment were also determined. The weight of the oil heat-treated wood increased considerably but it decreased in air heat-treated wood. The oil heat-treated samples showed a greater decrease in lightness (L*) than air heat-treated samples. A significant change in L* was observed in Paulownia tomentosa. The red/green chromaticity (a*) of both wood samples increased at 180 and 200 °C and slightly decreased at 220 °C. The yellow/blue chromaticity (b*) in both wood samples increased at 180 °C, but it rapidly decreased with increasing treatment durations at 200 and 220 °C. The overall color change (ΔE*) in both heat treatments increased with increasing temperature, being higher in Paulownia tomentosa than in Pinus koraiensis. In conclusion, oil heat treatment reduced treatment duration and was a more effective method than air heat treatment in improving wood color.

Download Full-text

Effects of aluminum sulfate soaking pretreatment on dimensional stability and thermostability of heat-treated wood

European Journal of Wood and Wood Products ◽

10.1007/s00107-020-01616-8 ◽

2020 ◽

Author(s):

Lijie Qu ◽

Zhenyu Wang ◽

Jing Qian ◽

Zhengbin He ◽

Songlin Yi

Keyword(s):

Heat Treatment ◽

Thermal Stability ◽

Thermal Degradation ◽

Structural Changes ◽

Aluminum Sulfate ◽

Treated Wood ◽

Treatment Temperature ◽

Chinese Fir ◽

Heat Treated ◽

Thermal Stability Of

Abstract Acidic aluminum sulfate hydrolysis solutions can be used to catalyze the thermal degradation of wood in a mild temperature environment, and thus reduce the temperature required for heat treatment process. To improve the dimensional and thermal stability of Chinese fir during heat treatment at 120 °C, 140 °C and 160 °C, this study investigated the effects of soaking pretreatment with 5%, 10% and 15% aluminum sulfate on the chemical and structural changes of the heat-treated Chinese fir. The results indicated that the samples treated at 15% aluminum sulfate concentration and 160 °C heat treatment achieved the best dimensional and thermal stability. Chemical analyses by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) indicated that the catalysis of aluminum sulfate resulted in degradation of hemicelluloses during the heat treatment, and an increase in the soaking concentration and heat treatment temperature also affected the thermal degradation of celluloses. The scanning electron microscope (SEM) and mass changes test results proved that the hydrolyzed aluminum flocs mainly adhered to the inner wall of the wood tracheid as spherical precipitates, and when the soaking concentration reached 10% and 15%, a uniform soaking effect could be achieved. The thermogravimetric (TG) analysis revealed the soaking pretreatment effectively improved the thermal stability of the heat-treated wood by physically wrapping and promoting the formation of a carbon layer on the wood surface during heat treatment. Thus, aluminum sulfate soaking pretreatment exerted a great effect on the dimensional and thermal stability of wood, allowing heat treatment to be performed at a lower temperature.

Download Full-text

Mechanical, thermal and morphological properties of heat-treated wood-polypropylene composites and comparison of the composites with PROMETHEE method

Plastics Rubber and Composites ◽

10.1080/14658011.2019.1638132 ◽

2019 ◽

Vol 48 (9) ◽

pp. 389-400 ◽

Cited By ~ 2

Author(s):

Deniz Aydemir ◽

Mizgin Alsan ◽

Ertugrul Altuntas ◽

Ahmet Oztel

Keyword(s):

Treated Wood ◽

Morphological Properties ◽

Polypropylene Composites ◽

Heat Treated ◽

Promethee Method

Download Full-text

The Effects of Residual Lignin Content on Wood Fibre Reinforced Polypropylene Composites

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.29-30.323 ◽

2007 ◽

Vol 29-30 ◽

pp. 323-326

Author(s):

M.D.H. Beg ◽

K.L. Pickering

Keyword(s):

Lignin Content ◽

Streaming Potential ◽

Potential Method ◽

Kraft Pulping ◽

Impact Testing ◽

Wood Fibre ◽

Accelerated Weathering ◽

Residual Lignin ◽

Polypropylene Composites ◽

Twin Screw

This study investigates the effect weathering on composites made from fibre subjected to various stages of a standard Kraft pulping process. Pre-washed, washed and bleached Kraft wood fibre of kappa numbers 27, 17, and 1 was assessed in terms of its surface potential using the streaming potential method and combined with polypropylene (PP) to produce composites. Composites were prepared using a twin screw extruder followed by pelletising and injection moulding. Tensile testing, hardness testing and impact testing were carried out to evaluate the composite mechanical properties. It was found that fibre with higher amounts of residual lignin content led to composites with lower tensile and impact strengths and increased degradability when subjected to accelerated weathering testing.

Download Full-text

Haptic and Aesthetic Properties of Heat-Treated Modified Birch Wood

Forests ◽

10.3390/f12081081 ◽

2021 ◽

Vol 12 (8) ◽

pp. 1081

Author(s):

Vlastimil Borůvka ◽

Přemysl Šedivka ◽

David Novák ◽

Tomáš Holeček ◽

Jiří Turek

Keyword(s):

Thermal Conductivity ◽

Heat Treatment ◽

Heat Capacity ◽

Moisture Content ◽

Thermal Characteristics ◽

Treated Wood ◽

Treatment Temperature ◽

Birch Wood ◽

Positive Perception ◽

Heat Treated

This paper deals with the effect of heat treatment on the selected physical properties of birch wood. Five stages of heat treatment were used, ranging from 160 °C to 200 °C, in 10 °C increments, having a peak treatment duration of 3 h for each level. Primarily, changes in thermal characteristics, namely conductivity, diffusivity, effusivity, volume heat capacity, changes in colour and gloss parameters, mass loss due to modification and different moisture content in wood under given equilibrium climatic conditions, were monitored. The ISOMET 2114 analyser was used to measure the thermal characteristics. The measurement principle of this analyser is based on the analysis of the thermal response of the analysed material to pulses of heat flow. Measurements of colour, gloss, density and moisture content were carried out according to harmonised EN standards. The aim was to experimentally verify the more or less generally known more positive perception of heat-treated wood, both by touch and sight, i.e., the warmer perception of darker brown shades of wood. In terms of thermal characteristics, the most interesting result is that they gradually decrease with increasing treatment temperature. For example, at the highest treatment temperature of 200 °C, there is a decrease in thermal conductivity by 20.2%, a decrease in volume heat capacity by 15.0%, and a decrease in effusivity by 17.7%. The decrease in thermal conductivity is nearly constant at all treatment levels, specifically at this treatment temperature, by 6.0%. The fact mentioned above is positive in terms of the tactile perception of such treated wood, which can have a positive effect, for example, in furniture with surface application of heat-treated veneers, which are perceived positively by the majority of the human population visually or as a cladding material in saunas. In this context, it has been found that the thermal modification at the above-mentioned treatment temperature of 200 °C results in a decrease in brightness by 44.0%, a decrease in total colour difference by 38.4%, and a decrease in gloss (at an angle of 60°) by 18.2%. The decrease in gloss is only one essential negative aspect that can be addressed by subsequent surface treatment. During the heat treatment, there is also a loss of mass in volume, e.g., at a treatment temperature of 200 °C and subsequent conditioning to an equilibrium moisture content in a conditioning chamber with an air temperature of 20 ± 2 °C and relative humidity of 65 % ± 5%, there was a decrease by 7.9%. In conclusion, the experiments clearly confirmed the hypothesis of a positive perception of heat-treated wood in terms of haptics and aesthetics.

Download Full-text

Effects of Heat Treatment on some Physical Properties of Douglas Fir (Pseudotsuga Menziesii) Wood

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.197-198.90 ◽

2011 ◽

Vol 197-198 ◽

pp. 90-95 ◽

Cited By ~ 4

Author(s):

Xian Jun Li ◽

Zhi Yong Cai ◽

Qun Ying Mou ◽

Yi Qiang Wu ◽

Yuan Liu

Keyword(s):

Heat Treatment ◽

Physical Properties ◽

Pseudotsuga Menziesii ◽

Treatment Time ◽

Treated Wood ◽

Untreated Wood ◽

Douglas Fir ◽

Treatment Temperature ◽

Color Changes ◽

Moisture Performance

In this study the effect of heat treatment on some physical properties of Douglas fir (Pseudotsuga menziesii) was investigated. Wood specimens were subjected to heat treatment at 160, 180, 200 and 220°C for 1, 2, 3 and 4h. The results show that heat treatment resulted in a darkened color, decreased moisture performance and increased dimensional stability of wood. Compared with untreated wood, equilibrium moisture content (EMC), water absorption (WA) and volume swelling (VS) for treated wood decrease up to 42.63%, 34.93% and 67.47%. The higher the treatment temperature and the longer the treatment time, the lower EMC, WA and VS. The VS of treated specimens has a more significant reduction than EMC and WA when the heat treatment temperature is above 180°C. The visual color changes were more distinct after heat treatment above 180°C. Temperature has a greater influence than time on these properties of specimens.

Download Full-text

On the Effect of Heat Treatments on the Adhesion, Finishing and Decay Resistance of Japanese cedar (Cryptomeria japonica D. Don) and Formosa acacia (Acacia confuse Merr.(Leguminosae))

Forests ◽

10.3390/f10070586 ◽

2019 ◽

Vol 10 (7) ◽

pp. 586 ◽

Cited By ~ 1

Author(s):

Chia-Wei Chang ◽

Wei-Ling Kuo ◽

Kun-Tsung Lu

Keyword(s):

Shear Strength ◽

Ph Value ◽

Research Work ◽

Treated Wood ◽

Untreated Wood ◽

Japanese Cedar ◽

Decay Resistance ◽

Formaldehyde Resin ◽

Wood Component ◽

Heat Treated

In Taiwan, it is important to maintain sustainable development of the forestry industry in order to raise the self-sufficiency of domestic timber. Japanese cedar (Cryptomeria D. Don and Formosa acacia (Acacia confusa Merr.(Leguminosae)) have abundant storage options and are the potential candidates for this purpose. Heat treatment is a new environment-friendly method used to enhance the dimensional stability and durability of wood. On treatment, a surface with new characteristics is produced because of wood component changes. Consequently, an inactivated surface and a weak boundary layer are generated, and the wettability for adhesives and coatings is reduced. Furthermore, it decreases the pH value of the wood surface, and results in delay or acceleration during the curing of adhesives. This phenomenon must be paid attention to for practical applications of heat-treated wood. Ideal heat-treated conditions of C. japonica and A. confusa woods with productive parameters such as temperature, holding time, heating rate, and thicknesses of wood were identified in our previous study. In this research work, we focus on the normal shear strength of heat-treated wood with adhesives such as urea-formaldehyde resin (UF) and polyvinyl acetate (PVAc), and the finishing performances of heat-treated wood with polyurethane (PU) and nitrocellulose lacquer (NC) coatings as well as assessing the decay-resistance of heat-treated wood. The results show that heat-treated wood had a better decay resistance than untreated wood. The mass decrease of heat-treated wood was only 1/3 or even less than the untreated wood. The normal shear strength of heat-treated wood with UF and PVAc decreased from 99% to 72% compared to the untreated wood, but the wood failure of heat-treated wood was higher than that of the untreated one. Furthermore, the adhesion and impact resistance of wood finished by PU and NC coatings showed no difference between the heat-treated wood and untreated wood. The finished heat-treated wood had a superior durability and better gloss retention and lightfastness than that of the untreated wood.

Download Full-text

Changes in chemistry, color, dimensional stability and fungal resistance of Pinus radiata D. Don wood with oil heat-treatment

Holzforschung ◽

10.1515/hf.2011.117 ◽

2012 ◽

Vol 66 (1) ◽

Cited By ~ 33

Author(s):

Manoj Kumar Dubey ◽

Shusheng Pang ◽

John Walker

Keyword(s):

Pinus Radiata ◽

Dimensional Stability ◽

Linseed Oil ◽

Treated Wood ◽

Wood Properties ◽

Treatment Temperature ◽

Fungal Resistance ◽

Oil Uptake ◽

Remarkable Feature ◽

Heat Treated

Abstract Pinus radiata wood specimens were heat-treated at 160–210°C in linseed oil and the effects of treatment on chemical composition, color, dimensional stability, and fungal resistance were examined. The degradation of hemicelluloses was the most remarkable feature, which is the principal reason for alterations in wood properties. Removal or migration of extractives, oil uptake and the accumulation of oil on the wood surface were observed. The color of heat-treated wood became more uniform and darker, and its dimensional stability (i.e., anti-swelling efficiency) and fungal resistance were improved by up to 60% and 36%, respectively. The viscosity of the oil after treatment was elevated with the treatment temperature and was higher in comparison to heated oil without wood present.

Download Full-text