Nano-SiO2 filled rice husk/polypropylene composites: Physico-mechanical properties

In this research, reinforcing effect of hybrid filler including rice husk (RH), beech bark (BB) and nano-SiO₂, in polypropylene has been investigated. In the sample preparation, four levels of filler loading were used for waste lignocellulosic materials (55-58 wt.%) and nano-SiO₂ (0-4 wt.%). In order to increase the interphase adhesion, polypropylene grafted with maleic anhydride was added as a coupling agent to all the composites studied. The physical properties, viz. the thickness swelling and water absorption, and mechanical properties, namely, the tensile, flexural and notched Izod impact strengths, of the composites were determined. Generally, high amount of filler content in composites can lead to the reduction of interfacial adhesion between matrix polymer and filler, and it limits their applications. The results showed that while flexural properties and elongation at break were moderately improved by the increase in the amount of filler in the matrix, tensile and Izod impact strengths decreased dramatically. However, the composites had acceptable mechanical strength levels. The mechanical properties of composites filled with RH are generally greater than BB composites. The thickness swelling and water absorption of the composites increased with the increase in the filler loading, but to a negligible extent as compared with the wood-based composites and the solid woods. Nano-SiO₂ addition showed little positive effect on the mechanical properties. It can be concluded from this study that the used waste lignocellulosic materials are attractive reinforcements from the standpoint of their physico-mechanical properties.     

Improving the barrier and mechanical properties of corn starch-based edible films: Effect of citric acid and carboxymethyl cellulose

The films produced from pure starch are brittle and difficult to handle. Chemical modifications (e.g. cross-linking) and using a second biopolymer in the starch based composite have been studied as strategies to produce low water sensitive and relatively high strength starch based materials. A series of corn starch films with varying concentrations (0-20%, W/W) of citric acid (CA) and carboxymethyl cellulose (CMC) were produced by casting method. The effects of CA and CMC on the water vapor permeability (WVP), moisture absorption, solubility and tensile properties were investigated. The water vapor barrier property and the ultimate tensile strength (UTS) were improved significantly (p < 0.05) as the CA percentage increased from 0 to 10% (W/W). At the level of 15% (W/W) CMC, the starch films showed the lowest WVP values (2.34 × 10⁻⁷ g Pa⁻¹ h⁻¹ m⁻¹) and UTS increased from 6.57 MPa for the film without CMC to 16.11 MPa for that containing 20% CMC.     

Mechanical behaviour of composites filled by agro-waste materials

The present paper is concerned with the effect of cork and rice husk ash micro particles fillers on the mechanical properties (flexural resistance, fracture toughness, impact absorbed energy, elastic and viscous moduli) of polyester based composite. Composite sheets were hand molded using weight filler fractions of 1, 2.5, and 5 %. Flexural strength of filled materials was much lower than the polyester matrix, with more pronounced effect for cork powder, decreasing significantly with filler content increases. Fracture toughness decreases also on the filled composites. Using cork powder fracture toughness decreases significantly when filler content increases, while for rice husk ash filler a slight increase was observed. Both fillers improve absorbed impact energy, peaking at about 2.5 % of filler content. Best improvements were obtained using rice husk ash powder, reaching about 30 %. Both fillers increase glass transition temperature and the maximum use temperature and also the elastic modulus compared with polyester. It can be concluded from this study that the used agro-waste materials are attractive reinforcements from the standpoint of their mechanical properties.     

Comparison of composites made from fungal defibrated hemp with composites of traditional hemp yarn

Aligned epoxy-matrix composites were made from hemp fibres defibrated with the fungi Phlebia radiata Cel 26 and Ceriporiopsis subvermispora previously used for biopulping of wood. The fibres produced by cultivation of P. radiata Cel 26 were more cellulose rich (78%, w/w) than water-retted hemp due to more degradation of pectin and lignin. The defibrated hemp fibres had higher fibre stiffness (88–94 GPa) than the hemp yarn (60 GPa), which the fibre twisting in hemp yarn might explain. Even though mild processing was applied, the obtained fibre strength (643 MPa) was similar to the strength of traditionally produced hemp yarn (677 MPa). The fibre strength and stiffness properties are derived from composite data using the rule of mixtures model. The fibre tensile strength increased linearly with cellulose content to 850 MPa for pure cellulose. The fibre stiffness increased also versus the cellulose content and cellulose crystallinity and reached a value of 125 GPa for pure crystalline cellulose.     

Effect of co-monomer ratio in ABS and wood content on processing and properties in wood/ABS composites

Acrylonitrile-Butadiene-Styrene copolymers (ABS) reinforced with wood flour were investigated for rheological, mechanical and thermal properties. Three grades of commercial ABS resin (high flow (HF-ABS), medium impact (MI-ABS) and super high impact (SI-ABS) grades) were characterized using H-NMR and elemental analysis for the determination of co-monomer content. Wood flour from Para rubber trees treated with N-2 (aminoethyl)-3-(aminopropyl) trimethoxy silane was blended with ABS in the melt blending process using a twin-screw extruder. Wood flour contents used in this work were 0.0 %, 9.1 %, and 33.3 % wt. The composites with higher acrylonitrile contents showed higher melt viscosity especially at the low shear rate. Carreau’s model was used for curve-fitting. The extrudate swell ratio of the composites tended to increase at the shear rate of 10–500 s⁻¹ and then decreased dramatically once the shear rate were further applied. Neat ABS and wood/ABS composites with higher butadiene content illustrated a higher swelling ratio. The neat MI-ABS and composites showed the highest ultimate tensile strength and modulus due to the butadiene content effect. As the wood flour loading was increased, the tensile modulus of all ABS composites increased with the sacrifice of the tensile strength of composites. The elongation at break and impact strength were noticeably the highest for wood/SI-ABS composites among all because of the effect of rubbery butadiene content. Thermal stability of plastic in 9.1 % wood in HF-ABS composites was improved compared with the neat HF-ABS due to the low acrylonitrile content.     

Analysis of green hemp fibre reinforced composites using bag retting and white rot fungal treatments

The main objective of this project was to investigate two low cost treatment methods, namely bag retting and treatment with white rot fungi, which could be applied to hemp fibre with low environmental impact to improve its interfacial bonding with polypropylene. Wet chemical analysis, FTIR, scanning electron microscopy (SEM), X-ray diffraction (XRD), zeta potential and single fibre tensile testing were used to characterise the effect of treatment on hemp fibres. It was found that all the treatments increased the tensile strength of composites. White rot fungi Schizophyllum commune (S.com) treated fibre composites had the highest tensile strength of 45 MPa, an increase of 28% compared to composites using untreated fibre.     

Thermoplastic films from wheat proteins

We show that the wheat proteins gluten, gliadin and glutenin can be compression molded into thermoplastic films with good tensile strength and water stability. Wheat gluten is inexpensive, abundantly available, derived from renewable resource and therefore widely studied for potential thermoplastic applications. However, previous reports on developing thermoplastics from wheat proteins have used high amounts of glycerol (30-40%) and low molding temperature (90-120 °C) resulting in thermoplastics with poor tensile properties and water stability making them unsuitable for most thermoplastic applications. In this research, we have developed thermoplastic films from wheat gluten, gliadin and glutenin using low glycerol concentration (15%) but high molding temperatures (100-150 °C). Our research shows that wheat protein films with good tensile strength (up to 6.7 MPa) and films that were stable in water can be obtained by choosing appropriate compression molding conditions. Among the wheat proteins, wheat gluten has high strength and elongation whereas glutenin with and without starch had high strength and modulus but relatively low elongation. Gliadin imparts good extensibility but decreased the water stability of gluten films. Gliadin films had strength of 2.2 MPa and good elongation of 46% but the films were unstable in water. Although the tensile properties of wheat protein films are inferior compared to synthetic thermoplastic films, the type of wheat proteins and compression molding conditions can be chosen to obtain wheat protein films with properties suitable for various applications.     

Composite materials of thermoplastic starch and fibers from the ethanol-water fractionation of bagasse

The aim of this study was to evaluate the potential of the fibrous material obtained from ethanol-water fractionation of bagasse as reinforcement of thermoplastic starches in order to improve their mechanical properties. The composites were elaborated using matrices of corn and cassava starches plasticized with 30 wt% glycerin. The mixtures (0, 5, 10 and 15 wt% bagasse fiber) were elaborated in a rheometer at 150 °C. The mixtures obtained were pressed on a hot plate press at 155 °C. The test specimens were obtained according to ASTM D638. Tensile tests, moisture absorption tests for 24 days (20-23 °C and 53% RH, ASTM E104), and dynamic-mechanical analyses (DMA) in tensile mode were carried out. Images by scanning electron microscopy (SEM) and X-ray diffraction were obtained. Fibers (10 wt% bagasse fiber) increased tensile strength by 44% and 47% compared to corn and cassava starches, respectively. The reinforcement (15 wt% bagasse fiber) increased more than fourfold the elastic modulus on starch matrices. The storage modulus at 30 °C (E_30 °C′) increased as the bagasse fiber content increased, following the trend of tensile elastic modulus. The results indicate that these fibers have potential applications in the development of biodegradable composite materials.     

A preliminary evaluation of matricaria maritimum fibres for polymer reinforcement

This short communication describes results from a preliminary characterization of the dimensions and mechanical properties of matricaria maritimum fibres. The aim is to develop a complementary industrial application of these plants, which are grown along the coast mainly for pharmaceutical use. The fibres are shown to be of small diameter, 5-10 μm, and tubular in form. Nano-indentation on fibres and tensile tests on fibre bundles provide an indication of the mechanical behaviour of these fibres, which are similar to those of sisal (leaf fibre) and miscanthus (grass fibre), and may be interesting for reinforcement of polymer matrix composites.     

Effect of pre-extraction on soda-anthraquinone (AQ) pulping of rice straw

The effect of hot-water and alkaline pre-extraction of rice straw on soda-anthraquinone pulping was carried out. The pre-extraction with hot water at 150 °C for 1 h dissolved 34.7% biomass and the pre-extracted liquor comprised of 16.6% sugars, 6.7% lignin, 6.6% acetic acid and other unknown products. But the pre-extraction with 1% NaOH at 100 °C for 1 h dissolved 10.2% sugars, 5.1% lignin and 10% acetic acid from rice straw. Pre-extracted rice straw was cooked by soda-anthraquinone process with varying alkali charges. The pulp from pre-extracted rice straw was low in kappa number with reduced pulp yield. The drainage resistance (°SR) improved obviously on pre-extraction of rice straw. Pulp strength properties such as the tensile index and the burst index were found to be lower, but the tear index was higher both with hot-water and alkaline pre-extraction. After bleaching, the gaps of the overall pulp yield and strength properties between pre-extracted and non-extracted rice straw became narrower. The alkaline pre-extraction showed improved yield and properties compared with hot-water pre-extracted rice straw.     

Effects of long-term use of sodic water irrigation, amendments and crop residues on soil properties and crop yields in rice-wheat cropping system in a calcareous soil

One of the options to ameliorate the deleterious effects of sodic water irrigation is to apply gypsum to soil. We examined whether the application of organic manures or crop residue can reduce the need for gypsum in calcareous soils. A long-term field experiment with annual rice-wheat cropping rotation was conducted for 15 years (1991-2006) on a non-saline calcareous sandy loam soil (Typic Ustochrept) in northwestern, India. The irrigation water treatments included good quality canal water (CW) and sodic water (SW) with residual sodium carbonate (RSC) of 10 mmol_c L⁻¹ from 1991 to 1999 and of 12.5 mmol_c L⁻¹ from 2000 onwards. Gypsum was applied at 0, 12.5, 25, and 50% of the gypsum requirement (GR), to neutralize RSC of the SW. Three organic material treatments consisted of application of farmyard manure (FYM) at 20 Mg ha⁻¹, Sesbania green manure (GM) at 20 Mg ha⁻¹, and wheat straw (WS) at 6 Mg ha⁻¹. The organic materials were applied every year to the rice crop. Continuous irrigation with sodic water for 15 years without gypsum or organic materials resulted in a gradual increase in soil pH and exchangeable sodium percentage (ESP), deterioration of soil physical properties, and decrease in yields of both rice and wheat. The cumulative yield loss in SW irrigated plots without gypsum and organic materials remained <1.5 Mg ha⁻¹ for up to eight years in the case of rice and up to nine years in the case of wheat. Thereafter, marked increase in pH and ESP resulted in further depression in yields of rice by 1.6 Mg ha⁻¹ year⁻¹ and wheat by 1.2 Mg ha⁻¹ year⁻¹. Application of gypsum improved physical and chemical properties of the soil. The beneficial effects on crop yields were visible up to 12.5% GR in rice and up to 50% GR in wheat in most of the years. All the organic materials proved effective in mobilizing Ca²⁺ from inherent and precipitated CaCO₃ resulting in decline in soil pH and ESP, increase in infiltration rate, and a increase in the yields of rice and wheat crops. Although the application of organic materials resulted in comparable reductions in pH and ESP, the increase in yield with SW was higher for both crops with FYM. Pooled over the last six years (2000-2006), application of FYM resulted in 38 and 26% increase in rice and wheat yields, respectively, over SW treatment; corresponding increases in 50% GR treatment (recommended level) was 18 and 19%. During these years, application of GM and WS increased wheat yields by 20%; for rice, GM resulted in 22% increase compared to 17% in WS amended SW irrigated plots. Combined application of gypsum and organic materials did not increase the yields further particularly in the case of FYM and GM treated plots. This long-term study proves that organic materials alone can be used to solubilize Ca from inherent and precipitated CaCO₃ in calcareous soils for achieving sustainable yields in sodic water irrigated rice-wheat grown in annual rotation. The results can help reduce the dependency on gypsum in sodic water irrigated calcareous soils.     

Development of wheat kernels with contrasting endosperm texture characteristics as determined by magnetic resonance imaging and time domain-nuclear magnetic resonance

Spikes and seeds from diploid ‘einkorn’ wheat Triticum monococcum and two near-isogenic hard and soft common wheat (Triticum aestivum) lines were harvested at regular intervals from 7 days post-anthesis (dpa) and analysed by non-destructive magnetic resonance imaging (MRI) and time domain-nuclear magnetic resonance (TD-NMR). A large amount of free water occurred in rachises, glumes and awns of spikes collected at 7 dpa, and accumulated in the physiologically active cells of the endosperm at 21 dpa. In the final stages of kernel development, awns and seed embryos exhibited a high MR signal due to the presence of free water likely associated with biological activities. TD-NMR relaxation time distributions obtained by discrete exponential fitting, distributed exponential fitting and SLICING multivariate analysis offered detailed information on mobility behaviour of water molecules in developing seeds and were able to differentiate two soft and hard isolines from common wheat cv. Enesco at early stages of seed development.     

Incombustibility,physico-mechanical properties and TVOC emission behavior of the gypsum–rice husk boards for wall and ceiling materials for construction

Rice husk is a by-product of rice milling process, and a great resource as a raw biomass material for manufacturing value-added composite products. One of the potential applications is to use rice husk as filler for manufacturing gypsum–rice husk boards for wall and ceiling materials for construction. We investigated the effect of rice husk, addition on selected physico-mechanical properties, total volatile organic compound (TVOC), and incombustibility, on the gypsum board. With increasing rice husk contents, water and moisture absorption was decreased. Because of the replacement of pore between gypsum particles by rice husk, the moisture absorption was decreased as rice husk adding contents. By rice husk adding, MOR of the gypsum–rice husk boards were increased up to 9.8 MPa at 30 wt%. However, MOR was decreased more than 40 wt% of adding contents. The modulus of elasticity (MOE) showed similar behavior with MOR. However, internal bonding strength (IB) was slightly increased as rice husk adding contents up to 20 wt%, 0.5 MPa and decreased over 20 wt%. The incombustibility of the gypsum–rice husk boards decreased on increasing the rice husk adding content. However, up to 30 wt% of rice husk adding contents board samples was of incombustibility first class. Gypsum particle can be replaced up to 30 wt% by rice husk with incombustibility first class for housing materials. In all cases, TVOC emission factor and formaldehyde emission remained under the ‘Excellent’ grade as defined by Korean Air Clean Association (KACA).     

Dynamic mechanical analysis of randomly oriented short bagasse/coir hybrid fibre-reinforced epoxy novolac composites

Hybrid composites of epoxy novolac reinforced with short bagasse fibres and short coir fibres were prepared. The mechanical and dynamic mechanical properties of these bagasse-coir hybrid fibres reinforced epoxy novolac composites were investigated with reference to different layering patterns of the composites. The tensile properties of the tri-layer composites are recorded higher than those of the bi-layer composites, whereas the flexural properties of the tri-layer composites are lower than bi-layer composites. The tensile strength of the intimate mix composite is comparable with trilayer composite having bagasse as skin material. The effect of layering pattern on storage modulus (E′), damping behavior (tan δ), and loss modulus (E″) was studied as a function of temperature and frequency. The E′ values of the bi-layer composites are recorded lower than those of tri-layer (bagasse/coir/bagasse) and intimately mixed hybrid composites. The minimum E′ value is obtained for the composites made with coir as skin layer. Bi-layer composite shows maximum damping property. The theoretical modeling showed good correlation with experimental results at above glass transition temperature (T _g ), while theoretical model deviates experimental data at lower T _g . The Arrhenius relationship has been used to calculate the activation energy of the glass transition of the composites.     

The implications of land preparation, crop establishment method and weed management on rice yield variation in the rice-wheat system in the Indo-Gangetic plains

The implications of adopting alternative seeding methods for rice and wheat establishment were examined at three geographically separate sites in the rice-wheat system of the Indo-Gangetic plains, across northern India. Rice yields in cultivated plots, established by either wet or dry seeding methods, were evaluated in comparison to yields from zero-tillage plots and under conventional transplanting methods. In the same trials, the effects of crop establishment methods in wheat were assessed both on wheat yields and rice yields. Rice crop establishment methods markedly influenced the emerging weed flora and attainable yields were measured in relation to intensity of weed management. Over four years, average rice grain yields in the absence of weed competition were greatest (6.56 t ha⁻¹) under wet seeding (sowing pre-germinated rice seed on puddled soil), and similar to those from transplanted rice (6.17 t ha⁻¹) into puddled soil, and dry seeded rice after dry soil tillage (6.15 t ha⁻¹). Lowest yields were observed from dry seeded rice sown without tillage (5.44 t ha⁻¹). Rice yield losses due to uncontrolled weed growth were least in transplanted rice (12%) but otherwise large (c. 85%) where rice had been sown to dry cultivated fields or to puddled soil, rising to 98% in dry seeded rice sown without soil tillage. Weed competition reduced multiple rice yield components, and weed biomass in wet seeded rice was six-fold greater that in rice transplanted into puddled soil and twice as much again in dry seeded rice sown either after dry tillage or without tillage. Wheat grain yields were significantly higher from crops sown into tilled soil (3.89 t ha⁻¹) than those sown without tillage (3.51 t ha⁻¹), and also were elevated (5% on average) where the soil had been dry cultivated in preparation for the previous rice crops rather than puddled. The method of wheat cultivation did not influence rice yield. Soil infiltration rates in the wheat season were least where the land had been puddled for rice (1.52 mm h⁻¹), and greater where the soil had been dry-tilled (2.63 mm h⁻¹) and greatest after zero-tillage (3.54 mm h⁻¹).These studies demonstrated at research managed sites across a wide geographic area, and on farmers’ fields, that yields of dry seeded rice sown after dry cultivation of soil were broadly comparable with those of transplanted rice, providing weed competition was absent. These results support the proposition that direct seeding of rice could provide an alternative to the conventional practice of transplanting, and help address rising costs and threats to sustainability in the rice-wheat rotation. Further, analysis of patterns of long-term rainfall data indicated that farmers reliant on monsoon rainfall could prepare fields for dry direct seeded rice some 30 days before they could prepare fields for either transplanting or seeding with pre-germinated seed. Dry, direct seeding of rice contributes a valuable component of an adaptive strategy to address monsoonal variability that also may advance the time of wheat establishment and yield. Whilst the results illustrate the robustness, feasibility and significant potential of direct seeded rice, they also highlight the critical nature of effective weed control in successful implementation of direct seeding systems for rice.     

Extraction, preparation and characterization of cellulose fibres and nanocrystals from rice husk

Cellulose fibres and cellulose nanocrystals were extracted from rice husk. Fibres were obtained by submitting the industrial rice crop to alkali (NaOH) and bleaching treatments. Nanocrystals were extracted from these fibres using sulphuric acid (H₂SO₄) hydrolysis treatment. The material obtained after each stage of the treatments was carefully characterized and its chemical composition was determined. Morphological investigation was performed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Fourier transform infrared (FTIR) spectroscopy showed the progressive removal of non-cellulosic constituents. X-ray diffraction (XRD) analysis revealed that the crystallinity increased with successive treatments. The thermal stability of the rice husk fibres and cellulose nanocrystals was also investigated using thermogravimetric analysis (TGA).     

Some of the mechanical and thermal properties of wheat straw filled-PP composites

The objective of this investigation was to evaluate the mechanical, thermal stability and viscoelastic behaviors of experimental PP composites made from wheat straw and PP-g-MA coupling agent. Four levels of wheat straw, 10, 20, 25 and 30 wt % and two levels of coupling agent, 0 and 3 % wt were mixed with PP in rotary type mixer and injection molding process, respectively. Tensile characteristics and impact strength, thermal gravity and dynamic mechanical and thermal analysis of the samples were evaluated. Based on the results, it was observed that the tensile properties increased and impact strength decreased with the increase in the fiber loading from 10 % to 30 %. Further, the composites treated with PP-g-MA exhibited improved mechanical properties which confirmed efficient fiber-matrix adhesion. DMT analysis showed that the PP composites made of 30 % wheat straw containing 3 % PP-g-MA showed the highest E’ and lowest tan δ than the untreated ones. Also, the thermal stability of wheat straw was lower than PP and as filler content in the composites increased, the thermal stability decreased and the ash content increased.     

Green composites. II. Environment-friendly, biodegradable composites using ramie fibers and soy protein concentrate (SPC) resin

Fully biodegradable and environment-friendly green composite specimens were made using ramie fibers and soy protein concentrate (SPC) resin. SPC was used as continuous phase resin in green composites. The SPC resin was plasticized with glycerin. Precuring and curing processes for the resin were optimized to obtain required mechanical properties. Unidirectional green composites were prepared by combining 65 % (on weight basis) ramie fibers and SPC resin. The tensile strength and Young’s modulus of these composites were significantly higher compared to those of pure SPC resin. Tensile and flexural properties of the composite in the longitudinal direction were moderate and found to be significantly higher than those of three common wood varieties. In the transverse direction, however, their properties were comparable with those of wood specimens. Scanning electron microscope (SEM) micrographs of the tensile fracture surfaces of the green composite indicated good interfacial bonding between ramie fibers and SPC resin. Theoretical values for tensile strength and Young’s modulus, calculated using simple rule of mixture were higher than the experimentally obtained values. The main reasons for this discrepancy are loss of fiber alignment, voids and fiber compression due to resin shrinking during curing.     

Large deformation stress relaxation and compression-recovery of gluten representing different wheat classes

Despite the great variety of physicochemical and rheological tests available for measuring wheat flour, dough and gluten quality, the US wheat marketing system still relies primarily on wheat kernel hardness and growing season to categorize cultivars. To better understand and differentiate wheat cultivars of the same class, the tensile strength, and stress relaxation behavior of gluten from 15 wheat cultivars was measured and compared to other available physicochemical parameters, including but not limited to protein content, glutenin macropolymer content (GMP) and bread loaf volume. In addition, a novel gluten compression–relaxation (Gluten CORE) instrument was used to measure the degree of elastic recovery of gluten for 15 common US wheat cultivars. Gluten strength ranged from 0.04 to 0.43 N at 500% extension, while the degree of recovery ranged from 5 to 78%. Measuring gluten strength clearly differentiated cultivars within a wheat class; nonetheless it was not a good predictor of baking quality on its own in terms of bread volume. Gluten strength was highly correlated with mixograph mixing times (r = 0.879) and degree of recovery (r = 0.855), suggesting that dough development time was influenced by gluten strength and that the CORE instrument was a suitable alternative to tensile testing, since it is less time intensive and less laborious to use.     

Performance of three thermally treated tropical wood species commonly used in Turkey

Thermally modified wood is being increasingly offered in Europe as an alternative to preservative-treated timber. The aim of this study is to determine the change of various physical properties (oven-dry density, air-dry density, weight loss, swelling and anti-swelling efficiency (ASE)), compression strength parallel to grain, colour difference (ΔE), glossiness and surface roughness of sapele (Entandrophragma cylindricum), limba (Terminalia superba) and iroko (Chlorophora excelsa) woods after heat treatment under different temperatures and durations. For this study wood specimens were subjected to heat treatment under atmospheric pressure and air at two different temperatures (160 °C and 180 °C) and two different times (2 h and 4 h). Multiple physical properties (oven-dry density, air-dry density, and swelling), compression strength parallel to the grain and surface roughness of the heat-treated wood and control samples were tested. A stylus method was employed to evaluate the surface characteristics of the samples. Roughness measurements using the stylus method were made in the direction perpendicular to the fiber. Four main roughness parameters which are mean arithmetic deviation of profile (Ra), mean peak-tovalley height (Rz), root mean square roughness (Rq), and maximum roughness (Ry) obtained from the surface of wood were used to evaluate the effect of heat treatment on the surface characteristics of the specimens. Significant difference was found (P = 0.05) between physical and technological properties, and surface roughness parameters (Ra, Rz, Ry, Rq) at two temperatures and two durations of heat treatment. Based on the findings of this study, the results showed that oven-dry density, air-dry density, swelling, compression strength parallel to grain and surface roughness values decreased with increasing treatment temperature and treatment time. Thus, sapele, iroko, and limba wood can be utilized with proper heat treatment techniques for outdoor and indoor applications.