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In this article, a comparative study was carried out on two types of thermosetting and thermoplastic matrices to study the effect of the fiber-matrix interface damage on the behavior of thermosetting and thermoplastic composites reinforced by the same natural alfa and wood fibers. The genetic modeling was based on the probabilistic formalism of Weibull. The results have been compared with those obtained by the nonlinear acoustic technique, the two results found to coincide perfectly. The numerical simulation also shows a good concordance with the real behavior of the materials studied, and shows that thermosetting composites are the most resistant to applied thermal stress by 21% compared to thermoplastic composites. Statistical analysis demonstrates that the correlation coefficient values found are very close to 1 (0.964 and 0.973), these values are very satisfactory, and confirm that the results obtained by the genetic model and the nonlinear acoustic technique are in very good agreement with the statistical analysis data. The experimental work presented by Antoine Le Duigou et al. and the work of Bodros et al. have shown that the use of natural fibers greatly improves the mechanical properties of composite materials.

Sediments remediated with a nature-based solution approach (NBS-sediments) can represent a suitable and affordable alternative to peat as a constituent of growing media for ornamental plant production based on the combination of advanced production efficiency and rational green use of resources, including peat and water. In a greenhouse experiment, the effect of different growing media containing NBS-remediated sediments on two-year-old container grown cherry laurel (Prunus laurocerasus cv. ‘Novìta’) under standard and induced restrictive irrigation was evaluated. Six ternary mixes with different proportion (45:30:25 and 30:20:50 v/v) of peat:pumice:sediment (PE:TS25, PE:TS50), coconut fiber:pumice:sediment (CF:TS25, CF:TS50) and wood fiber:pumice:sediment (WF:TS25, WF:TS50) were tested in comparison to the standard peat:pumice blend (60:40 v/v), commonly used for pot ornamental crops ad used as control (PE, control). Pots were drip irrigated with 200 and 250 cc daily water volume (DWV). Cherry laurels grown in the control showed the lowest sign of stress, maintaining the highest net CO2 assimilation and transpiration rates, however stomatal conductance was reduced compared to PE:TS mixes. On the other hand, photosynthetic performance was strongly depressed by WF:TS25 and WF:TS50 under reduced DWV compared to the control, due to the combined effect of physical properties of the used matrices and reduced water availability. Nevertheless, final biomass production of plants grown on sediment-based growing media was similar to that of control, indicating that photosynthetic performance of plants fully recovered during the cultivation period. Differences in final plant development were negligible when compared to quality standards of marketing categories. Thus, appropriately blended NBS-sediment-based growing media can be used on a larger scale to produce rustic outdoor ornamentals.

All-cellulose composites (ACCs) are manufactured using only cellulose as a raw material. Biobased materials are more sustainable alternatives to the petroleum-based composites that are used in many technical and life-science applications. In this study, an aquatic NaOH-urea solvent system was used to produce sustainable ACCs from wood-based woven textiles with and without the addition of TEMPO-oxidized nanocellulose (at 1 wt.-%). This study investigated the effects of dissolution time, temperature during hot press, and the addition of TEMPO-oxidized nanocellulose on the mechanical and thermal properties of the composites. The results showed a significant change in the tensile properties of the layered textile composite at dissolution times of 30 s and 1 min, while ACC elongation was the highest after 2 and 5 min. Changes in hot press temperature from 70 °C to 150 °C had a significant effect: with an increase in hot press temperature, the tensile strength increased and the elongation at break decreased. Incorporating TEMPO-oxidized nanocellulose into the interface of textile layers before partial dissolution improved tensile strength and, even more markedly, the elongation at break. According to thermal analyses, textile-based ACCs have a higher storage modulus (0.6 GPa) and thermal stabilization than ACCs with nanocellulose additives. This study highlights the important roles of process conditions and raw material characteristics on the structure and properties of ACCs.

International audience; Sustainable production in soilless cultivation systems may be achieved by using recycled organic materials as constituents of growing media (GM) and as organic fertilizers. Synchronizing nutrient releases from organic fertilizer mineralization with plant needs in containerized production is difficult to manage for greenhouse growers. This is further amplified by the diversification of GM constituents, driving microbial activities. We aimed to evaluate how the plant can adapt its nutrition to different organic fertilization strategies and ensure its growth depending on the GM and organic fertilizer types. Ocimum basilicum L. was grown for 60 days in a greenhouse in pots filled with three different GM: 100% peat (Peat); 70% peat and 30% coir fiber (GM1); and 50% coir pith, 25% composted bark, 25% wood fiber (GM2). Two contrasted organic fertilizers were used (horn and a granular fertilizer), mixed to the GM, localized in the pot, or combined with Bacillus sp. inoculation as plant growth-promoting rhizobacteria (PGPR). Standard mineral fertilization mixed to the GM was also used as a control treatment. We investigated basil growth (height, biomass, leaf area, chlorophyll and flavonol contents) as well as nitrogen (N) and phosphorus (P) use efficiencies, from their uptake by the roots to their allocation to the plant organs. Basil performances were mainly affected by the GM type. Peat provided optimal conditions for plant development. In GM1, basil maximized the utilization of available N and P taken up from the GM and reached the highest biomass production. Basil performances were especially low when it was grown on GM2 because of a strong competition for N between microbes and the roots. The fertilizer type, its localization and PGPR inoculation did not affect basil growth or nutrition in peat; these treatments had only little effect on basil grown on GM1 and GM2, and affected its performances differently depending on the GM type. This study provides evidence that fertilization must be thoughtfully managed depending on the GM in organically fertilized systems.Keywords

Reactive chemical modifications have been shown to impart decay resistance to wood. These modifications change hydroxyl availability, water uptake, surface energy, and the nanostructure of wood. Because fungal action occurs on the micro and nano scale, further investigation into the nanostructure may lead to better strategies to prevent fungal decay. The aim of this article is to introduce our findings using small angle neutron scattering (SANS) to probe the effects of chemical modifications on the nanostructure of wood fibers. Southern pine wood fiber samples were chemically modified to various weight percentage gains (WPG) using propylene oxide (PO), butylene oxide (BO), or acetic anhydride (AA). After modification, the samples were water leached for two weeks to remove any unreacted reagents, homopolymers or by-products and then the equilibrium moisture content (EMC) was determined. Laboratory soil-block-decay evaluations against the brown rot fungus Gloeophyllum trabeum were performed to determine weight loss and decay resistance of the modifications. To assist in understanding the mechanism behind fungal decay resistance, SANS was used to study samples that were fully immersed in deuterium oxide (D2O). These measurements revealed that modifying the fibers led to differences in the swollen wood nanostructure compared to unmodified wood fibers. Moreover, the modifications led to differences in the nanoscale features observed in samples that were exposed to brown rot fungal attack compared to unmodified wood fibers and solid wood blocks modified with alkylene oxides.

The aim of the current study was to create a high quality growing medium blend that replaces 70 vol% peat with 40 vol% woody green compost and 30 vol% bark compost and organic fertilizers (i.e., blood meal and chitin), all locally sourced. A range of “woody composts”, i.e., green composts based on feedstock selection with mainly woody material from tree prunings, were produced for this purpose at green compost facilities. First, the woody composts were characterized chemically and biologically, including their microbial biomass and net N release. In comparison with regular green composts or vegetable, fruit and garden (VFG) waste composts, woody composts are more suitable for use in growing media due to their lower pH, EC and inorganic C content; however, the woody compost had a low N mineralization rate. Three types of composts supported a higher microbial biomass than wood fiber or bark compost. The additional mineral N release after 100 days for compost mixed with blood meal was tested for different VFG and green composts. A significantly higher additional net N release was measured for composts with higher initial mineral N concentrations (317 mg Nmin/L) as well as VFG composts (417 mg Nmin/L) than for green composts with a lower initial mineral N concentration (148 mg Nmin/L). In a last step, woody compost, bark compost, wood fiber, coir and peat were mixed in different ratios, resulting in six blends ranging from 100% peat-free to 100% peat. Two batches of woody compost were compared, and the blends were mixed with blood meal or chitin. A strong effect of both the organic fertilizer and the blend composition on the mineral N release was observed, with a clear link between the microbial biomass and the net N release. There was a significant negative correlation between the net change in microbial biomass and the net N release (R = −0.85), which implies that a larger increase in microbial biomass during incubation with the organic fertilizer resulted in less N mineralization. The blends containing woody compost scored better for nitrification activity, as the NH4-N concentrations were lower in these than for the blends without woody compost. For the peat blends, no effect on the microbial biomass was observed after addition of organic fertilizers; mineral N did increase, however. Woody composts have the potential to be used in high vol% in growing media blends, but the blends still need further optimization when supplemented with organic fertilizers.

The project aims to develop a methodology to study the variation in properties of wood polymer composites (WPC’s) with/without surface treatment at different humidity conditions. The project aims to investigate the behavior of biocomposites at 50%, 80%and 100% relative humidity (RH). Also to clarify if the hydrophilization effect helps to preserve the structural integrity of the materials for longer periods at these conditions. The comparison between biocomposites comprising polypropylene (PP) with both untreated wood fibers (WF) or FibraQ (hydrophobic surface-treated wood fibers from Biofiber Tech) was made. The focus was on the mechanical properties, water absorption, macro- and microstructures. The results show that PP comprising FibraQ exhibits lower moisture uptake than the PP comprising untreated WF at high relative humidity conditions. The mechanical properties did not seem significantly affected by the surface treatment at high relative humidity conditions. It is also concluded that since the study only ran for four weeks, there was not enough time to fully understand the influence of moisture uptake over the materials’ properties.

Gelişen teknolojik yenilikler, sürekli iyileştirilen materyal nitelikleriyle beraber günümüz endüstrisinde polietilen, polipropilen, polivinil klorür gibi geleneksel petrol türevi polimerler ve bunlar ile oluşturulan kompozitler oldukça yaygın kullanılan materyaller haline gelmiştir. Ancak bu polimerlerin doğaya verdiği zararlar ile beraber sürdürülebilir bir materyal olamayışı, çevresel bilincin arttığı bilim dünyasında yerine koyulabilecek alternatif malzemelere ilgiyi arttırmıştır. Bu açıdan biyokompozitler konusunda yürütülen çalışmaların sayısı günden güne çoğalmıştır. Özellikle otomotiv endüstrisi, izolasyon, kaplama ve ambalaj endüstrilerinde sıkça kullanılan bu polimerlerin uygulama sonrasında oluşan atık problemi büyük sorun teşkil etmektedir ve çözümü mecburi kılınmıştır. Öte yandan alternatif olma arzusuyla ortaya çıkarılan biyokompozit malzemelerin saf polimer malzemelerden daha hafif olması, mekanik özelliklerinin iyileştirilmiş olması, kolay işlenebilir ve uygulanabilir olması, izolasyon nitelikleri ve akustik özelliklerinin istenilen düzeylere ulaşması gibi önemli bulgular bu malzemere olan ilgiyi daha da arttırmış ve günümüzde başta otomotiv, havacılık, izolasyon olmak üzere sayısız endüstride kullanımı had safhalara ulaşmıştır. Ayrıca mekanik niteliklerinin iyileştirilmiş olması ve yaygın kullanım alanları sebebiyle, polietilen (PE) ve doğal diğer katkılar ile bir arada ortaya çıkarılan yeni biyokompozitler birçok bağımlı mühendislik materyallerine ve endüstride kullanılan bir çok polimer ürünlere alternatif olabilme kapasitesine sahiptir. Yüksek sıkılık performansı ve verimli derecede izolasyon nitelikleri nedeniyle kaz tüyü, tekstilde kullanım alanına sahip doğal bir malzemedir. Bu çalışmada PE matrisli, yüksek izolasyon özelliklerine sahip kaz tüyü ve karaçam odun unu katkılı biyokompozit malzemeler üretilmiş ve yalıtım nitelikleri dahil olmak üzere mekanik başarım özellikleri araştırılmıştır. Bu iki katkılı biyokompozit malzemelerin üretimi ile daha iyi izolasyon özelliklerine sahip ve performansı geliştirilmiş, endüstriyel alanda saf polimerlere alternatif bir malzeme geliştirilmesi amaçlanmıştır. Kaz tüyü lifi ve karaçam odun unu katkılı biyokompozitler her biri ayrı olmak üzere farklı oranlarda numuneler haline getirilmiş ve birbirleri arasında kıyaslanmıştır. Üretilen numuneler ekstrüder (40 L/D) kullanılarak üretilmiş ve ortaya çıkarılan numunelerin mekanik niteliklerini belirlemek amacıyla çekme ve eğilme testleri uygulanmıştır.Üretilen biyokompozit malzemelerin fiziki niteliklerini incelemek için yoğunluk testi, kalınlık artışı ve su absorbe oranı testi, termal özelliklerini belirlemek için TGA analizi, kimyasal bağlarında oluşan gerilmeleri gözlemlemek için FTIR analizi, izolasyon özellikleri için ses yutum katsayısı ölçüm testleri ve ısıl iletkenlik katsayısı testleri yapılmıştır. Sonuç olarak takviye elemanlarının polimere kıyasla eğilme özelliklerini kaydadeğer anlamda iyileştirdiği görülmüştür. Isıl iletkenlik testlerinde ulaşılan sonuçlara göre takviye elemanı arttırıldığında verimli bir malzeme ortaya çıkarılacağı öngörülmüştür. Ses yutum katsayısı testlerinde ise bütün takviye elemanlarının AYPE matrisi için iyileştirici özelliklere sahip olduğu kanıtlanmıştır. Özellikle %7,5 hem odun unu hem kaz tüyü lifi karışımlı biyokompozit ve %2,5 hem odun unu hem kaz tüyü lifi karışımlı biyokompozitlerin ses yutum katsayısını ciddi biçimde arttırdığı gözlemlenmiştir. Bununla beraber takviye elemanları sebebiyle su emme testlerinde beklenen düzeyde su almanın arttığı kaydedilmiştir. Özellikle odun unu ilaveli selülozik malzemeli biyokompozitlerin higroskopik yapısı nedeniyle su alım ve şişme oranlarında daha yüksek değerlere ulaşılmıştır. Çalışma sonucunda elde edilen verilere göre, üretilen biyokompozitler içerisinde yer alan ucuz doğal takviyeler sayesinde saf polimere göre daha iyi mekanik özellikler ve nispeten kabul edilebilir oranda iyi fiziksel özelliklere sahip çevreye duyarlı yeni endüstriyel seçenekler ortaya çıkarılmıştır. Along with developing technological innovations and constantly improving material qualities, traditional petroleum-derived polymers such as polyethylene, polypropylene, polyvinyl chloride and the composites formed with them have become very common materials in today's industry. However, the fact that these polymers cannot be a sustainable material together with the harm they cause to nature has increased the interest in alternative materials that can be replaced in the scientific world where environmental awareness has increased. In this respect, the number of studies on biocomposites has increased day by day. The waste problem that occurs after the application of these polymers, which are frequently used in the automotive industry, insulation, coating and packaging industries, constitutes a major problem and its solution has been made mandatory. Given their good mechanical properties and wide area of application, biocomposites produced in conjunction with polyethylene (PE) and natural reinforcements have the capacity to become an alternative to many conventional engineering materials and polymer products used in the industry. Goose feather is a natural material that has a textile area due to its high filling performance and good insulation skills. In this study, PE matrix produced high insulation goose down and carcass wood flour reinforced biocomposites and its mechanical performance properties, including insulation properties, were studied. With the production of these double-reinforced biocomposite materials, a material alternative to pure polymers is developed in the industrial area with better insulation properties and improved mass performance. Wood and goose feather-reinforced composites were produced in different proportions and compared with double-reinforced composites containing both goose feather and wood flour. Biocomposites were manufactured using 40 L/D double screw extruder, and the biocomposites produced were subject to tapping and bending tests to determine their mechanical properties. In order to examine the physical properties of the biocomposite materials produced, density, thickness increase and water uptake tests have been performed; TGA analysis to determine the thermal properties and sound absorption coefficient measurements and thermal conductivity coefficient tests for insulation properties, FTIR analysis for the chemical bond characterization have been performed. As a result, it was observed that the reinforcement elements significantly improved the bending properties compared to the polymer. According to the results obtained in the thermal conductivity tests, it is predicted that an efficient material will be produced when the amount of reinforcement elements was increased. In the sound absorption coefficient tests, it has been proven that all reinforcing elements have improved properties compared to the LDPE matrix. It has been observed that the sound absorption coefficient of biocomposites with a mixture of 7.5% wood flour and goose fiber and 2.5% both wood flour and goose fiber biocomposites increases significantly. However, it was noted that the level of water absorption increased in the water absorption tests due to the reinforcement elements. Due to the hygroscopic nature of biocomposites especially with wood flour added composite material, higher values were achieved in water absorption and swelling rates. According to the data obtained as a result of the study, with utilization of the inexpensive natural reinforcements in the produced biocomposites, new environmentally friendly industrial options with better mechanical properties and relatively acceptable physical properties have emerged compared to the pure polymer.

During the last decades, attention to energy and environmental problems has significantly grown, along with the development of international and national policies addressing sustainability issues. In the construction sector, one of the most widespread energy efficiency strategies consists of thermal insulation of buildings thanks to external insulating panels. Among these, wood fiber is an insulating material characterized by a natural, eco-sustainable and biodegradable structure, coming from the recycling of waste wood from sawmills. The present study aimed to characterize small test building insulated with wood fiber panels from the thermal point of view, comparing the results with those of an identical, non-insulated reference test building. The experimental campaign highlighted several advantages and an excellent thermal performance provided by the eco-sustainable solution of wood fiber insulating panels: Lower values of the thermal transmittance (−57%), thus ensuring greater stability of the internal air temperature and better values in terms of attenuation (−60% in summer and −74 % in winter) and phase shift (+2 h in summer and +2.28 h in winter) compared to those obtained from the reference building. The material is also equipped with an Environmental Performance Declaration (EPD) that certifies its environmental benefits.

The use of wood-derived materials in soilless substrates for horticultural crop production is increasing; however, there is little information about the effects of wood on the incidence and severity of soilborne diseases of container-grown plants. The objectives of this research were to compare three differently processed wood substrate components blended with sphagnum peat and to investigate the effect of the peat:wood blend ratio on damping-off disease caused by Rhizoctonia solani using radish as a model system. In objective one, raw sphagnum peat was blended with three types of processed pine wood, screw-extruded, twin disc-refined, and hammer-milled, at a volumetric ratio of 70:30 and compared to a 70:30 peat:perlite mix. Radish plants grown in the hammer-milled wood and disc-refined wood had significantly lower damping-off disease severity compared to plants grown in the peat–perlite control. In objective two, sphagnum peat was blended with the three types of processed wood at a volumetric ratio of 90:10, 80:20, and 70:30 and compared to a 70:30 peat–perlite mix. The effect of the blend ratio varied by wood processing type. Higher percentages of Forest Gold and pine tree substrate resulted in lower disease severity. In both objectives, radish plants grown in any of the substrate treatments containing wood infested with R. solani tended to have lower disease severity compared to plants in the control. Results of this study indicate that the blending of processed pine wood-derived components into peat may enhance the natural suppression of damping-off disease of radish. Further research is needed to elucidate the mode of action of wood-derived materials on disease suppression in container-grown crops and to study the effects for other plant pathogens and crop species.

Made available in DSpace on 2021-06-25T10:31:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Wood biomass is an alternative for fossil fuels to produce bioenergy, due to its low cost, renewability and environmental friendliness. In order to use biomass as an energy source, understanding its thermal degradation behavior is highly recommended. This work focuses on the thermal degradation of wood fibers belonging to different species (Pinus elliotti (PIE), Eucalyptus grandis (EUG) and Mezilaurus itauba (ITA)), commonly used by the Brazilian lumber industry. The prediction of their degradation kinetics and overall thermal behavior was performed based on the most common theoretical data using the F-test statistical tool. The most probable degradation mechanism was found to be autocatalytic for all the wood fibers tested, with three different degradation steps. The results obtained were in accordance with the findings recently reported in the literature using other fitting methods. It was found that cellulose is the major contributor to Arrhenius parameters, while hemicelluloses – to reaction order. Federal University for Latin American Integration (UNILA) Postgraduate Program in Mining Metallurgical and Materials Engineering (PPGE3M) Federal University of Rio Grande do Sul, Av. Bento Gonçalves 9500 University of Caxias do Sul (UCS) Campus Sede, R. Francisco Getúlio Vargas Department of Materials and Technology Fatigue and Aeronautic Materials Research Group School of Engineering Sao Paulo State University (UNESP) Department of Materials and Technology Fatigue and Aeronautic Materials Research Group School of Engineering Sao Paulo State University (UNESP) CAPES: 153335/2018-1 CNPq: 153335/2018-1

Peat substrates are well known to become hydrophobic during desiccation, thus degrading their water retention properties. Synthetic wetting agents are commonly incorporated to limit the risk of hydrophobicity, but substrates companies are searching for more sustainable alternatives. To that end, the effect of wood fiber addition in peat-based mixes was measured using contact angles and hydration curves. The study was carried out on two raw materials (white milled peat and wood fiber) and binary mixes. The results showed a shift from hydrophilic to more hydrophobic character with a decrease in the ability to rewet of peat-based substrates in relation to the intensity of drying, whereas wood fiber remained hydrophilic. Increasing wood fiber content in peat-based mixes improved the rehydration efficiency, but with a lower intensity of that measured with synthetic wetting agent addition. Our results highlighted the hydrophilic nature of wood fiber and demonstrated an additional benefit of wood fiber use in peat-based growing media.

Despite the reduced demand for fiber boards, research related to their manufacture is relevant, since the production of wood-based materials significantly contributes to solving the problem of the integrated use of wood raw materials. The paper presents the results of experimental studies reflecting the dependence of the strength characteristics of dry and wet wood fiber boards on the structural and technological parameters of grinding plants of various modifications. The experiments were carried out in laboratory facilities and in the production environment on existing industrial equipment. Based on the results of processing multifactor experiments implemented in a second-order B plan, a mathematical description was obtained of the dependence of the tensile strength during static bending of solid wood fiber boards of the dry and wet production method on the gap between the grinding disks, wear of the segments and the concentration of wood fiber mass. The obtained regression models are adequate to the process and can be applied in practice to predict the strength characteristics of fiberboards depending on the parameters of the grinding process. As a result of the analysis of the calculated and graphical dependences obtained on the basis of studies in the production environment on the existing equipment, it is possible to determine what parameters on the grinding equipment must be set in order to obtain the necessary physical and mechanical properties of the fiberboard., Несмотря на сниженный спрос на древесноволокнистые плиты, исследования, связанные с их изготовлением, являются актуальными, так как производство древесноплитных материалов в значительной мере способствует решению проблемы комплексного использования древесного сырья. В работе приведены результаты экспериментальных исследований, отражающих зависимость прочностных показателей древесноволокнистых плит сухого и мокрого способа производства от конструктивных и технологических параметров размольных установок различной модификации. Эксперименты были реализованы на лабораторных установках и в производственных условиях на действующем промышленном оборудовании. По результатам обработки многофакторных экспериментов, реализованных по В-плану второго порядка, было получено математическое описание зависимости предела прочности при статическом изгибе твердых древесноволокнистых плит сухого имокрого способа производства от зазора между размалывающими дисками, износа сегментов и концентрации древесноволокнистой массы. Полученные регрессионные модели адекватны процессу и могут быть применены на практике для прогнозирования прочностных характеристик древесноволокнистых плит в зависимости от параметров процесса размола. В результате анализа расчетных и графических зависимостей, полученных на основании исследований впроизводственных условиях на действующем оборудовании, можно определить, какие параметры на размольном оборудовании необходимо установить, чтобы получить необходимые физико-механические показатели древесноволокнистой плиты.

Change of relative humidity (RH) in surrounding environment can greatly affect the physical and mechanical properties of wood-based panels. Commercially produced acetylated medium density fiberboard (MDF), Medite Tricoya&reg, was used in this study to predict strength and stiffness under varying humid conditions by separating samples in parallel (//) and perpendicular (&perp, ) to the sanding directions. Thickness swelling, static moduli of elasticity (MOEstat) and rupture (MORstat), and internal bond (IB) strength were measured at three different humid conditions, i.e., dry (35% RH_, standard (65% RH) and wet (85% RH). Internal bond (IB) strength was also measured after accelerated aging test. A resonance method was used to determine dynamic modulus of elasticity (MOEdyn) at the aforementioned humid conditions. Linear regression and finite element (FE) analyses were used to predict the MDF&rsquo, s static bending behavior. Results showed that dimensional stability, MOEstat, MORstat and IB strength decreased significantly with an increase in RH. No reduction of IB strength was observed after 426 h of accelerated aging test. A multiple regression model was established using MOEdyn and RH values to predict MOEstat and MORstat. In both directions (// and &perp, ), highly significant relationships were observed. The predicted and the measured values of MOEstat and MORstat were satisfactorily related to each other, which indicated that the developed model can be effectively used for evaluating the strength and stiffness of Medite Tricoya&reg, MDF samples at any humid condition. Percent errors of two different simulation techniques (standard and extended FE method) showed highly efficient way of simulating the MDF structures with low fidelity.

The goal of the present study was to develop a low-density thermal insulation board using wood fibers and a bio-based adhesive as a binder, which was prepared from a crude glycerol and citric acid mixture. The physical and mechanical properties of insulation boards manufactured using two ratios of crude glycerol and citric acid (1:0.66 and 1:1 mol/mol) and two adhesive contents (14% and 20%) were evaluated. The results show that the insulation boards with a range of density between 332 to 338 kg m−3 present thermal conductivity values between 0.064 W/m-K and 0.066 W/m-K. The effect of adhesive content was very significant for certain mechanical properties (tensile strength perpendicular to surface and compressive strength). The tensile strength (internal bond) increased between 20% and 36% with the increased adhesive content. In contrast, the compressive strength decreased between 7% and 15%. The thermo-mechanical properties obtained of insulation boards such as thermal conductivity, traverse strength, tensile strength parallel and perpendicular to surface, and compressive strength are in accordance with the requirements of the American Society for Testing and Materials C208-12 standard for different uses. The results confirm the potential of crude glycerol and citric acid mixture to be used as an adhesive in the wood fiber insulation boards’ manufacturing for sustainability purposes.

The aim of this study was to investigate the effect of recycling on polypropylene (PP) and wood-fiber thermoplastic composites (WPCs) using a co-rotating twin-screw extruder. After nine extrusion passes microscopy studies confirmed that the fiber length decreased with the increased number of recycling passes but the increased processing time also resulted in excellent dispersion and interfacial adhesion of the wood fibers in the PP matrix. Thermal, rheological, and mechanical properties were studied. The repeated extrusion passes had minimal effect on thermal behavior and the viscosity decreased with an increased number of passes, indicating slight degradation. The recycling processes had an effect on the tensile strength of WPCs while the effect was minor on the PP. However, even after the nine recycling passes the strength of WPC was considerably better (37 MPa) compared to PP (28 MPa). The good degree of property retention after recycling makes this recycling strategy a viable alternative to discarding the materials. Thus, it has been demonstrated that, by following the most commonly used extrusion process, WPCs can be recycled several times and this methodology can be industrially adapted for the manufacturing of recycled products.

In this study, a wood fiber/polylactic acid composite (WPC) filament was used as feedstock to print the WPC part by means of fused deposition modeling (FDM). The morphology and mechanical properties of WPC parts printed at different speeds (30, 50, and 70 mm/s) were determined. The results show that the density of the printed WPC part increased as the printing speed decreased, while its surface color became darker than that of parts printed at a high speed. The printing time decreased with an increasing printing speed, however, there was a small difference in the time saving percentage without regard to the dimensions of the printed WPC part at a given printing speed. Additionally, the tensile and flexural properties of the printed WPC part were not significantly influenced by the printing speed, whereas the compressive strength and modulus of the FDM-printed part significantly decreased by 34.3% and 14.6%, respectively, when the printing speed was increased from 30 to 70 mm/s. Furthermore, scanning electronic microscopy (SEM) illustrated that the FDM process at a high printing speed produced an uneven surface of the part with a narrower width of printed layers, and pull-outs of wood fibers were more often observed on the fracture surface of the tensile sample. These results show that FDM manufacturing at different printing speeds has a substantial effect on the surface color, surface roughness, density, and compressive properties of the FDM-printed WPC part.

Biopolymer-based flame retardants (FR) are a promising approach to ensure adequate protection against fire while minimizing health and environmental risks. Only a few, however, are suitable for industrial purposes because of their poor flame retardancy, complex synthesis pathway, expensive cleaning procedures, and inappropriate application properties. In the present work, wheat starch was modified using a common phosphate/urea reaction system and tested as flame retardant additive for wood fibers. The results indicate that starch derivatives from phosphate/urea systems can reach fire protection efficiencies similar to those of commercial flame retardants currently used in the wood fiber industry. The functionalization leads to the incorporation of fire protective phosphates (up to 38 wt.%) and nitrogen groups (up to 8.3 wt.%). The lowest levels of burning in fire tests were measured with soluble additives at a phosphate content of 3.5 wt.%. Smoldering effects could be significantly reduced compared to unmodified wood fibers. The industrial processing of a starch-based flame retardant on wood insulating materials exhibits the fundamental applicability of flame retardants. These results demonstrate that starch modified from phosphate/urea-systems is a serious alternative to traditional flame retardants.

International audience; Biopolymer-based flame retardants (FR) are a promising approach to ensure adequate protection against fire while minimizing health and environmental risks. Only a few, however, are suitable for industrial purposes because of their poor flame retardancy, complex synthesis pathway, expensive cleaning procedures, and inappropriate application properties. In the present work, wheat starch was modified using a common phosphate/urea reaction system and tested as flame retardant additive for wood fibers. The results indicate that starch derivatives from phosphate/urea systems can reach fire protection efficiencies similar to those of commercial flame retardants currently used in the wood fiber industry. The functionalization leads to the incorporation of fire protective phosphates (up to 38 wt.%) and nitrogen groups (up to 8.3 wt.%). The lowest levels of burning in fire tests were measured with soluble additives at a phosphate content of 3.5 wt.%. Smoldering effects could be significantly reduced compared to unmodified wood fibers. The industrial processing of a starch-based flame retardant on wood insulating materials exhibits the fundamental applicability of flame retardants. These results demonstrate that starch modified from phosphate/urea-systems is a serious alternative to traditional flame retardants.

A novel 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) graft γ-amino propyl triethoxy silane (KH550) was synthesized and introduced on the surface of wood fiber. Finally DOPO-g-KH550 treated wood fiber (DKTWF) was used to prepare DKTWF composite phenolic foams (DKTWFCPF). The structures of DOPO-g- KH550 was acknowledged by Fourier transform infrared (FT-IR) and nuclear magnetic resonance (1H-NMR). The structures of DKTWF were confirmed by FT-IR. Compared with wood fiber, the diffraction peaks’ position was basically unchanged, but the crystallinity was slightly increased and thermal stability were dramatically improved, T5% and Tmax increased by 21.9o and 36.1o respectively. But the char yield (800o) was slightly reduced. With the dosage of DKWF, there were different degrees of improvement including the mechanical properties, flame retardancy and microstructure of DKTWFCPF. Comprehensive analysis, the interfacial compatibility was significantly improved between DKTWF and phenolic resin, and the suitable content of DKTWF was 4%.

Potato contributes highly to the global food security. It is predicted that the production of this crop will be negatively affected by future climatic changes. Application of hydroponics for table potato production can mitigate crop loss in highly vulnerable regions. A preliminary small-scale case-study was performed to test theoretical perspectives of hydroponic production of table potatoes in wood fiber by comparing different fiber types and fertigation strategies. Potatoes were also grown in the field to obtain a reference control. Hydroponic production of potato in a stand-alone wood fiber resulted in ca. 200% higher yield, when compared to standard soil cultivation. However, the quality of the tubers was slightly reduced (lower dry matter content). Productivity of table potatoes was affected by the growing medium and fertigation strategy. Production of potatoes in wood fiber is possible and, in the future, might complement the conventional production systems, or even become an important alternative in locations where in-field cultivation is not possible. Nevertheless, the effect of wood fiber properties and the applied fertigation strategy on yield potential and tuber quality should be further studied. Optimization of these factors will be a topic of a following full-scale research.

In this study, wood plastic composite (WPC) materials were produced using high density polyethylene (HDPE) and wood fiber at various ratios ranging from 40% to 70%. The effects of fiber content on mechanical properties such as tensile strength, bending strength, elasticity modulus and shock resistance of these materials were investigated. In addition, maleic anhydride grafted polyethylene (MAPE) was also added to the materials, which had lowest and highest wood fiber additive, to investigate the effect of the binding agent effect. Composite samples were produced via a laboratory type twin screw extruder and test panels were prepared using hot press molding method. According to the results, the bending, tensile and shock resistances generally decreased with the increasing ratio of wood fiber in the composite material content while modulus of elasticity increased for the sample groups without coupling agent. However, the addition of the coupling agent MAPE into the material content significantly improved the mechanical properties. Especially, the addition of MAPE provided better resistance values than all sample groups without MAPE even for the samples containing 70% wood fiber. As a result, with this study, it has been shown that WPC materials with low cost, light weight, aesthetic appearance and good mechanical properties as well could be produced with high fiber ratio.

In this paper the thermal performance of synthetic and natural insulation materials under real applications are investigated through an experimental activity as well as numerical simulations. During the refurbishment of two houses in Turin (north western Italy) one roof was insulated with a natural material (wood fiber panels) and the other one with a business as usual synthetic material (XPS and polyurethane). An experimental activity was carried out, both during summer and winter seasons, and the results were used to validate a simplified model. During winter, as expected, the strongest influence on the global performance is related to the insulation thickness. As far as the summer season performance is regarded, for smaller roof surfaces, as for the analysed case study, no particular difference was noticed between the two solutions. A better control of the indoor air temperature was evaluated for the wood fiber insulation when applied on a large surface of the roof. In order to define the best cost-benefit retrofit solutions, ad-hoc evaluations need to be performed.

Copyright © 2019 The Author(s). Wood fibers were prepared as core materials for a vacuum insulation panel (VIP) via a dry molding process. The morphology of the wood fibers and the microstructure, pore structure, transmittance, and thermal conductivity of the wood fiber VIP were tested. The results showed that the wood fibers had excellent thermal insulation properties and formed a porous structure by interweaving with one another. The optimum bulk density that led to a low-cost and highly thermally efficient wood fiber VIP was 180 kg/m3 to 200 kg/m3. The bulk density of the wood fiber VIP was 200 kg/m3, with a high porosity of 78%, a fine pore size of 112.8 μm, and a total pore volume of 7.0 cm3·g-1. The initial total thermal conductivity of the wood fiber VIP was 9.4 mW/(m·K) at 25 °C. The thermal conductivity of the VIP increased with increasing ambient temperature. These results were relatively good compared to the thermal insulation performance of current biomass VIPs, so the use of wood fiber as a VIP core material has broad application prospects. Science & Technology Program in Fujian Province of China (2017N3009 ); Science & Technology Innovation Program in Fujian Agriculture and Forestry University of China (CXZX2017375 ).

The thermal performance of wood&ndash, plastic composites (WPCs) with different fiber, different fiber contents, and different lubricants were investigated in this paper. The results show that the thermal degradation temperature, melting temperature, crystallization temperature, crystallinity, and viscosity of WPCs with wood fiber were slightly higher than those of WPCs with floor sanding powder and rice husk. As the wood fiber content increased, the melting temperature and crystallinity of WPCs decreased while the crystallization temperature, viscosity, and pseudoplasticity increased. When the wood fiber content was increased to 60%, the dimensional stability of WPCs tended to be constant, and a higher wood fiber content was not conducive for processing of WPCs. WPCs had a small coefficient of linear thermal expansion at low temperature and demonstrated a good dimensional stability. The presence of lubricant reduced the viscosity and increased the pseudoplasticity of the WPCs, which is advantageous for the dimensional stability of WPCs at low temperature while making it worse for high temperatures.

Lignocellulosic biomass, encompassing cellulose, lignin and hemicellulose in plant secondary cell walls (SCWs), is the most abundant source of renewable materials on earth. Currently, fast-growing woody dicots such as Eucalyptus and Populus trees are major lignocellulosic (wood fiber) feedstocks for bioproducts such as pulp, paper, cellulose, textiles, bioplastics and other biomaterials. Processing wood for these products entails separating the biomass into its three main components as efficiently as possible without compromising yield. Glucuronoxylan (xylan), the main hemicellulose present in the SCWs of hardwood trees carries chemical modifications that are associated with SCW composition and ultrastructure, and affect the recalcitrance of woody biomass to industrial processing. In this review we highlight the importance of xylan properties for industrial wood fiber processing and how gaining a greater understanding of xylan biosynthesis, specifically xylan modification, could yield novel biotechnology approaches to reduce recalcitrance or introduce novel processing traits. Altering xylan modification patterns has recently become a focus of plant SCW studies due to early findings that altered modification patterns can yield beneficial biomass processing traits. Additionally, it has been noted that plants with altered xylan composition display metabolic differences linked to changes in precursor usage. We explore the possibility of using systems biology and systems genetics approaches to gain insight into the coordination of SCW formation with other interdependent biological processes. Acetyl-CoA, s-adenosylmethionine and nucleotide sugars are precursors needed for xylan modification, however, the pathways which produce metabolic pools during different stages of fiber cell wall formation still have to be identified and their co-regulation during SCW formation elucidated. The crucial dependence on precursor metabolism provides an opportunity to alter xylan modification patterns through metabolic engineering of one or more of these interdependent pathways. The complexity of xylan biosynthesis and modification is currently a stumbling point, but it may provide new avenues for woody biomass engineering that are not possible for other biopolymers.

A growing interest in peat alternatives, notably composts, resulted in the renewed interest for a model to predict the effects of mixing potting soil constituents. Our goal was to develop a mixing model which could predict the combination of 2 to 9 constituents. Parameters were EC, pH, nutrients including trace elements, water content at various suction pressures, air content at saturation and degradability. The outcome of the model and the results for measurements on the actual mixtures were compared. Most modeled values came to within 5% of the measured values which is considered acceptable for practise. The problem of interstitial filling is discussed and a parameter based on laboratory compacted bulk density is introduced. It is shown that pH and easily available water cannot yet be effectively modeled. It is argued that degradability and buffer capacity are new parameters of interest.

Due to strong global population growth, and particularly African, the population’s needs in terms of building have to be anticipated. The aim is to develop alternative materials with adequate multiphysical performances and low impact on the environment. This work investigates the elaboration and characterization of composites to be used as constructive partition products (partitions, false ceilings). The selection of raw materials takes into account sustainable development criteria, considering both the local availability of materials and their footprint in terms of resource depletion (recycled or bio-sourced materials). The binders used are plaster, potato starch and cassava starch. The loads are wood fiber, cellulose wadding and paper granules, for an original valorisation in building material. The performances of the developed composites are evaluated from a mechanical, hygric, thermal and fire resistance point of view. This work has shown the feasibility and the interest of such composites. These can in particular be used for their quality of hygric regulator and thermal corrector.; En réponse à une forte croissance démographique mondiale, et notamment africaine, il est nécessaire d’anticiper les besoins de la population en terme de bâtiment. Il s’agit alors de développer des matériaux alternatifs présentant des performances multi-physiques adéquates tout en ayant un faible impact sur l’environnement. Ce travail porte sur l’élaboration et la caractérisation de composites utilisables comme produits constructifs de partition (cloison, faux plafonds). La sélection des matières premières intègre des critères de développement durable, en considérant leur disponibilité locale mais également leur empreinte en terme d’épuisement des ressources (matériaux recyclés ou bio-sourcés). Les liants utilisés sont le plâtre, l’amidon de pomme de terre et l’amidon de manioc. Les charges sont la fibre de bois, la ouate de cellulose et les granules de papiers, pour une valorisation originale en matériau de construction. Les performances des composites développés sont évaluées d’un point de vue mécanique, hygrique, thermique et en terme de résistance au feu. Ces travaux ont montré la faisabilité et l’intérêt de tels composites. Ceux-ci peuvent notamment être utilisés pour leur qualité de régulateur hygrique et de correcteur thermique.

Reducing the pressure drop in biofilters is important for the reduction of the energy consumption of these devices. Usually, the pressure drop increases with time due to the biomass growth within the packing material. The aim of this study was to evaluate the aerodynamic processes in a laboratory-scale wavy lamellar (WL) plate-type biofilter equipped with a capillary system for humidifying the packing material. The packing material of a designed biofilter consisted of wavy polymer plates (WPP) vertically arranged next to each other. The pattern of arrangement of the plates allowed sufficiently large spaces, and therefore, the use of such structure had an impact on a decrease in the pressure drop of the biofilter. WPP were coated with three different kinds of materials, namely (I) wood fiber (WF), (II) non-woven caulking material (NWCM) and WF, and (III) linen material (LM) and WF. The results showed that the composition of the packing material influenced pressure drop of the biofilter. The packing material, which consisted of WPP covered with WF, had the lowest pressure drop compared with the other two packing material compositions. In this study, the experimental results were also compared with the results of the performed mathematical modeling of airflow movement.

In this study, some of the physical and mechanical properties of polypropylene fiber/ wood fiber/ cement composites were investigated. For this aim, three levels of polypropylene fiber, namely 2 wt.%, 3 wt.% and 4 wt.% were mixed with 15 wt.% of wood fiber mixed with cement in a rotary type mixer. The samples were formed by cold press method. Then water absorption, thickness swelling, flexural modulus, flexural strength, and impact strength of the manufactured composites were evaluated according to ASTM standard methods. The results showed that polypropylene fiber exhibited a positive effect on physical and mechanical properties of the wood- cement composites. The physical test results indicated that the hybrid composites containing 4% PP fiber/11% wood fiber exhibited the lowest water absorption and thickness swelling values. The mechanical test results also indicated that greater flexural strength and impact strength can be achieved by addition of 4% polypropylene fiber to wood- cement composites. Also the three point bending test results showed that addition of PP fiber from 2 to 4% decreased flexural modulus of the wood- cement composites, continuously.

To obtain a suitable refining process for Pinus massoniana cellulose fibers (PMCF) and China fir cellulose fibers (CFCF), the effects of the beating gap and the pulp consistency on the physical properties and the morphology of the two cellulose fibers were investigated. The results showed that the physical properties of the PMCF and the CFCF were well affected by the beating gap and the pulp consistency. The CFCF showed a smaller weight-average length and width than that of the PMCF. The CFCF exhibited smaller weight-average length, width, and kink index than the PMCF. It is easy to get the high beating degree, indicating it is more easily to be refined. Additionally, the tensile index and burst index of PMCFP and CFCFP increased with increasing beating degree, while the tear index decreased. Compared to the CFCF, the paper made from PMCF had superior strength properties. Consequently, the PMCF was suitable for refining with a high pulp consistency and a medium beating gap, whereas the CFCF had a medium pulp consistency and a big beating gap.

To develop a wood-based electromagnetic shielding composite, in-situ electroless plating was used to plate nickel onto the surface of expanded graphite (EG) to obtain nickel-plated EG (Ni-EG), and the Ni-EG was mixed with wood fiber to manufacture the composite. The optimal plating formula was as follows: 20 g/L NiSO4·6H2O as the main salt, 60 g/L N2H4·H2O as the reducing agent, 50 g/L Na3C6H5O7·2H2O as the complexing agent, 40 g/L CH3COONa·H2O as the buffering agent, pH value 11, and a temperature of 90 °C. These conditions yielded the highest quality of nickel coating (3.57 g). As EG concentration increased from 2 to 10 g/L, the percentage of the Ni-EG in the composite was 60%, the thickness of the composite was 2 mm, the density was 0.9 g/cm3, the magnetic properties and resistivity of the Ni-EG decreased from 29.5 to 5.57 emu/g and 80.2 to 10.7 mΩ·cm, respectively, and the electromagnetic shielding effectiveness (SE) and the reflectivity of the composite increased from 55 to 60 dB and −3.6 to -1.8 dB, respectively. Consequently, the introduction of nickel is suitable for improving the absorbing performance of Ni-EG/wood fiber composites, leading to better SE in a broad frequency range.

Wood cells constitute the main building block in engineered wood-based materials, whose delimiting property frequently is moisture induced swelling. The hygroexpansion properties of wood cells, technically known as fibers, are used as input in predictive micromechanical models aimed for materials design. Values presented in the literature largely depend on the microfibrillar angle, the geometry of the fiber and limiting modelling assumptions. Synchrotron X-ray micro-computed tomography has recently prompted means for detailed measurements of the geometry of unconstrained individual fibers undergoing moisture-induced swelling, which makes it possible to directly quantify the hygroexpansion properties of the cell wall. In addition to a well-defined three-dimensional geometry, the present approach also accounts for large deformations and the fact that cell-wall stiffness depends on the presence of moisture. A mixed numerical-experimental approach is adopted where a finite-element updating scheme is used to simulate the swelling of an earlywood spruce fiber going from the experimental fiber geometry at 47 % relative humidity to the predicted geometry of the fiber in the wet state at 80 % relative humidity at equilibrium conditions. The hygroexpansion coefficients are identified by comparing the predicted and the experimental three-dimensional fiber geometry in the wet state. The obtained values are 0.17 strain per change in relative humidity transverse to the microfibrils in the cell wall, and 0.014 along the microfibrils.

Herein, a novel process of diesel exhaust purification by non-thermal plasma combined with wood fiber has been investigated to understand the effect of purification efficiency on the emission. The dielectric barrier discharge (DBD) and wood fiber (WF) improved removal efficiency of nitrogen oxide (NOx) owing to the positive activity of oxygen-containing functional groups (such as O&ndash, H groups or C&ndash, O groups) on the wood surface, which promoted the removal of NOx by 10%&ndash, 13%. The mechanism to remove NOx in the presence of wood fibers was also deduced through FTIR spectra. When carbon black was loaded on the wood fiber, there was simultaneous removal of carbon soot and NOX. Although complete purification was not achieved, a high purification efficiency was obtained under the conditions of room temperature and no catalysts. These advantages highlight the importance of use of wood and non-thermal plasma (NTP), and this research work opens new avenues in the field of emissions treatment.

Recycling of construction and demolition waste (CDW) which contains materials with high resource value such as plastics, metals, wood, glass and concrete has been investigated in recent years due to tightening environmental legislation. Wood-plastic composites as an environmentally friendly material provide a possibility to enhance the recycling of material. The effect of the addition of CDW on the mechanical and moisture properties of WPC is studied in this paper. Three types of wood-plastic composites were manufactured with different amounts and composition of a CDW filler. Their properties were compared to the reference composite manufactured with virgin wood fibers and polypropylene as the polymer. It was found that the addition of the CDW filler weakened the mechanical properties of the composite generally, except for the fact that the Charpy impact strength was improved significantly. Minor variations in the composition of the CDW filler did not have an impact on the mechanical properties, but an increase in the amount of filler increased the deterioration of mechanical properties. For moisture properties, the addition of the CDW filler decreased the water absorption and thickness swelling of the composites. An increase in the filler content improved the thickness swelling more significantly than water absorption. Post-print / Final draft

Medium-density fi berboards (MDF) were produced, using two different resins of urea-formaldehyde (UF) and phenol-formaldehyde (PF) at 10 % and 8 % contents, respectively. In order to find new source of raw material to satisfy the increasing need of composite manufacturing industry, 10 % of chicken feather was added to the furnish. Moreover, nano-clay was added to investigate its potential improving effects on MDF panel properties. Results showed that panels with PF resin demonstrated significantly lower water absorption and thickness swelling values in comparison to the panels with UF resin. However, mechanical properties of panels containing UF resin were generally higher; this was partially attributed to the higher resin content. It was concluded that panels with PF resin are recommended for applications where panels may be more exposed to water and vapor. In cases where the mechanical properties are of prime importance, panels with UF resin are more preferable. NC can be recommended in panels containing UF-resin to improve the properties, while it is not recommended in panels with PF-resin. Moreover, chicken feather can be included in MDF furnish to provide part of raw materials, though its addition can have diminishing effect on the properties to some extent., Ploče vlaknatice srednje gustoće (MDF) izrađene su uz dodatak dviju različitih smola, ureaformaldehidne (UF) i fenolformaldehidne (PF), i to u udjelu od 10 odnosno 8 %. Kako bi se pronašao novi izvor sirovine i pritom zadovoljile povećane potrebe industrije kompozitnih materijala, smjesi sirovine za izradu ploča vlaknatica dodano je 10 % pilećeg perja. Nadalje, dodana joj je i nanoglina da bi se istražilo moguće poboljšanje MDF ploča. Rezultati su pokazali da su ploče s PF smolom znatno slabije upijale vodu i da im je debljinsko bubrenje u odnosu prema pločama s UF smolom bilo manje. Međutim, mehanička svojstva ploča koje su sadržavale UF smolu u osnovi su bila bolja, što je djelomično povezano s većim udjelom smole. Zaključeno je da se ploče s PF smolom preporučuju za primjenu u uvjetima veće izloženosti vodi i pari. Kada su, pak, važnija mehanička svojstva ploča, pogodnije su one s UF smolom. Nanoglina se preporučuje za poboljšanje svojstava ploča koje sadržavaju UF smolu, a ne preporučuje se za ploče s PF smolom. Nadalje, pileće se perje može dodati sirovini za izradu MDF ploča iako ono može donekle pridonijeti pogoršanju svojstava ploče.

The present study analyzed the effect of nanographene (NG) application at three rates (0.75, 1.5, and 3 %) on the production of PLA85/F15 and PLA70/F30 composites. The incorporation of NG into the PLA/wood fi ber composites significantly improved the tensile and bending properties. The results indicated that composites made from PLA68.5/F30/NG1.5 had the highest tensile and bending properties. Furthermore, it was revealed that the addition of fi bers to PLA decreased the composite impact strength in comparison with pure PLA, whereas the addition of NG improved its impact strength, but not as much as pure PLA. The highest impact strength was observed in the composites containing 15 % fi bers and 1.5 % NG (PLA83.5/F15/NG1.5 composites). The composites made from 30 % wood fiber and 1.5 % (PLA68.5/F30/NG1.5 composites) NG had the best interfacial surface between the wood fiber and the matrix of composites., U radu je analiziran učinak nanografena (NG), dodanoga u različitim količinama (0,75, 1,5 i 3 %), na svojstva kompozita proizvedenih od polilaktične kiseline (PLA) i drvnih vlakana (F) (kompoziti PLA85/F15 i PLA70/F30). Ugradnjom NG-a u kompozite PLA/F znatno su poboljšana vlačna i savojna svojstva kompozita. Rezultati su pokazali da su kompoziti s dodatkom 1,5 % NG-a (PLA68.5/F30/NG1.5) imali najbolja vlačna i savojna svojstva. Nadalje, iz rezultata se može zaključiti da se dodavanjem drvnih vlakana u PLA smanjuje otpornost kompozita na udarce u usporedbi s čistim PLA, a dodavanjem NG-a poboljšava se otpornost kompozita na udarce. Međutim, ta je otpornost i dalje manja od otpornosti kompozita od čistog PLA. Najveća otpornost na udarce zabilježena je za kompozite koji sadržavaju 15 % drvnih vlakana i 1,5 % NG-a (kompoziti PLA83.5/F15/NG1.5). Kompoziti proizvedeni od 30 % drvnih vlakana i 1,5 % NG-a (kompoziti PLA68.5/F30/NG1.5) imali su najbolju površinu između drvnih vlakana i matrice kompozita.

International audience; This work aims understanding the influence of the size distribution of wood flour particles on the physical and mechanical properties of an extruded wood plastic composite (WPC). A industrial-scaled process has been tested for both the wood flour production and the composite forming. Three size distributions of wood flour have been produced from the same batch of wood chips. The analyses of the particle size and form for the three wood flours were carried out by sieve column and by image analysis, revealing the limits of sieving in the case of particles with a high aspect ratio. The present study investigates the influence of the wood flour size distribution on the tensile and flexural behavior of WPC. The Charpy impact behavior of HDPE-WPC is also studied. In addition to the industrial process, the originality of this work lies in relating the microstructure to the mechanical performances of the extruded WPC; especially the orientation of the wood particles that differs according to the size distribution of the wood flour used. In general, mechanical performances of composites are improved by adding large particles. However, in the transverse direction to the extrusion, fine wood flour allows better performances. (C) 2017 Elsevier Ltd. All rights reserved.

Effect of silver nanoparticles on hardness in medium-density fiberboard (MDF) was studied here. A 400 ppm aqueous nanosilver suspension was used at three consumption levels of 100, 150, and 200 mL kg-1, based on the dry weight of wood fibers; the results were then compared with the control panels. The size range of silver nanoparticles was 30-80 nm. Composite mats were hot-pressed for 6, 8, and 10 min. Results showed that the uniform and even dispersion of nanoparticles throughout the MDF-matrix significantly contributed to an increase in the hardness at lower hot-press time of 6 min. In the longer hot-press times, however, over-heating of the mat resulted in significant a decrease of hardness values. Significant high correlation was observed between water absorption and thickness swelling.

Maleic anhydride (MAH) was used as the grafting monomer, which was prepared by melt grafting reaction in the twin screw extruder with dicumyl peroxide (DCP) as the initiator, polylactic acid grafted with maleic anhydride (MAH-g-PLA) was successfully prepared as the interface compatibilizer. The PLA/Wood fiber/MAH-g-PLA composites were prepared by melt blending and injection molding with different proportions of compatibilizer added, within which PLA was for the matrix phase and wood fiber was for the reinforcing phase. The crystallinity, microstructure, thermal stability and dynamic thermomechanical property of the composites were studied by X-ray diffraction (XRD), scanning electron microscope (SEM), thermo gravimetric analyzer (TGA) and dynamic mechanical thermal analysis (DMA). Furthermore, the mechanical and water absorption properties of the composites were also characterized. Results showed that the tensile strength and flexural strength of the composites attained the highest at 30% MAH-g-PLA added, where the crystallinity of the composites also showed the highest value. DMA results showed that the addition of MAH-g-PLA interfacial compatibilizer increased the loss modulus of the composites and improved the toughness. Scanning electron microscopy (SEM) showed that when the MAH-g-PLA was used, wood fiber is well dispersed in the PLA matrix phase, and that the interfacial compatibility between the matrix and the enhanced phase was improved. Therefore, the addition of MAH-g-PLA could improve the interfacial compatibility of PLA/Wood fiber composites and improve the mechanical properties of the composites.

In order to determine whether the fibers obtained meet the processing requirements in the extraction of wood fiber, the fibers need to be measured. The width of the fiber is usually obtained through manual measurement that requires sophisticated equipment, the error is large and the detection speed is slow. For solving this problem, a fast measurement based on image processing method was proposed to improve efficiency. Extracting fiber contour by the edge detection algorithm, combining connectivity area fulfills and binarization, the fiber region is completely extracted from the image. And then, the pixel width which was calculated by the gray projection algorithm compared with manual measurement data to calculate the fiber width. Experiments show that this method not only reduces errors caused due to manual measurement, but also accelerates the speed of the fiber's detection. This method has good accuracy.

Silica nano-particles are suspended in the colloidal silica and can be induced to gradually gel after the PH value changes. Thus colloidal silica can be utilized to rapidly seep through loose calcareous sand, and the silicon gel is gradually formed to bond sand particles. However, based on observation by scanning electron microscope(SEM), there are a lot of microcracks in the silica gel, which reduces the strength of the sand-gel composite. Therefore, in order to suppress crack growth, wood fibers are dispersed in the colloidal silica which still can seep through calcareous sand. 18 silicon-gel stabilized sand samples were prepared for tri-axial tests, where the concentration of colloidal silica is 20%, and wood fiber concentrations are 0%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, respectively. The results show that:(1) there exists an optimum ratio of wood fiber to colloidal silica, that is, as the concentration of wood fiber increases, the strength represented by the peak value of deviator stress rises first and then falls; (2) there are opposite trends between the two strength parameters, internal friction angle and cohesion, that is, when the wood fiber concentration is 0.04%, the cohesion reaches the maximum value and the internal friction angle reaches the minimum value; (3) The photos by SEM show that, there are wood fibers on the inner wall of the crack in the silica gel, which may reduce the extent of crack propagation and contribute to the strength of stabilized sand samples.

Microcellular polypropylene (PP)/wood fiber composite foams were fabricated via batch foaming assisted by supercritical CO2 (scCO2). Effects of wood fibers on rheology, crystallization, and foaming behaviors of PP were comprehensively investigated. The obtained results showed that the incorporation of wood fibers increased the complex viscosity and the storage modulus of the PP matrix. Jeziorny&rsquo, s model for non-isothermal crystallization kinetics indicated that wood fibers did not change the crystal growth. However, the crystallization rate of the PP matrix was decreased to a certain extent with increasing wood fiber loadings. The wood fiber exerts a noticeable role in improving the cell density and reducing the cell size, despite decreasing the expansion ratio. Interestingly, a &ldquo, small-sized cells to large-sized cells&rdquo, gradient cell structure was found around the wood fibers, implying cell nucleation was induced at the interface between wood fiber and PP matrix. When wood fiber loadings were specifically increased, a desirable microcellular structure was obtained. However, further increasing the wood fiber loadings deteriorated the cell structure. Moreover, the crystallinity of the composite foams initially decreased and then slightly increased with increasing wood fiber loadings, while the crystal size decreased.

Paper sludge generated from the paper industry is classified as solid waste, comprising primarily wood fiber with excellent toughness and CaCO3 with low thermal conductivity. The purpose of this work was to investigate the adaptability of paper sludge with wood fiber into cement-based insulation mortar. The addition of paper sludge with wood fiber was found to be beneficial for optimizing the performance of cement-expanded polystyrene (EPS)/paper sludge (CEP) mortar. In detail, the addition of paper sludge with low fiber content in the range of 2.5% to 7.5% improved the toughness and softening coefficient of CEP mortar. In comparison, an increase of wood fiber content notably improved the properties of CEP mortar when its addition level reached 15%. Additionally, paper sludge with different fiber contents decreased the thermal conductivity of CEP mortar, ranging from 0.0897 to 0.0885 W/(m·K). In conclusion, paper sludge with wood fiber exhibited good adaptability in CEP mortar.

This work test the feasibility and characterize the thermohygric properties of composite materials, realized with eco-friendly raw materials and designed to make suspended ceilings or interior partition walls. Several raw materials are considered: recycled paper (granules or cellulose wadding) and wood fibers. Aggregates or fibers are bonded with organic or mineral binder. One of the binder considered is starch, due to its availability in Ivory Coast (cassava flour). The calcium sulfate hemihydrate is also used for comparison. The density of the produced composites ranges from 400 to 1200 kg/m3 depending on formulation. The thermal conductivity increases proportionally with the density and ranges from 0.09 to 0.5 W/(m.K). The characterization of hygric behavior is based on the measurement of moisture buffer value (MBV) [1]. The hydric performances of the composites made of mineral binder goes from moderate (MBV around 1 g/(m².%RH)) to excellent (MBV > 2 g/(m².%RH)). The moisture buffer value of the paper granules -starch composite is also excellent (MBV > 2 g/(m².%RH))

Differing from the hot-pressing method in the manufacturing of traditional wood-rubber composites (WRCs), this study was aimed at fabricating WRCs using rubber processing to improve water resistance and mechanical properties. Three steps were used to make WRCs, namely, fiber-rubber mixing, tabletting, and the vulcanization molding process. Ninety-six WRC panels were made with wood fiber contents of 0%–50% at rotor rotational speeds of 15–45 rpm and filled coefficients of 0.55–0.75. Four regression equations, i.e., the tensile strength (Ts), elongation at break (Eb), hardness (Ha) and rebound resilience (Rr) as functions of fiber contents, rotational speed and filled coefficient, were derived and a nonlinear programming model were developed to obtain the optimum composite properties. Although the Ts, Eb and Rr of the panels were reduced, Ha was considerably increased by 17%–58% because of the wood fiber addition. Scanning electron microscope images indicated that fibers were well embedded in rubber matrix. The 24 h water absorption was only 1%–3%, which was much lower than commercial wood-based composites.

Recent studies demonstrated that perforated pit membranes (i.e., pit membranes with a large opening in their central portion) are commonly present between wood fibers in core eudicots. It is unclear whether this type of pit membranes might also occur in ancestral angiosperms. Therefore, structure of interfiber pit membranes was examined by field-emission scanning electron microscopy in nine species representing seven families that are located at more ancestral position than core eudicots. We found perforated pit membranes in three of the nine species. Our observations indicate that perforated pit membranes are relatively common even in ancestral groups of angiosperms. In the non-perforated pit membranes of the other six species, we found a range of structural variations. Thin-walled pit membranes without apparent intercellular layers were always found in three of the six species and the porosity of sheet-like pit membranes differed among the three species. Unlike the thin-walled pit membranes, interfiber pit membranes of Buxus microphylla var. japonica were thick-walled with obvious intercellular layers, and in Schisandra chinensis, we often observed torus-bearing pit membranes. Such variations in layered structure of pit membranes and homoplastic occurrence of torus-bearing pit membranes have not yet been reported for ancestral angiosperms. Our observations indicate that the structure of interfiber pit membranes might be more complicated than previous studies might suggest.

In order to accurately obtain the mechanical properties of wood fiber, paper, wood fiber-reinforced materials between ring density and moisture content as a model input, neural network modeling by particle swarm optimization PSO optimal control model to predict the longitudinal elasticity of wood fiber modulus, and thus a correct understanding of the true understanding of the mechanical properties of wood fiber. Modeling and simulation results show that particle swarm optimization technique based on wood fiber parametric modeling methodology is feasible and effective; the model has high generalization ability and prediction accuracy.

Wood fiber-reinforced polylactic acid (PLA) composites (WFRPCs) were used as a filament to manufacture the unidirectional WFRPC components by means of fused deposition modeling (FDM). The physico-mechanical properties of the WFRPC components printed at different extrusion temperatures (200, 210, 220, and 230 &deg, C) were determined. The results revealed that most of the physical properties (moisture content, surface roughness, water absorption rate, and thickness swelling rate) of the printed WFRPC component were not significantly influenced by extrusion temperature, while its density and color difference increased as the extrusion temperature increased. Additionally, the tensile and flexural properties of the FDM-printed WFRPC component decreased when the extrusion temperature was more than 200 &deg, C, whereas the compressive strength and internal bond strength increased by 15.1% and 24.3%, respectively, when the extrusion temperature was increased from 200 to 230 &deg, C. Furthermore, scanning electronic microscopy (SEM) demonstrated that the fracture surface of the tensile component printed at a higher extrusion temperature exhibited a better compatibility at fiber/PLA interfaces and good adhesion between the extruded filament segments. These results indicate that the FDM printing process using different extrusion temperatures has a substantial impact on the surface color, density, and mechanical properties of the printed WFRPC component.

Mechanical properties of polyethylene (PE) composites were evaluated as a function of the addition of bacterial cellulose (BC). It was found that BC could improve the mechanical properties of the composites with or without the combination of traditional wood fiber. The improvements were affected by post-treatment. It was confirmed that BC had a significant influence on impact strength. The pellicle form of BC was able to achieve superior impact strength compared to the fluffy form of BC, but had similar effects on the tensile strength in comparison to the composites with fluffy BC.