Changes in both formaldehyde legislations and voluntary requirements (e.g. Germany RAL) are currently the driving factors behind research on alternatives to amino-based adhesives; moreover, consumer interest in healthy and sustainable products is increasing in bio-based adhesives. Sources of formaldehyde emissions in wood-based panels as well as different emission test methods have been discussed, and the main focus of this review is on the research conducted on sustainable bio-based adhesive systems for wood panels. Lignin, tannin, protein, and starch have been evaluated as both raw materials and adhesive alternatives to existing amino-based thermosetting adhesives. Adhesion improving modifications of these bio-based raw materials as well as the available and experimental crosslinkers have also been taken into account.

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Development of sustainable bio-adhesives for engineered wood panels – A Review

Engineered mycelium composite construction materials from fungal biorefineries: A critical review

As a staple food for much of the world, rice production is widespread. However, it also results in the generation of large quantities of non-food biomass, primarily in the form of straw and husks. Although they have been little utilized and much rice straw is still simply burned, these lignocellulosic materials potentially have considerable values. This review considers the composition of rice straw and husks, the various processes involved in the production of valuable products, and a range of uses to which they can be put. These include agricultural amendments, energy production, environmental adsorbents, construction materials, and various speciality products.

Utilization of Waste Straw and Husks from Rice Production: A Review

Cellulose is a natural biopolymer that is abundantly available in plant cell walls and is secreted in its pure forms by many bacteria. Due to their unique features cellulose materials are considered as efficient replacements for conventional polymers. Cellulose nanofibers (CNF) have attracted wide interest due to their nano size, ease of preparation, low cost, tuneable surface properties and enhanced mechanical properties. However, the efficiency of CNF depends on the extraction method employed from its source and their features vary from source to source. Hence, there is a need to understand the specificity of CNF extraction from its source in order to obtain highly efficient CNF with maximum potential. CNF has been extracted from plant sources using physical, chemical and enzymatic methods. Although plant derived CNF possess excellent features, the involvement of chemicals and complexity in extraction process limits their usage. Bacterial CNF overcome this limitation through its extracellular secretion which makes extraction easy. CNF is also extracted from various marine filamentous algae. The percentage of CNF obtained from algal sources is less compared to plants and bacterial sources. CNF finds wide variety of applications such as drug carriers, tissue regenerating scaffolds, water purifying membranes, electrodes, supercapacitors, fluorescent probes and flexible electronics. In this review, various extraction techniques of CNF from different plant and bacterial sources are discussed critically with special emphasis on CNF based composites.

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Extraction and modification of cellulose nanofibers derived from biomass for environmental application

Novel hybrid panel composites based on wood, fungal mycelium, and cellulose nanofibrils (CNF) were developed and investigated in the present study. In one set of experiments, mycelium was grown on softwood particles to produce mycelium-modified wood which was then hybridized with various levels of CNF as binder. The other set of experiments were conducted on unmodified wood particles mixed with CNF and pure mycelium tissue. It was found that the composites made of mycelium-modified wood and CNF resulted in enhanced physical and mechanical properties compared to the ones made by physically mixing wood, mycelium, and CNF. Scanning electron microscopy (SEM) images showed that mycelium modification covered wood particles with a network of fungal hyphae whereas CNF formed a uniform mycelial film over wood particles. Mycelium modification had a significant effect on reducing water absorption and thickness swelling of the hybrid composites and CNF increased the modulus of rupture and modulus of elasticity, optimally at 2.5% addition. We also present results and analysis pertaining to the development of unique lightweight composite systems with physical and mechanical properties optimized at 5% CNF addition with potential to be used in packaging and furniture applications.

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Fully Bio-Based Hybrid Composites Made of Wood, Fungal Mycelium and Cellulose Nanofibrils.

Soil erosion causes land degradation which negatively impacts not only natural resources but also livelihoods of people due to low agricultural productivity. Cambodia is prone to soil erosion due to poor agricultural practices. In this research we use Battambang province as a case study to quantify impact of land use and land cover change (LULC) on soil erosion. This study assessed the impact from LULC changes to soil erosion. LULC change maps were analyzed based on Landsat satellite imagery of 1998, 2008, and 2018, computed in QGIS 6.2.9, while the soil erosion loss was estimated by the integration of remote sensing, GIS tools, and Revised Universal Soil Loss Equation (RUSLE) model. The results showed that the area of agricultural land of Battambang province significantly increased from 44.50% in 1998 to 61.11% in 2008 and 68.40% in 2018. The forest cover significantly decreased from 29.82% in 1998 to 6.18% in 2018. Various soil erosion factors were estimated using LULC and slope. Based on that, the mean soil loss was 2.92 t/ha.yr in 1998, 4.20 t/ha.yr in 2008, and 4.98 t/ha.yr in 2018. Whereas the total annual soil loss was 3.49 million tons in 1998, 5.03 million tons in 2008, and 5.93 million tons in 2018. The annual soil loss at the agricultural land dramatically increased from 190,9347.9 tons (54%) in 1998 to 3,543,659 tons (70.43%) in 2008 and to 4,267,439 tons (71.91%) in 2018 due to agricultural land expansion and agricultural practices. These losses were directly correlated with LULC, especially agricultural land expansion and forest cover decline. Our results highlight the need to develop appropriate land use and crop management practices to decrease land degradation and soil erosion. These data are useful to bring about public awareness of land degradation and alert local citizens, researchers, policy makers, and actors towards land rehabilitation to bring the area of land back to a state which is safe for increasing biodiversity and agricultural productivity. Measures to reduce or prevent soil erosion and the use of conservation agriculture practices, along with water and soil conservation, management, agroforestry practices, vegetation cover restoration, the creation of slope terraces, and the use of direct sowing mulch-based cropping systems should be considered.

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Assessment of Land Use and Land Cover Changes on Soil Erosion Using Remote Sensing, GIS and RUSLE Model: A Case Study of Battambang Province, Cambodia

Fiberboards are used in a variety of applications that can be for interior as well as for exterior. However, their production involves the consumption of virgin wood fibers and the use and production of formaldehyde-based adhesives, with the consequent impact on the environment and health. The removal of these adhesives results in a significant loss of physico-mechanical properties. To confront these major problems, the use of wheat straw, an agricultural waste, as raw material for the production of binderless fiberboards has been explored. As an alternative to synthetic adhesive, enzymatic treatment of fiber and lignocellulose nanofibers (LCNFs) addition, as well as their combination, have been studied. The different treatments produce an important increase in the mechanical properties in front of the untreated fiber and commercial fiberboard, being the combination of both which presents the best results. Separately, the enzymatic treatment produces a greater strengthening effect than the addition of LCNF. In terms of structural stability, the addition of LCNFs and treatment combinations shows the best results for water absorption and thickness swelling. The results obtained show the possibility to obtain fiberboards without synthetic adhesives with mechanical properties far superior to commercial fiberboardsas as such as bending strengths higher than 100 MPa, flexural modulus 5.5 GPa, internal bond 1.6 MPa, and 122.52 kJ/m2 of impact strength with an estimated added cost of 1 €/m3.

Effect of enzymatic treatment (endo-glucanases) of fiber and mechanical lignocellulose nanofibers addition on physical and mechanical properties of binderless high-density fiberboards made from wheat straw

Commercially, fiberboards are made of fresh wood resources and synthetic adhesives such as urea/phenol-formaldehyde. Although wood is widely available, natural resources must be used in a responsible way, trying to get the best out of the resources that Earth provides us. In my home country, Cambodia, rice and corn are abundant and the waste after their cultivation (straw and stalks, respectively) is merely left in the field, dumped or even burned. This practice could fall into disuse through the valorization of these wastes, contributing both to economic growth of rural areas and environment. On the other hand, formaldehyde-based resins come from non-renewable resources and, in addition, they are not biodegradable. In this sense, alternative binders based on natural resources must be developed. One strong alternative is the use of high-performance cellulose-based materials, such is the case of cellulose nanofibers (CNF), which could provide cohesion to the laminates. Another alternative is to recover lignin from industrial black liquors, which are a side stream from pulp industry. In 2013, I applied for an ERASMUS Mundus grant to develop my Doctoral Thesis in the field of natural fibers and therefore I was assigned to LEPAMAP research group, in the University of Girona. This group works on the use of natural fibers for several applications (i.e. papermaking, composites, fiberboard manufacturing and others) since the beginning of the Nineties and, in the last years, they have been intensively working on CNF. Overall, the motivation of this study is to find greener alternatives to fiberboards manufacturing, improving at the same time their properties and giving a “new life” to those resources that nowadays are considered as waste. The success of this study would show a business opportunity for rural areas wide world, but specifically in my home country where resources are not well managed, and, at the same time, an opportunity to contribute to the environment. 2.2 General objective The general objective of the study was to make fully bio-based and biodegradable fiberboards from two agricultural wastes, i.e. corn and rice biomass, with significantly better physical and mechanical properties than commercial fiberboards made from wood and synthetic adhesives.

Feasibility of incorporating treated lignin and cellulose nanofiber in fiberboards made from corn stalk and rice straw

The Comparison of Liquid Bio-slurry and Rice Husk Biochar Application on the Production Yield of Dai Neang Chili Pepper (Capsicum annum L)

Sustainable, green and environmental friendly materials for various applications are receiving increased attention, while the demand of forest products, including softwoods, hardwoods, and mixtures of different wood species is also increasing. As the biomass from crops has similar chemical composition to that of hardwoods, it could be used to as a substitute for wood fiber in the production of wood-plastic composites. Abdul Khalil et al [1] reported that the incorporation of cellulose nanofibers (CNF) into other polymers is an important strategy for producing nanocomposites with higher mechanical performance. The present work aims to develop medium density fiberboard (MDF) made from thermomechanical pulp (TMP) of corn biomass reinforced with eucalyptus nanofibers. The main purpose of the research is to enhance the mechanical properties of binderless corn MDF , relative to commercial MDF.

Dyna Theng

Papers

Assessment of Land Use and Land Cover Changes on Soil Erosion Using Remote Sensing, GIS and RUSLE Model: A Case Study of Battambang Province, Cambodia

Effect of enzymatic treatment (endo-glucanases) of fiber and mechanical lignocellulose nanofibers addition on physical and mechanical properties of binderless high-density fiberboards made from wheat straw

Feasibility of incorporating treated lignin and cellulose nanofiber in fiberboards made from corn stalk and rice straw

The Comparison of Liquid Bio-slurry and Rice Husk Biochar Application on the Production Yield of Dai Neang Chili Pepper (Capsicum annum L)

Lignocellulosic medium density fiberboards without synthetic adhesives: properties enhancement through the addition of cellulose nanofibers