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Research indicates that users of thermally modified wood lack information regarding the improved performance and any variations that may exist for the “same” product when manufactured by different companies. The goal of this study was to evaluate the variability in mechanical properties of three thermally modified hardwoods and determine the variability between three different manufacturers. To determine the hardness, bending (modulus of elasticity and module of rupture) and shrinkage values, testing was conducted following ASTM standard D143. The samples were conditioned at 20 °C and a relative humidity of 65% until they reached an equilibrium moisture content before testing. Analysis of variance was used to determine the variability within and between the different processes used by each company. Seven out of 18 (39%) tests indicated that there were statistical differences regarding the mechanical performances of the wood samples. Yellow poplar had the least variation between companies (only difference in equilibrium moisture content, EMC) and red maple had the most (hardness, tangential shrinkage, and EMC). While the means for these properties were statistically different, the differences in application for hardness and EMC are slight. For example, the largest difference between processes in hardness was 83.6 kg, for tangential shrinkage, 0.45% and 1.37% for EMC. These differences are suggested to be inconsequential when compared to the values that exist between different species of untreated wood. Published version

This study was aimed to examine the effects of basic properties, fiber morphological properties, strength properties, wettability and optical properties on offset printing of office papers. Widely used office papers with different brands were obtained from Istanbul-Turkey. Technical characteristics of papers; basic properties, strength properties including tensile, burst, tear, and Z direction tensile strength and optical properties such as gloss, whiteness, opacity, and wettability tests were determined according to TAPPI and ISO standards. The results obtained by the tests are as follows; i) there is a great difference in water resistance between the top and the lowest values (207 %), ii) there is little difference between the highest and the lowest brightness value (3.8 %), other papers values have close to each other, iii) in the printing process there is a little difference between the highest, and the lowest gloss values (36.7 %), although the others are close iv) the highest and lowest values in CIE C* showed that it ranged from the narrowest color gamut to the widest color gamut. By applying the widely used offset printing process to commercially produced office papers, the quality levels were evaluated to raise awareness of consumers and sellers.

TEMPO-oxidised cellulose fibres are often explored as nano-reinforcement for polymers. However, it is unclear whether micrometre-sized TEMPO-oxidised cellulose fibres also possess similar reinforcing potential. In this work, we report the mechanical response of polypropylene (PP) composites reinforced with TEMPO-oxidised cellulose (TOC) of different fibre widths. Micrometre-sized TOC fibres (TOCF) containing sodium carboxylate (TOCF-Na) and free hydroxyl (TOCF-H) groups, as well as nano-sized TOC nanofibrils (TOCN) were produced from dissolving pulp and incorporated into PP matrix via melt-extrusion. It was found that model PP composites containing micrometre-sized TOCF-Na and TOCF-H possessed the highest tensile modulus of up to 2.5 GPa; 40% improvement over neat PP and 30% increase over PP/TOCN composite. No significant differences in the tensile strength of PP/TOCF-Na and PP/TOCF-H composites were observed when compared to neat PP. The incorporation of nano-sized TOCN into PP however, led to a 6% decrease in tensile strength. Single-edge notched beam fracture toughness test further showed that PP/TOCN composite possessed the lowest fracture toughness of 2.52 MPa m1/2; a decrease of 18% over PP reinforced with micrometre-sized TOCF-Na and TOCF-H. Our study shows that micrometre-sized TOCFs serve as better reinforcement for polymers compared to nano-sized TOCN. This is attributed to the better dispersion of TOCF in the PP matrix. Furthermore, the presence of surface microfibrillation on TOCFs also enhanced the quality of the TOCF-PP interface through mechanical interlocking and local stiffening of the PP matrix.

Expanded polystyrene (EPS) is a material that is widely used in energy absorbing applications, especially in helmets, despite its non-renewable origin. Cork and its derivatives, however, are proposed as a substitute for polystyrene foam (EPS) due to their renewable origin and their easy recyclability. In spite of the low-environmental footprint of cork and its derivatives, there is insufficient data on their mechanical behaviour. Consequently, under dynamic and quasi-static loads, four different-density EPS, a natural cork material and five different cork products with different grain sizes and heat treatments were tested. They were compared in terms of their stress–strain and specific stress–strain curve, their volumetric capability to absorb energy, their specific energy, average decelerations and peak deceleration. Finally, EPS foams cannot recover their initial shape upon deformation due to their low resilience capability. This is especially important in applications such as helmets, which are bound to be subjected to multiple impacts. However, cork and its products could have this capability for resilience and would therefore be more suitable for certain applications. ispartof: WOOD SCIENCE AND TECHNOLOGY vol:55 issue:2 pages:419-443 status: published

Valuable papers, such as checks, promissory notes, money or printing papers used in wallpaper laminates, must be resistant to burning. For this reason, different flame retardants are used in papers. However, generally, the flame retardants used negatively affect printability by creating a hydrophobic surface. For this reason, it is thought that the combination of flame retardants with a filler that will positively affect the printability of paper will be more suitable for such printable papers. For this purpose, this work aimed to obtain paper with good printability and delayed ignition properties by using calcium carbonate, which is a good paper filler, and tin oxide, which is a flame retardant.

A commonly used natural cellulose fiber (flax) and a regenerated cellulose fiber (Lyocell) were used at 20 wt% to reinforce polylactide stereocomplex (sc-PLA) composites. Composites were prepared by melt compounding cellulose fibers and an equivalent proportion of PLLA/PDLA, followed by injection molding. The structures and properties of these two kinds of cellulose fiber/sc-PLA composites were compared and evaluated. The results showed that the total crystallinity and stereocomplex crystallite content of composites could be increased by reinforcing with cellulose fibers, and Lyocell fibers were more effective in accelerating crystallinity and the formation of stereocomplex crystallites than flax fibers. Mechanical properties of Lyocell fibers were much poorer than those of flax fibers, and the interfacial adhesion values of Lyocell/sc-PLA composites were inferior to those of flax/sc-PLA composites. Lyocell/sc-PLA composites showed higher impact strength and similar tensile strength vs. flax/sc-PLA composites, but the Young’s modulus values of Lyocell/sc-PLA composites were lower than those of flax/sc-PLA composites. The Vicat softening temperatures of both flax/sc-PLA and Lyocell/sc-PLA composites were increased to nearly 100 °C higher than that of PLLA. Lyocell/sc-PLA composites showed the highest Vicat softening temperature of ~ 170 °C. Published (Publication status)

Funding Information: KSK and AB acknowledge funding by the UK Engineering and Physical Sciences Research Council (EPSRC) (EP/K014676/1). KSK also acknowledges Academy of Finland (Project number 310943). EK is grateful for the support by the FinnCERES Materials Bioeconomy Ecosystem. Funding Information: Open access funding provided by Aalto University. KSK and AB acknowledge funding by the UK Engineering and Physical Sciences Research Council (EPSRC) (EP/K014676/1). KSK also acknowledges Academy of Finland (Project number 310943). Publisher Copyright: © 2021, The Author(s). Copyright: Copyright 2021 Elsevier B.V., All rights reserved. Cellulose nanopapers provide diverse, strong and lightweight templates prepared entirely from sustainable raw materials, cellulose nanofibers (CNFs). Yet the strength of CNFs has not been fully capitalized in the resulting nanopapers and the relative influence of CNF strength, their bonding, and biological origin to nanopaper strength are unknown. Here, we show that basic principles from paper physics can be applied to CNF nanopapers to illuminate those relationships. Importantly, it appeared that ~ 200 MPa was the theoretical maximum for nanopapers with random fibril orientation. Furthermore, we demonstrate the contrast in tensile strength for nanopapers prepared from bacterial cellulose (BC) and wood-based nanofibrillated cellulose (NFC). Endemic amorphous polysaccharides (hemicelluloses) in NFC act as matrix in NFC nanopapers, strengthening the bonding between CNFs just like it improves the bonding between CNFs in the primary cell wall of plants. The conclusions apply to all composites containing non-wovenfiber mats as reinforcement.

Despite the higher specific mechanical properties and the lower density of polymeric foams, these materials present cumulative damage behaviour that implies in the second and successive impacts, their mechanical properties decrease drastically. However, cork and cork agglomerates have the ability to absorb multiple impacts so they could be a more suitable material in some products, such as bumpers and helmets. This article is focused on the study of five different cork agglomerates and a natural cork under four different maximum deformations subjected to four consecutive compression loading cycles. Main diagrams, such as the stress–strain, energy density and efficiency, and the variation in diverse parameters, such as the absorbed energy density and maximum efficiency, were investigated and compared with an expanded polystyrene foam.

Lignocellulosic ethanol production at high temperature offers advantages such as the decrease of contamination risk and cooling cost. Recombinant xylose-fermenting Saccharomyces cerevisiae has been considered a promising strain for ethanol production from lignocellulose for its high inhibitor tolerance and superior capability to ferment glucose and xylose into ethanol. To improve the ethanolic fermentation by xylose at high temperature, the strain YY5A was subjected to the ethyl methanesulfonate (EMS) mutagenesis. A mutant strain T5 was selected from the EMS-treated cultures to produce ethanol. However, the xylose uptake by T5 was severely inhibited by the high ethanol concentration during the co-fermentation in defined YPDX medium at 40 °C. In this study, the simultaneous saccharification and co-fermentation (SSCF) and the separate hydrolysis and co-fermentation (SHCF) processes of sugarcane bagasse were assessed to solve this problem. The xylose utilization by T5 was remarkably improved using the SSCF process compared to the SHCF process. For the SHCF and SSCF processes, 48% and 99% of the xylose in the hydrolysate was consumed at 40 °C, respectively. The ethanol yield was enhanced by the SSCF process. The ethanol production can reach to 36.0 g/L using this process under high-temperature conditions.

Cork and cork agglomerates could be suitable replacements for petroleum-based polymeric foams due to their similar internal structure of cells and grains. Additionally, cork products have a renewable origin and are recyclable. Despite these notable properties, few studies have analysed the mechanical properties, especially the specific properties, of these materials under compressive loads. Moreover, although efficiency, ideality, and energy-normalized stress diagrams are commonly used for polymeric foams and 3D-printed lattice structures, these types of diagrams are not yet applied to cork products. It must be highlighted that efficiency diagrams are plotted only against nonspecific properties so, this article proposes additionally the use of nonspecific properties to compare materials not only in terms of properties per unit volume instead but also in terms of properties per unit mass that is more suitable for certain applications in which the weight is crucial. The materials studied herein include three different white cork agglomerates, a brown cork agglomerate, a black cork agglomerate, natural cork, and expanded polystyrene foam, which are subjected to quasi-static compressive loads.

As well known, cellulose fibers, defibrillated/activated in different degrees or even chemically modified, can be employed as additives in matrixes of different nature with the aim of modulating some properties such as the mechanical resistance, rheological behavior or hydrophobicity of the product. Consequently, there is an increasing interest in the incorporation of these materials in a wide variety of products, being necessary the development of green methodologies for their chemical modification. The objective of this work is the use of the ball milling technology as tool for the activation and chemical modification of cellulose fibers, specifically of cellulosic material from jute. The traditional method used to date for the NCO-functionalization of cellulose fibers requires a solvent as reaction medium, the action of a catalyst and a previous stage of mercerization to boost the reactivity of the fibers. Accordingly to the former, jute fibers were NCO-functionalized, on one side, evading previous mercerization and, on other side, applying two different alkali-based activation pre-treatments that lead to materials with different crystallinity index. In addition to this, and after having optimized milling conditions, both activation and NCO-functionalization were successfully carried out in a planetary ball mill avoiding solvent, catalyst and previous alkalization. Cellulose fibers esterification was successfully implemented over already ball milled cellulosic material, showing that activation and chemical modification do not need to be performed at the same time. Fourier transform infrared spectroscopy provided the follow-up of each reaction and the impact of ball milling on the fibers was analyzed by hydrodynamic diameter measurements. Thus, it is demonstrated that ball milling can be proposed as an efficient and environmentally friendly methodology for the activation and/or functionalization of cellulose fibers. ispartof: Cellulose vol:27 issue:2 pages:643-656 status: Published online

Vacuum drying of wood is a method to reduce drying time and inventory; however, there is limited information regarding the economic feasibility for vacuum drying 4/4 red oak compared with traditional drying methods. The benefits of this technology, mainly dramatically reduced drying times and higher flexibility, must be weighed against the higher initial capital investment. The goal of this project was to compare the economic feasibility, using capital budgeting techniques, of conventional drying and vacuum drying for 4/4 red oak lumber. The analysis was conducted for two actual flooring manufacturers. Conventional drying for this analysis was considered to be air-drying plus kiln drying, which is commonly done with red oak. The vacuum technology considered used hot platens for heating the wood. Species, thickness, drying methods, and lumber demand compared, both drying methods (conventional and vacuum drying) were determined to be economically feasible. However, vacuum drying had a slightly higher net present value, cost–benefit ratio, and sensitivity analysis than conventional drying, making it a slightly better investment for drying 4/4 red oak. The initial tied-up inventory and its respective cost in the conventional drying scenario represents an opportunity cost that can be recovered using vacuum drying. This recovered cost can result in freed capital that can be invested elsewhere to increase competitiveness. Published version

Native cellulose nanofibrils (CNF) were prepared from bleached birch pulp without any chemical or enzymatic pretreatment. These CNF were modified by adsorption of a small amount of water-soluble polysaccharides and used to prepare nanopapers, which were processed into composites by lamination with an epoxy resin and subsequently cured. The results were compared to the properties of composites prepared using bacterial cellulose nanopapers, since bacterial cellulose constitutes highly pure and crystalline cellulose. It was found that both types of nanopapers significantly improved both the thermal stability and mechanical properties of the epoxy resin. As anticipated, addition of only 2 wt% of water-soluble polysaccharides efficiently hindered crack-propagation within the nanopaper and significantly improved the tensile strength and work of fracture compared to composites containing a conventional nanopaper reinforcement. The mechanical properties of the composites thus reflected the improvement of the nanopaper properties by the polysaccharides. Moreover, it was possible to predict the properties of the final composite from the mechanical performance of the nanopapers.

Enzymatic treatments in textile are remarkable because of their environmentally friendly properties, such as less energy, water and chemical need, low waste water pollution. In this paper combined use of amylase, pectinase and cellulase in the same bath was studied in different parts. In the first part of the experiment, raw cotton woven fabrics were treated with amylase, pectinase and cellulase enzymes in the same bath at different process conditions to desize, scour and polish. Results showed that one-bath triple enzymatic mixture process could be done successfully. Therefore, it could be used instead of conventional processes. Moreover, the enzymatic process was completed almost in half of the conventional treatments’ durations and temperatures. In the second part, effects of enzymes’ dosages were analyzed by using enzymes in pairwise combinations. By this way, not only the effects of the amount of enzymes but also the effects of each enzyme on each fabric property were seen more distinctly. The increases of enzymes’ concentrations led to an increase in every tested value except tear strength. Pectinase ? cellulase combination resulted in minimum tear strength and whiteness, but maximum absorbency. Usage of enzymes one-by-one constituted the final part of the study. It had been found that amylase affected whiteness and absorbency, cellulase affected tear strength particularly. Although combined enzymatic treatments were conducted at more moderate conditions than conventional processes, comparable results were observed. Yürek Tekstil Sanayi ve Ticaret A.Ş. (Türkiye), Nuy Tekstil Sanayi ve Dış Ticaret Ltd. Şti. (Türkiye), Pentakim Kimya Sanayi

In this study, the effects of ultrasound on ozone treatment processes for bleaching cotton fabrics were investigated and compared with the conventional hydrogen peroxide bleaching process (60 °C over 90 min). Two ultrasonic + ozone treatments of cotton fabric samples were carried out: (1) ozone in an ultrasonic homogenizer (UH) and (2) ozone in an ultrasonic bath. Ozone dosages, temperature and time variations were determined with both ozone-ultrasonic bleaching processes. Whiteness, yellowness, weight, tensile strength properties, FTIR (ATR) spectra and visual appearance, via scanning electron microscopy of treated cotton fabrics as well as chemical oxygen demand (COD) of bleaching effluents, were investigated. It was concluded that the ozone + UH process, conducted for 30 min at 30 °C, produced closely equivalent values of cotton fabric whiteness and yellowness to the classic peroxide bleaching process, with slightly less weight loss, dramatically less COD in the process effluent (29 mg/l for ozone-UH vs. 4,316 mg/l for classical peroxide treatment), and without causing any adverse and/or detrimental effects on loss of fabric strength or elongation of the cotton fabrics. The ozone-UH process also leads to time and energy savings with much less environmental impact. Consequently, the combination of ozonation plus UH carried out at 30 °C over 30 min can be used successfully for cotton bleaching instead of the classic hydrogen peroxide bleaching process. © 2014, Springer Science+Business Media Dordrecht.

In this study, the effect of ultrasound on the activity of the glucose oxidase (GOx) enzyme for bleaching of the cotton fabrics was investigated. Hydrogen peroxide generation with the GOx enzyme from glucose was carried out under ultrasonic homogenizer (UH) and ultrasonic bath support. The aim of using ultrasonic support was to increase the yield of the enzyme reactions. The enzymatically generated hydrogen peroxide was used for bleaching of cotton fabrics. The bleaching process was performed at 90 °C and pH 11 (with NaOH) for 60 min, followed by rinsing at 70 and 50 °C then cold washing. The whiteness degrees of the cotton samples that were bleached by the generated peroxide were compared to the whiteness degrees of the conventionally bleached cotton fabrics. Sufficient whiteness degrees in cotton fabrics could be obtained by enzymatically generated hydrogen peroxide by UH support. The initial whiteness degree of the cotton fabric was 59.9 Stensby degrees; the whiteness was increased to 75.6 Stensby degrees by the GOx enzyme under UH support where the conventional bleaching process yielded a whiteness value of 76.7 Stensby degrees. For efficient cotton bleaching by the GOx enzyme, UH support contributed to the concentration of enzymatically generated hydrogen peroxide by the GOx enzyme. Bleaching of cotton by the GOx enzyme was approved as a more environmentally friendly process compared to the conventional bleaching method in respect of the results of chemical oxygen demand tests. © 2014 Springer Science+Business Media Dordrecht.

In 2010 Kimberly-Clark Australia (KCA) celebrated 50 years of operations at its site at Millicent in South Australia. During this time the mill has operated under an indenture agreement which expires in 2014. Under this agreement wastewater generated by the mill is permitted to be discharged into a drain adjacent to the mill. The drain, which also collects runoff water from the surrounding area, discharges into Lake Bonney SE Refereed/Peer-reviewed

Recent progress in research on the cutting processes of wood is presented, particularly in regard to new methods of accomplishing an increase in volume recovery by sawmills. The suitability of modern fracture mechanics was demonstrated for the estimation of the cutting power for saws in which kerfs are different from saws used in cutting tests, and whereby the data of sawn material - such as the specific work of surface formation ( toughness) and the shear yield stress - were determined. Cutting tests were carried out on the modern frame sawing machine ( sash gang saw) for narrow-kerf sawing with the hybrid dynamically balanced driving system and elliptical teeth trajectory movement.

Wood surfaces might be considered as geometrical structures combined with position dependent chemical properties. It is possible to access surface properties only from a methodical point of view, e. g., by measuring roughness, colour, surface energy and other features. This type of characterisation remains incomplete because it does not account for the complex interactions of the properties, which are caused by the machining process. A better approach might be to describe the surface as a system of time dependent properties including the history of machining operations performed for a specific purpose. This work presents the advancements in the understanding of wood surfaces achieved in the course of the COST Action E35. The interaction between raw material, machining, and techniques of measurement will be discussed in terms of surface characteristics including the tactile properties of wood surfaces.