Volume 10 Issue 4

Methylated fatty acid (FA) compounds in the heartwood and bark of some softwood species, specifically Pinus sylvestris, Abies alba, Picea abies, and Larix decidua, grown in the Czech Republic were evaluated. Strong H2SO4 was used for methylation of the lipids. The highest content of lipid was found in P. abies bark (40.132 mg/g o.d. sample), and the lowest content was in A. alba wood (11.027 mg/g o.d. sample). The highest concentration of FAs was observed in L. decidua bark. The highest percentages of FAs in wood of P. sylvestris were arachidic acid and oleic acid. In bark, the highest percentages of FAs were stearic acid, palmitic acid, and oleic acid. The FAs with the highest concentrations in A. alba wood were arachidic acid, palmitic acid, pentadecanoic acid, and margarinic, and those in bark were behenic acid, lignoceric acid, and arachidic acid. P. abies wood FAs showed arachidic acid, palmitic acid, and margarinic acid, and the bark contained lignoceric acid and arachidic acid. The FAs of L. decidua wood were arachidic acid, palmitic acid, and stearic acid, and in bark they were pentacosylic acid, docosahexaenoic acid (DHA), lignoceric acid, arachidic acid, and behenic acid. The lack of typically dominant unsaturated fatty acids (e.g. 18:1, 18:2), compared to literature values were attributed to the application of strong acid for the hydrolysis.

Wood and bark oil extractives components (OECs) of Pinus sylvestris, Abies alba, Picea abies, and Larix decidua grown in the Czech Republic were analyzed using gas chromatography/ mass spectrometry (GC/MS). The analysis showed the presence of monoterpene, sesquiterpene, diterpenoids, and resin acids. The highest percentages of OECs in the wood of P. sylvestris were α-fenchyl alcohol (26.04%), D-fenchyl alcohol (12.39%), and L-borneol (8.81%); the OECs in the bark included α-methyl-γ-butyrolactone (31.88%) and isodecyl octyl phthalate (15.85%). The most frequently occurring OEC in A. alba wood were 4-hydroxy-4-methyl-2-pentanone (73.36%), α-cedrol (10.08%), and 2,6-dimethyl-1,3,6-heptatriene (7.35%); the most OECs in the bark were di(2-ethylhexyl)phthalate (59.83%), methyl cyclopentane (16.63%), and 13-epimanool (6.31%). P. abies wood OECs included 4-hydroxy-4-methyl-2-pentanone (29.42%), α-cedrol (26.98%), ∆3-carene (6.08%), and terpinen-4-ol (5.42%); the most OECs in the bark were di(2-ethylhexyl)phthalate (30.91%), cyclohexane (12.89%), caryophyllene oxide (8.90%), and α-pinene (4.59%). OECs of L. decidua wood were α-terpineol (26.06%), isoborneol (14.12%), camphene (11.78%), D-fenchyl alcohol (10.39%), and larixol (4.85%); OECs in the bark were larixol (33.29%), phthalic acid mono-2-ethylhexyl ester (16.96%), 13-epimanool (15.40%), and cyclohexane (8.44%).

An environmentally benign approach is put forward with the focus on directly liquefying and depolymerizing Cunninghamia lanceolata (Lamb.)Hook. (Chinese fir) sawdust into ethyl levulinate (EL) under supercritical ethanol (scEtOH) conditions by using phosphotungstic acid (PTA) as a catalyst. The effects of parameters such as catalyst dosage, temperature, and reaction time on alcoholysis yield were investigated. The experimental results show that the biomass alcoholysis yield reached 95.35% with 0.5 g PTA as a catalyst at 260 °C for 30 min. Alcoholysis yield and quantitative content of EL depended on the catalyst. The light bio-oil was primarily composed of phenols, aldehydes, ketones, and esters. A high quantitative content of EL up to 20.82% (AR, Relative abundance) was achieved, compared to 0.73% AR when PTA was not added. Hence, scEtOH with dissolved PTA may offer novel media for both chemical reactions and biomass conversion technology as a replacement for environmentally undesirable organic solvents.

In hydrogen peroxide bleaching of thermomechanical pulp (TMP), reaction temperature and time are the main factors that can improve the bleachability of pulp fibers. However, high temperatures can induce some problems such as cellulose degradation, yield loss, low fiber strength, and high environmental load. These negative effects of high temperature are mainly caused by radicals formed from the decomposition of hydrogen peroxide. To avoid the adverse effects of high temperature, we used two-step thermal treatments during hydrogen peroxide bleaching of TMP. The temperatures used in the two-step thermal treatments were 80 and 45 ˚C for a total bleaching time of 1 hour. In H2O2 bleaching of TMP, two-step thermal treatments were found to have had positive effects on the optical and physical properties of the pulp. The ISO brightness of the pulp bleached by two-step thermal treatments with hydrogen peroxide was identical to that of pulp bleached by conventional hydrogen peroxide bleaching. The post color number (PC number) of TMP was sharply increased after bleaching at 80 ˚C for 40 minutes. The post color number of TMP bleached by two-step thermal treatments is lower than that of TMP bleached by a one-step thermal treatment. The zero-span tensile index was also improved by two-step thermal treatments.

Pine heartwood, sapwood, and spruce extracts were tested against methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecalis (VRE), Escherichia coli O157:H7, and Streptococcus pneumoniae. The bacterial strains were cultured in a broth with and without the wood extracts. Also, the antibacterial effect of the extracts was studied by performing the antimicrobial sensitivity test method on agar plates. Both pine extracts had a clear antibacterial effect on MRSA, VRE, and S. pneumoniae. Only pine sapwood extract had an effect on E. coli and it was weaker than on other strains. Spruce showed a clear antibacterial effect on S. pneumoniae and a weaker effect on MRSA and VRE. The results suggest that these wood species have potential as surface materials in hospital and day care environments.

In this paper, the optimization of computer numerical control (CNC) machining parameters were conducted using the Taguchi design method on the surface quality of massive wooden edge glued panels (EGP) made of European larch (Larix decidua Mill). Three machining parameters and their effects on surface roughness were evaluated. These parameters included tool clearance strategy, spindle speed, and feed rate. An analysis of variance (ANOVA) was performed to identify the significant factors affecting the surface roughness (Ra and Rz). Optimum machining parameter combinations were acquired by conducting an analysis of the signal-to-noise (S/N) ratio. Optimal cutting performance for the Ra and Rz was obtained for the cutter at a tool clearance strategy of an offset 16000 rpm spindle speed and 1000 mm/min feed rate. The surface roughness, both the Ra and Rz, increased with increasing feed rate. Optimal cutting performance for Ra and Rz was obtained for a tool clearance strategy of an offset 16000 rpm spindle speed, and 1000 mm/min feed rate cutting settings. Based on the confirmation tests, Ra decreased 2.2 times and Rz 1.8 times compared to the starting cutting parameters.

Cellulose etherification with 3-chloro-2-hydroxypropyl-trimethylammonium chloride (CHPTAC) was carried out in NaOH/urea aqueous solution, under homogeneous conditions. The substitution degree of the prepared quaternized cellulose, cellulose-CHPTAC, increased with increasing molar ratio of CHPTAC/anhydroglucose unit (AGU), reaction temperature, and reaction time. The structure of the cellulose-CHPTAC was characterized using Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (1H- and 13C-NMR), and thermal gravimetric analysis (TGA). Moreover, a cellulose-CHPTAC sample (DS=0.52) was used to modify ground calcium carbonate (GCC) fillers by the surface wrapping method. The results showed that the filler retention was improved by surface modification of GCC fillers using cellulose-CHPTAC, and the negative impact of filler addition on paper strength was reduced. The quaternized cellulose prepared in NaOH/urea aqueous solution could be considered a new, promising filler modifier.

Pyrolytic gasified charcoal (PGC) and tar are the solid and liquid products, respectively, yielded from biomass gasification technology. In this paper, PGC was molded with adhesives to prepare molded solid fuel (MSF). Tar and PGC were obtained from the pyrolytic gasification of wood chips and sawdust from pine and cedarwood. PGC was molded with phenol resin prepared by wood tar to prepare MSF (MSF-MP). Meanwhile, there were two other methods used to prepare MSF. PGC molded with common phenol resin was one method (MSF-P). PGC was molded with starch adhesive to prepare MSF-S. Wood powder carbonized carbon (WPCC) obtained from the marketplace was employed as a trial sample. The properties and combustion characteristics of MSFs and WPCC were studied. It was found that the shatter strength of these MSFs were more than 95%. MSFs had higher activation energy and comprehensive combustion index compared to WPCC. MSF-MP yielded the following data: shatter strength: 95.86%, lower heating value (LHV): 25.89 MJ∙kg-1, ignition: 325 °C, comprehensive combustion index: 1.73×10-10, and activation energy: 61.38 kJ∙mol-1. The LHV and activation energy of MSF-MP were superior to those of other MSFs. Therefore, MSF-MP has a market potential for use as barbecue charcoal in restaurant or family gatherings. The preparation of MSF-MP is a prospective method for the utilization of PGC and wood tar.

The wood of a mature (40-year-old) Eucalyptus globulus Labill tree was characterized at different stem height levels (0%, 10%, 35%, and 50% of total height) regarding pulping, bleaching, and paper properties. Pulp yields increased upwards from 46% to 50%, and Kappa number decreased from 17.5 to 12.3 at 0 and 50% height, respectively. The estimated specific wood consumption ranged from 3.2 m3 odt-1 to 3.1 m3 odt-1 at 0% and 50% height levels, respectively. Pulp drainage varied along the stem, with less drainability (20.3 ºSR) and higher water retention value (1.07 g.g-1) at the base. Pulp fiber length increased (827 µm vs. 877 µm) and width decreased (19 µm vs. 17 µm) from 0% to 50% height levels. Tensile, tear, and internal bond strength decreased upwards, with mean values of 34.9 N.m.g-1, 3.1 mN.m2.g-1, and 95.8 J.m-2, respectively. These findings support the use of mature E. globulus trees without loss of pulp production and quality.

Interfacial compatibility plays a key role in the performances of natural fiber-reinforced composites. The measures commonly used to improve the interfacial compatibility focus more on the addition of various compatibilizers than on the structural modification of the natural fiber. In this paper, an attempt was made to enlarge the interfacial interaction areas of the recycled polyethylene (rPE)/wood flour (WF) composites by steaming the WF. Multi-monomer graft copolymers of polyethylene (GPE) were used as compatibilizers for the composites. How the enlarged interfaces affected the morphology, mechanical properties, water resistance, thermal stability, and dynamic rheological properties of the rPE/WF composites was investigated. The steaming process was able to enlarge the voids of the WF and therefore activate more interfaces for interactions. It was found that the interfacial morphology of the composites was affected by the degree of interfacial compatibility of the composites and so was characterized by various distinctive blossom shapes having a variation of compositions. With the help of GPE, the steaming process was able to significantly improve the interfacial compatibility of the composites and therefore improve the mechanical properties, water resistance, thermal stability, and dynamic rheological properties of the composites.