The Wood-Water-Formaldehyde System

The physical interactions of the wood-water-formaldehyde system are reviewed.Swelling data at 20 and 40 C (68 and 104 F) are presented which show that Douglas-fir and red alder wood shrink relative to pure water in low concentration water-formaldehyde solutions, and swell in higher concentration solutions ultimately to 18% by volume for a 24% (weight) solution of formaldehyde at 40 C (104 F).The composite sorption isotherms of the wood-water-formaldehyde system are complex. There is seen, however, an initial relative increase in water concentration of the sorbed phase, followed by a general decrease of water concentration for most of the other concentrations studied. The reasons for this are not known

Utjecaj veličine sječke i uvjeta alkalne predhidrolize na natronski postupak proizvodnje celuloze od grabovine

The impact of chip size and hydrolysis temperature on changing chemical composition of hornbeam wood and following soda pulping is investigated. Three chip sizes, two temperatures (60 and 90 °C) and 120 minutes retention time in pre-hydrolysis step were selected. After pre-hydrolysis treatment, the sample was divided into two portions; one third was used for chemical analysis and the other two thirds for soda pulping. The reference soda pulping conditions were used on either treated or untreated chips. The influence of pre-hydrolysis was determined measuring cellulose and lignin content, residual alkali and the hemicelluloses removal. The lignin and cellulose content were marginally increased and the hemicellulose removal was higher at larger chip size. Total yield and rejects, kappa number and strength properties of the unbleached pulp were measured using corresponding Tappi standard test methods. The pulping total yield and rejects of the treated chips varied between 30.31 % and 48.14 % and 0.83 % to 7.31 %, respectively. The reject from soda pulping of untreated chips was 24.16. Prehydrolysis treatment reduced the tensile index, but the tear index was only marginally improved.U radu je istražen utjecaj veličine sječke i temperature hidrolize na promjene kemijskog sastava grabovine te naknadni natronski proces proizvodnje celuloze. Za predhidrolizu su odabrane tri veličine sječke, dvije temperature (60 i 90 °C) i retencijsko vrijeme od 120 minuta. Uzorak je nakon predhidrolize podijeljen na dva dijela, pri čemu je jedna trećina iskorištena za kemijsku analizu, a ostale su dvije trećine upotrijebljene za natronski postupak proizvodnje celuloze. Referentni uvjeti natronskog postupka primijenjeni su na predtretiranoj i netretiranoj sječki. Utjecaj predhidrolize određen je mjerenjem sadržaja celuloze i lignina, količine zaostale lužine i izdvajanja hemiceluloza. Sadržaj celuloze i lignina samo je neznatno porastao, dok je izdvajanje hemiceluloza bilo veće za sječku većih dimenzija. Ukupan prinos vlakana i udio neadekvatnih vlakana, kappa broj i čvrstoća nebijeljene natronske celuloze određeni su u skladu s odgovarajućim Tappi standardima. Ukupan prinos vlakana i udio neadekvatnih vlakana za netretiranu su drvnu sječku iznosili 30,31 i 48,14 %, odnosno 0,83 do 7,31 %. Udio neadekvatnih vlakana dobivenih natronskim postupkom netretirane sječke iznosio je 24,16 %. Predhidrolizom je smanjen vlačni indeks, uz neznatno poboljšanje indeksa kidanja

Kemijska karakterizacija biološkog ulja dobivenoga pirolizom zdravoga i natrulog drva bukve (Fagus orientalis)

Among forest diseases, fungi are the most important agents that cause irreparable losses to the wood of standing trees and logs. In this study, pyrolysis of undecayed and decayed beech (Fagus orientalis) wood were carried out using a fixed-bed reactor at pyirolysis temperature of 500 °C in nitrogen atmosphere. The influence of Trametes versicolor fungal decay on the yield and chemical composition of products was investigated. The bio-oil yield was 62.5 wt% at a pyrolysis temperature of 500 °C for decayed wood, while the bio-oil yield was found to be about 58 wt% at the same temperature for undecayed wood. Bio-oils were characterized using some chromatographic and spectroscopic techniques, such as gas chromatography-mass spectrometry (GC/MS). It as found that Tetracosamethyl-cyclododecasiloxane (5.50 %), tetradecamethyl-hexasiloxane (4.85 %), 2,6-dimethoxy-phenol (4.21 %), and benzene acetic acid (3.16 %) were the main oil components present in decayed beech wood, while syringol (14.86%), methoxyeugenol (6.59 %), naphthalene (4.41 %), o-guaiacol (3.60 %), isoeugenol (3.17 %), and 2-methoxy-4-methyl-phenol (3.08 %) were present in undecayed beech wood. These results show that decayed wood can be used for the production of bio-oil.Među šumskim štetnicima gljive su najopasniji činitelji koji uzrokuju nepovratne gubitke drva rastućih stabala i trupaca. U ovom je istraživanju provedena piroliza uzoraka od zdravoga i natrulog drva bukve (Fagus orientalis) u atmosferi dušika, uz pomoć fiksnog reaktora i pri temperaturi pirolize 500 °C. Istraživan je utjecaj gljiva truležnica (Trametes versicolor) na prinose i kemijski sastav produkata pirolize tretiranog drva. Prinos biološkog ulja od natrulog drva pri temperaturi pirolize 500 °C bio je 62,5 % (težinskog udjela), dok je prinos biološkog ulja od zdravog drva bio oko 58 % (težinskog udjela) pri jednakoj temperaturi pirolize. Biološkog ulja su karakterizirana uz pomoć određenih kromatografskih i spektroskopskih tehnika kao što je plinska kromatografija / masena spektrometrija (GC/MS). Utvrđeno je da su glavne uljne komponente zastupljene u natruloj bukovini tetracosametilciklododekasiloksan (5,50 %), tetradekametil heksasiloksan (4,85 %), 2,6-dimetoksi-fenol (4,21 %) i benzen octena kiselina (3,16 %), dok je u zdravom bukovu drvu bilo siringola (14,86 %), metoksieugenola (6,59 %), naftalena (4,41 %), o-gvajakola (3,60 %), izoeugenola (3,17 %) i 2-metoksi-4-metilfenola (3,08 %). Dobiveni rezultati pokazuju da se natrulo drvo može iskoristiti za proizvodnju biološkog ulja

STUDYING THE EFFECT OF CATIONIC STARCH- ANIONIC NANOSILICA SYSTEM ON RETENTION AND DRAINAGE

Nanoparticles are widely used in the papermaking industry as retention/ drainage aids, usually in conjunction with a high mass cationic polyelectrolyte such as cationic starch. However, little convincing knowledge of their role and mechanism in the wet-end system is yet found. This work focused on the role of nanosilica on papermaking wet end system in response to some processing parameters (drainage, retention, and electrostatic force of the whole system). The observations indicated that the nanosilica performance is defined by interactions of nanosilica with the complex aqueous environment of wet end system. The interaction mechanism seems to rely on introduction of nanoparticles into a cationic starch-fines-fibers network, converting the fiber mat on the forming wire into a porous structure that is responsive to retention and drainage

Investigation on production of bleachable chemi-mechanical pulp from wheat straw

In an attempt to develop pulping process suitable for small scale implementation, production of bleachable chemi-mechanical pulp from wheat starw is investigated. Four levels (10, 12, 14 and 16% based on oven dry weight of straw) NaOH and three pulping times (20, 30 and 40 minutes) at 95°C pulping temperature were used. After digester yield varied between 64.65 and 71.7% and the total yield after defibration was measured as 54.45% and 62%.  Unrefined pulp freeness varied between 708 and 765 ml CSF. Pulps produced applying 10-16% NaOH, 40 minutes pulping time and 95°C pulping temperature was selected from further evaluation. These pulps were refined to about 365 ml CSF in a PFI mill and then handsheets were made for strength evaluation. The apparent density of the handsheets varied between 437-488 kg/m3, tear index between 6.51-7.11 mN.m2/g, and tensile index between 29.2 -30.8 N.m/g. Significant difference at 99%  was not observed between the strength of the pulps. Then pulp produced applying 10% NaOH, 40 minutes pulping time and 95°C pulping temperature was selected for bleaching trials. Totally Chlorine Free (TCF) bleaching sequence was used for bleaching the selected pulp.  Pulps bleached applying 4% H2O2 and 3.5% NaOH, 3% sodium Silicate, 0.5% MgSO4 and 0.3% DTPA for 2 hours showed the highest brightness of 50.69% compared to 29.2% for unbleached pulp

Investigation on the influence of cooking intensity on strength properties of bagasse soda pulp

The influence of pulping temperature and time on strength properties of bagasse soda pulp was investigated. Two cooking temperatures)175ْC,185 ْC (and three cooking times (20,30,40 minutes) were selected .The other variables were kept constant at 18 % NaOH and l/w=8. Tensile strength, tear strength index and folding endurance of hand sheets measured . Factorial experiment and randomized block design was used for statistical analysis and DMRT was used for grouping the means. The results indicate that, application of intermediate cooking intensity produced better pulp than more intense pulping at highest pulping time and temperature. However, more intense pulping produced better folding endurance and pulp prepared at 30 minutes cooking time showed better folding endurance than pulp produced at 20 minutes. The highest tear index was obtain at 185 ْC and 20minutes and lowest at 185ْC and 40 minutes. Results indicate that undamaged fibers will product highest tear index. The highest folding endurance was produced at 175 ْC and 30 minutes and the lowest at 185ْC and 30 minutes .Increasing pulping time reduced tensile index and the highest and lowest tensile index obtained at 20 and 40 minutes pulping time respectively

THE INVESTIGATION ON ANATOMICAL, CHEMICAL AND PHYSICAL CHARACTERISTICS OF SAXAUL WOOD (HALOXYLON PERSICUM) FROM HARESABAD-E-SABZEVAR

For the determined of Anatomical, Chemical and Physical characteristics of SAXAUL wood (Haloxylon persicum) from Haresabad-e-Sabzevar research station located in Khorasan-e- Razavi province 4 trees from this specie were selected and cut. Samples transferred to the Chemical laboratory in Alborz-e-Karaj research center for studies. Anova-1 in mstat-c statistical software was used for statistical analysis. Anatomical characteristics measured Fiber length, Fiber diameter, lemun and cell wall thickness 336.22, 13.61, 3.68 and 4.99 micron, respectively. Paper making coefficients were also measured. Mix up coefficient; Flexibility coefficient and Rankle coefficient were 24.72, %27.05 and %2.71, respectively. Chemical characteristics measured cellulose, lignin, alcol-acetone soluble extractives, NaoH 1% soluble extractives, hot water soluble extractives and ash 46.50%, 29.54%, 7.37%, 16.25%, 6.92% and 1.27%, respectively. Physical characteristics measured of density, dry density and critical density 1024.25, 1003.83 and 913 gr. per cubic centimeter

THE PERFORMANCE OF CORN AND COTTON STALKS FOR MEDIUM DENSITY FIBERBOARD PRODUCTION

Severe shortage of suitable wood for Medium Density Fiberboard (MDF) production makes it necessary to consider using uncommon and non-conventional raw materials such as agricultural residues. In order to demonstrate the suitability and the potential of two agricultural residues (cotton and corn stalks), laboratory MDF boards were produced. Three press temperatures (170, 180 and 190 ºC) were used. Test samples were prepared from the boards after conditioning at 65% RH and 21 ºC, and all tests were performed according to relevant EN standard methods. The results indicated that the MOR and MOE of boards produced from corn stalks were higher than those from cotton stalks, by almost 25%. However significant difference was not observed for internal bonds of boards. Thickness swelling of MDF boards from corn stalks was lower than cotton stalks. Comparing the results obtained with the strength of boards produced from hardwoods showed similarity between corn stalks and wood, but the strength of MDF boards from cotton stalks was lower. However, the results almost satisfied the EN 622-5;1997 requirement

INVESTIGATION ON THE PROPERTIES OF MEDIUM DENSITY FIBERBOARDS FROM MIXTURE OF SAXAUL AND HORNBEAM WOOD

The property of MDF obtained the mixture of Haloxylon persicum wood (Saxaul) with Carpinus betulus (Hornbeam) at 100:0, 75:25, 50:50, 0:100 ratios is investigated in this study. The results of this study showed that there is significant statistical differences (1%) among combinations of woods for MOR, MOE, IB, thickness swelling after 2 & 24 hours and water absorption after 2 & 24 hours. The bending strength (MOR) of MDF produced of Hornbeam wood fibers was highest and Saxaul wood fibers were lowest. Boards produced from 50% Hornbeam and 50% Saxaul, showed the important of bending strength 57%. The average modulus of elasticity (MOE) of MDF showed significant statistical differences (1%). MDF produced from Hornbeam wood fibers had showed highest MOE and Saxaul wood fibers showed lowest MOB. The result of internal bonding (IB) showed that MDF produced from Saxaul wood fibers possessed lowest IB and Hornbeam wood fibers had highest IB. In other two combinations of Hornbeam and Saxaul wood fibers, there are no significant statistical differences (1%) with MDF produced from only of Hornbeam wood fibers

Comparative Investigation on the properties of Soda and Soda-Ethanol pulps from three hardwoods

Strength properties and the yield of soda and soda-ethanol pulps produced using hornbeam, beech and poplar woods were investigated. Soda pulps were produced applying 20% active alkali and the soda-ethanol pulps were made using 10% active alkali and 50% ethanol. The pulping temperature was constant at 175 C and the soda pulping time was selected at 120 minutes and the soda-ethanol pulping times were 120 and 180 minutes. The highest accepted pulping yield at 58.54% was reached using soda pulping on poplar wood and the lowest yield (49.29%) was related to soda-ethanol pulp produced from beech wood applying 180 minutes pulping time. The accepted yield of soda-ethanol pulping was low, but the kappa numbers of these pulps were almost 20 units lower than soda pulps. The strength properties of soda-ethanol pulps were superior to soda pulps and the difference was statistically significant at 99% confidence level. The results of this study indicated that the delignification of soda-ethanol pulping process is faster than soda pulping from the selected hardwoods especially poplar wood