Wyniki wyszukiwania - BazTech

1

Effect of thermal modification on some physical and mechanical properties of yellow poplar (liriodendron tulipifera)

Kurul Fatih, Görgün Hizir Volkan

Drewno : prace naukowe, doniesienia, komunikaty

|

2022

|

Vol. 65, nr 209

art. no. 1644-3985.380.01

EN

Thermal modification is a treatment method used to improve some properties of wood in order to expand its range of usage and extend its lifetime. Although it generally causes a worsening of mechanical properties, some of them can change due especially to lower equilibrium moisture content when compared with untreated wood. Therefore, we wanted to compare some properties of thermally modified and untreated samples having either the same moisture contents or those of the area of use. For this purpose, we tested untreated and thermally modified (at 180° C for 3 hours) yellow poplar (Liriodendron tulipifera) solid wood samples. We investigated density, swelling and shrinkage ratios, and anisotropy of shrinkage as physical properties, and compression and bending strength, modulus of elasticity and impact bending as mechanical properties, according to the relevant ISO standards. The results showed that thermal modification increased the dimensional stability while having a negative impact on the mechanical properties (except modulus of elasticity) at the same moisture content, as indicated in the literature. However, thermally modified samples with moisture content as in the area of use exhibited improved properties (except in the case of impact bending).

2

Influence of thermal modification in nitrogen atmosphere on the gloss of black poplar (Populus nigra L.)

Bytner Olga, Laskowska Agnieszka, Drożdżek Michał, Zawadzki Janusz

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

|

2022

|

No. 117

89--96

EN

Influence of thermal modification in nitrogen atmosphere on the gloss of black poplar (Populus nigra L.). Heat treatment of wood is a process to which improve mechanical and physical properties. During this treatment is observed changes aesthetic properties of wood among others gloss. The aim of this research was to conduct the influence of time and temperature on surface gloss of black poplar wood (Populus nigra L.). Wood was modified by heat treatment process in nitrogen atmosphere in temperaturę from 160 °C to 220 °C, and during the following time periods 2 h - 8 h. Under the influence of modification Surface of modified wood change the gloss of black poplar wood. There was correlation between temperaturę and gloss changing and longer time of treatment. In temperaturę 220 °C decrease og gloss was 45 % for radial section and 52 % for tangential section. Influence of time and temperature on modified black poplar wood was different and depend on section. Temperature of modification was in 20 % accountable for gloss change on radial section and in 38 % for gloss change on tangential section. Influence of time during the proces was much smaller then temperaturę parameters and was 3 % and 5 % respectively for radial and tangential section.

PL

Wpływ modyfikacji termicznej w atmosferze azotu na połysk drewna topoli czarnej (Populus nigra L.). Modyfikacja termiczna drewna przeprowadzana jest w celu poprawy właściwości fizycznych oraz mechanicznych. Pod wpływem obróbki następuje zmiana właściwości estetycznych drewna, w tym również połysku. Celem prowadzonych badań było określenie wpływu temperatury i czasu modyfikacji na połysk drewna topoli czarnej (Populus nigra L.). Drewno topoli czarnej było modyfikowane termicznie w atmosferze azotu w temperaturze od 160 °C do 220 °C, od 2 h do 8 h. Pod wpływem procesu modyfikacji nastąpiła zmiana połysku drewna topoli czarnej. Zmiany były intensywniejsze im wyższa była temperatura i dłuższy czas obróbki. W temperaturze 220 °C uzyskano spadek wartości połysku o 45 % oraz o 52 % odpowiednio dla przekroju promieniowego i stycznego. Wpływ parametrów modyfikacji na połysk drewna topoli czarnej był różny w zależności od analizowanego przekroju. Temperatura modyfikacji w 20 % odpowiadała za zmienność połysku na przekroju promieniowym, natomiast w 38 % za zmienność połysku na przekroju stycznym. Wpływ czasu modyfikacji był znacznie niższy niż wpływ temperatury i wynosił 3 % i 5 % odpowiednio dla przekroju promieniowego i stycznego.

3

Surface roughness and wettability performance of thermally modified rowan wood as a fast-growing species

Candan Zeki, Görgün Hızır Volkan, Korkut Süleyman, Ünsal Öner

Drewno : prace naukowe, doniesienia, komunikaty

|

2021

|

vol. 64, nr 208

35--44

EN

This study aims to examine the effect of the thermal modification process on the surface roughness properties of the wood of rowan (Sorbus aucuparia L.) as a fast-growing species. Four thermal modification processes were applied, with temperatures of 160 and 180°C and durations of 2 and 4 hours. In total five groups were compared, including the untreated group. Arithmetical mean roughness, maximum height, ten-spot average roughness, and root-mean-square deviation were measured using a stylus-type profilometer, both parallel and perpendicular to the grain, according to the JIS B 0601 standard. Wettability was determined by measuring the contact angle of a droplet of distilled water. After dripping, the camera captured several images to measure the contact angle. The results showed that thermal modification decreases the wettability of the samples. Moreover, increments in temperature and duration may further decrease wettability. On the other hand, there are no significant differences between groups in terms of the surface roughness values, measured both parallel and perpendicular to the grain, except for two groups. It is concluded that these process conditions did not substantially change the surface roughness properties of rowan wood panels. However, the decrease in wettability may provide new possibilities for the use of less-known wood species.

4

Influence of environment, temperature and time of the thermal modification of ash wood (Fraxinus excelsior L.) on the cellulose weight average degree of polymerization

Gawron Jakub

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

|

2021

|

No. 116

39--45

EN

Influence of environment, temperature and time of the thermal modification of ash wood (Fraxinus excelsior L.) on the cellulose weight average degree of polymerization . Using the size-exclusion chromatography (HPLC SEC) method, the weight average degree of cellulose polymerization was determined. The polymer was isolated by the Kürschner-Hoffer method from ash wood (Fraxinus excelsior L.). The wood was thermally modified in different environments (nitrogen, steam and air) at 190°C and modification times of 2, 6 and 10 hours. Depending on the anaerobic atmosphere used, the highest values of the weight average degree of cellulose polymerization were obtained for the nitrogen environment, followed by steam and air. The effect of modification time on the weight average degree of polymerization was observed. The highest values were obtained for wood modified at 2 hours, then 6 and 10 hours of modification. The native wood showed the highest degree of polymerization. On the basis of the results obtained, it can be concluded that for the material studied the oxidation and degradation reactions occurring depend on the environment and time for a given temperature of wood modification.

PL

Wpływ środowiska, temperatury i czasu modyfikacji termicznej drewna jesionu wyniosłego (Fraxinus excelsior L.) na wagowo średni stopień polimeryzacji celulozy. Wykorzystując metodę chromatografii wykluczania przestrzennego (HPLC SEC), wyznaczono wagowo średni stopień polimeryzacji celulozy. Polimer wyodrębniono metodą Kürschnera-Hoffera z drewna jesionu wyniosłego (Fraxinus excelsior L.). Drewno poddano modyfikacji termicznej w różnym środowisku (azot, para wodna i powietrze) w temperaturze 190°C i czasach modyfikacji wynoszących 2, 6 i 10 godzin. W zależności od zastosowanej atmosfery beztlenowej uzyskano największe wartości wagowo średniego stopnia polimeryzacji celulozy dla środowiska azotu, następnie pary wodnej i powietrza. Zaobserwowano wpływ czasu modyfikacji na wagowo średni stopień polimeryzacji. Największe jego wartości uzyskano dla drewna modyfikowanego w czasie 2 godzin następnie 6 i 10 godzin modyfikacji. Drewno natywne wykazuje największy stopień polimeryzacji. Na podstawie uzyskanych wyników można stwierdzić, że dla badanego materiału zachodzące reakcje utlenienia i degradacji są zależne od środowiska i czasu dla zadanej temperatury modyfikacji drewna.

5

Effect of thermal modification temperature of spruce wood on cutting parameters during circular saw blade cutting

Hlásková Luďka, Kopecký Zdeněk, Novák Vit

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

|

2021

|

No. 113

30--35

EN

Effect of thermal modification temperature of spruce wood on cutting parameters during circular saw blade cutting. The work examines the effect of temperature on energetical parameters (specific cutting resistance and cutting force) when cutting heat-treated wood of Norway spruce (Picea Abies) by a circular saw. The test samples were heat-treated at 160°C, 180°C, 200°C and 220°C. One sample was not heat treated and was used as a reference sample. In comparison with the theoretical assumptions, the influence of temperature on the cutting force and specific cutting resistance was confirmed. With increasing temperature of modification, the specific cutting resistance and cutting force decreased. The reduction of value of cutting force is related to changes in the chemical structure of the wood components, weight and density loss due to the increasing temperature of modification.

PL

Wpływ temperatury modyfikacji termicznej drewna świerkowego na parametry skrawania podczas cięcia piłą tarczową. W pracy zbadano wpływ temperatury modyfikacji na parametry skrawania (oprór skrawania i siła skrawania) przy cięciu piłą tarczową drewna świerka pospolitego (Picea Abies) poddanego obróbce termicznej. Próbki drewna do badań poddano obróbce w temperaturze 160°C, 180°C, 200°C i 220°C. Jako wariant kontrolny wykorzystano drewno naturalne (nie poddane obróbce termicznej). W ramach badan potwierdzono wpływ temperatury modyfikacji na siłę skrawania i opory skrawania drewna. Wraz ze wzrostem temperatury modyfikacji zmniejszały się wartosci oporu skrawania i siły skrawania. Zmniejszenie wartości siły skrawania związane jest ze zmianami struktury chemicznej składników drewna, ubytkiem masy i gęstości pod wpływem wzrostu temperatury modyfikacji.

6

Influence of geometry and annealing temperature in argon atmosphere of TiO2 nanotubes on their electrochemical properties

Nycz Marta, Paradowska Ewa, Arkusz Katarzyna, Pijanowska Dorota Genowefa

Acta of Bioengineering and Biomechanics

|

2020

|

Vol. 22, no. 1

165--177

EN

In this paper, electrochemical properties of the as-formed and thermally treated titanium dioxide (TiO2) nanotubes with diameter in the range of 20–100 nm and height in the range of 100–1000 nm were presented. In addition, the effects of annealing temperature (450–550 °C) on the electrochemical characteristics of these structures, as well as the influence of diameter and height of TiO2 nanotubes on these properties were examined. The results were referred to a compact TiO2 layer (100 nm thick). Methods: The electrochemical test included open circuit potential, impedance spectroscopy and cyclic voltammetry measurements. The scanning electron microscope with energy dispersive spectroscopy analyser, x-ray photoelectron spectroscopy, and x-ray diffraction analysers were used for surface morphology characterisation as well as elemental, phase and chemical composition of TiO2 layers. Results: It was found that nanotubes with the diameter of 50 and 75 nm (height of 1000 nm) annealed at 550 °C exhibit the lowest impedance and phase angle values. However, the voltammetric detection of potassium ferricyanide indicated that the closest to 1 Ipc /Ipa ratio were shown by nanotubes with a diameter of 50 and 75 nm annealed at 450 °C. Conclusions: On the basis of performed analysis, it can be stated that the TiO2 layer with nanotubes of 50 nm in diameter and of 1000 nm in height, annealed in 450 °C may be indicated as the ones having the most favourable sensing and biosensing properties.

7

The impact of calcination on changes in the physical and mechanical properties of the diatomites of the Leszczawka Member (the Outer Carpathians, Poland)

Figarska-Warchoł Beata, Rembiś Marek, Stańczak Grażyna

Geology, Geophysics and Environment

|

2019

|

Vol. 45, no. 4

269--282

EN

The work concerned the effects of the thermal treatment of diatomites from the Jawornik deposit (an example of the diatomites of the Leszczawka Member of the Polish Outer Carpathians). Five distinct lithological varieties were subjected to calcination at 600°C in ambient air. The thermal impact induced the following changes to the rocks. Their overall rock porosity increased, most distinctly in the initially softer varieties, and the internal pores of the siliceous frustules themselves usually became larger due to the initial melting of the silica phases. Most of the diatoms, quartz and feldspars cracked as a result of their brittle fracturing under compressive strain resulting from substantial and differing size changes of growing grains. Clay minerals were thermally transferred, changing their volume. The organic matter dispersed throughout the diatomites was partly oxidized and removed. At the same time, the structure of the rocks was strengthened, as confirmed by an increase in their microhardness. The microhardness of soft and porous diatomite varieties increased considerably on heating, but that of the hard and compact variety changed to a smaller degree. The increase is directly related to the content of the clay minerals. The impact of other mineral components was not detected. The calcination of lithologically diversified diatomites provided the mineral with raw material with deicing and antisliding properties. The technology of its production has been determined by the authors and submitted as a patent.

8

Thermal modification of wood by the method of thermo-mechanical dehydration with pressure drop

Zashchepkina N.M., Prokopovich O.V., Makarenko D.S.

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

|

2019

|

No. 106

128--133

EN

Thermal Modification of Wood by the Method of Thermo-Mechanical Dehydration with Pressure Drop. The results of experimental research of thermal wood processing by the method of high temperature drying with pressure drop are presented. Drying was carried out cyclically by heating the material under pressure to the temperature 100-140 oC followed by pressure drop. After that the temperature was raised up 160-210 oC and the samples were processed briefly in those conditions. This treatment is shown to be effective for largesized wood.

PL

Termiczna modyfikacja drewna metodą termo-mechanicznego suszenia z redukcją ciśnienia. Przedstawiono wyniki badań eksperymentalnych obróbki termicznej drewna metodą suszenia wysokotemperaturowego ze spadkiem ciśnienia. Suszenie prowadzono cyklicznie poprzez ogrzewanie materiału pod ciśnieniem do temperatury 100- 140 oC, a następnie redukcji ciśnienia. Kolejno temperaturę podwyższano do 160-210 oC i realizowano obróbkę termiczną. Modyfikacja tego typu okazała się szczególnie skuteczna w przypadku elementów drewnianych o dużych rozmiarach.

9

ATR-FTIR spectroscopic analysis of thermally modified wood degraded by rot fungi

Ozgenc O., Durmaz S., Hakki Boyaci I., Eksi-Kocak H.

Drewno : prace naukowe, doniesienia, komunikaty

|

2018

|

vol. 61, nr 201

91--105

EN

The resistance of thermally modified oriental spruce, Scots pine, and oriental beech wood samples against fungi is investigated under different temperatures. Thermally modified wood samples are subjected to brown-rot fungi or white-rot fungi. In the control samples, 32-43% of the total mass losses are caused by fungal degradation, but only 0.47-0.78% was caused by the thermally modified wood samples. The changes in the wood cell walls main components, in the wood samples were analysed via attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. The thermally modified and the control wood samples’ spectra after the decay test exhibit different intensities. Thermal modification increases wood’s resistance against decay by removing hemicellulose polymers from the wood cell wall. The resistance against the decay of thermally modified wood is quite high due to the loss of hemicellulose polymers in the wood cell wall. The thermally modified wood structure was also investigated via scanning electron microscopy (SEM) after decay testing. SEM images clearly elucidate that fungal degradation was not effective on the thermally modified wood samples. Conclusively, our study reveals that thermal modification improves some wood’s resistance in Turkey against fungal activity.

10

The Effect of Phosphates and Fluorides, Included in TiO2 Nanotube Layers on the Performance of Hydrogen Peroxide Detection

Arkusz K., Krasicka-Cydzik E.

Archives of Metallurgy and Materials

|

2018

|

Vol. 63, iss. 2

765--772

EN

Titania nanotube (TNT) arrays fabricated by anodizing of titanium foil in organic (ethylene glycol) and inorganic (phosphoric acid) electrolytes and thermally modified in argon revealed much improved properties to detect hydrogen peroxide. Horseradish peroxidase and acetate thionine co-absorbed by a dip coating on the TNT electrode were used to detect hydrogen peroxide in phosphate buffered saline. The morphology and electrochemical properties of TNT arrays were studied by scanning electron microscopy, electrochemical impedance spectroscopy and cyclic voltammetry. Well defined oxidation and reduction peaks for potassium ferricyanide have been observed for TNT formed in ethylene glycol and annealed in argon. TNT arrays formed in organic electrolyte and annealed in argon indicated more favorable adsorption and electrochemical properties what was confirmed by detection of hydrogen peroxide towards analyte in phosphorate buffered saline solution.

11

Anatomical changes of thermal modified hornbeam wood

Pinčevskaâ E., Gorbačeva A., Lihanov A.

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

|

2018

|

No. 104

207--212

EN

The results of wood anatomical structure change study due to the high temperatures effect are presented. As samples, was used heat-treated hornbeam wood at temperatures of 160, 190 and 220 °C for 1, 10 and 20 hours. The diameter of pores in the cell walls of the vessels and fibrous elements increases in the hornbeam wood treated at a temperature of 160 °C for 20 hours also the thickness of the cell walls were decreased slightly. When the treatment temperature is increased to 190 °C, significant and irreversible changes occur in the tissues and at 220 °C were discovered complete or partial charring of the organics of the cells of the core rays.

12

Characterization of thermally modified wood at different industrial conditions

Herrera R., Krystofiak T., Labidi J., Llano-Ponte R.

Drewno : prace naukowe, doniesienia, komunikaty

|

2016

|

vol. 59, nr 197

151--164

EN

In this study European ash wood (Fraxinus excelsior L.) was modified at 192ºC and 202ºC in Thermo-Drewno®, Poland; and at 212ºC in Termogenik®, Spain. After modification, samples were characterized by wet chemistry according to standard methods (TAPPI) and by instrumental methods (FT-IR); in addition, surface and physical properties were measured (density, acidity, moisture, water uptake, contact angle, colour) in order to quantify changes due to treatment and temperature. The results showed that chemical composition of modified wood presents a gradual variation according to the heating regime, regardless of the industrial process applied; the greatest differences were obtained in treatment at 212°C compared to untreated wood. Furthermore, the density (< 0.68 g·cm-3) of modified wood decreased proportionally to treatment temperature. Colour measurements showed proportional changes to darker colours depending on the treatment temperature. On the other hand, some physical properties did not vary significantly between treatments, obtaining similar values of contact angle (97°-99°) and of moisture content (<7%).

13

Thermogravimetric analysis of commercial thermally modified wood

Grześkowiak W. Ł., Bartkowiak M.

Drewno : prace naukowe, doniesienia, komunikaty

|

2015

|

vol. 58, nr 194

23--36

EN

In the article the results are shown of a thermogravimetric analysis of four thermally modified wood species. Thermally modified wood before and after the extraction process was used for the tests. The extraction process had no significant effect on changes in the thermal characteristics either in the raw wood or in the modified wood, irrespective of the tested wood species.

14

Badanie wpływu modyfikacji termicznej na zachowanie elementów rozciąganych w podwyższonych temperaturach

Ogrodnik P., Tatka B.

Zeszyty Naukowe SGSP / Szkoła Główna Służby Pożarniczej

|

2014

|

Nr 50 (2)

43--51

PL

W artykule przedstawiono wyniki badań wpływu rodzaju modyfikacji termicznej na wytrzymałość drewna przy rozciąganiu podczas oddziaływania termicznego. W badaniach wykorzystano próbki o kształtach i wymiarach zgodnych z obowiązującą normą. Modyfikacja termiczna próbek drewnianych została przeprowadzona w dwóch różnych procesach do temperatury maksymalnej wynoszącej odpowiednio 165°C oraz 210°C. Badania wytrzymałościowe zostały wykonane na uniwersalnej maszynie typu FPZ 100/1 z jednoczesnym ogrzewaniem próbek do 200°C. Wyniki badań przedstawione w formie tabelarycznej wykazały istotny wpływ modyfikacji termicznej na wytrzymałość drewna zarówno w temperaturze normalnej po ochłodzeniu próbek do temperatury otoczenia, jak i w podwyższonej. Wykazano również różnice, które występują podczas badań wytrzymałościowych w zakresie zniszczenia próbek. W przypadku badań prowadzonych w 200°C zniszczenie próbek jest równomierne i następuje w środku ich długości, natomiast w temperaturze normalnej 20°C rozciągane drewno rozrywało się w sposób nierównomierny.

EN

The article presents the results of tests on the influence of the thermal modification on wood strength while being spread during thermal interaction. The shape and size of the samples used in the tests are compatible with the standard in force. The wood thermal modification has been done in two different processes up to max temperatures of 165°C and of 210°C. The strength tests have been made in the universal machine of the FPZ 100/1 type with the simultaneous heating the samples up to 200°C. The tests results ,presented in a tabular way, have shown the considerable influence of the thermal modification on wood strength, both in normal temperature after cooling the samples to surrounding temperature and in higher. Some differences which occur during the strength tests and during the failure of the test samples have been presented. During the tests conducted in the temp of 200°C ,the failure of the test samples is at a uniform rate and occurs inside their length while in the normal temperature of 20°C the spreading wood was tearing itself in a non-uniform way.

15

Intensyfikacja właściwości bakteriobójczych lizozymu na drodze jego termicznej modyfikacji

Kopeć K., Lutyńska A., Dąbkowska K.

Inżynieria i Aparatura Chemiczna

|

2014

|

Nr 4

259--260

PL

Termiczna modyfikacja lizozymu jest jedną z metod zwiększania jego właściwości antybakteryjnych przeciwko bakteriom Gram-ujemnym. W pracy przedstawiono wyniki badań nad doborem najlepszych wartości podstawowych parametrów tego procesu. Wykazano, że modyfikacja prowadzona przy pH 4,40 przez 15 minut w temperaturze 80°C znacząco zwiększa właściwości bakteriobójcze lizozymu przeciwko bakteriom E. coli (Gram-ujemne) nie powodując spadku aktywności przeciwko bakteriom M. luteus (Gram-dodatnie).

XX

Thermal modification of lysozyme is one of methods of increasing its antimicrobial properties against Gram-negative bacteria. The paper presents research on determining the best values of basic parameters of this process. It is shown that modification carried out at pH 4.40 for 15 minutes at 80°C significantly increases the lysozyme antibacterial properties against E. coli (Gram-negative bacteria) without causing a decrease in activity against M. luteus (Gram-positive bacteria).

16

Influence of thermal modification of Scots pine wood (Pinus sylvestris L.) on color changes

Jankowska Agnieszka, Kozakiewicz Paweł

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

|

2014

|

No. 88

92--96

EN

Influence of thermal modification of Scots pine wood (Pinus sylvestris L.) on color changes. This study describes experiments of testing color of heat treated wood samples. Heat treatment was done at 150, 160, 170 i 180 °C during 2,5 h in over heated steam. Color measurement was made according CIE LCh system. The experiment show that thermally treatment caused darkening of wood. The higher temperature of modification is, the greater changes in color are and difference between sapwood and heartwood are lower. Heartwood of Scots pine showed higher changes than sapwood.

17

Influence of pine wood (Pinus sylvestris L.) thermal modification on the withdrawal force of screws

Kurowska A., Kozakiewicz P., Kędzierski A.

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

|

2014

|

No. 88

130--135

EN

Influence of pine wood (Pinus sylvestris L.) thermal modification on the withdrawal force of screws. In the study the force required to withdraw the screw from thermally treated pine wood was examined. Modification of pine wood was performed at a temperature range of 150 - 180oC. It was concluded that the process of wood modification does not significantly affect the force needed to pull a screw out, and therefore also the withdrawal capacity and the ability to maintain the screw. In the case of 3.5 x 35 mm and 4.0 x 35 mm screws, the withdrawal capacity constituted respectively 63% and 50% of the ability to maintain the screw.

18

The effect of thermal modification of ash wood on granularity and homogeneity of sawdust in the sawing process on a sash gang saw prw 15-M in view of its technological usefulness

Dzurenda L., Orlowski K. A.

Drewno : prace naukowe, doniesienia, komunikaty

|

2011

|

vol. 54, nr 186

27-37

EN

This paper presents the results of granulometric analyses of sawdust of unmodified and thermally- modified ash wood (Fraxinus exelsior L.) sawed on a narrow-kerf sash gang saw. The sawdust of dry thermally-modified ash produced in the sawing process on a frame sawing machine PRW15-M at a feed speed in the range of 0.36-1.67 mźmin-1 has chip granularity ranging from 33.5 micro m to 9.9 mm; whereas unmodified ash wood sawdust consists of chips in a granularity range from 35.6 micro m to 13.8 mm. It was observed that thermally-modified ash sawdust is finer, with a distinctly larger share of the fraction in the granularity range a = 125-500 micro m and a slightly increased share of the fraction in the range a = 32-125 ěm. Changes in mechanical characteristics of modified wood were also observed in the technological usefulness of a part of dry sawdust chip in the granularity range a = 250 micro m-2.4 mm. While the homogenous share of chips in sawdust produced in the process of sawing of dry ash wood was HSCha = 81-84 %, the demonstrated homogenous share of chips in ash sawdust formed in the process of sawing of dry thermally-modified wood was lower by 4-6 %.

PL

Przedstawiono wyniki analiz granulometrycznych trocin, drewna jesionowego niemodyfikowanego (Fraxinus exelsior L.) i modyfikowanego termicznie, otrzymanych w procesie przecinania drewna na pilarce ramowej wielopiłowej PRW15-M. Przecinanie drewna prowadzono dla dwu prędkości posuwu 0,36 mźmin-1 oraz 1,67 mźmin-1. Ziarnistość powstających trocin dla drewna jesionowego modyfikowanego termicznie zawierała się w przedziale od 33,5 micro m do 9,9 mm, podczas gdy dla drewna niemodyfikowanego ziarnistość trocin mieściła się w przedziale od 35,6 micro m do 13,8 mm. Stwierdzono, iż trociny otrzymywane z drewna modyfikowanego termicznie są bardziej miałkie, z większym udziałem frakcji o ziarnistości w przedziale a = 125 – 500 micro m, z nieznacznie większym udziałem frakcji z zakresu a = 32 – 125 micro m. Zaobserwowano również, że przydatność technologiczna trocin mieszczących się w zakresie ziarnistości a = 250 micro m – 2.4 mm dla drewna jesionowego niemodyfikowanego termicznie zawiera się w przedziale 81 – 84 %, zaś dla drewna jesionowego modyfikowanego termicznie jest mniejsza o około 4 – 6%.

19

Physical and mechanical properties and resistance to fungi of Scots pine and birch wood modified thermally and using natural oil

Fojutowski A., Noskowiak A., Kropacz A.

Drewno : prace naukowe, doniesienia, komunikaty

|

2009

|

vol. 52, nr 181

43-62

EN

Thermal modification and impregnation with natural oil may improve functional properties of wood. However, to a great extent changes in wood properties depend on the conditions of thermal modification process and on the impregnation method and type and amount of the oil used. The Wood Technology Institute in Poznan conducted research on thermal modification of wood which joined thermal modification and introduction of natural oils into wood. The aim of the research was to identify properties of Scots pine and birch wood subjected to such modification. This paper presents results of determinations of the effect of thermal and thermo-oil treatment of wood on its strength, equilibrium moisture content, and resistance to fungi. It was observed that some functional properties of wood improved and resistance to Basidiomycotina fungi increased, even after the wood was subjected to accelerated ageing by evaporation or leaching with water.

PL

Celem badań było określenie wytrzymałości, hydrofobowości i odporności drewna termomodyfikowanego i drewna poddanego modyfikacji termo-olejowej na działanie grzybów powodujących rozkład (Basidiomycotina). Obiektem badań były próbki bielu drewna sosny zwyczajnej oraz drewna brzozy. W wyniku termomodyfikacji gęstość drewna zmniejszyła się o 8%, ale wzrosła o 18% w wyniku modyfikacji termo-olejowej. W porównaniu z wartościami wytrzymałości dla drewna naturalnego, drewno sosny zwyczajnej i brzozy poddane termomodyfikacji i modyfikacji termo-olejowej wykazało zwiększoną wytrzymałość na ściskanie wzdłuż włókien oraz moduł elastyczności przy zginaniu, ale zmniejszoną wytrzymałość na zginanie. W porównaniu z drewnem naturalnym wilgotność równowagowa drewna poddanego termomodyfikacji i modyfikacji termo-olejowej była wyraźnie niższa w przypadku obu badanych gatunków drewna. Modyfikowane drewno sosny zwyczajnej i brzozy badane metodą opartą na normie EN 113 cechowało się zwiększoną odpornością na działanie grzybów Coniophora puteana lub Trametes versicolor odpowiednio po wymywaniu (EN 84) lub odparowaniu (EN 73).