Issue 13 (1979)

Investigations carried out were aimed directly at the establishment of new guidelines in the development of optimal parameters of wood-polymer composites production with the application of thermal treatment.

Styrene was used as a wood modifying agent while Perkadox 16 and Pianofor AN were applied as radical polymerization initiators. Polymerization process was carried out in mineral oil Termol 190 heating medium, using four kinds of thermal treatment parameters.

Assuming the quality of wood-plastic composite as a criterion of assessment, it was ascertained that the most advantageous method consistent in simultaneous application of both polymerization initiators characteristic by different temperatures of half-disintegration, and heat treatment at 65°C initial temperature followed by 85°C temperature. Using initially 85°C temperature is not recommended because of monomer losses and deterioration of composite's properties. Temperature of heating medium should be raised only after achieving exothermic reaction peak in the process of styrene polymerization.

Beech bark was carbonized in laboratory under fixed conditions. Material balance of the process regarding assumed parameters, as well as some properties of carbonizates obtained are given.

The solid product (charcoal), after proper preparation with adhesive added, was subjected to activation process using physical-mechanical method and steam as an activating factor. The texture of carbonates was determined on the basis of densimetric, penetrometric and sorptive methods. Densitrometric investigations covered the determination of actual and apparent densities and calculation of the total porosity of investigated charcoal. Penetrometric studies aimed at the determination of pores structure with pore radius above 1000 Å, were carried out using mercury porosimetry method. The structure of pores with the radius below 1000 Å was determined on the basis of benzene vapour adsorption on the surface of investigated samples. Obtained results allowed to draw isotherms and were used in further calculations regarding charcoal texture.

It was ascertained, that parameters of raw material thermal processing are affecting changes in capillary structure of obtained active charcoal. The final temperature of 500°C proved to be most advantageous among three assumed temperatures (400, 500 and 600°C) in thermal treatment of beech bark. It was proved also, that active charcoal from beech bark is characteristic by capillary structure similar to charcoal from wood with somewhat higher content of mineral compounds only.

The pure of semi-pure substances being isolated from wood colphony (abietic acid, pimatic acid, hydroxy-acids, non-saponifiables) and those expected to be in colophony (aliaphatic- and aromatic-hydrocarbons, waxes, fatty alcohols, sterols) were added to gum — and wood-colophony to observe the changes of velocity of crystallisation (10 g colophony in 10 g of acetone in test tube by Viershuk).

The best results were obtained when apolar aliphatic substance, like hydrocarbons or waxes were used. It is interesting that small amount of pimaric acid moderates the crystallisation. Probably the particle of pimaric acid forms the nuclear point for the slow crystallisable part of colophony, and disturbs at the same time to form the crystals of well-crystallisable abietic acid.

Powdered wood-colophony was oxidated by standing on open place for five weeks in layer 5 mm thick. The best method to take out hydroxyacids from colophony is following:

1. extraction of colophony in Soxiet-apparatus with gasoline (b.p. 40-50°C),

2. residue dissolved in acetone was treated with cyclohexylamine to precipitate the rest of non-oxidated acids,

3. solution evaporated, residue treated with isooctane. Hydroxyacids of resin acids are insoluble.

The results of separation were tested by TLC. Spots after extraction were examined by UV and IR spectra.

The best solvent mixture for TLC was benzene:methanol = 85:15 by volume. Plates were sprayed with anisicaldehyde. Hydroxyacids separated by routine methods extraction with gasoline or isooctane as well as by the scientific ones, are mixtures of oxidated and non-oxidated resin acids.

Some methods of isolation of resin acids were compared to obtain pure abietic- and neoabietic acids. All methods used were those yielding crystalline salts of resin acids with amines. The crop of purest acids was obtained by method described by Harris and Sanderson.

UV spectroscopy as well as TLC were found as the most useful methods to control the purity of isolated compounds. It was found, that despite of literature, diethylamine is not the selective reagent for isolation of neoabietic acid, although this reagent forms mixture rich of this acid. Similar observation was taken for butanolamine. We observed butanolamine is the selective reagent precipitating salts of neoabietic acid only when abietic acid is absent in solution.

Comparison of sources of resin acids enables to find colophony as the right raw material to obtain pure acids abietic-type. Pine gum in the contrary is more easily purified form traces of abietic-type acids and therefore the gum is a more useful raw material for isolation of resin acids pimaric-type.

The purpose of work was to examine possibilities of the enrichment in proteins of needles as a fodder product.

Experiments were carried out in two variants. For the fresh pine and spruce foliage basic substances were determined, then the foliage was subjected to petrol extraction and the residue was hydrolyzed with 3% H₂SO₄ under a regular pressure. On the so obtained hydrolysis product Candida mycoderma XXV yeasts were shown. The culture was kept during 4 days at the temperature of 30°C. Remarkable increase in protein content in biomass was obtained.

In another variant foliage was subjected to the distillation with water vapour in order to remove volatile oils and afterwards to pressure hydrolysis at temperature of 120 and 140°C. Yeast culture was carried in the same way as in the first variant. There was obtained a considerable increase in protein content.

As it results from experiments the foliage of pine and spruce constitutes a valuable raw-material for the production of fodder with a high content of protein and other nutrients.

The paper concerns studies on the influence of the extraction substances upon selected hygroscopic properties of oak heartwood. Extraction of samples was done with the alcohol-benzene mixture and methanol. Examination of sorption and desorption of steam as well as swelling and shrinkage was done in air washers at adequately adjusted relative air humidities φ.

On the basis of results obtained, it was found that the isolation of extraction substances from wood causes the impairment of its hygroscopic properties studied. Sorptive and desorptive properties of wood following to extraction both with alcohol-benzene mixture and with methyl alcohol diminish and differences in the course of isotherms are marked within the entire range of relative air humidity — from 0 to 100%.

Lower swelling and shrinkage characterizes wood following to extraction.

The purpose of the work was to determine the negative impact, the dust and extracts of “manson” and “makore” wood may have upon persons employed in its processing. Experiments were carried out on mice, rats, and rabbits with the appraisal of general toxic impact, that irritating locally mucosa and allergic one. Results of studies permit to state that both kinds of wood, and particularly so their dust, indicate all those properties. Dust from “manson” and “makore” wood causes more intensive inflammatory changes in respiratory tracts than the dust of pine wood. General toxic action is caused by compounds soluble in water, ethanol, and chloroform, in the case of “makore” wood the most toxic being aqueous extract. All extracts from both kinds of wood and its dust reveal local irritating action. Chloroform extracts indicated allergen properties. In the light of carried out studies remarkable biological activity of substances contained in both kinds of tropical wood may be considered proved.

One can suppose that cordial glucosides identified by Sandermann are most important compounds with general toxic impact in the “manson” wood, while benzochinone, identified by the same researcher, is the substance with the nature of allergen. On the other hand carried out studies do not enable any conclusion about the kind of compounds causing the local irritating action. In the case of “makore” wood saponin is probably the compound with general toxic and locally irritating action, while unidentified substances soluble in chloroform are allergens.

It was aimed to establish experimentally the effect of pine sawtimber quality on the optimization of dimension stock production. Investigations carried out are constituting an attempt of the elaboration of the technology of complex raw material processing beginning from tree-length slashing and ending on obtaining material of final dimensions. The paper deals with chosen half-products for furniture and building joinery manufacture. During experiments, the method of simulated raw material conversion into lumber and half-products was applied, which enable the assessment of different assortments obtained from the same batch of timber. For showing out the effectiveness of roundwood conversion, the productivity index determined on the basis of ratio of production value to the unit of material cost was used.

Verification and generalization of investigation results demonstrated that sawtimber of I, II, and III quality classes can be utilized depending on quantitative radio of log quality groups. It was found that most usable logs for the production of half-products are those belonging to the “b” quality group and to the lesser extent logs of “a” and “c” quality groups.

Depending on half-products dimensions, lumber of III-V quality classes can also used. In the manufacture of dimension stock with the “width” method, 1-12% higher yield was obtained that with conversion by “length” method.

There were carried out the laboratory investigations, of the frequencies of natural vibrations of flat circular saws in a constant temperature, as well as of the influence of the temperature difference along the semidiameter of the saw upon the frequencies of natural vibrations of saws with diameter between 298 and 496 mm, thickness between 1.85 and 2.60 mm, with the application of clamp collars of various diameter (35, 90, 180, 220, and 240 mm). The saws had Small internal stresses resulting from the technological process of their production (they were not subject to the operation of initial stressing).

On the basis of the research carried out the following most essential conclusions can be drawn.

1. The most dangerous type of resonance vibration is the asymmetric vibration. They may occur in all values of the ratio between the diameter of the clamp collars and the diameter of the circle by the tooth bases of the saw.

2. Less dangerous types of resonance vibration are symmetric and mixed vibrations. They may appear only when the ratio between the diameter of clamp collars and the diameter of the circle by the bases of the teeth does not exceed 0.3. Thus we can eliminate those type of vibration by using larger clamp collars.

3. Saws with compensation gaps show a lower amplitude of resonance vibration than respective saws without compensation gaps.

4. Frequencies of natural vibrations and resonance rotations of a uninodal form of vibrations increase with the rise in the temperature difference between the circle of the saw tooth bases and the external perimeter of clamp collars.

5. The frequencies of natural vibrations and resonance rotations for higher forms of vibrations than uninodal decrease with the rise in the temperature difference between the circle of the saw tooth bases and the external perimeter of clamp collars.

6. Since there is still lack of adequate data in literature on the forced vibration of circular saws, it seems purposeful to carry out more extensive research in this field, since in the present paper this problem was only one of mentioned issues and could not be discussed in more detail.

The purpose of work was to examine possibilities of the application of high frequency current in plasticization and drying of beech furniture laths in manufacturing of bent furniture. While solving this problem the effect of variable parameters of time and intensity of high frequency current upon: temperature and moisture of furniture laths during heating, size of strength required to bend laths, course of moisture during the drying for furniture laths, the number of fractures and rejects occurring in the process of bending and drying of laths were determined. Tests were carried out in a press combined with generator of a high frequency current, while using adequate instrumentation. Plasticization, bending, and drying of laths according to conventional methods was done with the aid of machines and devices used in the current production of the plant. Tests included beech laths designated for the production of support boards, seat frames, and support legs. The best effects of the plasticization and drying of furniture laths were obtained under following parameters: intensity of current for plasticization — 2 A, heating duration — 20 s, current intensity during the drying of laths — 0.5 A, duration of drying — 8 min. Unit time of the operation of plasticization, bending, and drying of furniture laths is by 120-150 times shorter when compared to the conventional technique. Laths plasticized and dried in the field of high frequency current maintained in further technological process external features similar to those of laths plasticized and dried conventionally. The introduction of this technique on an industrial scale depends first of all upon supplies of generators of high frequency current.

Principles of the analytical determination of the extent of utilization of machines and technological devices with the possibility of the application of digital computers in electronic computation for a factory of furniture industry were developed in the paper with particular reference to diverse assortment and serial production.

Quantitative approach to the problem studied was presented in the form of mathematical model including leading factors exerting an important influence upon the extent of the utilization of machines and technological devices in a microeconomic scale (enterprise, furniture factory). The mathematical model constructed accounts for a serial production both of a single as well as numerous assortments.

The principles developed were verified against actual data in production practice with consideration to definite technical, organizational, and economic conditions of the factory of furniture industry producing bent-wood furniture in numerous assortments and big series during an annual period of economic activity with the application of electronic processing of data in calculations. The solution of the problem posed under conditions of the most complex field of furniture production (bent-wood furniture production) permits a broader concluding referring to the entire furniture production within the area discussed.

Results of studies carried out by the author under international cooperation on the development of an universal method of the determination of fungicidal value of wood preservatives in relation to soft-rot fungi were presented.

Two means of wood preservatives, namely of CCB and CCA type, were subjected to studies with the use of beech and pine wood infected with natural microflora in unsterilized soil and with a pure culture of Chaetomium globosum in a sterilized soil. Both methods of infection gave similar results in respect to fungicidal value.

The comparison of author's own results with those obtained by nine other laboratories enables to state that the sue of natural soils of native origin does not warrant the replicability of studies.

Alterations of conventional density of wood samples used for the determination of fungicidal value and their moisture during the final stage of studies were also identified.