Investigation of some technological properties of particleboards produced from wood chips impregnated

In this study, effects of various impregnation substances on some technological properties of particleboards produced in the laboratory by using wood chips treated with various chemicals were investigated. The wood raw material used in the experiments were the mixture of coniferous tree species [70 %, Pinus brutia Ten., Pinus nigra Arn var. Pallasiana (Lamb. ) Holmboe, Cedrus libani Ait.] and black poplar (30 %, Populus nigra L.). In the mixture of the above mentioned species, bark have been accepted up to 5 percent. As preservatives, the following chemicals were used with the consentrations given in the brackets; urea-formaldehyde resins (65 %), ammonium clorure (33 %), rosin (10 %), synthetic resin (20 %, long chained alkyd resin), boric acid (5 %), ammonium sulfate (7 %), tanalith-CBC (10 %), borax (5 %), immersol-WR 2000 (1. 76 %), boric acid I borax (2. 5 I 2. 5 %), tanalith-CBC I boric acid I borax (5 I 2.5 I 2.5 %). Three layers of particleboards were prepared by using 10 % adhesive for ciphs of outer layers and 8 % for middle layer according to weight of oven dry chips. As chemicals, 10 % ammonium clorure, 1, 1. 5 and 3 % rosin, 1, 1.5 and 3 % alkyd resin, 1, 1. 5 and 3 % ammonium sulfate, 0. 5, 0.75 and 1.5% boric acid, 0. 5, 0. 75 and 1.5% borax, 0. 5, 0. 75 and 1.5 % boric acid I borax, 0. 6, 0. 9 and 1.8 % tanalith-CBC, 0. 6, 0. 9 and 1.8 % tanalith-CBC I boric acid I borax, 0. 3, 0.45 and 0.9 % immersol-WR 2000 were used for each layers according to weight of oven dry adhesive. The press conditions and the production properties of particleboards were as follows; press temperature = 150 °C, pressing time = 6 min, press closing time = 70 - 80 sec, press pressure = 25 - 28 kp/cm2, thickness = 20 mm, width and length = 56 x 76 cm, outer layers = 35 % of thickness of boards, middle layer = 65 % of the thickness. The experimental boards were conditioned at 20 ± 2 °C temperature and 65 ± 5 % relative humidity for three weeks. All the samples used in the experiments were prepared from those boards with the dimensions given in the national and international standards. The samples were used for determination of following properties of the boards; specific density, moisture content, amounts of water absorption and thickness swelling for 2, 24 and 48 hours immersion in water, bending strength, modulus of elasticity in bending, tensile strength perpendicular to the plane, flame and non-flame (flaming, embering) resistances, amount of weight lost after flame and non-flame. The values obtained from the experiments were evaluated statistically with the analysis of variance, the multiple range tests (duncan) and the correlation analysis (p < 0. 05). The results were compared with values given in the standards and the related literature. As a result; specific density, moisture content, bending strength, modulus of elasticity in bending, tensile strength perpendicular to the plane, flame and non-flame resistances, amount of weight lost after flame and non-flame of the particleboard showed a certain improvement with increasing of use rates of impregnation substance for all of the board groups. However, amounts of water absorption and thickness swelling at 2, 24 and 48 hours immersion in water decreased for rosin and alkyd resin board groups, whereas it increased for other the groups. Also, water absorption and thickness swelling increased with the increase of soaking time. The rates of increase in water absorption and thickness swelling decreased with the increase of soaking time. The preventive effects of water repellents also decreased with the increase of time. Keywords: Water Repellents, Water - Soluble Salts, Organic Solvent - Soluble Substances, Boron Solutions, Fungicits, Insecticits, Fire Retardants, Impregnation, Impregnated Chips, Particleboard, Physical Properties, Mechanical Properties, Cumbostion Resistance, Rots Resistance, Insects Resistance.