Proceedings e report - Firenze University Press

2. Materials and Methods
UTILIZATION OF POMEGRANATE WOOD FOR PARTICLEBOARD PRODUCTION
In this study, several of the factors related to manufacturing conditions had been taken to be variable.
These variables were as follow:
1. Resin content level in making the particleboard was at 10% and 12% (based on the weight of the
particleboard).
2. In this research, the press time in making the particleboard was 4 and 5 minutes.
3. In this research, the third variable factor was the combination of pomegranate wood and poplar
wood. Four combinations exhibited in Table 1 were used.
Table 1-Percentage of pomegranate wood and poplar wood in wood combination and their abbreviated names
Abbreviated Name of the Percentage of Used Wooden Material
Wood Combination Pomegranate Poplar P.n
A 100 Zero
B 75 25
C 50 50
D Zero 100
Other manufacturing factors including specific gravity of the board (0.75 gr/cm3), pressure (30
kg/cm2), moisture content of particle wood mat (12%), press temperature (175°C), thickness of the
board (15 mm), liquid urea formaldehyde (UF) (50%) were taken to be fixed in all treatments.
For making particleboard for this research, the wood of pomegranate trees of suburbs of Kashan City
of Esfahan Province was used. After being transported to the laboratory, the pomegranate woods were
chopped to smaller parts by one rolling laboratory chipper and then were converted by a ring mill into
particles usable in making particleboards. The moisture content of the prepared particles was about
30%. Using a drier and temperature of 120°C, the particles were dried and the degree of moisture
content lowered to 1%. They were packed in resistant bags which were moisture insulators. For
including poplar wood in the combination of the wood material used in making particleboard, 3 poplar
trees of P. nigra species were cut down and carried to the laboratory. In the laboratory, particles were
prepared from the carried poplar wood. For applying resin to the particles, one laboratory gluing
instrument was used. From a nozzle and by using compressed air, the resin solution and one catalyst
were sprayed on the fibres which were rotating inside in the resin spraying compartment. The resin
solution, catalyst, and fibres were mixed together thoroughly. For making the mat, a wooden mould
with dimensions of 40 x 40 cm was used. The wood particles, treated with the resin and weighed in a
laboratory scales, were sprayed into the mould uniformly.
When the mats were prepared, they were pressed with a laboratory press and experimental
particleboard samples were made. In this research, by combing the three variables in different levels,
16 treatments were obtained. Each treatment was repeated three times. So, totally 48 boards were
made. After termination of press stage, for conditioning and making the moisture of the boards
uniform as well as for giving equilibrium to internal stress, the produced boards were kept in
laboratory conditions (relative humidity 65±1% and temperature 20±3°C).
For determining physical and mechanical properties of the boards, experimental samples were
prepared by using one round saw. First, the boards were trimmed and then in compliance with DIN-
68763 standard, samples were cut for determining Modulus of Rupture (MOR), Modulus of Elasticity
(MOE), Internal Bonding (IB), Thickness Swelling (TS) after 2 and 24 hours immersion in water
(T.S.2 and T.S.24).
After performing mechanical and physical tests on prepared samples, the results were analyzed using
Randomized Complete Block Experimental Design under 3-variable tests and through using Dunken
Test (DMRT) and with the aid of variance analysis technique. By this statistical method, the
independent and mutual effects of each variable factor on the studied properties were analyzed at the
confidence level of 99 and 95%. Table 2 shows the dimensions and number of the specimens in each
repetition and treatment.
326