Research Paper
Composite wood products
Ahmad Jahan latibari; Abdolrahman Hosseinzadeh; Taghi Tabarsa
Abstract
In this investigation, the effect of mat moisture content, press temperature and time on polymerization reaction of urea-formaldehyde (UF) resin and the strength of UF bonded hornbeam particleboard is studied. Variation of three variables is as followed:
-mat moisture content; 10, 13 and 16% (Based ...
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In this investigation, the effect of mat moisture content, press temperature and time on polymerization reaction of urea-formaldehyde (UF) resin and the strength of UF bonded hornbeam particleboard is studied. Variation of three variables is as followed:
-mat moisture content; 10, 13 and 16% (Based on oven dry weight of wood)
-Press temperature; 150, 170 and 190 ᵒC
-Press time; 4, 6, and 8 min.
Fore boards were manufactured for each combination of variables. Modulus of rupture (MOR), modulus of elasticity (MOE), Internal bond (IB), water absorption (Wa2 and Wa24) and thickness swelling (Ts2 and Ts24) after 2 and 24 hours immersion in water were determined according to ASTM 1037 standard. All data was analyzed using factorial design. The effect of mat moisture content on MOR was not statically different, but its effect on MOE was statistically different at 5% significance level, and increasing the mat moisture content from 10 to 16% bout MOR & MOE. Highest level of MOE (4262 MPa) corresponds to board pressed at 16% mat moisture content. On the contrary, mat moisture content decreased the IB and lowest value of IB ( 1.447 MPa) corresponds to boards pressed at 16% mat moisture content. The effect of mat moisture content on IB was statistically different at 1% significance level. Increasing mat moisture content decreased water absorption and increased thickness swelling. Lowest Wa2 & Wa24 was observed on boards pressed at 16% mat moisture content (67.35% & 86.78% respectively) and lowest Ts2 & Ts24 was observed on boards pressed at 10% mat moisture content (21.89% & 27.32% respectively). There force for the production of suitable boards, ma moisture content must be kept at 10-13% range.
Research Paper
Composite wood products
Ahmad Jahan latibari; Abdolrahman Hosseinzadeh; Amir Nourbakhsh; Abolfazl Kargarfard; Fardad Golbabaei
Abstract
The influence of production variable such as residues moisture content at time of chipping or flaking, hardner and press time on properties of particleboard from date palm residues is investigated. Each variable was investigated at three different levels and a total of 24 combinations of variables were ...
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The influence of production variable such as residues moisture content at time of chipping or flaking, hardner and press time on properties of particleboard from date palm residues is investigated. Each variable was investigated at three different levels and a total of 24 combinations of variables were studied. The results of this investigation indicate that:
- Residues moisture content at the time of chipping or flaking affects both physical and mechanical properties of boards. MOR and MOE of board made from flakes produced by dry chipping and either wet or dry flaking was higher than others and its dimensional stability was better.
Chipping or flaking moisture did not affect IB significantly.
- Hardner consumption did not significantly influence the properties, but increasing hardner consumption to 3 percent of resin content (solid basis) improved board properties.
- Press time also did not influence board properties and for the production of 15 mm. boards, either 5 or 6 minutes press time can be used.
-For the production of boards to satisfy DIN requirement, following variable combination can be utilized: dry chipping - wet flaking, 3 percent hardner and 6 minutes press time.
