بررسی ویژگیهای تخته فیبر با دانسیته متوسط‭(MDF) ‬ساخته شده از چوب پهن برگان شمال کشور

In this investigation, four hardwoods (Poplar, Hornbeam , Beech and Alder ) for medium density fiberboard (MDF) production and determining of anatomical characteristics , mechanical and physical properties of boards have been studied. variables factors such as streaming time in three levels (5,10 and 15 minutes), press time in Two levels (4 and 6 minutes) and resin content in two levels (9 and 11 percent) were investigated. The results indicated that with increasing steaming time, internal bonding (IB) and modulus of elasticity (MOE) of poplar boards decreased. However these properties with increasing of press time, increased.The maximum modulus of rupture (MOR), modulus of elasticity and internal bonding were related to MDF boards produced after 5 minutes steaming time, 6 minutes pressing time and 9 and 11 percent resin consumption. The maximum thickness swelling after 2 and 24 hours soaking in water (T.S2 & T.S24) of boards obtained at the same combination. The results indicates that the minimum MOR of hornbeam boards related to MDF boards produced after 10 minutes steaming time and maximum MOR of boards related to MDF boards produced after 5 and 15 minutes steaming time. However maximum MOE observed in MDF boards produced after 5 minutes steaming time. The maximum IB and minimum of T.S2 and T.S24 of boards , obtained under 15 minutes steaming time and 11% resin consumption condition. The results indicated that boards produced from alder fibers in 6 minutes of press time and 11% resin consumption had the highest of MOR. However , the maximum IB observed in boards that produced after 15 minutes steaming time and 11% resin consumption. In other hand the minimum T.S observed in boards produced after 6 minutes of press time . The results showed that the MOR of beech boards produced under 10 minutes of steaming time , 4 minutes of press time and 11% resin consumption was the highest . The results indicated that with increasing of steaming time to 15 minutes and press time to 6 minutes , MOR and MOE of boards to minimum decreased , but IB of boards decreased with increasing steamhng and press time . The minimum of T.S observed in MDF boards produced after 15 minutes steaming time . The results of measurement of mechanical and physical properties of MDF boards produced from four hardwoods showed that in generally the properties of boards produced with alder fibers is significantly better than other boards produced with three specieses fibers . Keyword: Medium Density Fiberboard, Poplar, Horn beam , Alder , Beech , Resin content, Steaming time, Press time, Physical and mechanical properties.

کلیدواژه ها:

چوب ، تخته فیبر ، صنوبر ، دانیسته ، متوسط ، پهن برگ ، ممرز ، راش ، توسکا ، درخت ، خصوصیات ، الیاف ، خواص فیزیکی ، خواص شیمیایی ، مقاومت خمشی ، مدول الاستیسیته ، چسبندگی ، بخارزنی ، زمان پرس