Effects of refining steam pressure on the properties of loblolly pine (Pinus taeda L.) fibers

摘要

Medium density fiberboard is widely used with increasing tendency in North America, particularly in the furniture sector, including door skin and cabinets. Sorption property is one of the most important factors for quality judgment. This study will present water vapor sorption behavior of fibers in the range of varying relative humidity from 11 % to 89% as affected by steam pressure of ther-momechanical refining in small-scale measurement. A 54-year-old loblolly pine tree was refined at 2 to 18 bar of steam pressure. Fiber properties were determined by scanning electron microscope, dynamic contact angle analyzer, wide angle X-ray diffractometer, and water activity meter. The results showed that steam pressure has a dramatic effect on sorption behavior and surface properties of the refined fiber. In conclusion, a higher rate of sorption was found in juvenile fiber at low steam pressure. Higher water activity and lower crystallinity was found at low steam pressure. The sorption isotherm of refined fiber was fitted very well by the Hailwood-Horrobin model.