TECHNOLOGY FOCUS - POLYMERS - Preferred Process: The process steps are carried out simultaneously or continuously. The apparatus for carrying out the process for treating fibers comprises chamber having longitudinal central axis, cylindrical enclosure, feed zone and exit zone, interior portion having interior surface and exterior portion, the feed zone is adapted for communication with fiber feeding device; shaft disposed along the longitudinal central axis of the chamber and is adopted for rotation around the axis; several pins affixed to the central axis, the pins protruding from the central axis, the pins are perpendicular in relation to the central axis; and several channels disposed in an inner wall surface of the cylindrical enclosure, each channel having predetermined width, predetermined depth and predetermined clearance from the pins. At least one of the pins has an upright shape, and helical shape. An upper portion of at least one pin comprises triangular extension. Removing at least a portion of the lignin fraction and hemicellulose fraction from the fibers comprises treating the fibers with a mixture of gaseous amine and superheated steam in gas phase, where the amine comprises ethylenediamine. Softening the fiber bundles comprises subjecting the fiber bundles to superheated steam. Swelling the fibers comprises treating the fibers with a mixture of gaseous ammonia and superheated steam in gas phase. The gaseous ammonia is produced by heating anhydrous ammonia to an anhydrous ammonia boiling point; and is produced by heating urea to urea decomposition temperature. The gaseous ethylenediamine is produced by heating a water solution of ethylenediamine to a boiling point of the ethylenediamine, the heating resulting in a mixture of ethylenediamine gas and superheated steam. The alternative process for treating fibers involves providing fibers and fiber bundles having a moisture level of 2-10%; providing a treatment apparatus comprising treatment chamber having feed zone and exit zone, where the treatment chamber is adapted for pressurization; feeding fibers and fiber bundles into the feed zone of treatment apparatus and moving the fibers and fiber bundles from the feed zone toward the exit zone; pre-treating the fibers and fiber bundles via a feed port disposed in the feed zone of the treatment chamber; macerating the fibers and fiber bundles comprises rotating the shaft at a speed of 800-2000 revolutions per minute; feeding a gaseous mixture containing steam, ammonia and ethylenediamine into the treatment chamber via at least one feed port disposed immediately downstream from the feed zone at 140-180 degrees C and pressure of 2 kilopascals gauge; and collecting the fibers at the exit zone of the treatment apparatus, the fibers exiting from the treatment chamber having a moisture level of 40-60%. The clearance between the channels and an upper portion of the pins is 0.1-0.3 inches. The depth and the width of the groves are 0.2-0.5 inches. The method of producing the gaseous mixture containing steam, ammonia and ethylenediamine involves heating an aqueous solution containing an ammonium base compound and ethylenediamine at 140-180 degrees C. The alternative process further involves washing the fibers collected at the exit of the treatment apparatus, and drying the fibers, or involves defiberizing the fiber bundles prior to feeding the fiber bundles into the treatment chamber. The gaseous mixture further comprises ethanol (10 vol.%). The ammonium base compound is selected from urea and ammonium anhydride, and feed rate of the ammonium base compound is 4-30 wt.% of the dry fibers. The feed rate of the ethylenediamine is 2-15 wt.% of the dry fibers. Pre-treating the fibers and fiber bundles comprises spraying droplets of an alkaline solution at an application rate of 0.01-0.3 wt.% of the oven dry fiber, where an alkaline component of the alkaline solution is selected from sodium hydroxide, calcium hydroxide and potassium hydroxide. Pre-treating the fibers and fiber bundles comprises spraying droplets of an acid solution at an application rate of 0.01-0.1 wt.% of the oven dry fiber, where the acid is selected from sulfuric acid, nitric acid and hydrochloric acid. EXAMPLE - No suitable example given.