Fabrication of pondcypress fiber with intact structure and multiple active hydroxyl groups by alkali aided two-step mechanical refining.

Due to the compact tissue structure and stable molecule structure of plant fiber, converting fiber into high value-added products in current biomass utilization is still challenging, which restricts the application of many fiber-based composite materials. Herein, chemical impregnation and two-step mechanical refining (1st mechanical refining and 2nd mechanical refining) were proposed to solve this problem. The pondcypress (taxodium ascendens) fibers containing multiple surface active sites were prepared, based on the degradation and dissociation effects of alkaline hydrogen peroxide (AHP) and disc milling. The prepared fibers showed the intact spatial structure with excellent cellulose accessibility. It was found that the degradation of lignin and hemicellulose (excluding glucan) was 12.09% and 60.45%, respectively, at the optimized dosage of 10% H₂O₂ and 17.5% NaOH, in which the treated fibers remained high cellulose content. As expected, the cellulose accessibility was increased from 6.42% (raw fiber) to 47.26% after the treatment. Significantly, the treated fibers displayed higher specific surface area and active hydroxyl content (1.49 × 10^–3 mol/g) due to the exposure of internal cell wall. This makes decomposed fibers an interesting candidate of ideal carrier for fiber composite. [ABSTRACT FROM AUTHOR]