Chemical esterification of wood biopolymers using acetic acid is a green method to sustain and improve the physical properties of native tropical hardwoods in part by drastically reducing the surface energy.

The sustainable development of lignocellulose fibers exhibits significant potential to supplant synthetic polymer feedstocks and offers a global platform for generating sustainable packaging, bioplastics, sanitary towels, wipes, and related products. The current research explores the dynamics of fiber production from wood, non‐wood, and agro‐residues using carbonate hydrolysis and a mild kraft process without bleaching agents. With respect to carbonate hydrolysis, high yield, and good coarseness fibers are attained using a simple, low‐cost, and ecofriendly process. Fibers produced using a mild kraft process have lower Klason lignin, carboxyl content, surface charges, and higher fiber length, and crystallinity. Eucalyptus fibers show the highest crystallinity while softwood carbonate fibers show the lowest crystallinity. Hemp hurd fibers contain the highest concentration of hard‐to‐remove water, and thus, suffer maximum flattening visualized by the microscopic images. The relatively high yield sustainable fibers with versatile properties can provide a significant economic benefit since fiber is the dominant cost for producing various bioproducts to meet society's current and future needs.

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Two laboratory high-lignin-content softwood (SW) kraft pulps with kappa values of 48.0 and 49.5, prepared by cooking at high and low active alkali (AA), were used for the study of fiber charge development during two-stage oxygen delignification with inter-stage washing (OwO). It was established that the first oxygen delignification (O) stage increased total fiber charge by 2-4%, and further O-delignification via a second O-stage led to a 3-18% decrease in total fiber charge. Carboxylic acid content in pulp holocelluloses decreased by 12-26% with respect to a 35-70% kappa number reduction due to an O and OwO stage of delignification for high and low AA cooked SW kraft pulps. After an OwO-stage delignification, the residual lignin was found to exhibit a 50-100% increase in carboxylic acid content. 13 C NMR spectral data for the residual lignin samples indicated that the unconjugated/ conjugated acid ratio was approximately (3-4):1. Generally, the carboxylic acid content in low AA cooked softwood kraft pulp and the corresponding oxygen-delignified pulps was systematically higher (13-23%) than that in high AA cooked SW kraft pulp and the corresponding oxygen-delignified pulps. The experimental results also demonstrated that maximum acid-group content in total fiber occurred after 45-50% oxygen delignification of the SW kraft pulps studied.