Capillary rise and sorption ability of hemp fibers oxidized by non-selective oxidative agents: hydrogen peroxide and potassium permanganate

ABSTRACT

In this paper, the capillary rise and sorption ability of hemp fibers oxidized with hydrogen peroxide and potassium permanganate were studied, with the aim to get more insight into the changes in the structure of hemp fibers caused by oxidation, and to compare the influence of applied oxidative agents on hemp fibers. Capillary rise was presented as a function of a liquid rise height vs times, with determined all three capillary coefficients, while sorption ability was determined as water retention values and moisture sorption. For structural analysis of the samples the ATR-FTIR technique was used. Also, the amount of aldehyde and carboxyl groups and the lignin content in oxidized fibers were determined. The surface fibers morphology was observed by FESEM. In all oxidized hemp fibers an increase in capillarity was obtained for both oxidizing agents (33–75 mm for H₂O₂, and 40–114 mm for KMnO₄), compared to 31 mm for unmodified fibers, but decreased sorption ability. Application of both oxidative agents, were successful for introduction of functional groups into oxidized fibers, for reduction of the amount of non-cellulosic substances, as well as moisture sorption. Simultaneously, the fibers became finer, cleaner, whiter, softer and more suitable for further processing, while, generally, higher influence on changes into oxidized hemp fibers was achieved by oxidation with KMnO₄, compared to oxidation with H₂O₂.

摘要

本文研究了大麻纤维经过氧化氢和高锰酸钾氧化后的毛细上升和吸附性能，旨在进一步了解氧化对大麻纤维结构的影响，比较不同氧化剂对大麻纤维的影响. 毛细上升是液体上升高度与时间的函数，确定了所有三个毛细系数，而吸附能力则确定为保水值和水分吸附. 采用ATR-FTIR技术对样品进行结构分析. 同时测定了氧化纤维中醛基、羧基的含量和木质素的含量. 用FESEM观察了表面纤维的形貌. 在所有氧化大麻纤维中，两种氧化剂（H2O2为33-75mm，KMnO4为40-114mm）的毛细性均比未改性纤维的31mm增加，但吸附能力降低. 两种氧化剂的应用，成功地将官能团引入到氧化纤维中，减少了非纤维素物质的数量，并具有吸湿性. 同时，纤维变得更细、更清洁、更白、更柔软，更适合进一步加工，而高锰酸钾氧化对氧化大麻纤维变化的影响比H2O2氧化更大.

KEYWORDS:

• nonselectively oxidized hemp fibers
• hydrogen peroxide
• potassium permanganate
• capillary rise
• water retention
• moisture sorption

关键词:

• 关键词: non-selectively oxidized hemp fibers
• 非选择性氧化大麻纤维，hydrogen peroxide
• 过氧化氢，potassium permanganate
• 高锰酸钾，capillary rise
• 毛细血管上升，water retention
• 保水性，moisture sorption吸湿

Additional information

Funding

This work was supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia [Contract No. 451-03-68/2020-14/200135].