Extraction and Characterization of Fiber and Cellulose from Ethiopian Linseed Straw: Determination of Retting Period and Optimization of Multi-Step Alkaline Peroxide Process

Kibrom Feleke; Ganesh Thothadri; Habtamu Beri Tufa; Ali A Rajhi; Gulam Mohammed Sayeed Ahmed

doi:10.3390/polym15020469

Extraction and Characterization of Fiber and Cellulose from Ethiopian Linseed Straw: Determination of Retting Period and Optimization of Multi-Step Alkaline Peroxide Process

Polymers (Basel). 2023 Jan 16;15(2):469. doi: 10.3390/polym15020469.

Authors

Kibrom Feleke¹, Ganesh Thothadri², Habtamu Beri Tufa¹, Ali A Rajhi³, Gulam Mohammed Sayeed Ahmed^{1

4}

Affiliations

¹ Department of Manufacturing Engineering, School of Mechanical, Chemical and Materials Engineering, Adama Science and Technology University, Adama P.O. Box 1888, Ethiopia.
² Department of Materials Engineering, School of Mechanical, Chemical and Materials Engineering, Adama Science and Technology University, Adama P.O. Box 1888, Ethiopia.
³ Department of Mechanical Engineering, College of Engineering, King Khalid University, Abha 61421, Saudi Arabia.
⁴ Centre of Excellence (COE) for Advanced Manufacturing Engineering, Program of Mechanical Design and Manufacturing Engineering, School of Mechanical, Chemical and Materials Engineering, ASTU, Adama P.O. Box 1888, Ethiopia.

Abstract

Flax is a commercial crop grown in many parts of the world both for its seeds and for its fibers. The seed-based flax variety (linseed) is considered less for its fiber after the seed is extracted. In this study, linseed straw was utilized and processed to extract fiber and cellulose through optimization of retting time and a multi-step alkaline peroxide extraction process using the Taguchi design of experiment (DOE). Effects of retting duration on fiber properties as well as effects of solvent concentration, reaction temperature, and time on removal of non-cellulosic fiber components were studied using the gravimetric technique, Fourier transform infrared (FTIR) spectroscopy and thermal studies. Based on these findings, retting for 216 h at room temperature should offer adequate retting efficiency and fiber characteristics; 70% cellulose yield was extracted successfully from linseed straw fiber using 75% ethanol-toluene at 98 °C for 4 h, 6% NaOH at 75 °C for 30 min, and 6% H₂O₂ at 90 °C for 120 min.

Keywords: cellulose; extraction; fiber; linseed straw; optimization; retting.

Grants and funding

We thank Adama Science and Technology University School of Mechanical, Chemical and Material Science and Engineering for Ph.D. research funding and laboratory access. Furthermore, the authors extend their appreciation to the Deanship of Scientific Research at King Khalid University, Saudi Arabia, for funding this work through the Research Group Program under grant No. RGP. 2/129/43.