Department of Textile and Leather Technology

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    Advanced biopolymer-based green composites: their processing and damage mechanism
    (Sustainable Biopolymer Composites : Woodhead Publishing, 2021-09-17) Mwesigwa, Ronald; Nkomo, Nkosilathi Zinti; Mwasiagi, Josphat Igadwa; Wanyama, Aaron
    Composites are constructions of lightweight bearing high toughness and custom-made properties for precise use, globally. In addition, bio-based composites are constructions made from natural and/or synthetic fibers and petroleum-based polymers and/or biodegradable polymers. Furthermore, green composites are constructions obtained from biopolymers and agricultural/natural or biofibers that are more environmentally friendly hence highly sought after worldwide. Currently, green composites are offering enormous benefits that are promoting them in the automotive, packaging, construction, electrical and insulation, furniture, consumer, and household industries among others. This chapter therefore presents advanced biopolymer-based green composites in relation to their processing and damage mechanism. Subtopics covered include processing and characterization of biopolymers, agricultural/natural fibers, and green composites. Various failure and damage mechanisms pertaining to green composites are also covered.
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    Bifunctional catechol-based coating strategy to construct highly effective antimicrobial polyethylene microfibers for personal protective equipment
    (ScienceDirect: Progress in Organic Coatings, 2025-01) Mbonimpa Innocent; Gongxun Zhai; Mugaanire Tendo Innocent; Jialiang Zhou; Xin Dai; Tianqi Jiang; Jinqi Wang; Hengxue Xiang; Meifang Zhu
    Polyethylene (PE) microfiber materials are of great interest in the production of personal protective equipment (PPE) due to their cost-effectiveness and excellent mechanical and barrier properties. However, they lack inherent antibacterial properties and are therefore susceptible to attack and contamination by microorganisms, leading to the spread of associated infections. Incorporating antibacterial agents onto the material's surface is an effective approach to achieve antimicrobial functionality. Nevertheless, this is limited by the chemical inertness of PE, thus requiring surface modification treatments. Here, we successfully synthesized bifunctional catechol-based antibacterial polymeric coatings and applied them to develop durable antibacterial PE fabrics through dip-coating. Cationic copolymers comprising dopamine methacrylamide (DMA) and hexylated vinyl pyridine (QVP) moieties were prepared through free radical polymerization (FRP) followed by N-alkylation with hexyl bromide. The copolymers were extensively studied to investigate the effect of composition on the yield and antibacterial properties. The copolymers exhibited good antibacterial properties in an aqueous solution, and the antibacterial activity and yield were higher in copolymers with higher QVP units. In addition, the prepared antibacterial PE fabrics exhibited good antibacterial activity against gram-positive Bacillus subtilis (B. subtilis) and gram-negative Escherichia coli (E. coli), which remained unaffected by several laundering cycles, thus hold potential for use in antibacterial protective textiles.
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    Performance comparison of decoction and ultrasound assisted extraction of Allium burdickii extracts for tie-dyeing cotton fabrics
    (Discover chemistry, 2025-12-01) Agulei, Karen D.; John T. Githaiga; Benson Dulo; Eric O. Nganyi; John Khafafa
    The selection of precise variables during the extraction and colouration with natural dyes either enhances or vitiates their yield. This research study focused on the extraction of total phenolic content from Allium burdickii bulbs and their application to cotton fabric. The extraction performed using two methods, namely decoction and ultrasound-assisted extraction, was varied under three different parameters (temperature, time, and solvent type). The extracts were qualitatively and quantitatively analysed using Raman, UV-Vis spectroscopy, and Gas ChromatographyMass Spectrometry (GC-MS). Subsequently, the extracts were applied on cotton fabric using four dyeing conditions (temperature, time, salt, and mordant concentration) and three mordanting methods (pre, meta, post), using the tie and dye method. The results confirmed the presence of compounds such as phenols, tannins, flavonoids, and saponins in the Allium burdickii bulb. The GC-MS profile revealed the presence of eight compounds in the extract. The highest TPC of 984.1 ± 5.6 mg GAE/g DW was attained using 50% glycerol, at 40 ˚C and for 60 min, using ultrasound-assisted extraction. Furthermore, Raman spectroscopic analysis confirmed the presence of functional groups, including nitroso, phenols, azo, triazenes, aromatic ethers, and alkenes. For fabric colouration, the highest exhaustion and fixation were 81.0% and 59.1%, respectively, obtained at 69.8 ˚C, 20 min, 5% mordant concentration, and 2% salt concentration conditions. This study has therefore demonstrated that the Allium burdickii bulb is a sustainable source of dye compounds suitable for use in textile colouration, and hence, can potentially substitute for the often toxic synthetic analogues.