ETİYOPYA'DA YETİŞTİRİLEN ERI İPEK LİFLERİNİN MORFOLOJİK VE MEKANİK KARAKTERİZASYONU

Öz

Eri ipeği (Samia ricini), gelişmiş tekstil, biyomedikal ve kompozit uygulamaları için güçlü potansiyele sahip, sürdürülebilir ve etik, iplik haline getirilemeyen bir ipek olarak giderek daha fazla kabul görmektedir. Bununla birlikte, Etiyopya'da yetiştirilen Eri ipeğinin yapısal ve mekanik davranışına ilişkin bilimsel anlayış sınırlı kalmaktadır. Bu çalışma, farklı Etiyopya tarımsal ekolojik koşullarında (Bahir Dar, Arba Minch ve Awash-Melkasa) yetiştirilen üç Eri ipeği çeşidinin (Çin Beyazı, Borduar Beyazı ve Kokrajhar Tuğla Kırmızısı (Hint kökenli)) ilk kapsamlı morfolojik ve mekanik karakterizasyonunu sunmaktadır. Tarama elektron mikroskobu (SEM), uzunlamasına ve enine kesit morfolojisinde önemli farklılıkları ortaya koymuştur. Zamk giderme işleminden önce, tüm lifler karakteristik granüler serisin kaplamaları sergilemiştir; ancak Çin Beyazı çeşidi, fibroin çekirdeğinin homojen serisin kapsüllenmesini gösteren en pürüzsüz ve en homojen yüzeyi sergilemiştir. Borduar Beyazı ince, ayrık serisin kümeleri gösterirken, Kokrajhar Tuğla Kırmızısı daha büyük ve daha düzensiz serisin birikimleri sergilemiştir. Kesit analizi ayrıca, Çin Beyazı liflerinde üçgen ve orta derecede paketlenmiş bölümlerin, Borduar Beyazı'nda karışık bükülmüş geometrilerin ve Kokrajhar Tuğla Kırmızısı'nda kompakt uzunlamasına morfolojilerin baskın olduğu farklı yapısal organizasyonu ortaya koymuştur. Mekanik karakterizasyon, ipek çeşidinin ve yetiştirme bölgesinin incelik, dayanıklılık, uzama ve Young modülü üzerinde önemli etkileri olduğunu göstermiştir (p < 0.0001). Lif inceliği 2,4-4,0 denye ve dayanıklılık 2,5-3,5 g/denye arasında değişti. Çin Beyazı sürekli olarak üstün dayanıklılığa ve modüle sahip daha ince lifler üretirken, Kokrajhar Tuğla Kırmızısı daha düşük mekanik performansa sahip daha kaba lifler üretmiştir. Bu bulgular, Etiyopya'da yetiştirilen Eri ipeği için kritik yapı-özellik ilişkilerini ortaya koymakta ve çeşit seçimi, ekolojik optimizasyon ve yüksek değerli sürdürülebilir ipek biyomalzemelerinin geliştirilmesi için bilimsel bir temel sağlamaktadır.

Anahtar Kelimeler

• Eri ipeği
• Elyaf inceliği
• Mekanik özellikler
• Çeşit-çevre etkileşimi
• Sürdürülebilir tekstiller

MORPHOLOGICAL AND MECHANICAL CHARACTERIZATION OF ERI SILK FIBERS CULTIVATED IN ETHIOPIA

Öz

Eri silk (Samia ricini) is increasingly recognized as a sustainable and ethical non-reelable silk with strong potential for advanced textiles, biomedical, and composite applications. However, scientific understanding of the structural and mechanical behavior of Ethiopia-grown Eri silk remains limited. This study presents the first comprehensive morphological and mechanical characterization of three Eri silk varieties: Chinese White, Borduar White, and Kokrajhar Brick-Red (Indian origin) cultivated under different Ethiopian agroecological conditions (Bahir Dar, Arba Minch, and Awash-Melkasa). Scanning electron microscopy (SEM) revealed significant varietal differences in longitudinal and cross-sectional morphology. Prior to degumming, all fibers exhibited characteristic granular sericin coatings; however, the Chinese White variety displayed the smoothest and most homogeneous surface, indicating uniform sericin encapsulation of the fibroin core. Borduar White showed fine, discrete sericin agglomerates, whereas Kokrajhar Brick-Red exhibited larger and more irregular sericin accumulations. Cross-sectional analysis further demonstrated distinct structural organization, with triangular and moderately packed sections dominating Chinese White fibers, mixed bent geometries in Borduar White, and compact oblong morphologies in Kokrajhar Brick-Red. Mechanical characterization demonstrated significant effects of both silk variety and rearing zone on fineness, tenacity, elongation, and Young’s modulus (p < 0.0001). Fiber fineness ranged from 2.4–4.0 denier and tenacity from 2.5–3.5 g/den. Chinese White consistently produced finer fibers with superior tenacity and modulus, whereas Kokrajhar Brick-Red generated coarser fibers with lower mechanical performance. These findings establish critical structure-property relationships for Ethiopia-grown Eri silk and provide a scientific foundation for varietal selection, ecological optimization, and the development of high-value sustainable silk biomaterials.

Anahtar Kelimeler

• Eri silk
• Fiber fineness
• Mechanical properties
• Variety- environment interaction
• Sustainable textiles

Destekleyen Kurum

This study was supported by a competitive grant awarded through the 2024/25 Mega Research Proposal Call of the Research Affairs Directorate, Office of the Vice President for Research and Community Engagement, Bahir Dar University.

Etik Beyan

This research did not involve human participants, clinical trials, or vertebrate animals. The experimental work was conducted in accordance with institutional and national ethical guidelines for research involving invertebrates. The handling and rearing of silkworms (Eri and Mulberry) followed standard sericulture practices approved by the Ethiopian Institute of Textile and Fashion Technology (EiTEX), Bahir Dar University.

Teşekkür

The authors gratefully acknowledge the Ethiopian Institute of Textile and Fashion Technology, Bahir Dar University, for providing access to mulberry and Eri silk plantation facilities essential for this research. The support of technical staff and colleagues during the course of the study is also sincerely appreciated.

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