Investigation of thermal oxidative stabilization process of viscose rayon fibers by multi-step heat treatment technique

Öz

This study investigates the thermal oxidative stabilization (TOS) process of viscose rayon fibers. Before stabilization, a chemical pretreatment containing ammonium sulfamate and urea was applied to the fibers, and then stabilization was carried out at temperatures between 200 °C - 250 °C for different times with a multi-step heat treatment strategy. The effects of the TOS process on fiber density, tensile strength, FT-IR spectroscopy, X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were evaluated in detail. The results show that as the TOS time increased, the density increased to 1.73 g/cm3 and the carbonization efficiency increased from 15% to 64%, but the tensile strength decreased by 60%. FT-IR and XRD analyses revealed that the cellulose II crystal structure was disrupted, the structure became 100% amorphous after 5 min of stabilization and cross-linked aromatic structures increased. DSC and TGA results show that the thermal resistance of stabilized fibers is significantly improved. These findings indicate that stabilized viscose rayon fibers have attained sufficient thermal stability for the subsequent stages while also making significant contributions to the optimization processes for the efficient production of viscose rayon-based activated carbon fibers.

Anahtar Kelimeler

• Viscose rayon
• activated carbon
• ammonium sulfamate
• thermal oxidative stabilization
• multi-step heat treatment

Destekleyen Kurum

Erciyes University, Department of Mechanical Engineering, YÖK 100/2000 Ph.D. Program

Etik Beyan

This study was conducted in accordance with research and publication ethics. There is no conflict of interest among the authors.

Teşekkür

This study was supported within the scope of the CoHE 100/2000 Ph.D. Scholarship Program provided during the doctoral education at the Department of Mechanical Engineering, Erciyes University, carried out under the Council of Higher Education (CoHE). I would like to thank the Council of Higher Education for its financial and academic support.

Çok adımlı ısıl işlem tekniğiyle viskoz rayon liflerin termal oksidatif stabilizasyon sürecinin incelenmesi

Öz

Bu çalışma, viskoz rayon liflerin termal oksidatif stabilizasyon (TOS) sürecini incelemektedir. Stabilizasyon öncesinde liflere amonyum sülfamat ve üre içeren bir kimyasal ön işlem uygulanmış, ardından çok adımlı bir ısıl işlem stratejisi ile 200°C-250°C arasındaki sıcaklıklarda farklı sürelerde stabilizasyon gerçekleştirilmiştir. TOS sürecinin lif yoğunluğu, mukavemet, FT-IR spektroskopisi, X-ışını kırınımı (XRD), diferansiyel taramalı kalorimetri (DSC) ve termogravimetrik analiz (TGA) üzerindeki etkileri detaylı olarak değerlendirilmiştir. Sonuçlar, TOS süresi arttıkça yoğunluğun 1,73 g/cm3 değerine ve kömürleşme veriminin %15’den %64’e yükseldiğini, ancak gerilme mukavemetinin ise %60 oranında azaldığını göstermektedir. FT-IR ve XRD analizleri, selüloz II kristal yapısının bozulduğunu, 5 dakikalık stabilizasyon sonrasında yapının %100 amorflaştığını ve çapraz bağlı aromatik yapıların arttığını ortaya koymuştur. DSC ve TGA sonuçları ise, stabilize edilmiş liflerin termal dayanıklılığının önemli ölçüde iyileştiğini göstermektedir. Bu bulgular, stabilize olmuş viskoz rayon liflerin sonraki aşamalar için yeterli termal kararlılığa ulaştığını gösterirken diğer yandan viskoz rayon esaslı aktif karbon liflerinin verimli bir şekilde üretimi için optimizasyon süreçlerine önemli katkılar sağlamaktadır.

Anahtar Kelimeler

• Viskoz rayon
• aktif karbon
• amonyum sülfamat
• termal oksidatif stabilizasyon
• çok adımlı ısıl işlem.

Destekleyen Kurum

Erciyes Üniversitesi, Makine Mühendisliği Bölümü, YÖK 100/2000 Programı

Etik Beyan

Yapılan bu çalışmada, araştırma ve yayın etiğine uyulmuştur. Yazarlar arasında herhangi bir çıkar çatışması bulunmamaktadır.

Teşekkür

Bu çalışma, Yükseköğretim Kurulu (YÖK) tarafından Erciyes Üniversitesi Makine Mühendisliği Bölümü bünyesinde yürütülen doktora eğitimi süresince sağlanan 100/2000 YÖK Doktora Burs Programı kapsamında desteklenmiştir. Sağladığı mali ve akademik katkılar nedeniyle Yükseköğretim Kurulu’na teşekkür ederim.

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