Flammability and Thermal Degradation Behaviour of Wool/Polyamide 6.6 Blends

Yıl 2020, Cilt: 27 Sayı: 117, 22 - 30, 30.03.2020

Elif Kaynak Mustafa Erdem Üreyen Ali Savaş Koparal

Öz

Wool (WO) is often blended with polyamide 6.6(PA) at certain ratios in order to obtain fabrics with superior comfort and mechanical features. This type of wool rich upholstery fabrics are commonly preferred in aircraft seats. Flammability is an important characteristic of aircraft materials in terms of safety and regulatory purposes and it is highly dependent on the composition of blends. Since WO/PA blended fabrics cannot meet the flammability requirements, they are used in aircraft after flame retardant finishing. Needs for innovative new flame retardant chemicals for wool and wool blended fabrics are continuing. This study aims to present a comprehensive investigation and understanding of the fire and thermal degradation behaviour of 100% WO and wool rich blends (88.6% WO/11.4% PA and 78.5% WO/21.5% PA). The data obtained in this work can be used to identify the effect of polyamide 6.6 on the flammability of the wool and to develop new flame retardant chemicals for WO/PA blended fabrics. According to the results, the peak of heat release rate of 100% WO increased about 25% when blended with 21.5% PA as measured by the cone calorimeter and decreased about 12% as measured by the micro-scale combustion calorimeter. This is because the decomposition steps of the two materials are different. Regardless of the equipment used for measurements, the total heat release during combustion increased with the increasing PA ratios in blends. The thermal analyses were performed to study various stages occurred during thermo-oxidative decomposition of wool and its blends. The thermal degradation of PA could be observed as a separate stage during decomposition. On the other hand, the kinetics of thermal decomposition, even during the early stages of decomposition was modified for the blended fabrics. The results will contribute to the understanding of the effect of polyamide ratio on the flammability of the wool.

Anahtar Kelimeler

wool, polyamide 6.6, thermal analysis, micro-scale combustion calorimeter, cone calorimeter

Destekleyen Kurum

Eskişehir Technical University Scientific Research Projects Commission

Proje Numarası

1504F172

Teşekkür

The authors gratefully acknowledge the funding by Eskişehir Technical University Scientific Research Projects Commission, Turkey under grant no. 1504F172.

Yün/Poliamid 6.6 Karışımlarının Yanma ve Isıl Bozunma Davranışları

Öz

Yün (WO), konfor ve mekanik özelliklerin iyileştirilmesi için, genellikle poliamid 6.6(PA) ile belirli oranlarda karıştırılarak kullanılmaktadır. Bu tip yünlü döşemelik kumaşlar sağladıkları yüksek konfor nedeniyle özellikle uçak koltuklarında tercih edilmektedir. Ancak yanma dayanımı uçak malzemelerinde mutlaka olması gereken bir özelliktir ve yasal kurallarla düzenlenmiştir. Malzemenin yanma davranışı bileşime önemli oranda bağlıdır. Yün/poliamid karışımlı kumaşlar bu gereksinimleri karşılayamadık-larından güç tutuşur apre işlemlerinden sonra uçaklarda kullanılırlar. Günümüzde yün ve yün karışımlı kumaşlara etkin güç tutuşur özellik kazandıran yenilikçi aprelere ihtiyaç bulunmaktadır. Bu çalışmada %100 WO ve WO/PA karışımlı kumaşların (%88,6 WO/ %11,4 PA ve %78,5 WO/%21,5 PA) yanma ve termal bozunma davranışlarının farklı teknikler kullanılarak incelenmesi ve açıklanması amaçlanmıştır. Buradan elde edilen veriler uygun WO ve WO/PA karışımlarının belirlenmesi ve bu kumaşlar için yeni güç tutuşur kimyasallar geliştirilmesi için kullanılabilecektir. Elde edilen sonuçlara göre %100 yün için konik kalorimetreyle ölçülen maksimum ısı salım hızı, %21,5 PA içeren kumaşa göre, %25 daha düşük çıkarken mikro ölçekli yakma kalorimetresinde %12 oranında daha fazla çıkmıştır. Bu durum iki malzemenin bozunma adımlarının farklı olmasından kaynaklanmaktadır. Test ekipmanından bağımsız olarak yanma sırasında açığa çıkan toplam ısının, karışımda artan PA oranına bağlı olarak arttığı tespit edilmiştir. Yün ve yünlü kumaşların termo-oksidatif bozunması sırasında meydana gelen çeşitli proseslerin belirlenmesi için termal analizler gerçekleştirilmiştir. Karışımların termal analizinde PA’nın bozunması ayrı bir adım olarak gözlenebilmiştir. Diğer taraftan, karışımların termal bozunma kinetiğinde, bozunmanın ilk aşamalarından itibaren yüne kıyasla meydana gelen farklılıklar, kinetik analizlerle ortaya konmuştur. Bu sonuçlar poliamidin yün ile karıştırılmasının yanma mekanizmasına etkisinin açıklanmasına katkı sağlayacak niteliktedir.

Anahtar Kelimeler

Yün, poliamid 6.6, termal analiz, mikro ölçekli yakma kalorimetresi, konik kalorimetre

Proje Numarası

1504F172

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