Flammability and Thermal Degradation Behaviour of Wool/Polyamide 6.6 Blends

Year 2020, Volume: 27 Issue: 117, 22 - 30, 30.03.2020

Elif Kaynak Mustafa Erdem Üreyen Ali Savaş Koparal

Abstract

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.

Keywords

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

Supporting Institution

Eskişehir Technical University Scientific Research Projects Commission

Project Number

1504F172

Thanks

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

Abstract

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.

Keywords

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

Project Number

1504F172

References

• Horrocks, A. R., Anand, S. C. (Eds.). (2000). Handbook of Technical Textiles: Technical Textile Applications (Vol. 2). UK: Woodhead Publishing.
• Cardamone, J. M. (2013). Flame resistant wool and wool blends. In F. S. Kilinc (Ed.), Handbook of fire resistant textiles. UK: Woodhead Publishing Ltd.
• Horrocks, A. R., Alongi, J. (2013). Fundamental Aspects of Flame Retardancy. In J. Alongi, A. R. Horrocks, F. Carosio ,G. Malucelli (Eds.), Update on Flame Retardant Textiles: State of the Art, Environmental Issues and Innovative Solutions (pp. 19-52). Shropshire: Smithers Rapra Technology Ltd.
• Benisek, L. (1984). Zirpro Wool Textiles. Fire and Materials, 8(4), 183-195.
• Horrocks, A. R., Davies, P. J. (2000). Char Formation in Flame-Retarded Wool Fibres. Part 1. Effect of Intumescent on Thermogravimetric Behaviour. Fire and Materials, 24, 151-157.
• Cheng, X.-W., Guan, J.-P., Chen, G., Yang, X.-H., Tang, R.-C. (2016). Adsorption and Flame Retardant Properties of Bio-Based Phytic Acid on Wool Fabric. Polymers, 8(4), 122.
• Deopura, B. L., Padaki, N. V. (2014). Synthetic Textile Fibres: Polyamide, Polyester and Aramid Fibres. In R. Sinclair (Ed.), Textiles and Fashion Materials, Design and Technology (pp. 98-114). UK: Woodhead Publishing.
• Fukatsu, K. (1990). Kinetic and Thermogravimetric Analysis of Thermal Degradation of Polychlal Fiber/Cotton Blend. Journal of Fire Sciences, 8, 194-206.
• Pereira, C. M. C., Martins, M. S. S. (2014). Chapter 17 - Flame Retardancy of Fiber-Reinforced Polymer Composites Based on Nanoclays and Carbon Nanotubes. In C. D. Papaspyrides ,P. Kiliaris (Eds.), Polymer Green Flame Retardants (pp. 551-595). Amsterdam: Elsevier.
• Janssens, M., Parker, W. J. (2013). Oxygen Consumption Calorimetry. In V. Babrauskas ,S. J. Grayson (Eds.), Heat Release in Fires (pp. 31-60). London: Interscience Communications Ltd.
• Babrauskas, V. (2016). Heat Release Rates. In M. J. Hurley (Ed.), SFPE Handbook of Fire Protection Engineering (5 ed., pp. 799-904). New York, NY: Springer-Verlag.
• Babrauskas, V. (2016). The Cone Calorimeter. In M. J. Hurley (Ed.), SFPE Handbook of Fire Protection Engineering (5 ed., pp. 952-980). New York, NY: Springer-Verlag.
• Yang, C. Q., He, Q., Lyon, R. E., Hu, Y. (2010). Investigation of the flammability of different textile fabrics using micro-scale combustion calorimetry. Polymer Degradation and Stability, 95(2), 108-115.
• Yang, C. Q., He, Q. (2012). Textile heat release properties measured by microscale combustion calorimetry: experimental repeatability. Fire and Materials, 36(2), 127-137.
• Price, D., Liu, Y., Hull, T. R., Milnes, G. J., Kandola, B. K., Horrocks, A. R. (2000). Burning behaviour of fabric/polyurethane foam combinations in the cone calorimeter. Polymer International, 49, 1153-1157.
• Galaska, M., Sqrow, L., Wolf, J., Morgan, A. (2019). Flammability Characteristics of Animal Fibers: Single Breed Wools, Alpaca/Wool, and Llama/Wool Blends. Fibers, 7(1), 3
• Apaydin, K., Laachachi, A., Ball, V., Jimenez, M., Bourbigot, S., Toniazzo, V., Ruch, D. (2014). Intumescent coating of (polyallylamine-polyphosphates) deposited on polyamide fabrics via layer-by-layer technique. Polymer Degradation and Stability, 106, 158-164.
• Popescu, C., Vasile, M., Oprea, C., Segal, E. (1992). A thermogravimetric study of flame-proofed wool. Thermochimica Acta, 205, 205-211.
• Vyazovkin, S. (2000). Computational aspects of kinetic analysis. Part C. The ICTAC Kinetics Project- the light at the end of the tunnel? Thermochimica Acta, 355, 155-163.
• Budrugeac, P. (2001). The evaluation of the non-isothermal kinetic parameters of the thermal and thermo-oxidative degradation of polymers and polymeric materials: its use and abuse. Polymer Degradation and Stability, 71, 185-187.
• Vlaev, L., Nedelchev, N., Gyurova, K., Zagorcheva, M. (2008). A comparative study of non-isothermal kinetics of decomposition of calcium oxalate monohydrate. Journal of Analytical and Applied Pyrolysis, 81(2), 253-262.
• Khawam, A., Flanagan, D. R. (2006). Solid-State Kinetic Models: Basics and Mathematical Fundamentals. J. Phys. Chem. B, 110, 17315-17328.
• Vyazovkin, S., Burnham, A. K., Criado, J. M., Pérez-Maqueda, L. A., Popescu, C., Sbirrazzuoli, N. (2011). ICTAC Kinetics Committee recommendations for performing kinetic computations on thermal analysis data. Thermochimica Acta, 520(1-2), 1-19.
• Órfão, J. J. M. (2007). Review and evaluation of the approximations to the temperature integral. AIChE Journal, 53(11), 2905-2915.
• Balart, R., Garcia-Sanoguera, D., Quiles-Carrillo, L., Montanes, N., Torres-Giner, S. (2019). Kinetic Analysis of the Thermal Degradation of Recycled Acrylonitrile-Butadiene-Styrene by non-Isothermal Thermogravimetry. Polymers, 11(2), 281.
• Schartel, B., Hull, T. R. (2007). Development of fire-retarded materials—Interpretation of cone calorimeter data. Fire and Materials, 31(5), 327-354.
• Hirschler, M. M. (1992). Smoke and Heat Release and Ignitability as Measures of Fire Hazard from Burning of Carpet Tiles. Fire Safety Journal, 18, 305-324.
• Hirschler, M. M. (1991). The Measurement of Smoke in Rate of Heat Release Equipment in a Manner Related to Fire Hazard. Fire Safety Journal, 17, 239-258.
• Bhattacharyya, D., Subasinghe, A., Kim, N. K. (2015). Natural fibers: Their composites and flammability characterizations. In K. Friedrich ,U. Breuer (Eds.), Multifunctionality of Polymer Composites Challenges and New Solutions (pp. 102-143). Oxford, UK: Elsevier.
• Zhuge, J., Chen, X., Ks, A., Manica, D. P. (2016). Microscale combustion calorimeter-application and limitation. Fire and Materials, 40(8), 987-998.
• Popescu, C., Segal, E., Iditoiu, C. (1995). A kinetic model for the thermal decomposition of wool. Termochimica Acta, 256, 419-427.
• Lian, D., Ren, J., Han, W., Ge, C., Lu, J. (2019). Kinetics and evolved gas analysis of the thermo-oxidative decomposition for neat PPS fiber and nano Ti–SiO2 modified PPS fiber. Journal of Molecular Structure, 1196, 734-746.
• Albano, C., Trujillo, J., Caballero, A., Brito, O. (2001). Application of different kinetic models for determining thermal stability of PA 66/HDPE blends. Polymer Bulletin, 45, 531–538.