Most cotton fleece fabrics are not able to meet the federal flammability standard for general apparel (16 CFR 1610). In this research, we applied three carboxylic acids, i.e., succinic acid (SUA), malic acid (MLA), and tartaric acid (TTA), as flame retardant finishing systems for cotton fleece. We found that all three acids are able to esterify cotton in the presence of sodium hypophosphite as the catalyst, and SUA is the most reactive and the most hydrolysis-resistant when it is bound to cotton. The a-hydroxyl group with both MLA and TTA appears to hinder esterification and to facilitate hydrolysis for MLA and TTA bound to cotton. All three bifunctional carboxylic acids are effective in reducing the flammability of cotton fleece from ‘Class 3’ to ‘Class 1’. The micro-scale combustion calorimetry data reveal that SUA reduces cotton flammability by reducing its peak heat-release rate and heat-release capacity. The cotton fleece treated with SUA also has the highest bursting-strength retention and the least fabric yellowing.
16 CFR Part 1610, Code of Federal Regulations, Title 16, Chapter II-Consumer Product Safety Commission, Office of the Federal Register, Washington, DC, 2007, 603-620; 16 CFR Part 1610, Standard for the Flammability of Clothing textiles; Proposed Rules, Federal Register, 72(38): 2007, 8844-8868.
2.
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3.
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4.
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5.
Horrocks, A.R. ( 2003). Flame Retardant Finishes and Finishing, In: Heywood, D. (ed.), Textile Finishing , pp. 214-250, Society of Dyers and Colourists, West Yorkshire, UK.
6.
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7.
Rearick, W.A. , Wallace, M.L. and Martin, W.B. (2002). Flammability Considerations for Raised Surface Apparel, AATCC Review, 2(2): 12-15.
8.
Blanchard, E.J. and Graves, E.E. (2002). Polycarboxylic Acids for Flame Resistant Cotton/Polyester Carpeting, Textile Research Journal, 71(1): 39-43.
9.
Blanchard, E.J. and Graves, E.E. (2005). Improving Flame Resistance of Cotton/Polyester Fleece with Phosphorous Based Polycarboxylic Acids, AATCC Review, 5(5): 26-30.
10.
Wu, W. and Yang, C.Q. ( 2007). A Comparative Study of Different Organophosphorus Flame Retardant Agents for Cotton: Part II. The Fabric Flammability and Physical Properties, Polymer Degradation and Stability, 92(3): 363-369.
11.
Wu, W. and Yang, C.Q. ( 2004). Comparison of DMDHEU and Melamine-Formaldehyde as the Bonding Agents for a Hydroxyl-Functional Organophosphorus Flame Retarding Agent on Cotton, Journal of Fire Sciences, 22(2): 125-142.
12.
Yang, C.Q. and Wu, W.D. ( 2003). Combination of a Hydroxy-Functional Organophosphorus Oligomer and a Multifunctional Carboxylic Acid as a Flame Retardant Finishing System for Cotton: PartI. The Chemical Reactions, Fire and Materials, 27(5): 223-237.
13.
Yang, C.Q. and Wu, W.D. ( 2003). Combination of a Hydroxy-Functional Organophosphorus Oligomer and a Multifunctional Carboxylic Acid as a Flame Retardant Finishing System for Cotton: Part II. Formation of Calcium Salt during Laundering, Fire and Materials, 27(5): 239-251.
14.
Yang, C.Q. and Qiu, X. ( 2007). Flame Retardant Finishing of Cotton Fleece: Part I. The Use of A Hydroxyl-Functional Organophosphorus Oligomer and DMDHEU, Fire and Materials, 31(1): 67-81.
15.
Wu, X. and Yang, C.Q. ( 2008). Flame Retardant Finishing of Cotton Fleece. Part II. Phosphorus-Containing Inorganic Compounds, Journal of Applied Polymer Sciences, 108: 1582-1590.
16.
Wu, X. and Yang, C.Q. ( 2008). Flame Retardant Finishing of Cotton Fleece Fabric: Part III. The Combination of Maleic Acid and Sodium Hypophosphite, Journal of Fire Sciences, 26(4): 351-368.
17.
Yang, C.Q. and Wang, X. ( 1996). Formation of the Cyclic Anhydride Intermediates and Esterification of Cotton Cellulose by Multifunctional Carboxylic Acids: An Infrared Spectroscopy Study, Textile Research Journal, 66(9): 595-603.
18.
Yang, C.Q. ( 1993). Infrared Spectroscopy Studies of the Cyclic Anhydride as the Intermediate for the Ester Crosslinking of Cotton Cellulose by Polycarboxylic AcidsI. Identification of the Cyclic Anhydride Intermediate, Journal of Polymer Science, Part A: Polymer Chemistry, 33: 1187-1193.
19.
Yang, C.Q. , Xu, L., Li, S. and Jiang, Y. ( 1998). Nonformaldehyde Durable Press Finishing of Cotton Fabrics by Combining Polymers of Maleic Acid with Citric Acid, Textile Research Journal, 68(6): 457-464.
20.
Yang, C.Q. , (2000). Cross linking Agents of Cellulose Fabrics, U.S. Patent6,165,919, assigned to University of Georgia Foundation, 26 December, 2000.
21.
Yang, C.Q. ( 1991). Characterizing the Ester Cross-Linkages of Cotton Cellulose with FT-IR Photoacoustic Spectroscopy, Textile Research Journal , 61(9): 298-305.
22.
Lyon, R.E. and Walters, R.N. ( 2004). Pylolysis Combustion Flow Calorimetry, Journal of Analytical and Applied Pyrolysis , 71(1): 27-46.
23.
Lu, Y. and Yang, C.Q. ( 1999). Fabric Yellowing Caused by Citric Acid as a Crosslinking Agent for Cotton, Textile Research Journal, 69(9): 685-690.
24.
Kang, I., Yang, C.Q., Wei, W. and Lickfield, G.C. ( 1998). The Mechanical Strength of the Cotton Fabrics Crosslinked by Polycarboxylic Acids: PartI. Acid Degradation and Crosslinking of Cellulose, Textile Research Journal, 68(11): 865-870.
