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Abstract: Polycarboxylic acids have been used as nonformaldehyde crosslinking agents for cotton with sodium hypophosphite (NaH2PO2) as the catalyst to replace the formaldehyde-based dimethyloldihydroxyethleneurea (DMDHEU). Maleic acid (MA), an α, β-unsaturated bifunctional carboxylic acid, can esterify cotton but is not able to form crosslinking between two cellulose molecules by itself. In this research, we discovered that the wrinkle resistance of the cotton fabric treated with MA and NaH2PO2 was significantly increased and phosphorus was bound to cotton when the treated fabric was exposed to temperatures higher than that required for esterification of cotton by MA. Elevation of the fabric wrinkle resistance and increase in quantity of the phosphorus bound to cotton had similar dependency on curing temperature, on MA concentration, and on NaH2PO2 concentration. All the data support the hypothesis that H–P–(residual of NaH2PO2) added to >Cf the MA already bound to cotton by esterification, thus forming a new crosslink between two cotton cellulose molecules. The cotton fabrics treated by MA/NaH2PO2 showed fabric wrinkle resistance similar to that treated with DMDHEU, but the breaking strength and tearing strength of the MA-treated cotton fabrics were significantly improved. [Copyright &y& Elsevier]

Abstract: In this research, we studied the mechanism of bonding a hydroxy-functional organophosphorus oligomer (HFPO) to nylon 6.6 fabric using the formaldehyde derivatives of urea and melamine, including dimethyloldihydroxyethyleneurea (DMDHEU) and trimethylolmelamine (TMM), as the bonding agents. The nylon fabric treated with HFPO/DMDHEU or HFPO/TMM retained significant amount of phosphorus after multiple launderings. The laundering durability of the HFPO applied to nylon was probably attributed to the formation of a crosslinked polymeric network on the nylon fiber. The nylon fabric treated with HFPO/DMDHEU showed higher percent phosphorus retention than that treated with HFPO/TMM. The percent phosphorus retention of the treated nylon increased as the DMDHEU or TMM concentration was increased, and the nylon fabric''s stiffness follows the same trend. The micro-scale combustion calorimetry and thermal analysis data indicate that the HFPO bound to nylon reduced peak heat release rate and heat release capacity of the nylon fabric, decreased decomposition temperature and promoted the char formation of the treated fabric. The nylon/cotton blend military fabric treated with HFPO/DMDHEO or HFPO/TMM demonstrated flame retardant performance after 10 laundering cycles. [Copyright &y& Elsevier]

Abstract: Flame retardancy is a desirable property for silk textiles, and it becomes necessity when silk textiles are for interior decorative use in building with public access. However, the flame retardant finishing technology available for silk has significant limitations. In this research, we studied the use of the combination of a hydroxyl-functional organophosphorus oligomer (HFPO) and 1,2,3,4-butanetetracarboxylic acid (BTCA) as a formaldehyde-free flame retardant finishing system for silk. When BTCA is applied to silk, most of BTCA reacts with the hydroxyl group on silk by single ester linkage. In the presence of HFPO, BTCA is able to bond HFPO onto silk by either a BTCA “bridge” between silk and HFPO or a BTCA–HFPO–BTCA cross-linkage between two silk protein molecules. We evaluated the flammability and physical properties of the silk fabric treated with HFPO and BTCA. The treated silk fabric demonstrated a high level of flame retardancy with modest loss in fabric tensile strength. The treated silk passed the vertical flammability test after 15 hand wash (HW) cycles. Increasing the HFPO concentration from 20% to 30% does not show significant improvement in the flame retardant performance of the treated silk. The thermal analysis data demonstrated that HFPO reduces silk''s initial thermal decomposition temperature and promotes char formation. [Copyright &y& Elsevier]

In our previous research, we developed flame retarding systems for cotton based on a hydroxy-functional organophosphorus oligomer (FR) and a binder, such as 1,2,3,4-butanetetracarboxylic acid (BTCA), dimethyloldihydroxyethyleneurea (DMDHEU) and melamine–formaldehyde (M–F), which are able to form covalent binding between FR and cotton. In this research, we used a factorial experimental design method to study the performance of the flame retarding system based on FR and the mixture of DMDHEU and M–F. We found that an increase in the DMDHEU/(DMDHEU + M–F) ratio in the mixture increases the amount of FR bound to cotton, increases the laundering durability of FR on cotton, and reduces the fabric tensile strength retention. DMDHEU and M–F also function as nitrogen providers and enhance the flame retarding performance of the treated fabric due to phosphorus–nitrogen synergism. M–F is a more efficient nitrogen provider than DMDHEU. The effect of reduced phosphorus–nitrogen synergism as a result of increasing the relative amount of DMDHEU in the mixture (DMDHEU + M–F) outweighs that of the improved bonding of FR to cotton. An increase in FR concentration in a formula increases the amount of FR bound to cotton, whereas it reduces the percent retention of FR on the fabric and also reduces the fabric strength loss. Desirable performance of treated cotton fabrics can be achieved by adjusting the concentrations of FR and the ratio of the two binders in a formula. [Copyright &y& Elsevier]

The increasing demand for easy care cotton apparel in the marketplace has made it urgent to develop competitively priced formaldehyde-free durable press finishes to replace the traditional N-methylol reagents. A cost-effective nonformaldehyde durable press finishing system was developed based on citric acid and a terpolymer of maleic acid. This system was applied to garment finishing on both laboratory and industrial production scales and compared with the traditional DMDHEU systems as well as one commercial nonformaldehyde system. The durable press rating, crease retention rating, wrinkle recovery angle, mechanical strength, and abrasion resistance of the garments finished with the new system are comparable to those treated with the conventional DMDHEU systems. The garments finished with the new system maintained satisfactory fabric smoothness and crease retention after 30 home laundering washing/ drying cycles. [ABSTRACT FROM AUTHOR]