https://www.alice.cnptia.embrapa.br/bitstream/doc/1027384/1/ART15032.pdf

Wheat straw hemicellulose films as affected by citric acid

Citric acid based durable and sustainable flame retardant treatment for lyocell fabric

The kinetics, activation energy, and mechanism of esterification of cotton by mixed polycarboxylic acids, namely, 1,2,3,4-butanetetracarboxylic acid (BTCA) and citric acid (CA), were studied during the curing process of cotton fibers in comparison with the esterification by BTCA alone. The reaction rates of these two polycarboxylic acid finishing systems under different temperatures and the dependency of their reaction rate constants on temperature were studied. Consequently, in the temperature range from 120°C to 180°C, the activation energy of the mixed polycarboxylic acids (BTCA+CA) was obtained as , which was slightly lower than that for the BTCA finishing system. The reaction occurring between the carboxylic acid group of BTCA and the hydroxyl group of CA was proposed. To confirm and prove the speculation, experiments were conducted to investigate the changes in wrinkle recovery angle and tensile strength retention by changing the concentration of both the single polycarboxylic acid and mixed polycarboxylic acids. The results show that, besides esterification of cotton fibers, citric acid probably functioned as an extender in the curing process, when it was combined with BTCA.

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Mechanism of Antiwrinkle Finishing of Cotton Fabrics Using Mixed Polycarboxylic Acids

Direct characterization of cotton fabrics treated with di-epoxide by nuclear magnetic resonance.

ABSTRACT The innovation anticipated here is the use of our previously prepared chitosan nanoparticles in conjunction with citric acid and sodium hypophosphite for rendering viscose fabrics dyed and finished concurrently in one step with dual classes of dyes, namely basic and acid dyes, using a pad-dry-cure process. This was done to see the effect of the aforementioned eco-friendly finishing formulation on creating dual anchoring sites onto finished fabrics for dye-ability using Basic Red 2 and Acid Orange 7, which have no direct affinity to viscose fabric. So, different concentrations of CA, CNPs, and dyes were mixed into a viscose fabric cross-linking formulation together with a set concentration of SHP (50% based on weight of CA concentration) and cured at 170°C for 2 minutes. Citric acid is predicted to react with the hydroxyl groups in viscose and CNPs to produce ester crosslinking and/or to form an inter-ionic attraction with the amino groups of CNPs. The latter was responsible for viscose fabrics dye ability with Basic Red 2 by anchoring the free carboxyl groups in citric acid, as well as their dye ability with Acid Orange 7 by anchoring the residual amine groups in CNPs.

Rendering Viscose Fabrics Dye-able with Basic and Acid Dyes Using Citric Acid and Chitosan Nano Particles Based Finishing Formulation

Polycarboxylic acid finishing of cotton fabrics was studied.In order to eliminate the effect of formaldehyde released by DP finishing,and reduce the yellowness caused by high temperature curing and phosphorus content in wastewater,DP finishing of cotton fabrics was performed with mixed citric acid and tartaric acid as finishing agent,and the effects of mass fraction of citric acid and tartaric acid,curing conditions,kinds and concentration of catalyst,and mass concentration of additives on the treatment were investigated.The experiment demonstrated that the optimum finishing results are obtained when mass fraction of citric acid to tartaric acid is 1∶ 1,curing temperature is 180 ℃,curing time is 2 min,mass concentration of nanosilica is 2 g /L,mass concentration of sodium hypophosphite is 20 g /L,and mass concentration of softener LD-5030 is 20 g /L.

Zhang Jianli

Papers

Durable press finishing of cotton fabrics