Study On The Optimization And Reaction Kinetics Of The Anti-wrinkle Finishing Of Cotton Fabric With Polycarboxylic Acid

In recent years,the application of polycarboxylic acid in formaldehyde-free durable press(DP)finishing of cotton fabrics has become a hot research field.However,most of the studies only use single-factor repeated experiments,which have large workload and less analysis of the interaction between factors.At the same time,there are few studies on the reaction process and kinetics of polycarboxylic acid with cotton fabric.In order to solve the above problems,two-dimensional numerical models were developed to investigate and optimize the DP finishing process of cotton fabric with 1,2,3,4-butanetetracarboxylic acid(BTCA)and a combination of BTCA and citric acid(CA)separately using Box-Behnken design(BBD)based on response surface methodology(RSM).The accuracy of the model was analyzed by using statistical theory such as "F value test" and "P value test".The model can predict and optimize the DP finishing process of polycarboxylic acid in a certain range of parameters efficiently and accurately.On the basis of above numerical models,the reaction process of polycarboxylic acid on cotton fabric was studied by infrared analysis and calcium acetate titration.The reaction kinetics models under different finishing conditions were established,and the esterification degree was associated with the actual finishing results.Statistical software(design expert 8.0.6.1)was used to fit the model and variance analysis.Analysis of variance(ANOVA)for the model of DP finishing process of cotton fabric with BTCA revealed that the concentration of BTCA was the most significant variable affecting the wrinkle resistance angle(WRA),followed by the curing time,the curing temperature and the concentration of sodium hypophosphite(SHP).As to the breaking strength,curing time was the most significant variable,followed by the curing temperature,the concentration of BTCA and the concentration of SHP.The optimum finishing process was conducted by adding 73 g/L BTCA together with 38 g/L SHP with the curing condition of cotton at 167? for 83 s.Treated with this optimum process,WRA of the finished fabric is 252° and retention rate of breaking strength is 69%.ANOVA for the model of DP finishing process of cotton fabric with a combination of BTCA and CA revealed that the curing time was the most significant variable affecting WRA,followed by the concentration of BTCA and CA,the curing temperature and the concentration of SHP.As to the breaking strength,curing time was the most significant variable,followed by the curing temperature,the concentration of SHP,the concentration of CA and the concentration of BTCA.The optimum finishing process was conducted by adding 50 g/L BTCA together with 45 g/L CA and 40 g/L SHP with the curing condition of cotton at 162? for 63 s.Treated with this optimum process,WRA of the finished fabric is 260° and retention rate of breaking strength 72%.WRA of cotton fabric finished with a combination of BTCA and CA in optimum process is 3.2% higher than that of cotton fabric finished with BTCA,the retention rate of breaking strength is increased by 4.3%.Compared with untreated cotton fabrics,the yellowness index of cotton fabric finished with BTCA is the lowest,followed by the cotton fabric finished with a combination of BTCA and CA,and the yellowness index of cotton fabric finished with CA alone is the highest.Infrared analysis of finished fabrics shows that the crosslinking efficiency of BTCA and cotton fabrics is not high.Under the optimum concentration of finishing solution and the ratio of finishing agent,the activation energy of cotton fabric finished with BTCA is higher than the cotton fabric finished with a combination of BTCA and CA,which indicates that the cross-linking reaction is easier to occur in compound finishing rather than in BTCA finishing alone.As to the cotton fabric finished with BTCA,when the curing temperature is lower then 140?,the esterification degree increases with the increase of curing time,but even if the curing time is increased continuously,the esterification degree is still lower.When the curing temperature is higher than 160?,the esterification degree can reach a high level in a relatively short time.As to the cotton fabric finished with a combination of BTCA and CA,the esterification degree increased greatly when the curing temperature was increased from 140? to 120?.The esterification degree did not change obviously with the increase of curing temperature when the curing temperature is above 160?.The finishing process of the maximum esterification degree under two finishing processes are basically consistent with optimum finishing process.