Formaldehyde-free Anti-wrinkle Finishing Agents For Cotton:Synthesis And Application

Cotton fabric plays an important role in textile industry because of its advantages such as being comfortable to wear and eco-friendly material.Unfortunately,cotton fabric wrinkles easily during wearing and washing process.Anti-wrinkle finishing agents are applied on cotton fabric to produce high resiliency fabric.Currently most of anti-wrinkle finishing agents are N-methylol compounds including its ether modified versions and polycarboxylic acids.N-methylol compounds are prepared by the reaction of formaldehyde with corresponding amide.Therefore,there is formaldehyde during making N-methylol agents,finishing process and wearing,which causes formaldehyde problem.One of the effective methods to reduce the formaldehyde released from N-methylol agents is modifying the agents by etherification.However,the formaldehyde cannot be eradicated.Therefore,developing formaldehyde-free finishing agents is the main research subject in current anti-wrinkle field.Polycarboxylic acids are the most possible formaldehyde-free anti-wrinkle finishing among the researched agents.1,2,3,4-tetracarboxylic acid(BTCA)is the most effective agent which is as effective as N-methylol agent.However,the high cost of finishing and high curing temperature block its application in industrial scale.In addition,the finishing formulations of N-methylol agents and polycarboxylic acid are acidic solutions.Besides,both need high curing temperature.Acidic condition and high curing temperature accelerate the decomposition of cellulose macromolecular chain,which reduces the mechanical strength of the fabric.The severe strength loss affects the wearing performance which is an urgent issue to be solved.In order to avoid formaldehyde,new agents containing reactive group should be synthesized,in which select the effective agents as formaldehyde-free anti-wrinkle finishing agents.In order to relief the strength loss caused by high temperature and acidic condition,on the one hand synthesizing new agent which could be used in alkaline condition,on the other hand synthesizing new agent which could be used at low temperature.Therefore,the research“Formaldehyde-free anti-wrinkle finishing agents:synthesis and application”was proposed.In this dissertation,the main contents were as follows.(1)Synthesis of alkaline anti-wrinkle finishing agents and preliminary studyThe target compounds containing two groups which could react with hydroxyl of cellulose in alkaline condition including 2,4-di(acrylamide)benzenesulfonic acid(AC-DABS1),2,5-di(acrylamide)benzenesulfonic acid(AC-DABS2),2,4-di(chloracetylamide)benzenesulfonic acid(CAC-DABS1),2,4-dichloro-6-(4-?sulfatoethylfonyl)aniline-1,3,5-triazine(TCT-PE),para-?-sulfatoethylfonyl acrylaniline(AC-PE),as well as model compound para-acrylamide-benzenesulfonic acid(AC-PABS),para-chloracetylamide benzenesulfonic acid(CAC-PABS)were synthesized.All synthesized products were characterized by High Performance Liquid Chromatography(HPLC),Hydrogen Nuclear Magnetic Resonance(¹HNMR)and Attenuated total reflectance Fourier transform infrared spectroscopy(ATR-FTIR)method.AC-DABS1,AC-DABS2 and AC-PE are effective formaldehyde free anti-wrinkle finishing agent after treatment with steaming process and curing process.Steaming process is more suitable than curing process.CAC-DABS1 and TCT-PE didn't present anti-wrinkle performance in various conditions so that they cannot be used as anti-wrinkle finishing agents.The stability of chloracetylamide group in alkaline solution was studied using model compound CAC-PABS.The results showed that there are two reactions:hydrolysis of methylene chloride group and hydrolysis of amido group.Hydrolysis of methylene chloride is prior to hydrolysis of amido group.The stability of acrylamide group in alkaline solution was studied using model compound AC-PABS.The results showed that in strong basic solution the amide bond of acrylamide group hydrolyzed and carbon-carbon double bond of acrylamide group reacted with water to produce adduct.Both reactions accelerated as alkalinity increased.The reaction rate constant of chloracetylamide group and acrylamide group were compared.It concluded that acrylamide group is more stable than chloracetylamide group in alkaline solution.(2)Optimization of alkaline anti-wrinkle finishing and reaction mechanism.Steaming method was more suitable for new synthesized agents treating the cotton fabric compared with curing method.AC-DABS1 and AC-DABS2 were used as anti-wrinkle finishing agents through steaming process.The effect of concentration of agents,concentration of sodium carbonate,steaming temperature,steaming time,steaming humidity and washing cycle on the performance of the treated fabric including wrinkle recovery angle(WRA),breaking strength retention(BSR)and whiteness index was investigated.The optimal conditions for AC-DABS1 and AC-DABS2 are finishing agents 80 g/L,sodium carbonate 10 g/L,steaming temperature 110?,steaming humidity 75%and steaming time 5min.The WRA and breaking strength retention is230°and 85%after treatment using optimal conditions.The DP rating is between 3.0and 2.5 from 1 washing cycle to 9 washing cycles.The performance of 1,3,5-triacryloylhexahydro-1,3,5-triazine(FAP)treated cotton was investigated and the optimal condition are concentration of FAP 80 g/L,sodium carbonate 10 g/L,steaming temperature 120?,steaming humidity 65%,steaming time 4 minutes.The WRA and BSR of fabric treated with FAP under optimal condition is 250°and 73.6%,respectively.The reaction efficiency of acrylamide group on cotton fabric was studied by model compound AC-PABS.There are two side reactions occurred on cotton including hydrolysis of amido group and addition of carbon-carbon double bond with water.Those two side reactions lead to low efficiency of acrylamide group reacting with hydroxyl group on cotton.By analyzing the structure of newly synthesized agents and FAP along with the different anti-wrinkle performances,suggestions to designing new acrylamide containing agents are as follows:more acrylamide groups and low reactivity.Anti-wrinkle treatment using AC-PE through“pad-dry-steaming”method was researched.The effect of AC-PE concentration,sodium carbonate concentration,drying time,steaming conditions(temperature,time,humidity),polyol additives and softener on winkle recovery angle(WRA),tearing strength retention(TSR)and whiteness index were investigated.The optimal conditions for AC-PE treatment are AC-PE 80 g/L,sodium carbonate 15 g/L,two pads and two nips,drying at 50?for 5 min,steaming at 110?for 5 min with 75%steaming humidity.The WRA,TSR,whiteness index and DP rating is 231°,80%,93.8 and 3.0,respectively.It was found that polyols had little positive effect on the cotton performance,whereas softener additives not only improved WRA but also TSR.The performance of the cotton fabric treated with AC-PE by“grafting-crosslinking”two-step method was studied.The effects of temperature,time,sodium carbonate and sodium sulfate on the adsorption efficiency and fixing efficiency was investigated to optimize“grafting”step.This two-step method was not suitable for finishing the cotton because of hydrolysis of AC-PE during grafting step.The crosslinking mechanism of AC-PE was studied by scanning electron microscope(SEM)and ATR-FTIR method.Results showed that part of AC-PE was grafted onto cotton during drying step,while grafting reaction and crosslinking reaction continued during steaming process.Compared with polycarboxylic acid,alkaline anti-wrinkle finishing agents including AC-DABS1,AC-DABS2 and AC-PE could not only impart the treated fabric satisfactory WRA and high strength retention,but also conserve energy.(3)Synthesis and application of a new tetracarboxylic acidA new tetracarboxylic acid named MASESMA was synthesized by reaction of maleic acid(MA)or maleic anhydride(MAH)with ethanedithiol through sulfur Michael addition mechanism.The effect of reaction time and catalyst on the yield were investigated.The structure of MASESMA was confirmed by ¹H NMR and ¹³C NMR.The effects of MASESMA concentration,catalyst concentration,curing temperature,curing time,softener and washing cycle on the performance(WRA,TSR,WI)of the treated fabric were investigated.The results showed that MASESMA is an effective anti-wrinkle finishing agent,The optimal conditions for MASESMA treatment are MASESMA 100 g/L,sodium hypophosphite(SHP)65 g/L,two dips and two nips,drying at 80?for 3 min,curing at 160?for 90 seconds.The WRA,TSR and WI of the fabric treated under optimal condition is 257°,53.6%and 115,respectively.The WRA is more than 235°and DP rating ranges from 3.5 to 3.0 after 11 washing cycles.It was found that softener improved both WRA and TSR of the MASESMA treated fabric.The performance of softener treated fabric using two bath method is better than using one bath method.High concentration of softener benefits the performance.The performances of the fabric treated with BTCA and MASESMA were compared.The results showed that MASESMA could impart the cotton fabric high WRA at relative low curing temperature,while BTCA needs more higher temperature to get the same WRA.This phenomenon was analyzed by ATR-FTIR method,thermogravimetric(TG)and molecular simulation software(Material Studio,Chemoffice 3D,Guassian 09).The results indicate that the temperature of BTCA starting to form one-ring anhydride is lower than that of MASESMA starting to form one-ring anhydride,while the temperature of BTCA startting to form two-ring anhydride is higher than that of MASESMA starting to form two-ring anhydride.Which could account for the better WRA of MASESMA treated fabric than that of BTCA treated fabric.Therefore,the suggestions for designing new polycarboxylic acis as anti-wrinkle agents was proposed.In the aspect of thermodynamics,reducing the temperature at which the anhydride starts to form,such as decreasing the number of polar group,increasing the nonpolar group,reducing the melting point,restraining the hydrogen bond forming.In dynamics,the length of ester groups and rigidity of the molecular should also been taken into consideration.