Synthesis And Application Of Water And Oil Repellent Finishing Agent With Short Fluoroacrylate Chain

With the development of social economy,people are no longer satisfied with the basic performance of textiles.Textiles with special properties and environmental requirements are attracting more attention.Water repellent and oil repellent textile is one of the most important examples.Florinated polymers have been widely used in the field of textile finishing due to their ultra-low surface energy,unique water repellency and oil repellency,splendid heat resistance and chemical stability.Fluorine finishing agents especially contain those with perfluoroalkyl group(C_n F_2n+1,n?8).Unfortunately,the production of these perfluoroalkyl polymers with long fluoroalkyl may result in the release of perfluorooctane sulfnate?PFOS?and perfluorooctanoic acid?PFOA?by oxidative degradation.Both substances have a potential environmental risk for their permanent bioaccumulation,PFOA and PFOS are also linked with damage to children's immune system and harmful to the health of people.Considering the biohazardous effect of PFOA and PFOS,the EU issued bans on the use of 8C and above fluoropolymers.Because of these prohibitive actions,it is urgent to develop alternative materials to replace the perfluoroalkyl with long fluoroalkyl substances.In this work,the fluorinated copolymers composed of fluor inated monomer?perfluorobutyl?ethyl acrylate?C₄F?,acetyl acrylate?SA?and butyl acrylate?BA?which were used as basic monomer,glycidyl methacrylate?GMA?which was used as crosslinking monomer were prepared by miniemulsion copolymerization.The fluoroacrylate miniemulsion was synthesized under the condition of the dodecanethiol?SH?and the compound emulsifiers cetyltrimethylammonium bromide?C TAB?and polyoxyethylene lauryl ether?Brij L4?,water-soluble initiator 2,2'-azobis?2-methylpropionamidine?dihydrochloride?AIBA?.The influence of co-emulsifier dosage,type and amount of emulsifier,monomer ratio,dosage of initiator,polymerization temperature and holding time on the properties of emulsion and the water and oil repellent properties of cotton fabric were discussed t hrough univariate analysis,and the optimum synthesis process was obtained:C₄F:SA:GMA:BA=2:1:0.1:0.5?mol/mol?,emulsifier?CTAB:Brij L4=1:4?dosage was 6%of the mass of the monomers,SH dosage was 1/3 of the mass of emulsifier,AIBA dosage was 0.5%of the mass of the monomers,polymerization temperature was 70?,the holding time was 2.5 h.In this process,the contact angle of cotton fabric is WCA=153.6°,OCA_{olive oil}=143.1°,OCA_hexadecane=123.7°,the level of water repellency reached 5,the level of oil repellency reached 3.Particle size distribution analyze,FTIR,XPS and TG measurements,characterized the structure and properties of the prepared fluoroacrylate miniemulsion.The results showed that the miniemulsion was uniform and delicate in appearance,the solid conte nt was 29.5%,and the gel rate was 0.325%.The particle size test showed that the miniemulsion was evenly distributed with good stability.FTIR and XPS evidenced that the fluoroacrylate polymer was successfully synthesized and the content of fluorine on the surface of polymer film reached40.75%.TG showed the initial decomposition temperature of the fluoropolymer was significantly increased and exhibited excel ent heat resistance.Then,the cotton fabric was treated by the fluoroacrylate miniemulsion,which was synthesized under optimum condition.Based on the evaluation of static contact angle of water and oil,the effects of ultrasonic and plasma pretreatment method,padding process,and impregnation time,concentration of miniemulsion,drying and curing process on the water and oil repellent of cotton fabric were investigated in detail.The optimal process for water and oil repellent finishing was determined:the concentration of miniemulsion is 60 g/L,impregnation for 35 min,drying at 80?for 3 min,curing at 160?for 3 min.Under the above condition,the contact angle of cotton fabric is WCA=160.5°,OCA_{olive oil}=154.6°,OCA_hexadecane=135.2°,the level of water repellency reached 5,the level of oil repellency reached 3.Moreover,the water and olive oil droplets can easily shake off the cotton fabric.SEM images showed that plasma pretreatment has an etching effect on the cotton fabric,and fabric treated with fluoroacrylate polymer exhibited a continuo us film on the surface of fiber.FTIR and XPS images indicated that the fluoropolymer reacted with the cotton fiber,and the content of fluorine on the surface of cotton fabric with plasma pretreatment increased to 42.60%,which was higher than the cotton fabric without pretrea tment.Plasma pretreatment can significantly improve the laundering durability of cotton fabric,and it can still maintain good water and oil repellency after 30 times washing.The wrinkle recovery angle of pretreated cotton fabric increased by more than 35%and the weight reduction rate of fabric decreased from 7.8%to 1.5%after 100 times abrasions.The retention rate of breaking strength was 95.2%,and the air permeability and moisture permeability decreased by 5.5%and 4.3%,respectively,which did not affect the daily intake requirements.