Study On The Prepartion Of Functional Cotton Fabrics By "Mist Polymerization" Method

Cotton fabric occupies an important position in the textile industry.In addition to warmth and decoration,a variety of functional cotton fabrics,such as superhydrophobic cotton fabric,antibacterial cotton fabric,conductive cotton fabric,and ultraviolet protective cotton fabric have been industrialized.Especially,the superhydrophobic cotton fabric and antibacterial cotton fabric not only have been widely applied in the clothing and home textile industries,but also play important roles in self-cleaning,oil-water separation,medical treatment,and other potential fields.In the practical application process,people found that superhydrophobic cotton fabrics and antibacterial cotton fabrics have problems such as poor durability and serious degradation on the inherent properties of cotton fabrics caused by the modification treatment.These problems are the key technical obstacles limiting the application of superhydrophobic cotton fabrics and antibacterial cotton fabrics,needing urgently solved but still facing challenges in the field of textile materials.At present,the main reason can be concluded on that most of the functional coatings on the surface of cotton fibers lack covalent bond connection units with the fibers,resulting in the poor durability.This research focuses on the grafting polymerization on the surface of cotton fabric,studying the grafting methods to construct superhydrophobic polymer layer and antibacterial grafted functional layer,systematically analyzing the relationship between the surface structures and the performance of superhydrophobic and antibacterial cotton fabrics,and thus comprehensively improving the durability of the superhydrophobic and antibacterial cotton fabrics.In addition,to solve the problems that the traditional pad-dry-cure technology generally damage the inherent cotton properties,e.g.,air permeability,water absorbability,flexibility and mechanical strength,the present research trieda “Mist Polymerization” technology for finishing cotton fabrics without significantly influence on the inherent properties of the cotton fabrics.The specific research results are as following:(1)A diblock copolymer,poly[(methyl methacrylate)-b-(trifluoroethyl methacrylate)](PMMA-b-PTFMA),was synthesized via reversible addition-fragmentation chain transfer(RAFT)polymerization,and covalently grafted on the cotton fabric surface via the “grafting to” strategy to construct a self-healing superhydrophobic coating by “Mist Polymerization” method.The PMMA block in the copolymer enabled covalent linkages with cellulose molecules on the fiber surface via transesterification reactions,while the PTFMA block acted as a functional part to endow the cotton fabric with new surface features.As a result,the modified cotton fabric displayed superhydrophobicity,with a water contact angle(WCA)above 160.0°.The superhydrophobic coatings of modified cotton fabric exhibited excellent stability against laundering and abrasion.Even after 60 laundering cycles or 2000 abrasion cycles,the fabric still demonstrated a WCA higher than 140.0°.Moreover,the superhydrophobicity of damaged fabric can be repaired after treatment in the tetrachloroethylene,with the WCA above the 150.0°.The “Mist polymerization” method constructs a functional layer on the fiber surface of one side of the cotton fabric,lead the inherent properties the cotton fabric such as air permeability,water absorbability,flexibility,and mechanical strength has no significantly changed.(2)The fluorine-containing superhydrophobic coating on the modified cotton fabric may be harmful to human health and environment.Therefore,this work further developed a new method to prepare superhydrophobic cotton fabric by grafting fluorine-free polymers.A fluorine-free diblock copolymer poly[(methyl methacrylate)-b-(lauryl methacrylate)](PMMA-b-PLMA)was synthesized via RAFT polymerization,with the aid of fumed silica particles,a superhydrophobic cotton fabric with high durability was prepared by the “Mist Polymerization” method.As a result,the modified cotton fabric displayed remarkable superhydrophobicity,with a water contact angle(WCA)above 156.7°.Moreover,the modified cotton fabric also exhibited excellent stability against laundering and abrasion.Even after 1600 abrasion cycles or 80 laundering cycles,the WCA values of the modified cotton fabric were still kept at a level higher than 150.1°.The modified cotton fabric also showed an excellent self-cleaning performance and oil-water separation performance.In addition,the “Mist Polymerization” method could save the air permeability,water absorbability,flexibility,and mechanical strength of the modified cotton fabric has no largely changed.(3)To obtain single-side antibacterial cotton fabric with high durability,the carboxymethyl chitosan(CMCTS)and silver nanoparticles(Ag NPs)were successfully linked onto a single surface of cotton fabric via “Mist Polymerization” method.The CMCTS binder was covalently linked to the cotton fabric via esterification and the Ag NPs were tightly adhered to the fiber surface by coordination bonds with the amino groups of CMCTS.As a result,the modified cotton fabrics showed an excellent antibacterial properties and laundering durability.After 50 consecutive laundering cycles,the bacterial reduction rates(BR)of the modified cotton fabric against both Staphylococcus aureus(S.aureus)and Escherichia coli(E.coli)remained over 95.0%.Moreover,the air permeability,water absorbability,and mechanical strength of modified cotton fabric have been retained to a largely extent.These excellent properties of modified cotton fabric make it has the huge potential application in many fields such as sportswear,socks,and medical textiles.(4)The interaction of the coordination bond between the Ag NPs and the thiol group is stronger than that of the Ag NPs with amino groups.In order to further improve the adhesion of the Ag NPs to cotton fabric,the L-cysteine(Cys)and Ag NPs were linked on the single side of cotton fabric via the “Mist Polymerization” method.Cys molecules were covalently linked to cotton fibers via esterification with the cellulose hydroxyl groups,and the Ag NPs tightly adhered to the fiber surface via coordination bonds with the Cys thiol groups.As a result,the modified cotton fabric showed an excellent antibacterial function with an outstanding laundering durability.Even after 90 consecutive laundering tests,the modified cotton fabrics still showed satisfactory BR rates against both S.aureus and E.coli,and the rates were are all higher than 94.0%.Moreover,the “Mist Polymerization” method does not make the air permeability,water absorbability,and mechanical strength of the modified cotton fabric largely changed.(5)One fabric has different functions on its two side surfaces can improve the practical application value of cotton fabric products.However,it is difficult to endow the different functional properties onto the two sides of a cotton fabric by conventional modification methods.In this work,the “grafing through” manner and “Mist Polymerization” technology were combined to develop new method for finishing cotton fabrics.Acrylic acid(AA)was firstly linked onto cotton fibers via an esterification reaction.Then the incorporated AA moieties on cotton fabric surfaces were further copolymerized with other monomers using “Mist Polymerization” technique to graft different functional coatings.Poly(methacryloxyethyltrimethyl ammonium chloride)(PDMC)was covalently grafted on one side surface of a cotton fabric via “grafting through” strategy.The opposite surface of modified fabric was first covalently grafted with the poly(acrylic acid)via “grafting through” strategy,and then covalently grafted by polyethylene glycol-400(PEG-400)via an esterification.As a result,the functional coating on the both surface of the modified cotton fabric showed the excellent antifouling and antibacterial performance.The both surfaces of the modified cotton fabric were not induced skin stimulation and toxic effects to animals.Moreover,the air permeability,water absorbability,flexibility,and mechanical strength of the modified cotton fabric have been retained in a large extent.