Application Of Atmospheric Pressure Plasma Technology In Antibacterial Finishing Of Cotton Fabrics

Fiber materials are essential basic materials in daily life,and the pore structure of fabrics make it easy to absorb bacteria.Due to good hydrophilicity of cotton fabrics and abundant polysaccharide nutrients in fiber macromolecules,creates a favorable living environment for bacteria.Therefore,blocking the transmission pathway of bacteria is of great significance for improving the application value of textiles,which makes the antibacterial finishing of cotton fabrics particularly important in textile functional finishing.The traditional antibacterial finishing process for cotton fabrics is mostly wet chemical treatment,which requires high-temperature curing,high energy and water consumption,and heavy wastewater treatment burden.Plasma technology is a dry treatment process that reduces water and energy consumption,and can significantly improve the surface properties of materials without damaging the properties of the substrate itself.Based on this,this study utilized plasma technology to carry out antibacterial treatment on cotton fabrics,exploring the feasibility of directly imparting antibacterial properties to cotton fabrics by atmospheric pressure plasma active particles,as well as the feasibility of initiating antibacterial agents containing reactive groups to react on the surface of cotton fabrics,and studying the properties of antibacterial fabrics.This study includes the following four parts:（1）Under vacuum conditions,cotton fabrics was treated with ammonia plasma（referred to as“Cotton-NH₃”）,and then chlorinated with sodium hypochlorite solution.N-halamine groups were introduced on the surface of the cotton fabrics,endowing it with renewable antibacterial properties（referred to as“Cotton-NH₃-Cl”）.In order to avoid danger,this was used to determine whether the fabrics could still be endowed with antibacterial properties after being diluted 30 times by the carrier gas plasma under atmospheric pressure.By measuring the surface chlorine content of modified fabrics,the ammonia plasma antibacterial finishing process was optimized.The optimal ammonia plasma antibacterial finishing process was as follows:input power of 300 W,treatment time of 10 min,and gas flow rate of 250m L/min.The cotton fabrics modified by the optimal ammonia plasma process could kill100%E.coli O157:H7 and 100%S.aureus within 10 min of contact time;After 11 days of storage,the active chlorine completely disappears,and the chlorine content could recover by45%after rechlorination.The retention rates of warp and weft breaking strength of modified cotton fabrics were 76.8%and 78.3%,respectively,and the crystallinity could be increased by3.05%.The thermal stability and hydrophilicity of modified cotton fabrics were not affected,the whiteness remained almost unchanged,and the stiffness was improved.（2）Antibacterial cotton fabrics were prepared by grafting curcumin onto cotton fabrics surface initiated by atmospheric Ar plasma（referred to as“Cotton-curcumin”）.By measuring the K/S value of the Cotton-curcumin,the process of grafting curcumin onto the cotton fabrics surface initiated by atmospheric Ar plasma was optimized.The optimal plasma process conditions were as follows:input power of 170 W,treatment time of 1 min,gas flow rate of11 L/min.The cotton fabrics modified with curcumin initiated by the optimal atmospheric pressure Ar plasma could kill 94.36%S.aureus and 86.43%E.coli O157:H7 within 3 h of contact time.The retention rates of breaking strength in warp and weft directions of the cotton fabrics were 87.7%and 96.6%,respectively,and the crystallinity could be increased by 4.55%.The thermal stability of modified cotton fabrics were not affected.The hydrophobicity of curcumin affected the hydrophilicity of cotton fabrics.Although this cotton fabrics antibacterial finishing process avoids the danger caused by vacuum in the“Cotton-NH₃-Cl”process,its antibacterial effect was not ideal.（3）Using Ar plasma to initiate the grafting of N-hydroxymethylacrylamide（N-MA）,a N-halamine precursor of unsaturated double bonds,onto cotton fabrics（referred to as“Cotton-N-MA”）,and then chlorinating with sodium hypochlorite solution to endow the fabrics with antibacterial properties（referred to as“Cotton-N-MA-Cl”）.By measuring the surface chlorine content of modified fabrics,the process of grafting N-MA onto the cotton fabrics surface initiated by atmospheric Ar plasma was optimized.The optimal plasma antibacterial finishing process were as follows:input power of 170 W,treatment time of 1 min,gas flow rate of 8 L/min.The N-MA modified cotton fabrics initiated by the optimal atmospheric Ar plasma could kill 100%E.coli O157:H7 and S.aureus within 10 min of contact time;After 12 days of storage,the active chlorine completely disappeared,and the chlorine content could recover by 52%after rechlorination.The retention rates of warp and weft breaking strength of modified cotton fabrics were 84.3%and 91.9%,respectively,and the crystallinity could be increased by 2.13%.The thermal stability and hydrophilicity of modified cotton fabrics were not affected,the whiteness remained almost unchanged,and the stiffness was improved.This cotton fabrics antibacterial finishing process not only avoided the danger caused by vacuum in the“Cotton-NH₃-Cl”process,but also endowed the fabrics with excellent antibacterial properties.However,this antibacterial cotton fabrics will release a certain amount of free formaldehyde,which was harmful to human health and the environment.（4）The antibacterial cotton fabrics were prepared by grafting polyhexamethylene biguanidine hydrochloride（PHMB）onto cotton fabrics using atmospheric Ar plasma（referred to as“Cotton-PHMB”）.Under the conditions of atmospheric Ar plasma,input power of 170W,treatment time of 1 min and gas flow rate of 8 L/min,15%PHMB modified cotton fabrics could kill 100%E.coli O157:H7 and S.aureus within 10 min of contact time,and the retention rates breaking strength of modified fabrics in warp and weft directions were 84.0%and 89.5%respectively,and the crystallinity could be increased by 2.13%.The thermal stability and hydrophilicity of modified cotton fabrics were not affected,the whiteness remained almost unchanged,and the stiffness was improved.This cotton fabrics antibacterial finishing process not only avoided the danger caused by vacuum in the“Cotton-NH₃-Cl”process,but also endowed the fabrics with excellent antibacterial properties,and the fabrics were healthy and environmentally friendly.