Study On Antibacterial Finishing Of Cotton Fabrics With Nano Zinc Oxide And N-Haloamine

Cotton fabrics show good moisture absorbability and air permeability,as well as comfortable to wear.However,it hides the risk of microbial reproduction in the process of wearing,which is easy to cause body odor or disease transmission.Because the temperature,water and nutrients(sweat,dead skin cells,stains,and other body secretions)on the surface of the fabric are ideal media for bacterial growth.Therefore,it is necessary to carry out antibacterial finishing on cotton fabrics.At present,the antibacterial finishing of cotton fabric usually indicates some defects,including poor durability,which restricts its practical application.In this paper,silver-carrying nano zinc oxide(Ag@ZnO),nano zinc oxide(ZnO)and 3-allyl-5,5-dimethylhydantoin(ADMH)were separately used as antibacterial agents to treat the cotton fabric with different finishing processes.It is expected that the finished cotton fabrics will present good antibacterial properties and durability.First,the agglomeration of Ag@ZnO powders is easy to occur in aqueous solution.Thus,a stable antibacterial dispersion was prepared by the combination of ultrasonic treatment and dispersants.The dispersing stability was observed by gravity settling experiment,and the dispersing effect was characterized by the size distribution of nano particles.The best technological conditions for the stable dispersing liquid of Ag@ZnO(0.3wt%)were sodium dodecyl benzene sulfonate(SDBS)of 0.2wt% and ultrasonic dispersing of 30 min.An adhesive PH-N01 was added to the dispersion to stabilize Ag@ZnO onto the treated fabrics.By comparing the difference between pad-dry-curing finishing and coating finishing,the adhesive PH-N01 has insufficient effect on improving the antibacterial durability of the treated fabrics.In order to improve the durability,1,2,3,4-butane tetracarboxylic acid(BTCA)was further adopted as the cross-linking agent hoping to firmly attach Ag@ZnO onto the treated fabrics through chelation between carboxyl groups and Ag@ZnO,The response surface optimization experiment of three factors,three levels,and three response values was designed carefully.The expected response values obtained by setting the parameters of the regression model was used to predict the best antibacterial finishing process as follows: the concentration of BTCA was 5wt%,and curing temperature and time were 160 °C and 2.99 min,respectively.Under the similar conditions to the predicted one from the regression model,the experimental results showed that the wrinkle recovery angle of the treated fabrics was 232.2°,the tearing strength was 326.69 cN,and the antibacterial rate was 90.6%,which were consistent with the expected response values of the regression model.This proved the credibility of the model.Then,the same dispersing method as that of preparing the Ag@ZnO solution was used fornanometer ZnO.And the pad-dry-curing and coating finishing processes were used for antibacterial finishing of cotton fabrics.Through the study of the influence of binder type,binder dosage,and concentration of the nano ZnO on the antibacterial rate and durability of the treated fabrics,the optimal process of pad-dry-curing finishing solution was obtained.The results showed that the antibacterial rate of the treated fabric was 99.9% before washing,and it was 94.2% after one-time washing.By studying the effects of coating method,thickener dosage,curing temperature,and dosage of the binder PH-N01 on the antibacterial rate and durability of the treated fabrics,the optimal coating finishing process was determined.The antibacterial rates of the treated fabric were 99.9% before washing and 90.1% after one-time washing,respectively.Finally,the monomer ADMH was grafted onto cellulose by free radical grafting polymerization.The characteristic peaks of ADMH appeared in the infrared spectrum of the grafted fabrics,indicating successful grafting.then the ADMH-grafted fabric was immersed in the sodium hypochlorite(NaClO)solution to complete the chlorination process and obtain the antibacterial function.The influence of pH on the chlorination process was studied.The results showed that when the pH of NaClO solution was adjusted to acid(pH=4)or neutral(pH=7),the active chlorine content of ADMH-grafted fabrics increased greatly after the chlorination process,and the storage time of the treated fabrics was extended.However,after recycling chlorination processes under the specific pH condition,the active chlorine content of the fabrics decreased gradually with the increase of recycling times.