Research On The Antibacterial Properties Of Polyester Microfiber Fabrics Grafted With N-Halamine Monomers And Cotton Fabrics Crosslinked With Sophorolipids

Chemical fabrics and cotton fabrics are the most widely used materials in textiles.However,they are easily contaminated by microorganisms,especially for the cleaning textiles applied in hospital or other public places,which will be the medium of diseases and pathogen transmitting in daily use.Therefore,endowing textiles with antibacterial property is important and necessary to interrupt the pathogen and diseases transmission.However,it is difficult to provide a durable antibacterial performance to polyester fabrics because of their chemical inertness.N-halamine antibacterial agents could kill pathogen by halogen that bonded in their chemical structures.Grafting N-halamine antibacterial monomers by free radical polymerization process could solve that problem and simultaneously provide a durable and rechargeable antibacterial property for fabrics depending on the chemical conversion between N-H bond and N-Cl bond in the structure of N-halamine.According to the reports lots of solvent was needed in the grafting process because the initiator having good performance on polyester fabrics could not dissolve in water,which was harmful and noxious for the environment and limited the application of N-halamine monomers.What's more,the antibacterial performance of modified fabrics in actual situation has not been discussed,which has attracted a lot of attention of hospital and other public health department.Cotton fabrics is the most widely used natural fabrics.And natural antimicrobial agents are the first choice to modified cotton fabrics.A new natural antibacterial agent,sophorolipids,was applied in many fields like cosmetic,medicine,environmental protection and so on.However,it has not been used in textile fabrics.The content in this thesis is divided into four parts:?1?The water unsolvable initiator was dissolved in small amount of solvent and mix with water containing N-halamine monomer,3-allyl-5,5-dimethylimidazolidine-2.4-dione?ADMH?to form a stable emulsion,which was used to graft the polyester fabrics.And investing the antibacterial property and grafting mechanisms of modified fabrics.?2?Applying the emulsion to graft ADMH onto PET/PA?80/20?microfiber fabrics for cleaning textiles by manufacturing methods.And testing the antibacterial performance of modified cleaning textiles in actual situation.?3?Synthesizing a N-halamine monomer,1-acryloyl-2,2,5,5-tetramethylimidazolidin-4-one?ACTMIO?.And investigating the grafting mechanism and comparing the modified fabrics grafted with ADMH and ACTMIO.?4?Crosslinking natural antibacterial agent,sophorolipids,with cotton fabrics with 1,2,3,4-butanetetracarboxyic acid?BTCA?and investigating the mechanism of crosslinking and antibacterial property of modified fabrics.The details as following:1.An aqueous insoluble initiator,benzol peroxide?BPO?,was emulsified in water to form a stable emulsifier which could be used to graft N-halamine monomers ADMH onto polyester fabrics.By investigating the amount of emulsifier,the HLB value,emulsifying time and stirring speed,the optimum process to obtain the emulsion is determined.The emulsion could be stored for 7 days.After grafting polyester fabric with the emulsion,the grafting ratio of modified fabric was 0.61%,which was almost same with the grafting ratio?0.72%?of fabric grafting ADMH in solvent.Furthermore,the FTIR spectrum,SEM pictures and washing durability proved that the monomer grafted onto polyester fabrics successfully.It means that the emulsion is feasible for grafting N-halamine onto fabrics.The Hansen solubility parameter?HSP?distance was applied to analyze the affinity between the EB and polyester fabrics,and it showed that EB could swell the fabrics and promote the BPO diffusing into polyester fabric so that it improved the grafting efficiency.And by using Gaussian software to infer the grafting mechanism,we found that the free radical generated by BPO could abstract H atom in the chemical structure of polyester to make the macromolecule generate free radicals,which could open the double bond in the structure of ADMH.The ADMH bonded with polyester and generated a new free radical to form a long ADMH chain.Finally,ADMH was grafted onto the fabrics.The grafted polyester fabrics could load about 65 ppm active chlorine after activating it sodium hypochlorite solution with the concentration of 1000 ppm for 30 min.The chlorinated fabrics could kill 99.00%of 10⁴ CFU/mL L.innocua and E.coli with a contact time of30 min according to AATCC 100-2004 testing method.Adding crosslinker,1,3,5-Triallyl-1,3,5-triazine-2,4,6?1H,3H,5H?-trione,could improve the grafting ratio and antibacterial property to 1.8%and 99.99%by increasing the active sites which could react with ADMH.After 20 times machine washing,the modified fabric could still load above 180 ppm active chlorine and strong antibacterial property.2.The wipers made of PET/PA?80/20?microfiber were grafted with ADMH emulsion by commercial finishing facility.The FTIR subtract spectrum of grafted wipers and original wipers appeared the characteristic peaks at 1679 cm^-1 and 1705 cm^-1 belong to ADMH,and the surface of grafted wiper became rough according to the SEM pictures,which proved that ADMH was successfully incorporated onto the surfaces of wipers.The antibacterial performance of chlorinated grafted wiper was tested in an actual use situation in a university student dining hall and in ICU ward of hospital.The results of testing in dining hall showed that by wiping the surfaces of 30 tables consecutively?equivalent to 18 m²?with one piece of wet chlorinated wiper,all the surfaces of tables were sterilized.One piece of grafted wipers chlorinated in sodium hypochlorite solution and cleaned the surfaces of 30 tables as a cleaning cycle,after five cycles,the antibacterial property of the wipers was not changed.It means that the fabrics have a strong antimicrobial property and could interrupt the microbial transmission.The results of testing in hospital showed that the chlorinated grafted wiper wetted with tap water and the ordinary wiper wetted with sodium hypochlorite solution exhibited same antimicrobial performance by wiping the surface of bedrail and side cabinet.It means that the chlorinated grafted wipers could meet the requirement of sterilizing in hospital.By investigating the antibacterial efficiency and stability of grafted wipers,we found that antibacterial ratio of the grafted wipers loading about 350 ppm active chlorine against S.aureus and E.coli in concentrations of 10⁵ CFU/mL in a contact time of 3 min was 99.999%according to the AATCC100 testing method,and it could maintain 100 ppm active chlorine after storing in the environment with 65%humidity for 5 days.The wipers after 10 times successive machine washes?equivalent to fifty household machine washes?could still load above 300 ppm active chlorine.The chlorinated grafted wipers showed a better performance on durability and antibacterial property than the wiper modified with commercial antibacterial agents.By investigating the sodium hypochlorite concentration,soaking time,soaking temperature and drying temperature on the chlorinating property of grafted wipers,we found that increasing the concentration of sodium hypochlorite solution could shorten the chlorinating time,and the temperature higher than 60°C could accelerate the chlorinating process,and detergent could not influence the chlorinating property.The active chlorine lost less when the wetted chlorinated wipers dried at 60°C for 20 min.The results provided an instruction of chlorinating process and showed that the grafted wipers could be chlorinated in laundering process.3.The allyl structure in ADMH easily formed a stable allyl free radical which effect the polymerization property of ADMH,resulting in the grafting ratio of ADMH was very low.A high active N-halamine monomer,1-acryloyl-2,2,5,5-tetramethylimidazolidin-4-one?ACTMIO?,was synthesized and successfully grafted onto polyester?PET?fabrics with aforementioned emulsion.By comparing the durability and chlorinating ability of grafted fabrics modified by plasm initiation or thermal initiation,we found that thermal initiation was better than plasma initiation.The grafted fabrics modified with thermal initiation could load about 300 ppm active chlorine by soaking in the sodium hypochlorite solution containing 1000 ppm active chlorine for 30 min after 50 times machine washing.And in the FTIR spectrum the characteristic peak of ACTMIO appeared and SEM pictures of modified fabrics provided a firm evidence of grafting happening on PET fabrics.The chlorinated PET-g-ACTMIO and PET-g-ADMH exhibited a similar active chlorine lost ratio of 10%every day during the storage period in the environment humidity of 65%,because the conversion between N-H and N-Cl is sensitive to humidity.The grafted fabrics could achieve a 99.99999%antibacterial ratio against 10⁷ CFU/mL of L.innocua and E.coli with a contact time of 30 minutes after loading above 130 ppm active chlorine according to AATCC 100 testing method.By analyzing the HSP distance and Gaussian calculation results we inferred the grafting mechanism may be that ACTMIO was more active than ADMH.HSP distance between polyester and ACTMIO is 1.86which closer than the HSP distance between polyester and ADMH.It means that ACTMIO have a higher affinity to fabrics.The HSP distance between BPO and ACTMIO?3.50?is further than HSP distance between BPO and polyester?2.11?,which mean that it would avoid the BPO react with ACTMIO firstly.Therefore,BPO may diffuse into fabrics by the swelling ability of EB and initiated the fabrics to form free radicals which would graft ACTMIO on it.4.Research on the antibacterial property of cotton fabrics modified with natural surfactant sophorolipids?SLs?.The antibacterial durability was obtained by the cotton fabrics depending on the combination of 1,2,3,4-butanetetracarboxyic acid?BTCA?.By investigating the factors influencing the antibacterial property of the fabrics in the finishing process,such as the amount of SLs,treatment temperature,curing time,amount of BTCA,and sodium hypophosphite?SHP?,an optimized procedure for treating fabrics was two dips and two nips with a wet pickup of 90%in an aqueous solution containing 20 g/L of SHP,40 g/L of SLs and 90 g/L of BTCA,then drying at 100°C for 2 min and curing at 120°C for 2 min.By testing the antibacterial property of modified fabrics,we found that the SLs showed a higher antimicrobial property on gram-positive bacterium than gram-negative bacterium.And 99%of the S.aureus in a concentration of 10⁴ CFU/mL were killed by the modified fabrics in one hour contact according to ASTM method E2149-10.By analyzing the FTIR results,SEM pictures and Gaussian calculation results and crosslinking mechanism,we found that the electronic potential 8-O and 9-O in hydroxyl group of lactonic sohporolipid were-0.562 and-0.596,which showed a high reactivity,and their Hirshfeld charge were-0.232638 and-0.244554 which were similar to the O atom in C6 hydroxyl group.Therefore,we inferred the mechanism was that BTCA could react with the hydroxyl group both in the SLs structure and cellulose,by which connected cotton fabric and lactonic sophorolipid?LSL?.And the crosslinked SLs could be observed on the surface of fabric by SEM pictures and the subtract spectrum of modified fabric and BTCA crosslinked fabrics appeared the peak at 1643 cm^-1 belonging to the SLs.By analyzing the MS spectrum,we found that the antibacterial property of modified fabrics decreased because lactonic sohporolipid would hydrolyze in alkaline washing process.The antimicrobial ratio of modified fabric could be above 80%after machine washing 3 times?equivalent to fifteen household machine washes?in neutral washing condition.And the toxicity of fabrics modified with SLs only was week according to the CCK-8 testing method.