| Bio-based surfactants are synthesized by microorganisms through the action of various enzymes in cells and have a wide range of applications.Rhamnolipid is an environmentally friendly bio-based surfactant that can be degraded by microorganisms and has good application value.This thesis investigates the potential application of the bio-based surfactant rhamnolipid in dyeing and finishing by determining some of its physicochemical properties,including emulsification,critical micelle concentration（CMC）,surface tension,permeability and tolerance to acid,alkali,salt and temperature.In the study of rhamnolipid as a cotton knitted fabric finishing agent,the optimum process for rhamnolipid as a finishing agent was explored by exploring single factors such as temperature,time,dosage and bath ratio and optimising the optimum process by orthogonal experiments,and compared with the finishing effect of commercial finishing agent729-100%.The feasibility of rhamnolipids as wetting agents and dyeing promoters for the reactive dyeing of cotton blanks was investigated by testing the wettability of rhamnolipids on cotton blanks and the changes of various factors in dyeing.Firstly,the physicochemical properties of rhamnolipids were investigated.Rhamnolipids have a low critical micelle concentration,with a CMC value of only 40mg/L,and can reduce the surface tension of water to 40 m N/m,which is better than chemical surfactants such as SDBS and JFC;in terms of permeability,the performance of rhamnolipids is significantly higher than that of refiner 729-100%,SDS and SDBS.At a concentration of 1.5 g/L,the permeability of rhamnolipids is closer to that of JFC,with a settling time of 114 s for rhamnolipids and 89 s for JFC,compared to154 s for the refiner 729-100% and more than 30 min for SDS and SDBS.Rhamnolipids at a concentration of 0.5 g/L can maintain the stability of oil-water mixed systems for more than 5 min,and those at a concentration of 2.5 g/L can maintain the stability of oil-water mixed systems for more than 8 min;rhamnolipids have good tolerance to temperature and salt,making them suitable for dyeing baths in reactive dyeing;rhamnolipids are sensitive to p H,and are stable at p H 5-8.The properties of rhamnolipids are more stable in the p H range of 5-8 and change considerably when the p H is further increased or decreased.In the investigation of the application of rhamnolipids as pretreatment refining agent,the best process was 1.5g/L rhamnolipids,boiling temperature 80°C,holding time 30 min,bath ratio 1:10.In comparison with the refining effect of the factory process,the gross efficiency of rhamnolipids after refining was 13.5cm,the wax removal rate was 61.47% and the top breaking strength was400 N,all of which were better than that of the factory commercial refining agent process These were better than the 12.3cm,59.36% and 364 N of the commercial refiner process.When the fabrics were dyed with reactive dyes after refining with rhamnose resin,the dyeing rate of reactive black ED-H was 63.3% and that of reactive navy ST-RH was 61.23%;the dyeing rate curves of reactive black ED-H and reactive navy ST-RH were basically the same as the dyeing rate curves after refining with Refiner 729-100%,and in the tests of colour fastness to rubbing and washing after dyeing,the Although the fastness did not improve,all the fastnesses were able to reach the fastness of the dyeing after 100% refining with Refiner 729.Although the whiteness after rhamnolipid refining was not as good as the commercial refiner process,the whiteness after the bleaching process was able to reach 76 in line with the factory standard sample.In the subsequent dyeing of Reactive Yellow 3RS,Reactive Red 3BS and Reactive Brilliant Blue RSP,the dyeing rates of the three dyes were 79.39%,67.25% and 78.78% respectively,and the total colour difference test DE was within the range of 0-1.Finally,the application of rhamnolipids as wetting agents in reactive dyeing of cotton blanks was explored.The optimum application process was rhamnolipids 0.3g/L,dyeing temperature40°C,dyeing time 20 min,fixing temperature 60°C,fixing time 60 min.The amount of metamines and sodium carbonate required for different dye concentrations was different,with 1% dye pair applying 30% and 10%,3% dye concentration Corresponding dosage is 60% and 20%,5% dye concentration corresponds to 80% and 25%.In comparison with the conventional dyeing process,the K/S values are slightly worse and thus the dyeing colour difference exceeds the maximum error,but the evenness,dry rubbing fastness and wet rubbing fastness are all better and can meet the dyeing requirements.Although the K/S values of the rhamnolipid dyed fabric are not as good as the conventional dyeing process at the same dye concentration,the problem of light dyeing can be solved by increasing the dye concentration appropriately. |
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