Surface Modification Of Wool Fabric And Its Application In Reactive Dye Inkjet Printin

With the requirement of"emission peak"and"carbon neutrality",it is the general trend to develop green,fast and high-resolution digital inkjet printing technology.Inkjet printing on wool fabric to improve the added value of wool fabrics has great potential.However,the existence of the scale layer on the wool fiber leads low color yield and poor printing image quality of the wool fabric in the process of digital inkjet printing.Generally,the shrinkage effect due to the directional friction effect of the wool fabric in washing process is also a long-term difficulty.In this study,the disadvantage of the scale layer was removed and the wool fabric with other excellent properties was fabricated on this basis.This improves the added value and market application potential of wool fabrics.The main research contents are as follows:Firstly,two green reagents,hydrogen peroxide and papain were selected to pretreat wool fiber,and the mechanism of the combined treatment of hydrogen peroxide and papain was explored.After the combined treatment,the surface scale layer of wool fiber was obviously destroyed and the fiber surface became relatively smooth.The wettability of the fabric was improved,the contact angle was reduced from 137°to118°.Thus,the fabric became relatively hydrophilic.The Zeta potential of wool fabric increased from-49.6 m V to-35.3 m V,which reduced the electrostatic repulsion between reactive dye ink and wool fabric.Digital ink-jet printing was carried out on the combined treated wool fabric with monochlorotriazine reactive dye solution represented by reactive red 218.The K/S value of the pattern increases from 20.54 to25.4.The color block became darker and the color saturation was higher.As expected,the H₂O₂ firstly oxidized the disulfide bond of cystine on the keratin surface,breaking the dense crosslinking structure on the surface,which passivated the scales.And then more proteases were allowed to hydrolyze the amide bond of the protein.As a result,smooth fiber surface was generated and more sites were created on the fibers that can bond to reactive dyes.Inspired by the good film forming,antibacterial and hydrophilic properties of chitosan macromolecules,chitosan macromolecules were successfully crosslinked onto wool fibers by glutaraldehyde solution on the previous pretreated fabric.The effect of different crosslinking time was studied,and it was concluded that the crosslinking time of 1h had the best printing effect.A series of characterization methods were used to analyze and test the fabric and the results were as follows.The structure of crosslinked wool fibers was covered by chitosan film.The wettability of the crosslinked fabric was improved obviously,the contact angle decreased from 119.3°to 79.7°.After digital inkjet printing process,the K/S value of the printed patterns was increased to 26.6.The shrinkage resistance of fabric was improved obviously,the area of shrinkage was reduced from 10.96%to 2.53%.The crosslinked fabric also showed certain bacteriostatic effect on Escherichia coli and Staphylococcus aureus.The prepared wool fabric not only had excellent printing effect,but also had good shrinkage resistance and antibacterial properties.Subsequently,based on the previous research,the pretreated wool padded with chitosan was crosslinked with ethanol solution of carbodiimide hydrochloride.The influence of crosslinking time on the digital inkjet printing effect of wool fabric was also explored.The results showed that the best ink-jet printing effect was obtained when the crosslinking time was 3 h.The characterization showed that the wool fibers were covered by chitosan films and chitosan existed between fibers.After crosslinking,the wool fabric becomes hydrophilic with a contact angle of 84°.The K/S value of fabric patterns was 26.9,which is about 1.5 times higher than that before crosslinking,and the area shrinkage was reduced to 4.7%.The crosslinked fabric showed obvious bacteriostatic effect on Escherichia coli and Staphylococcus aureus.In this paper,a green combined treatment process for removing the scale layer of wool fibers is proposed.It can provide guidance for the development of multi-functional and high value-added printing wool fabrics.