Preparation Of Waterborne Polyurethane/Silk Sericin/Wool Keratin Composite Films And Application In Wool Fabrics

Polyether waterborne polyurethane has some characterization and behavior in theory and application research.However,its low breaking strength and poor water resistance limit its application in industry.Wool keratin and sericin,as two natural animal proteins,has magnificent achievements,especially in the silk sericin and wool keratin composite materials.The silk sericin is discharged as waste liquid in the process of silk reeling,resulting in waste of resources.In this paper,the waterborne polyurethane and sericin/wool keratin mixture are blended in different ratios to prepare the WPU-WS composite films,which is then used for finishing wool fabrics,and composite film and finished wool fabrics are characterized to obtain new materials which are suitable for the environmental regulations and provide application data and preparation methods.The WPU-WS composite films are fabricated by blending waterborne polyurethane and sericin/wool keratin mixture,which are characterized by FTIR spectroscopy and UV-Visible spectrum,in order to investigate the effect of blending ratio of waterborne polyurethane and sericin/wool keratin on its structure.The results show that the WPU-WS composite film exhibits better mechanical properties,UV absorption,swelling properties and surface hydrophobicity.As the waterborne polyurethane content increases from 20% to 100%,the ?-helix and ?-sheet content in the composite film declines from 5.84% and 5.66% to 0.3% and 4.13%,respectively,while the soft and hard segments respectively increase from 23.82% and 64.04% to 25.36% and 69.77%,indicating that the increase in waterborne polyurethane content resulted in more hard segment structure and soft segment structure in the composite film.Correspondingly,the strain of films increases from 117.8% to 242.7%,while stress and modulus decrease from 10.5Mpa and 116.8Mpa to 5.2Mpa and 9.9Mpa,respectively,implying that the addition of wool keratin improve its flexibility.This is because the long-chain soft segment long chain supports the flexible properties of the composite film and forms a tensile strengthening effect.The WPU-WS blending solution are ultrasonically modified to study the effect of ultrasonic modification time on the structure and tensile properties of WPU-WS composite films.The results show that the ultrasonic modification time has a significant effect on the performance of the composite films.When the modification time beyond 6min,the composite films contains the lowest content of soft segment structure,and the ?-helix and ?-sheet content increase,indicating that the ultrasonic action at this time makes the structure of the composite films more regular.When the mixed solution is treated under ultrasonic wave,the macromolecular chains of waterborne polyurethane,sericin and wool keratin combine to promote the rearrangement of the structure of the composite films,and as the ultrasonic time increases,the weak hydrogen bond crosslink between the macromolecular chains will be interruption affects the performance of the composite films.Different ratios of waterborne polyurethane/silk/wool keratin blends are used to finish the wool crepe fabric.Under the same finishing liquid concentration,with the increase of waterborne polyurethane content.As the content of waterborne polyurethane increases,the strain of the finished wool fabric increases,while stress and modulus decrease,the gas permeability decreases,and the ultraviolet absorption capacity and surface water repellency increase.However,with the increase of concentration,the strain of the finished wool fabric increased,stress and modulus decreased,and the ultraviolet absorption capacity increased,but the gas permeability decreased.Therefore,adjusting to an appropriate ratio can be applied to fabric finishing to prepare a waterproof and breathable fabric.