Research on Anti-felting Treatment of Wool Fabric and Biomedical Application of Wool Keratin

Author:Du Zhuang

Supervisor:yan ke lu


Degree Year:2019





The presence of the scale layer on the wool fiber surface can easily cause the shrinkage of wool fabric subject to the mechanical action.Wool fibers are rich of keratin,which possess a large amount of reactive groups.These groups can interact with various cross-linking agents as well as nano-noble metals.The excellent biocompatibility and biodegradability of keratin make it widely used in textile,biomedical and other fields.Therefore,the research in this dissertation was divided into two parts.The first part is to study the chlorine-free anti-felting treatment of wool fabric by keratin.The second part is to explore the biomedical application of wool keratin encapsulated gold nanorods.Firstly,the alkaline protease was used to extract keratin from wool fibers.According to the fact that the L-cysteine is totally environmentally friendly and the reductive sulfhydryl group existed in it.The L-cysteine was used to pretreat wool fabric under proper conditions to destroy the disulfide bond on the surface of wool fiber and improve the fiber reactivity.Then the KPs was crosslinked onto the surface of wool fabric and recycled using the KPs to make the anti-felting treatment more environmentally friendly.The optimal enzyme activity was pH 8.0 at 60°C.It will reach the maximum extraction efficiency when the concentration of enzyme was 2.0 mg/mL,about 51.5%fibers was dissolved.The weight-average molecular weight of extracted keratin was 5271 according to gel permeation chromatography(GPC)test,which should contain a large amount of polypeptides in the extracted solutions,the solution should be keratin polypeptides(KPs).Considering the strength and area shrinkage of pretreated wool fabric,the optimum pretreatment process by L-cysteine was discussed and the area shrinkage of pretreated fabric was about 7.8%.After the fabric was treated with the KPs solution,collected the residue KPs and take the treated fabric for crosslinking treatment by glycerol diglycidyl ether(GDE),followed by curing to complete the finishing,collected KPs residues were recycled by adding fresh KPs.The properties of treated fabric were analyzed and the results showed that the area shrinkage of KPs cross-linked fabric was only 0.3%,and the softness was improved compared with control fabric,besides the hydrophilicity was improved,weight and strength loss of the treated fabrics were acceptable.Recycle using of KPs10 times showed almost the same properties with original KPs crosslinked fabric,and the molecular weight of KPs was slightly decreased.X-ray electron spectroscopy(XPS)and Raman spectroscopy(Raman)were used to analyze the surface of the fabric before and after finishing.The results showed that L-cysteine could destroy the scale layer of the fiber and the active groups on the surface were exposed.The oxgen and carbon element were significantly increased and decreased,respectively.And the disulfied bond content was decreased,which made KPs can be effectively crosslinked onto the surface of the fabric.Due to the large amount of active groups such as-OH,-NH2 and-COOH presented in KPs,which improved the hydropgilicity of wool faric effectively.The surface morphology of the fabric was not affected by the KPs recycle using.Secondly,waterborne polyurethane(WPU)as an effective chlorine-free anti-felting agent were widely used for wool fabric anti-felting treatment,while the relative higher concentration of WPU must be applied for coating the fiber surface and the handle of the treated fabric is hard.If the WPU can be reinforced effectively,then small amount of WPU would be used for anti-felting treatment and the handle of treated fabric could be improved.Based on the fact that the extracted KPs possess excellent water solubility and rich of active groups such as–NH2,-COOH,etc.,which theoretically has good compatibility with the waterborne polyurethane and can react with–NCO group of waterborne polyurethane.In this study,industrial waterborne polyurethane(WPU-1)and protease extracted KPs were mixed to prepare composite emulsions and the mixture was applied as anti-felting agent for wool fabrics to save WPU-1 consumption and improve the handle of fabrics.The effect of WPU-1 concentration and KPs dosage on the properties of treated wool fabric were discussed.When the fabric was treated by pure WPU-1,at least 110 g/L of WPU-1 should be applied for anti-felting treatment.Although the fabric has a good anti-felting effect at such high concentration of WPU-1,the handle was very hard.When we added 4%KPs to the 50 g/L WPU-1and the composite emulsions treated fabric can reach the same anti-felting effect and strength as 110g/L pure WPU-1,reduced about 55%WPU-1 consumption.The composite films were prepared to analyze the mechanism of improving the anti-felting effect.The strength and dynamic mechanical analysis(DMA)of composite films were investigated.When we added 2%or 4%KPs into the WPU-1,the results showed that the storage modulus of composite films increased by twice o8=r 1.5times over the pure WPU-1 at their glass transition temperature,respectively.And the strength increased by 55.6%when we added 2%KPs,which indicated that the KPs can strengthen the WPU-1 effectively.The FTIR showed that there was the crosslinking and hydrogen bond between KPs and WPU-1,which could be ascribed to the–NH2 and–COOH that existed in the KPs can react with the–NCO or form hydrogen bond with carbonyl groups of WPU-1.In addition,the biocompatibility of WPU-1/KPs composite film was improved owing to the excellent biocompatibility of KPs,which indicated that the composite emulsion was more environmentally friendly,which means the wool fabrics that treated by WPU-1/KPs composite emulsions should be more easily biodegraded after we abandoned them.Moreover,based on the principle of reducing the amount of waterborne polyurethane on the anti-felting treatment of wool fabrics by reinforcing the waterborne polyurethane,attempts have been made to use amino-modified hollow nano-silica(HSNs-NH2)to enhance WPU-1 for anti-felting treatment of wool fabrics.The results showed that the composite emulsions has great anti-felting effect for wool fabric and the handle of treated fabric was improved.Lastly,we explored the application of keratin encapsulated gold-nanorods.In view of the first chapter,we found that the L-cysteine can reduce the wool fibers effectively,which can destroy the fiber peptide chains and produce disulfide bond exchange,as well as free sulfhydryl groups,and these groups can form stable bonds with gold nanorods.So,we extracted keratin from wool fibers by L-cysteine under proper conditions and encapsulated the gold nanorods by the free-SH groups and-S-S-bonds existed in keratin to explore its biomedical application.The L-cysteine extracted keratin from wool fibers was soluble in water and containing about 0.25 mM/g of sulfhydryl group.The extracted keratin was dissolved in water and encapsulated gold nanorods.The size of the prepared gold nanorods was about 55 nm by TEM and DLS analysis.The TEM,TGA,DLS,UV-visible spectrum and zeta-potential analysis showed that keratin has been successfully encapsulated the gold nanorods(AuNRs@Kr)and also improve the stability of gold nanorods in PBS and medium.AuNRs@Kr showed lower cytotoxicity to fibroblasts and good hemocompatibiliy,besides a good photothermal effect.The drug-releasing behavior of nanoparticles at different pH,laser irradiation or glutathione(GSH)environment was investigated after loading doxorubicin hydrochloride(AuNRs@Kr-DOX)into AuNRs@Kr.The results showed that AuNRs@Kr-DOX had pH/NIR/GSH stimulus responsiveness.The drug-releasing behavior was qualitatively analyzed by flow cytometry and laser scanning confocal microscopy(LSCM).Subsequently,fluorescence microscopy and cytotoxicity analysis confirmed that AuNRs@Kr-DOX has a good chemo-photothermal synergistic therapy on breast cancer cells(4T1).