Study on the structure and properties of modified silk with ultraviolet absorbent北大核心CSCD

The silk fiber has an irreplaceable position in textile fibers and related silk fabrics have the advantages of light and airy texture good moisture absorption and breathability comfort in wear etc. It is also widely used in other fields such as the biomedical sector. However silk also has its own limitations poor light resistance and susceptibility to ultraviolet light especially the ultraviolet light of 290-400 nm wavelength in daylight such as under which condition it is prone to yellowing and photodegradation. The yellowing of silk is due to the photo-oxidation of tyrosine and tryptophan in silk protein under the action of ultraviolet light from sunlight and due to the production of yellow substances which affects the whiteness of silk. In addition from the molecular structure of silk most of the amino acids susceptible to UV light are distributed in the amorphous region. As the amorphous region is affected the structure of the crystalline region is also gradually relaxed the local degradation begins and the silk protein macromolecule chain is cleaved which leads to the decrease of the mechanical properties of silk fibers and accelerates the aging of silk fibers and fabrics. Therefore it is necessary to modify the silk products outside the anti-purple line. The current methods used to modify silk are mostly for post finishing modification including coating impregnation and chemical grafting methods but these methods often affect the original color or feel of the fabric and the durability of the modified effect is also poor. The feeding method is a green method to obtain modified silk by spraying mulberry leaves or artificial feed mixed with modifier which is ingested by silkworm and transferred to silk gland. In this study five aminobenzene UV absorbers were used as exogenous additive food for silkworms. The effect of molecular polarity on the transport of modifiers to silk glands was investigated and their effects on silkworm development and silk structural properties were studied. It was found that the aminobenzene UV absorbers were more easily transferred to the central silk gland silk glue and less to the posterior silk gland (fibroin). 4-dimethylaminobenzoic acid was found to be the highest in the posterior silk gland with a content of 3. 27 μg / strip. The cocoon width and cocoon quality of this group were significantly lower than those of the control group and the silk gum content was increased when this group was used as the study object. Compared with the control group the relative content of β-folded structure and crystallinity of the silk in the addition feeding group decreased slightly. The silkworm silk in the feeding group showed a certain UV absorption ability. After 330 h UV irradiation the breaking strength and elongation of the control group decreased by 48. 95% and 43. 52% respectively while those of the feeding group decreased by 42. 03% and 34. 18% respectively. In this paper UV absorbers were added to silkworms to obtain modified silk mainly focusing on the transfer of the modifier to the silk gland and the structural properties of the modified silk only for the most UV absorbers to enter the silk gland of the posterior group of silk. Other properties of the modified silk such as washing resistance have not been studied and some more in-depth studies are required. For instance it needs to be studied in depth for the limited absorption of exogenous additives by silkworms additive food's being not always absorbed by silkworms and transferred to the silk gland and the mechanism of action between the additive food and silk protein after the former's entering the silk gland. © 2022 Authors. All rights reserved.     

抗紫外剂改性石榴皮色素及其功能性染色

为提高蚕丝织物的功能性和附加值,文章采用抗紫外剂改性天然染料石榴皮色素染色蚕丝织物。通过单因素实验确定改性反应最佳pH值,探讨了改性反应的机理,研究了染浴pH值对织物染色性能及抗紫外性能的影响。结果表明,染浴pH值分别为3.0、4.0、5.0、6.0时,相同pH值染浴中,改性后石榴皮色素染色织物的K/S值高于改性前。染浴pH值分别为3.0、4.0、5.0、6.0、7.0时,改性后石榴皮色素染色织物的抗紫外性能显著提高,相同pH值染浴中UPF比值在1.87～2.57。染浴pH值为3.0时,改性前、后石榴皮色素染色织物的K/S值均较高,耐皂洗色牢度及耐摩擦色牢度达4～5级,UPF值分别为24.54和10.73。     

Research progress on chemical modification of silk fibroin and its applications北大核心CSCD

Mulberry silk is composed of the two major parts of two triangle-like silk fibroin fibers and sericin covering the fibers and a few lipids. After removing the sericin on the raw silk what is left is the silk fibroin fiber. Silk fibroin is the main part of silk accounting for about 75% of the total weight. Silk fibroin contains 18 natural amino acids such as glycine Gly alanine Ala serine Ser serine aspartic acid Asp and tyrosine Tyr . The secondary structure of silk fibroin has three main conformations α-helix β-fold and random coil. Under certain conditions the three conformations can transform into each other and change the mechanical properties of the silk fibroin material. Silk fibroin extracted from silk fiber is a natural polymer with biocompatibility and biodegradability. It can be further processed into different forms of materials nanoparticles films hydrogels sponges etc. It has been applied in many fields such as biomedicine and cosmetics. In order to meet the needs of different fields researchers have conducted further chemical modification treatment based on the original excellent properties of silk fibroin. Meanwhile the active groups on various amino acid residues in silk fibroin also provide chemical reaction sites for the chemical modification of silk fibroin. The chemical modification methods of silk fibroin mainly include amino acid residue modification macromolecular grafting modification and crosslinking reaction modification. Among them amino acid residue modification can modify protein amino acid residues by chemical reagents and some groups can be introduced into the side chains of silk fibroin macromolecules. Grafting modification of silk fibroin macromolecules is one of the main means to bind functional compounds to silk fibroin macromolecular chains. The properties of grafted silk fibroin are affected by the type and grafting rate of the grafts. The chemical crosslinking reaction modification of silk fibroin macromolecules is to make the macromolecular chains connected by covalent bonds and form a network structure by means of crosslinking agents enzymes or ultraviolet irradiation. The cross-linking reaction can not only form covalent bonds within and between the molecular chains of silk fibroin thus changing its structural properties and improving its stability but be used to form covalent bonds with other polymers. At present the chemical modification of silk fibroin is mainly applied in the fields of silk textiles biomedicine and environmental science. In the field of silk textiles graft copolymerization modification of vinyl and other monomers crosslinking agent modification and other methods are used to overcome the shortcomings of silk like being easy to wrinkle. The graft modified monomers mainly include ethylene methacrylate and methylacrylamide. The active groups on crosslinking agents such as polycarboxylic acid / anhydride and epoxide are covalently combined with carboxyl hydroxyl and amino groups on macromolecules of silk fibroin to improve the wrinkle resistance of silk fabrics. In the field of biomedicine silk fibroin materials with appropriate chemical modification have better biological activity drug delivery ability antimicrobial properties and mechanical properties. The optimization of these properties enables silk fibroin materials to show great potential in drug control delivery tissue regeneration and wound repair. The applied research in the field of environmental science mainly focuses on the adsorption separation and catalysis of impurities in water. Therefore the modification of amino acid residues grafting and cross-linking of protein macromolecules can change some important properties of silk fibroin and meet the requirements of various applications and functionalization of silk fibroin. In many fields of chemical modification and application of silk fibroin protein fruitful results have been achieved which has laid a good foundation for the further development of related fields and also shows that the chemical modification of silk fibroin material has great potential and application prospects. However there are still some problems that need to be overcome and further improved in the current chemical modification methods such as mild modification conditions and accurate adjustment of the degree of modification which will be the research direction of related fields in the future. © 2022 Authors. All rights reserved.     

Performance testing and evaluation of reactive dye inks for silk digital printing北大核心CSCD

In order to explore suitable reactive inks for silk digital printing, reactive dye inks of eight brands were selected from the domestic market to evaluate their pH, Conductivity, absorption spectrum, color gamut range and their application performance including color yield, dry and wet rubbing fastness. The results showed that pH values of ink of different brands ranged from neutral and weakly acidic property, which would be helpful to reduce hydrolysis of the reactive dye and improve their stability. Reactive inks with lower conductivity could avoid salt crystallization which would cause nozzle blocking and corrosion problem. The hue of three primary colors (CMY) was stable, while that of spot color (BRO) had some differences, and the overall gamut range of these ink sets were different at different brightness levels. The application performance of the printed silk demonstrated that the increase in the stability of reactive ink would improve the color yield and color fastness of the printed fabric. © 2018 China Silk Association. All rights reserved.     

Preparation and characteristics of bombyx mori sericin / tussah silk fibroin / gelatin-based blended antibacterial films北大核心CSCD

A large number of wound dressings are currently used in the treatment of burns chronic ulcers etc. An ideal wound dressing should prevent dehydration of the wound and retain a favorable moist environment at the wound interface. It should have good antibacterial properties and be easily removed without trauma too. Wound dressings are generally made of readily available bio-materials that require minimal processing possess nontoxic non-allergenic and antimicrobial properties as well as promote wound healing. Clinically collagen chitin chitosan etc. are usually used as materials for producing wound dressings as these materials are capable of accelerating the healing processes at molecular cellular and individual levels. Tussah silk fibroin bombyx mori sericin and gelatin non-toxic and extensive have good bio-compatibility degradability and film-forming properties which are conducive to cell adhesion. In order to prepare safe biofilms with excellent antibacterial properties we prepared a kind of bombyx mori sericin / tussah silk fibroin / gelatin BS-TSF-GEL blended film by using tussah silk fibroin bombyx mori sericin and gelatin as bio-based materials and polyethylene glycol 200 as the cross-linking agent. Firstly we designed the single factor experiment and orthogonal experiment to optimize the preparation process of the BS-TF-GEL blended film. On this basis the blended film was modified with ethanol of different concentrations to improve its strength and crystallinity. The structure and properties of the blended film were characterized by measuring the dissolution loss rate tensile properties microscopic morphology and crystal structure. Finally antimicrobial peptides were loaded by adsorption to obtain the BS-TSF-GEL antimicrobial film. The results showed that the ratio of the optimum formula for the (BS-TSF-GEL) blended film required a mixture of bombyx mori sericin (4. 50 μg / mL) and tussah silk fibroin (27. 5 mg / mL) with a volume ratio of 2:1 polyethylene glycol 200 and gelatin solution (360 mg / mL) which accounted for 35% 40% and 25% respectively of the total system. The dissolution loss rate of the BS-TSF-GEL blended film was 34. 62% the elongation at break was 34. 15% and the breaking strength was 578. 8 kPa after being treated with anhydrous ethanol. FTIR and X-ray diffraction results showed that Silk Ⅱ dominated the BS-TSF-GEL blended film while Silk Ⅰ was in a small amount. The BS-TSF-GEL blended film was pale yellow and porous on the surface which was the ideal material for loading antimicrobial peptides. The BS-TSF-GEL blended film loaded with antimicrobial peptides had a good inhibitory effect on both Escherichia coli and Staphylococcus aureus. It is expected to be used in the field of disposable biomedical materials such as wound dressings. In this study three natural materials with unique advantages were selected as substrates for biofilms and polyethylene glycol with high bio-safety was used as the cross-linking agent to enhance the application value of the blended film by loading antimicrobial peptides. The results broaden the application field of silkworm silk and provide a new way for the development and exploitation of silk fibroin in biological dressings and other medical bio-materials. Bombyx mori sericin tussah silk fibroin and gelatin have been widely used in biological tissue engineering as natural biological materials. In this study three natural materials were used as the biofilm substrate to successfully prepare excellent-performance BS-TSF-GEL blend film using polyethylene glycol cross-linking and ethanol post-treatment techniques. Moreover specific properties can be conferred by replacing different loading substances such as antimicrobial biofilm carrying antimicrobial peptides and biofilm sustained release carrier loading drugs. In addition 3D printing electrostatic spinning and other technologies can also be used to shape the BS-TSF-GEL into different shapes to meet the application requirements under different conditions. In conclusion the research results explore a new way for the application of silk protein. © 2022 Authors. All rights reserved.     

反应性抗紫外剂改性天然染料紫草素北大核心CSCD

为提高紫草素水溶性和紫外线吸收性能,采用水溶性、反应性紫外线吸收剂对天然染料紫草素进行改性,本文合成了一种新型水溶性紫草素染料。通过单因素条件实验确定了改性反应的最佳条件,分析了反应机理,对反应物和产物进行了FTIR红外光谱和紫外光谱表征。结果表明,改性反应最佳条件为紫草素与抗紫外剂的近似摩尔比约1︰0.8,在pH值为9.0的碳酸钠溶液中,80℃水浴振荡40 min。改性紫草素在1 250 cm^(-1)处出现芳香醚中C—O(Φ)键的反对称伸缩振动,紫外-可见吸收光谱显示在波长288 nm处出现吸收峰,且可见光区吸光度增加。通过改性提高了紫草素的水溶性和紫外线吸收性能,用于织物染色可以提高织物的功能性和附加值。     

Study on spinning process and properties of blended silk/luminous polyester yarn北大核心CSCD

Energy storage luminous polyester fiber is a new functional and environmentally friendly material, whose application in the market is becoming wider and wider. In order to further improve the performance of luminous polyester fiber and broaden its market applicability, luminous polyester staple fiber is blended with silk staple fiber in this study. By giving full play to the advantages of silk fiber, we enhance the afterglow strength and mechanical properties of luminous polyester, and improve the appearance effect of luminous polyester staple yarn. The silk is blended with luminous staple fiber, according to different addition ratios, and then spun into blended yarn through the processes of blowing,carding, intermediate drawing, roving, and spinning. After an analysis of the process and properties of blended silk and luminous polyester yarn, the results indicate that when the content of silk staple fiber in the blended yarn is less than 8% , the luminous intensity, mechanical properties and evenness of the luminous staple fiber yarn are improved. © 2021 China Silk Association. All rights reserved.