Silk Samples Research Articles

Degumming and characterization of Bombyx mori and non-mulberry silks from Saturniidae silkworms

In this study, cocoons and degummed silk samples of Bombyx mori and twenty Saturniidae species of the genera Actias, Attacus, Argema, Antheraea, Caligula, Callosamia, Cricula, Epiphora, Hyalophora, Loepa, Samia and Saturnia are studied to gain an insight into their morphology, chemical composition and physical structure. For this purpose, silk samples are characterized by optical microscopy and FTIR spectroscopy in attenuated total reflection mode (ATR-FTIR spectroscopy). Furthermore, degummed silk samples are analyzed for their amino acid (AA) composition by GC-FID. In the course of method development, various degumming methods are tested using alkalis, citric acid, enzymes and detergents. A mixture of 0.1% sodium carbonate and 2.5% ethylenediamine proves to be an effective agent for degumming Saturniidae and B. mori cocoons. After hydrolysis of the fibroin filaments with 6 N hydrochloric acid and derivatization with propyl chloroformate, fifteen AAs are identified and qualified. This method shows a satisfactory overall analytical performance with an average recovery rate of 95% at the medium concentration level. The chemical composition of the different silks was considered comparatively. Within a genus, the analyses usually show a high degree of similarity in AA composition and the resulting structural indices, whereas differences are found between genera.

Textiles Dyeing with Pomegranate (Punica granatum) Peel Extract Using Natural Mordant

ABSTRACT Agricultural waste represents a potential source of raw materials as natural dyes. The peel from pomegranate (Punica granatum) is a waste product, it is used in the textiles industry as dye. The objective of the study is to improve dyeing properties of pomegranate peel dyed silk fabric. We analyzed the pigment composition of pomegranate peel extract through ultraviolet-visible and Fourier-transform infrared (FTIR) spectroscopy; evaluated natural mordants and metallic mordants on fabrics dyed with pomegranate peel extracts by testing the K/S value, color characteristics, and color fastness; examined the morphology of dyed fabrics before and after color fixing treatment by scanning electron microscopy. The major pigment component in pomegranate peel is ellagic acid. An orthogonal array experiment revealed that the optimum dyeing conditions were pH 9, 60°C 60 min for silk fibers. Under the natural mordant, the K/S value of dyed fabric could acquire maximum (8.70). Moreover, the K/S value and color fastness of dyed fabrics could be further enhanced to 11.74 and level 5 by color-fixing treatment of natural gum rosin. Overall, the dyed silk samples with pomegranate peel represented good dyeing properties with natural mordant and natural color-fixing agent of gum rosin.

Future prospects of biocleaning application in textile conservation

Studies of sustainable preservation methods are an important element of ongoing research into minimising the environmental impact of conservation treatment. Of these methods, the cleaning of antique surfaces using selected microbial cultures is attracting attention in the field of heritage conservation. Due to the highly specific nature of the action of these microorganisms, which is similar to enzymatic cleaning, it is generally assumed that individual cultures can remove dirt without endangering the complex structures of textiles. The emphasis is placed on the use of nonpathogenic microbial cultures that have proven to be effective in the cleaning of other historical materials, and which are active in a neutral environment and show relevant metabolic activity. The aims of this work were to study the application of Pseudomonas putida to clean iron gall ink staining and the feasibility of using a selected bacterial strain to clean historic textiles. A relevant procedure for the application of this method to the controlled biocleaning of textiles was also developed. The use of water-based gel systems as a matrix for microorganisms seems to be optimal in terms of providing suitable living conditions for the bacteria and maintaining controlled contact with the surface of the object while simultaneously ensuring efficiency. Tests were carried out on appropriately prepared model samples consisting of cotton and silk. The changes emerging on the surface were evaluated using optical microscopy, and the rate of cleaning was assessed using FTIR and colorimetric methods. In addition, FTIR spectroscopy was employed for microbial control after biocleaning. The research demonstrates the feasibility of cleaning iron gall ink from textiles with viable microbial cells. The selected microorganism was able to reduce undesired discolouration from iron gall ink on model textiles. The results indicate that P. putida has a profound impact on silk samples, and prove that microbial cleaning can achieve a high level of efficiency in the removal of concentrated dirt.

Phytochemical and Nutritional Profile, Mineral Ratio and Mineral Safety Index of Young and Matured Corn Silk Collected from Ekiti State, Nigeria

Corn silk is an agricultural waste material from corn cultivation. The need for a supplement feed material that would be readily available, affordable and has nutritional qualities prompted this study. Fresh and dry corn silk were collected from a farm land in Ado Ekiti, Ekiti State, Nigeria and evaluated for phytochemical and nutritional composition using standard techniques. The phytochemical analysis revealed that both the young and matured corn silk contained alkaloids, tannins, saponins, flavonoids, phenols, steroids and reducing sugar. The qualitative phytochemical estimates showed high concentration of flavonoids and total phenols while tannins were found in moderate quantities. The proximate estimation (%) revealed high values of carbohydrate and crude fiber, moderate crude protein and ash, low crude fat, low moisture as well as high energy content in young and matured corn silk respectively. Both samples contained high K, P, Ca, Mg, moderate Na, Fe, Mn, Zn and Cu while Pb and Ni, toxic metals, were absent. The results showed low mineral CV% which ranged from 1.32-38.92. The results of the mineral safety index were lower than the standard, an indication that there would be no mineral overload. The two corn silk samples were rich in active secondary metabolites which could offer protective health benefits, also safe and contained nutritional qualities that could make them suitable to be incorporated into man’s diet and domestic feed.

Antimicrobial protection of two controlled release silver nanoparticles on simulated silk cultural relic

HypothesisSilver nanoparticles coated with organic-inorganic hybrid silica or inorganic silica have antimicrobial ability, and the coating can also effectively improve the dispersion and stability of the particles. The slow release of silver ions (Ag+) can improve the antimicrobial activity of silver nanoparticles. The synthesized nanoparticles are light yellow, which does not affect the look and feel of the silk cultural relics and meets the requirements of the principle of minimum interference. ExperimentsTwo kinds of silver-based nanoparticles were synthesized: silver core-shell nanoparticle (Ag@mSiO2) and silver yolk-shell nanoparticle (Ag@YSiO2). The morphology, surface properties and Ag+ release efficiency of two nanoparticles were characterized. The antimicrobial effects of two nanoparticles on Aspergillus niger (A. niger) and Penicillium citrinum (P. citrinum) were compared. FindingsBoth of Ag@mSiO2 and Ag@YSiO2 had uniform size and good stability. Two nanoparticles had pore structure and silver nanocore, which provided the basis for the dissolution and exchange of Ag+. Because more silver ions were released, Ag@mSiO2 had higher antimicrobial activity than Ag@YSiO2 for A. niger and P. citrinum. For various silk samples, Ag@mSiO2 exhibited excellent antimicrobial properties. Meanwhile, there was little change in the color and tearing strength of Ag@mSiO2 coated silk.

Multifunctional modification of silk fabrics via a combination of sophora flower extract, phytic acid and silicone-containing organics: Flame retardancy, water repellency, antibacterial activity and ultraviolet resistance

Herein, a multifunctional composite coating is constructed on silk fabrics by a facile impregnation strategy. In detail, the pre-period involves the aggregation growth of sophora flower extract/phytic acid-lanthanum ion-silk fibroin complex network, while the post-period introduces a water repellent layer that is composed of hydroxyl-terminated polydimethylsiloxane and hexadecyltrimethoxysilane composite. Benefiting from the synergistic effect of P, Si and N elements, the optimized finished silk sample denoted as D/FR/WR-SF exhibits a limiting oxygen index value of up to 29.3%, and shows a damage length as low as 9.4 cm in the vertical burning test. Since the sophora flower extract contains flavonoids such as rutin and quercetin, it confers good antibacterial activity and ultraviolet resistance to silk fabrics. The results display that D/FR/WR-SF inhibits the colony propagation of Escherichia coli and Staphylococcus aureus, and achieves an ultraviolet protection factor value of 38.61 compared with the control silk fabrics. Attributed to the directional arrangement of long-chain alkane and Si-CH3, D/FR/WR-SF exhibits good water repellency with a water contact angle of 138°. Additionally, D/FR/WR-SF also presents satisfactory washing resistance (integrated properties after 25 laundering cycles). Therefore, such a complete multifunctional composite coating scheme shows great potential for expanding advanced textile applications.

A Physicochemical Study of the Antioxidant Activity of Corn Silk Extracts.

Corn silk (CS) extracts are reported to contain flavonoids (appx. 59.65 mg quercetin/g), polysaccharides (appx. 58.75 w.%), steroids (appx. 38.3 × 10-3 to 368.9 × 10-3 mg/mL), polyphenols (appx. 77.89 mg/GAE/g) and other functional biological substances. This study investigated the antioxidant activity of corn silk extracts related to their functional compounds. The radical scavenging effect of corn silk extracts was evaluated by the spin-trapping electron paramagnetic resonance (EPR) technique, 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonate) (ABTS•+) free radical measurement, ferric ion-reducing antioxidant power, and copper ion reductive capacity. It was found that the maturity stage of CS plant materials and the applied extraction procedure of their bioactive compounds have a profound effect on the radical scavenging capacity. Differences in the antioxidant activity of the studied corn silk samples based on their maturity were also confirmed. The strongest DPPH radical scavenging effect was observed for the corn silk mature stage (CS-M)stage (CS-MS) (65.20 ± 0.90)%, followed by the silky stage (CS-S) (59.33 ± 0.61)% and the milky stage (CS-M) (59.20 ± 0.92)%, respectively. In general, the final maturity stage (CS-MS) provided the most potent antioxidant effect, followed by the earliest maturity stage (CS-S) and the second maturity stage (CS-M).

Key to the conservation of calligraphy and painting relics in collection: proposing a lighting damage evaluation method

As an important supporting material for calligraphy and painting relics in collections, the silk substrate is generally in acidification. And owing to an extremely high light response, it is very prone to different forms of lighting damage, including color and mechanical aspects. Considering that the Light Emitting Diode (LED) with flexible spectral compositions is widely used in the lighting environment of collections, the spectral responsivity of acidified silk substrates is the core issue concerning the long-term conservation of calligraphy and painting relics. In this study, based on the accelerated aging experiment of nine narrowband LEDs with different wavelengths (λ) in the visible range on silk samples with different acidification degrees (pH values), the infrared spectrum was measured non periodically. Processed with the Principal Component Analysis (PCA), the obtained ΔPC1 was used to evaluate the lighting damage of silk samples. Based on the damage change curve, its spectral responsivity function, that is, the mathematical relationship between lighting damage and λ and pH values, was further fitted. Combined with the previous research on the spectral responsivity of colorants, an evaluation method for lighting damage was proposed, which is the key to the conservation of calligraphy and painting relics.

Functionalization of silk with chitosan and Rubia cordifolia L. dye extract for enhanced antimicrobial and ultraviolet protective properties

Natural dyes have attained the interest of scientists over the last decade due to their functional activities in addition to their primary role of color impartation on textile materials. This study is the first report on the functionalization of silk with antimicrobial and ultraviolet protective properties using a dye extract from the roots of Rubia cordifolia L. in conjunction with chitosan as a bio-mordant. Alum mordant was also used in the dyeing process alongside chitosan for comparison purposes. Fourier transform infrared spectroscopy and ultraviolet-visible spectroscopy were utilized to determine the anthraquinone-based components of the dye extract. Furthermore, the structure and surface morphology of silk fibers before and after dyeing were investigated. The dyed silk samples exhibited good fastness against washing, rubbing, and lighting. The chitosan mordanted-dyed silk presented remarkable antimicrobial properties with maximum inhibitions of 96.71% and 99.08% against Escherichia coli and Staphylococcus aureus, respectively, and only 2.3% spore germination of white mold ( Aspergillus spp.). Likewise, an excellent ultraviolet protection factor was achieved in the chitosan modified-dyed silk. The findings of this study demonstrated the potential of the Rubia cordifolia L. extract as a functional dye, as well as the advanced properties of chitosan in increasing the fastness and functional performance for the dyed silk compared to alum mordant.

Mapping Materials and Dyes on Historic Tapestries Using Hyperspectral Imaging

Hyperspectral imaging has emerged as a promising analytical method of artwork due to its potential in combining non-invasive analytical capabilities and imaging allowing the survey of the entire (or of a large area of the) surface of an artwork, which is a highly significant application for historic tapestries. This project deployed a high-resolution ClydeHSI Art Scanner, which was used with both a push-broom visible to very-near infrared (VNIR; 400–1000 nm) and near infrared (NIR; 900–1700 nm) hyperspectral cameras. Initial testing focused on the characterisation and mapping of the different materials used on historic tapestries (wool, silk, metal threads). To facilitate the dye characterisation, a collection of wool and silk samples dyed with recipes based on medieval practices was used. The samples measured using the system and the data collected formed an external reference library including the type of the natural dyes and mordants used during their production. The outcomes of the on-site deployment of this analytical instrumentation for the characterisation and analysis of 16th century tapestries on display at Hampton Court Palace will be discussed.

ENHANCING THE PROTECTION PROPERTY ON SILK FABRIC BY THE TREATMENT OF POLYACRYLIC ACID AND CHITOSAN

Silk is valued as one of the prominent protein textile fibers under the animal category famous for the distinct properties such as lustrous appearance, comfort performance, remarkable shiny sheen and also towards the bio-applications. In general, silk is highly sensitive and delicate; hence, there is a need for the protection in order to protect silk from the unwanted impacts of chemicals, light and insects. According to this consideration, in this work it is decided to give an application with polyacrylic acid (PA) and chitosan (CT) followed by adopting coloration process using selected natural dyes and a synthetic reactive dye. The silk fabric samples were undergone to specific tests like measuring the common physical properties, color values and the respective fastness aspects, hand values, antibacterial, uv protection performances and FTIR studies. The outcome of the results give very considerable improvement towards the protection aspects for the silk fabric specific for the textiles / garments and other utility products.

Determination of Resmethrin in Corn Silk Matrix by Gas Chromatography-Flame Ionization Detector (GC-FID)

The use of pesticides provides benefits such as growing food products necessary for life, sustainability of production efficiency and prevention of diseases caused by pests. However, these benefits can turn into negative effects for humans and other living organisms with the use of pesticides in inappropriate doses and application methods. In this study, it was aimed to determine resmethrin, which belongs to the insecticide class, by gas chromatography-flame ionization detector (GC-FID) method. Hence, a suitable temperature program was utilized to determine resmethrin at a certain retention time. Limit of detection (LOD) and limit of quantification (LOQ) values were recorded as 0.02 and 0.08 mg/L under the proposed conditions, respectively. After corn silk sample was extracted using acetonitrile, analytical measurements were carried out to investigate the presence of resmethrin. There was no analytical signal detected that belonged to resmethrin in the analyzed sample. Recovery experiments were performed using external calibration method with spiked samples at three different concentrations and good percent recovery results were obtained between 93 and 97%.

Aqueous and chemical extraction of saponin of Acacia concinna (Willd.) Dc.: An effective Bio-surfactant solution to extract silk fibroin from muga silk cocoons

• Extraction of silk fibroin by utilizing bio-surfactant saponin. • Aqueous and Chemical extraction process utilized to extract silk fibroin. • Acacia concinna (Willd.) Dc. is utilized for the extraction process. • Formation of micelles to eliminate the sericin from silk fibroin . • Analysis of the degummed fibers properties by SEM, XRD, TGA/DSC, tensile strength. Silk fibroin is generated from the silkworms and enclosed in a glue-like protein called sericin. In recent years, silk fibroin has been recognized for its significant biomedical significance, especially in tissue engineering, wound dressing, and drug and gene delivery. Numerous degumming methods have already been employed to extract the fibroin protein from the silk cocoons, which discharges large volumes of toxic admixture of sericin and chemicals through effluents. A sustainable, cleaner and environmentally promising silk fibroin extraction technique of muga silk have been investigated by utilizing the bio-surfactant saponin that has been isolated from the Acacia concinna (Willd.) Dc. in two different extraction processes aqueous extraction and chemical extraction. The degumming efficacy has been performed with respect to saponin concentration, degumming period, and temperature. After the completion of the degumming process, the silk samples were subjected to examination by SEM, XRD, TGA/DSC, and mechanical (tensile) capacity study. This novel and greener degumming treatment was potentially applied to extract the silk fibroin from the silk cocoons in a cleaned state. The toxicity level generated in the degumming process was observed to be very low owing to the adoption of non-toxic chemicals. Overall study ascertains about can be an effective usage of the extracted silk fibroin for medical applications because of its low toxicity.

Preparation and physical properties of conductive silk fabrics used in wearable clothes and flexible supercapacitors

The present work was designed to study several functions of Silk coated with polyaniline (PANI), graphene oxide (GO), and a composite of PANI@GO. The samples were characterized by XRD, SEM, FTIR, and thermal analysis. The investigated fabrics' resistivity, weight gain, tensile strength, elongation, and antimicrobial efficiency were monitored according to ASTM procedures. The FTIR spectra show the presence of the GO and PANI functional groups in the treated fabrics, and the SEM images show the formation of coating materials on the silk surface. The electrical conductivity of the coated silk with composite PANI@GO is 29 times higher than that of the uncoated one. The heat generation efficiency of the studied fabrics is in the order: of PANI@GO-SL > PANI-SL > GO-SL > SL. All coated silk samples have antimicrobial activity in the order: PANI@GO-SL > PANI-SL > GO-SL > SL. The results showed that the PANI@GO-SL sample exhibits the highest specific capacitance of all the coated silk electrodes with 450 Fg−1 at 10 mVs−1, which renders PANI@GO-SL fabric a promising electrode material for supercapacitors. The capacitance value of the symmetric capacitor of PANI@GO-SL/PVA/PANI@GO-SL using PVA-H3PO4 gel as an electrolyte is 71.2 Fg−1 at a current density of one Ag−1 and 87.4% retention at 5000 cycles. The Ragone plot of the symmetric cell showed the highest energy density is 25.31 Wh/kg and a power density of 8018 W/kg. The results suggest using coated silk (PANI@GO-SL) prepared via low-cost processing as smart textiles for different applications.

Antimicrobial activity of chitosan/ZnO blended coating on silk fabric against Escherichia coli

Antimicrobial coated fabrics have a wide spectrum of use in grooming, biomedical and water purification applications. In this work, we report the antimicrobial property of a nano blend prepared from crab-shell based chitosan and nano ZnO and dip-coated on a silk fabric sample. All the synthesized materials were subjected to FT-IR, XRD and TGA studies to assess the functionality, crystallinity and thermal stability. Deacetylation of chitin to chitosan was revealed by the decrease in the intensity of the acetyl group peak at 1641 cm-1 in chitosan. The crystallite size of the synthesized nano ZnO was found be 15 nm from XRD analysis. Appearance of the characteristics peaks of chitosan (9.58°, 19.98°) and ZnO (31.86°, 34.71°, 36.44°, 56.65°, 62.99° and 68.02°) together in XRD pattern of the blended sample confirmed the blending of chitosan and nano ZnO. The deposition of the nanoblend on the coated silk fabrics was shown by SEM analysis. An inhibition zone of 3mm around the nanoblend coated silk fabric sample against E. coli bacteria clearly indicated that synthesized chitosan/ZnO nanoblend possessed good antibacterial activity.

Physicochemical Analysis, Elemental and Amino Acid Composition of Wool and Silk

The ash content of wool and silk was determined by burning the corresponding samples. The elemental composition of wool and silk was determined by ICP-mass spectral analysis, 26 macro- and microelements were found. Phosphorus has the maximum content in wool and silk samples, magnesium has the minimum content for wool, and potassium for silk. Chromato-mass spectrometry revealed 17 amino acids in wool and silk samples. Wool is characterized by a high content of phenylalanine, glycine, tyrosine, while silk is characterized by a high content of serine, glycine and threonine. Wool and silk proteins are also balanced in terms of nonessential amino acids. The analysis of the obtained IR spectra of proteins from wool and silk is carried out, absorption bands for the corresponding groups are marked. The corresponding vibrations of the amino groups of the carbonyl group are shown, which have an essential role in the structure of proteins.

Dyeing of silk fabric with eco-friendly natural dye obtained from Nyctanthes arbor-tristis using single mordants

The silk fabric was dyed with natural dyes obtained from the flower of Nyctanthes arbortristis. The fastness properties and colour strength of dyed silk fabric was determined, compared and tabulated. From the comparative study of fastness properties and colour strength of the dyed silk samples, Nyctanthes arbor-tristis.in simultaneous mordanting method with 3% mordant combination gives better results.

Insight into the measurements for determining the ageing degree of ancient silk

Evaluating the degradation degree of aged silk is a challenge but worthwhile to determine the structure change and stability of silk. To date, the characterizations of silk degradation are widely studied, however, it still remains a lack of systematic research on measuring and quantifying the degradation degree of silk with effective ageing indicators. In this research, ancient silk samples from two different ages and regions were investigated by means of X-ray diffraction, X-ray photoelectron spectroscopy, EPR spectroscopy and 13C CPMAS NMR in an attempt to provide numerical indicators for assessing their ageing degree. As a result, the crystallinity, oxidation and carbonization degree, variation of amino acid content and content of random coil were proved to be the valuable indexes for interpreting the distinct deterioration and fragility level of aged silk. This work may shed light on studying the ageing status and stability of historical silk and further providing evidence for the conservation and preservation of silk cultural relics.

Performance and retention mechanisms of corn silk to atmospheric heavy metal lead

Atmospheric heavy metals are seriously harmful, and porous materials have unique advantages in the control of air pollutants. However, the direct use of plant porous materials to purify atmospheric heavy metals are rare. So agricultural waste corn silk with porous structures was selected to analyze the retention capability and mechanism to the atmospheric lead. The results show that the corn silk can effectively retain atmospheric lead in natural growing state or fixed experimental conditions. The analysis of a total of 765 corn silk samples from 17 different regions in Shandong province, China, shows that atmospheric lead is the main source of lead in the corn silk, and corn silk can be used for biological monitoring of atmospheric lead to some extent. Based on the analysis with different techniques including scanning electron microscope (SEM), energy spectrum dispersive X-ray spectrometer (EDS), Fourier infrared spectrometer (FTIR) and Zeta potential, the effective retention of lead by corn silk is due to a variety of mechanisms, including physical adsorption, electrostatic adsorption, complexation, chelation and ion exchange. So agricultural waste corn silk has great potential in the application of biosorption or preparation of porous materials in purification of atmospheric heavy metals.

The Effect of Laser Radiation in Different Mordant and Ratios on Silk Fabrics Dyed with Weld (Reseda luteola L.)

ABSTRACT In this study, the silk fabrics mordanted at the ratio of 1%, 5%, 10%, 20% of aluminum potassium sulfate (KAl(SO4)2·12H2O) and 0.1%, 0.5%, 1%, 3%, of iron sulfate (FeSO₄) were separately dyed 50% weld (Reseda luteola L.). Then firstly, laser radiation was used on un-mordanted silk fabrics and as a second step, silk samples with different ratios mordanted and dyed with weld were irradiated to investigate the laser radiation effects on color using several combinations of the two main laser parameters namely energy density and number of pulses. Nd:YAG laser device was used two different wavelengths of 1064 nm and 532 nm, and it was found that the laser wavelength of 532 nm is most appropriate to all dyed fabrics, while 1064 nm wavelength causes damages such as discoloration and burning in the iron sulfate mordanted fabrics. Colorimetric analysis was performed to examine surface alterations of silk samples. The CIEL*a*b* color values of the silk fabrics were measured and compared with each other. In general, the use of iron sulfate (FeSO₄) as a mordant increased the color difference (ΔE*) of dyed fabrics at 1064 nm. The color coordinates and fastness values of rubbing and light were investigated. Morphological analysis was performed using optical and scanning electron microscopy. Elemental analysis was performed using SEM-EDX (scanning electron microscopy–energy-dispersive X-ray spectroscopy) to identify mordants. A reserved phase high-performance liquid chromatography (RP-HPLC) with the diode-array detection (DAD) method was utilized for the identification of the components of dyes present in the silk samples.