Electrospinning and rheology of regenerated Bombyx mori silk fibroin aqueous solutions: The effects of pH and concentration

In this study, we prepared regenerated silk fibroin (RSF) aqueous solution to approach the environmental condition in the gland of silkworm, Bombyx mori. Then electrospinning technique was used to prepare the silk fibers. The results showed that pH and concentration had a remarkable influence on the properties of RSF aqueous solutions. With the increase in concentration and the decrease in pH, the rheological behavior of RSF aqueous solutions exhibited a transition from Newtonion fluid to non-Newtonion fluid. At the same time, lowering the pH could induce gel formation and decrease the electrospinnable concentration of RSF aqueous solutions. With the decrease in pH and concentration, the morphology of the electrospun silk fibers changed from belt-like shape to uniform cylinder. The conformation of the electrospun silk fibers was characterized by RS, WAXD and DSC. It was found that electrospun fibers were predominantly random coil/silk I conformation.     

Preparation and characterization of biomimetic tussah silk fibroin/chitosan composite nanofibers

Tussah silk fibroin (TSF)/chitosan (CS) composite nanofibers were prepared to mimic extracellular matrix by electrospinning with hexafluoroisopropanol (HFIP) as a solvent. The viscosity and conductivity of TSF/CS blend solution were analyzed and the morphology, secondary structure, and thermal property of TSF/CS composite fibers were investigated by SEM, ¹³C CP/MAS-NMR, X-ray diffraction, and DSC Techniques. The electrospinnability of TSF solution was improved significantly by adding 10 wt% CS, and morphology of electrospun TSF nanofibers changed from flat strip to cylindrical. At the same time, the average fiber diameters decreased from 542 to 312 nm, accompanying by an obvious improvement in fiber diameter uniformity. However, when the CS content in blend solution was more than 15 wt%, the diameter of electrospun TSF/CS nanofibers appeared to be polarized which can be attributed to phase separation of the two components in composite nanofibers. Blending 10 wt% CS did not change the conformation of TSF in TSF/CS composite nanofibers, and TSF in composite nanofibers at various composition ratios had mainly taken the α-helix structure. The thermal decomposition temperature of electrospun TSF/CS composite nanofibers decreased with the increase of CS content due to the lower decomposition temperature of CS. To study the cytocompatibility and cell behavior on the TSF/CS nanofibers, human renal mesangial cells were seeded onto electrospun TSF/CS composite nanofibers. Results indicated that the addition of CS promoted cell attachment and spreading on TSF nanofibers significantly, suggesting that electrospun TSF/CS composite nanofibers could be a candidate scaffold for tissue engineering.     

A new consolidation system for aged silk fabrics: Effect of reactive epoxide-ethylene glycol diglycidyl ether

A new consolidation system for fragile ancient silk fabrics by fibroin with the support of ethylene glycol diglycidyl ether (EGDE) was developed in our group. To figure out the mechanism and the effect of EGDE in the system, aged silk fabrics treated with EGDE have been investigated in this paper. Silk fabrics were artificially aged in sodium hydroxide aqueous solution to simulate fragile ancient silk fabrics. The aged silk fabrics were treated with EGDE aqueous solution by spraying. The resultant silk fabrics were systematically investigated by tensile test, thermogravimetric analysis (TGA), thermal ageing resistance test, attenuated total reflection Fourier transform infrared spectroscopy (ATR–FTIR), solid-state ¹³C cross polarization/magic angle spinning nuclear magnet resonance (¹³C CP/MAS NMR) and amino acid analysis (AAA), etc. Results indicate that the breaking stress and strain of the treated silk fabrics increase more than four and two times, respectively. The maximum decomposition temperature of the treated silk fabrics is much higher than that of the aged silk fabrics. The treated silk fabrics exhibit a better thermal ageing resistance than the aged silk fabrics. Chemical interactions occurred between EGDE and silk fibroin molecules in silk fabrics. This work provides useful information for the protection of historic silk fabrics.     

Condensed‐phase flame retardation in nylon 6‐layered silicate nanocomposites: Films,fibers, and fabrics

Flame‐retardant properties of nylon 6/organically modified montmorillonite (OMMT) thin films, fibers, and fabrics were investigated to determine the efficacy of condensed‐phase flame‐retardant mechanism in relation to montmorillonite concentration, sample geometry, and flame test conditions. Horizontal flame spread conducted on thin films revealed no significant difference in burning behavior between nylon 6 and nanocomposites with 5 wt% OMMT. However, with a higher concentration level of 8–10 wt% OMMT, the films burned without any dripping. The flame spread rate was reduced by 30–40% as compared with nylon 6 films. Cone calorimeter study on nanocomposite films showed that the peak heat release rate of nylon 6 was reduced by 65–67% with 8–10 wt% OMMT. Undrawn nanocomposite monofilaments with 10 wt% OMMT burned slowly and steadily in Bunsen flame without dripping. In cone calorimeter, nanocomposite fabrics with 8 wt% OMMT showed reduced heat release rate and mass loss rate compared to nylon 6 fabrics with increase in fabric tightness factor. The mass loss rate was about 40–60% less when compared with nylon 6 fabrics. The fabric char structure remained intact after burning. This demonstrated the interdependence of fabric tightness factor, OMMT concentration, and source of heat flux in forming a protective char and affecting the flammability of fabrics. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Silk/Rayon Webs and Nonwoven Fabrics: Fabrication,Structural Characteristics,and Properties

Silk is a naturally occurring material and has been widely used in biomedical and cosmetic applications owing to its unique properties, including blood compatibility, excellent cytocompatibility, and a low inflammatory response in the body. A natural silk nonwoven fabric with good mechanical properties was recently developed using the binding property of sericin. In this study, silk/rayon composite nonwoven fabrics were developed to increase productivity and decrease production costs, and the effect of the silk/rayon composition on the structure and properties of the fabric was examined. The crystalline structure of silk and rayon was maintained in the fabric. As the silk content increased, the porosity and moisture regain of the silk/rayon web and nonwoven fabric decreased. As the silk content increased, the maximum stress of the web and nonwoven fabric increased, and the elongation decreased. Furthermore, the silk/rayon web exhibited the highest values of maximum stress and elongation at ~200 °C. Regardless of the silk/rayon composition, all silk/rayon nonwoven fabrics showed good cytocompatibility. Thus, the silk/rayon fabric is a promising material for cosmetic and biomedical applications owing to its diverse properties and high cell viability.     

Flame resistant cotton fabrics prepared by radiation-initiated polymerization with vinyl phosphonate oligomer and N-methylolacrylamide

Radiation-initiated polymerization of vinyl phosphonate oligomer (molecular weight 500–1000) and N-methylolacrylamide from aqueous solutions was investigated with cotton printcloth, flanelette, and sateen fabrics and with cotton (50%)–polyester (50%) flannelette fabrics. Determinations were made of the effects of radiation dosage, mole ratio of vinyl phosphonate in the oligomer to N-methylolacrylamide in aqueous solution, concentration of reactants, wet pickup of solutions on fabrics, and irradiation of both dry and wet fabrics on efficiency of conversion of oligomer and monomer in solution to polymer add-on. The effects of vinyl phosphonate oligomer and N-methylolacrylamide radiation-initiated polymerization on some of the textile properties of cotton printcloth and on flame resistances of cotton and cotton–polyester fabrics were evaluated. The breaking strength of modified cotton printcloth was about the same as that of unmodified fabric; however, the tearing strength and flex abrasion resistance of modified fabric were reduced. The textile hand of the modified printcloth fabrics that had flame resistance indicated: interaction between cellulose and vinyl phosphonate oligomer–poly(N-methylolacrylamide) and uniform deposition in the fibrous cross section (transmission electron microscopy); surface areas of heavy deposits of oligomer–polymer (scanning electron microscopy); and phosphorus located throughout the fibrous cross section (energy dispersive x-ray analysis). Polymerization of vinyl phosphonate oligomer and N-methylolacrylamide was radiation initiated with cotton–polyester fabric; however, this modified fabric did not have flame-resistant properties.     

Preparation and properties of Fe(II)‐ion‐sensitive colour‐changing fabric

Textile fabrics were dyed with complexometric indicators (ionochromic dyes) to develop Fe(II) ionochromic fabric. Three kinds of ionochromic dye were used to dye silk fabric, and they were evaluated for colour changes triggered by Fe(II) solution. The K/S values and photos of the fabrics were then recorded. It was found that 1,10‐phenanthroline was the most suitable ionochromic dye in these dyes. Colour change from white to red could be clearly seen when 1,10‐phenanthroline‐dyed silk fabric was triggered by Fe(II) solution, but it showed no colour change when triggered by Cu(II), Mg(II), or Ca(II) solution. Moreover, 1,10‐phenanthroline‐dyed nylon, polyester, and cotton fabrics showed no obvious colour changes after triggering by Fe(II) solution. Ion concentration, pH value, and reaction time could affect the colour changes. When triggered by 8 mg l^?1 of Fe(II) solution at neutral pH for about 15 min, the ionochromic fabric showed a clear colour change. In addition, three coloured fabrics in green, blue, and yellow were also dyed with 1,10‐phenanthroline. It was found that they could also show clear colour changes when triggered by Fe(II) solution. These ionochromic fabrics may find broad application in many fields, such as Fe(II) detection, magic toys, anticounterfeiting materials, and bionic silk flowers.     

Chemical modification of nylon 6 and polyester fabrics by ozone‐gas treatment

In a previous article, we reported on the ozone‐gas treatment of wool and silk fabrics in relation to the gas‐phase processing of textile fabrics. The treatment incorporated an oxygen element into the fiber surface and contributed to an increase in water penetration into the fabric. In this study, nylon 6 and polyester fabrics were treated with ozone gas in the same way as that of the wool and silk fabrics. The treatment incorporated much more oxygen into the fiber surface in the form of ? COH and ? COOH, as shown by electron spectroscopy for chemical analysis. Water penetration increased considerably with treatment, and the apparent dyeing rate and equilibrium dye uptake were also improved, especially for the polyester fabric, despite an increase in the crystallinity. Therefore, it seemed that the treatment brought about a change not only in the fiber surface but also in the internal structure of the fibers (the crystalline and amorphous regions) with regard to the dyeing behavior. Further, the mechanical characteristics of the ozone‐gas‐treated polyester and nylon 6 fabrics were measured with a Kawabata evaluation system apparatus. The shearing modulus and hysteresis widths increased with treatment, especially for the polyester fabric. Therefore, it was clear that the treatment caused a change in the fabric hand to crisp. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1344–1348, 2006     

Horseradish peroxidase-mediated polyethylene glycol-templated polymerisation of gallic acid and pyrrole to improve the functionalisation and dyeing properties of silk fabrics

Silk fabrics treated with gallic acid/pyrrole (PGA/PPy) complexes polymerised using horseradish peroxidase have higher electrochemical activity than silk fabrics dyed with gallic acid alone. However, the degree of polymerisation decreases. As a result, the ultraviolet (UV) protection and fastness of the silk fabric were lowered. To solve this problem, we studied the degree of polymerisation of the complex and the functionality of dyed silk fabrics by applying a polyethylene glycol (PEG) template to the enzymatic polymerisation of PGA/PPy. The polymerisation mechanism of the complexes was analysed in detail using UV-visible spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and high-performance liquid chromatography electrospray ionisation mass spectrometry (HPLC-ESI-MS). Consequently, the PGA/PPy/PEG complex has a higher degree of polymerisation than the PGA/PPy prepared without PEG, indicating that the PEG template can promote the polymerisation of PGA and PPy. As a result, we found that the presence of the PEG template improved the thermal stability and UV protection function of the dyed silk fabric, but did not impair the electrochemical activity of silk fabric. As a result of analysing the colour depth, it exhibited a higher K/S value compared to the dyed silk fabric in the absence of PEG. Additionally, its colour fastness was improved.     

Effects of crosslinking agents,dyeing temperature,and pH on mechanical performance and whiteness of silk fabric

The effects of bleaching and dyeing conditions on abrasion resistance, tear strength, and whiteness of silk fabrics were studied. Different crosslinking agents at various concentrations were introduced into the silk fabrics under various dyeing temperatures and pH. The results indicated that the oxidatively bleached silk fabric exhibited better mechanical properties than those of reductively bleached silk fabric. Sodium citrate was found to be the most suitable crosslinking agent for enhancing the abrasion resistance and tear strength of the silk fabrics with no significant effect on the whiteness. The mechanical property improvements of sodium citrate–dyed silk fabric were attributed to a chemical reaction between –COOH groups and amino acid side chains in silk fabric, the mechanism proposed in this work. Increasing sodium citrate resulted in improved mechanical properties and whiteness, but the opposite trend was found with increasing dyeing temperature. An optimum pH for dyeing the silk fabric in this work was 5.5. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1000–1007, 2004     

Effect of carbon fabric type on the mechanical performance of 2D carbon/carbon composites

A stabilized PAN fabric was carbonized and graphitized from 800°C to 2500°C. Two-dimensional (2D) carbon/carbon composites were made using the stabilized PAN fabric, carbonized fabrics, and a resol-type phenol-formaldehyde resin. These composites were heat-treated from 600°C to 2500°C. The influence of different heat-treated fabrics and heat treatment on the fracture and flexural strength of these composites was also studied. The composite reinforced with higher heat-treated fabrics showed a lower weight loss than that with lower heat-treated fabrics. When the composites were graphitized at 2500°C, the loss was 49.7 wt% for the composite made with stabilized PAN fabric and 26 wt% for that with carbonized fabric at 2500°C. Those composites also have a higher density than composites produced by other methods. Composites made with stabilized PAN fabric exhibited a strong bonding in the fiber/matrix during pyrolysis. This composite showed catastrophic fracture and a smooth fracture surface with no fiber pullout. Composites made with higher carbonized fabrics exhibited a weak interface bonding. These composites showed a pseudo-plastic fracture pattern with fiber pullout during pyrolysis. Composites made with carbonized fabrics at 2000°C and 2500°C showed the highest flexural strength at the prolysis temperature of 1000°C. Composites made with carbonized fabric at 1300°C showed the highest flexural strength above 1500°C to 2500°C. The composite made with stabilized PAN fabric exhibited the lowest flexural strength during pyrolysis.     

Role of capillarity in penetration into and flow through fibrous barrier materials

Hydrophobic fibrous media, in the form of barriers, provide protection to its user against fluids. Important aspects to consider are the pressure at which liquids (nonwetting fluids) will penetrate into the fabric and the rate at which it will flow through. At the same time we need to consider the comfort level that the fabric provides, that is, the pores should be large enough to allow the exchange of air. The objective of this study was to develop an experimental technique to determine (1) the displacement pressure of medical barrier fabrics in combination with aqueous solutions and (2) the flow rates once the aqueous solutions had penetrated. A pressure/flow cell was used to make these determinations during sequences of increasing and decreasing pressures applied to the nonwetting fluids (aqueous solution). The resulting flow rate–pressure curves exhibited hysteresis, that is, lower flow rates existed during increasing pressures (increasing liquid contact) than during decreasing pressures (decreasing liquid contact) at corresponding pressure values. The reasons for this hysteresis were investigated. The flow rate–pressure curves also provided information about the pore size distributions of the fabrics. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 841–846, 2005     

Pretreatment of silk fabric surface with amino compounds for ink jet printing

This research studied pretreatments of silk fabric with amino compounds for ink jet printing. The pre-treating solutions were serine, glycine, aspartic acid, sericin, chitosan, and a commercial pre-treating chemical called Sanfix 555. Both untreated and treated fabrics were printed with in-house formulated pigmented inks and later steamed to fix the ink on the fabric surface. The pretreatments containing the amino compounds improved hydrophilicity of the silk fabric with the exception of chitosan. The color gamut from sericin, chitosan, and Sanfix 555 pretreatments was wider than that from the amino acid pretreatments. The chroma of the cyan color was most improved. The fabric, after pretreatment with sericin, showed a significant improvement in dry crock fastness while wet crock fastness was improved by serine and glycine. The chitosan slightly improved both dry and wet crock fastness. Wash fastness of all pretreated and printed fabrics including untreated and the printed fabrics was excellent because the pigmented ink was formulated with pigment and binder. Bending stiffness of the silk fabrics after chitosan pretreatment was significantly higher than those with other pretreatments. The ink penetration in sericin and chitosan padded layers was shallower than those for amino acids, enhancing ink deposition on the fabric surface. The amino compound pretreatments held and fixed additional ink on the fabric surfaces resulting in a wider color gamut of the inks.     

Chemical and property modification of silk with dibasic acid anhydrides

In an attempt to provide information for improving silk fiber and fabric properties including crease recovery and yellowing, silk modification has been studied by using succinic and glutaric anhydrides. Glutarylation has been found to protect silk fibers from yellowing caused by the high energy radiation and to be more effective on increasing the crease proofing. The silk fabrics did not reduce the tensile properties such as strength and elongation at break even after the chemical modification with dibasic acid anhydrides. Thermal properties of the fibers remained unchanged in spite of the succinylation or glutarylation. From all the considerations of the survey of dye uptake, it would seem that the ester crosslinks are easily formed much more by the glutarylation than by the succinylation. The recovery values and yellowness indices of the modified silk fabrics and the measuring results of thermal and thermomechanical properties are explicable, taking into account of the different reactivity of the functional groups induced by the chemical modification with the dibasic acid anhydrides.     

Chemical modification of tussah silk fabrics with ethyleneglycol diglycidyl ether by a pad-batch method

Tussah silk fabrics have been chemically modified by pad-batch treatment with ethyleneglycol diglycidyl ether (EDGE). The maximum amount of weight gain attained was 5–6%. Epoxide adducts were formed with tyrosine and basic amino acid residues. The moisture regain of the fabric with 3% weight gain decreased slightly compared with that of the untreated sample. The crease recovery in the wet state improved significantly, while in dry state it remained unchanged. Mechanical and optical properties, and X-ray crystallinity did not exhibit noticeable changes. The position of the major DSC endothermic transition at 358d?C remained unchanged, regardless of the epoxide modification. Similar comments apply to the TMA contraction peak occurring at about 359d?C. The storage and loss modulus curves of EDGE-treated tussah silk fibres exhibited some changes, the most relevant consisting in a shift to higher temperature of the loss modulus peak.     

TREATMENT OF VULCANIZED STYRENE-BUTADIENE RUBBER (SBR) WITH MIXTURES OF TRICHLOROISOCYANURIC ACID AND FUMARIC ACID

In this study, mixtures of trichloroisocyanuric acid (TCI) and fumaric acid (FA) solutions were applied to a difficult-to-bond, vulcanized styrene-butadiene rubber (R2) to analyze the combined effect of both surface treatments. The treated R2 rubber surfaces were characterized using advancing contact angle measurements, ATR-IR and XPS spectroscopy, and SEM. T-peel tests of treated R2 rubber/ polyurethane adhesive/leather joints have been obtained in order to quantify the adhesion properties. The wettability of R2 rubber was improved by treatment with 3 wt% TCI/EA (ethyl acetate) or 0.5 wt% FA/EtOH, and lower contact angles were obtained by treatment with both 3 wt% TCI/EA and 0.5 wt% FA/EtOH. The improved wettability was ascribed to the creation of carbon-chlorine moieties, the removal of zinc stearate and paraffin wax, and the creation of surface roughness on the R2 rubber surface. Treatment of R2 rubber with 3 wt% TCI/EA before or after treatment with 0.5 wt% FA/EtOH, or with a solution containing 3 wt% TCI/EA + 0.5 wt% FA/EtOH mixture produced a noticeable increase in peel strength. Always, the effects of the treatment of R2 rubber with 3 wt% TCI solution were dominant over those produced by treatment with 0.5 wt% FA solution in ethanol (FA/EtOH). On the other hand, the treatment of R2 rubber with 3 wt% TCI/EA + 0.5 wt% FA/EtOH mixture was more effective than the treatment with 0.5 wt% TCI/EA+ 2 wt% FA/EtOH because the lower amount of chlorinating agent in this mixture.     

Tailoring Unidirectional Water-Penetration Janus Fabric with Surface Electrospun Deposition

This paper provides a new method to fabricate an integrated Janus fabric that has excellent unidirectional water-penetration property. Based on commercial polyester fabric that is pretreated with CaCl₂ solution, polyvinyl alcohol/sodium alginate (PVA/SA) solution is deposited directly on the fabric via electrospinning and in situ chelated with Ca²⁺ contained in the fabric. The in situ formed PVA/SA gel coating not only transfers the surface of polyester fabric from hydrophobic to hydrophilic but also retains original porous structure of polyester fabric. As the water droplet contacts with unelectrospun side of modified polyester fabric (M-PET) pretreated with 10 wt% CaCl₂, it penetrates through the M-PET within 1 s from unelectrospun side to electrospun side after application, and disappears on unelectrospun side within 2 s, and in turn, droplet spreads out on electrospun side of M-PET within 2 s after application and no penetration occurs. The M-PET pretreated with CaCl₂ solution has outstanding antistatic property, vapor, and air permeability. The impact of ratio (v/v) of the PVA and SA solution and the concentration of CaCl₂ pretreating solution on properties of the M-PET are investigated.     

Temperature‐sensitive poly(N‐tert‐butylacrylamide‐co‐acrylamide) hydrogels bonded on cotton fabrics by coating technique

Different from the conventional method of developing stimuli‐sensitive textiles by graft copolymerization of environmental responsive polymers onto the fabric, the coating technique was applied to bond temperature‐sensitive hydrogels with cotton fabric through chemical covalent in our work. A temperature‐sensitive linear copolymer of N‐tert‐butylacrylamide (NTBA) and acrylamide (AAm) was prepared in methanol. Then, the cotton fabrics were coated using an aqueous solution of this copolymer containing 1,2,3,4‐butanetertracarboxylic acid as a crosslinker and sodium hypophosphite (SHP) as a catalyst, followed by drying and curing. The surface of the cotton fabrics was bonded on more or less coatings of poly (NTBA‐co‐AAm) hydrogels, as verified by Fourier transform infrared spectroscopy and scanning electron microscopy images. The poly(NTBA‐co‐AAm) hydrogels‐coated fabrics exhibited temperature sensitive, and the temperature interval of the deswelling transition was higher than lower critical solution temperature of linear copolymer solution. The coated fabrics presented good water‐impermeable ability because of the swelling of hydrogels bonded, especially when the add‐on was as high as 14.14%. Environmental scanning electron microscopy images revealed that coating hydrogels swelled and covered on the surface as a barrier to prevent water from penetrating once the coated fabric came into contact with water. The findings demonstrate that the temperature‐sensitive hydrogels can be covalently bonded on the cotton fabrics by coating technique and the coated fabrics have potential on immersion fabrics. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Treatment of vulcanized styrene-butadiene rubber (SBR) with mixtures of Trichloroisocyanuric Acid and Fumaric Acid

In this study, mixtures of trichloroisocyanuric acid (TCI) and fumaric acid (FA) solutions were applied to a difficult-to-bond, vulcanized styrene-butadiene rubber (R2) to analyze the combined effect of both surface treatments. The treated R2 rubber surfaces were characterized using advancing contact angle measurements, ATR-IR and XPS spectroscopy, and SEM. T-peel tests of treated R2 rubber/ polyurethane adhesive/leather joints have been obtained in order to quantify the adhesion properties. The wettability of R2 rubber was improved by treatment with 3 wt% TCI/EA (ethyl acetate) or 0.5 wt% FA/EtOH, and lower contact angles were obtained by treatment with both 3 wt% TCI/EA and 0.5 wt% FA/EtOH. The improved wettability was ascribed to the creation of carbon-chlorine moieties, the removal of zinc stearate and paraffin wax, and the creation of surface roughness on the R2 rubber surface. Treatment of R2 rubber with 3 wt% TCI/EA before or after treatment with 0.5 wt% FA/EtOH, or with a solution containing 3 wt% TCI/EA + 0.5 wt% FA/EtOH mixture produced a noticeable increase in peel strength. Always, the effects of the treatment of R2 rubber with 3 wt% TCI solution were dominant over those produced by treatment with 0.5 wt% FA solution in ethanol (FA/EtOH). On the other hand, the treatment of R2 rubber with 3 wt% TCI/EA + 0.5 wt% FA/EtOH mixture was more effective than the treatment with 0.5 wt% TCI/EA+ 2 wt% FA/EtOH because the lower amount of chlorinating agent in this mixture.     

Absorption of metal cations by modified B. mori silk and preparation of fabrics with antimicrobial activity

Silk fabrics were modified by treatment with tannic acid (TA) solution or by acylation with ethylenediaminetetraacetic (EDTA) dianhydride. Kinetics of modification with TA and acylation with EDTA–dianhydride was investigated. The physico‐mechanical properties of silk fabrics acylated with EDTA–dianhydride remained unchanged regardless of chemical modification. The absorption of metal cations (Ag⁺, Cu²⁺) by untreated and modified silk fabrics was studied as a function of the kind of modifying agent, weight gain, and pH of the metal solution. The absorption of Cu²⁺ at alkaline pH was not significantly influenced by chemical modification of the silk substrate. The absorption of Ag⁺ by acylated silk remained at a level as low as untreated silk, while was enhanced by TA. The higher the content of TA, the higher the absorption of Ag⁺. With respect to the pH of the metal solution, the acylation with EDTA–dianhydride enabled silk to absorb and bind metal cations even in the acidic and neutral pH range, where tannic acid had no effect. Medium to high levels of metal desorption were exhibited by untreated and modified silk fabrics towards the metal cations, with the only exception of the silk–tannic acid–Ag complex, which displayed an extraordinary stability. All metal‐containing silks exhibited significant antibacterial activity. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 297–303, 2001