Physical,chemical, and dyeing properties of Bombyx mori silks grafted by 2‐hydroxyethyl methacrylate and methyl methacrylate

To obtain silk weight gain and to improve silk properties, Bombyx mori silks were grafted with either 2‐hydroxyethyl methacrylate (HEMA) or methyl methacrylate (MMA). The moisture regain of the HEMA‐grafted and MMA‐grafted silks depended on the hydrophilicity of the used monomers. The acid and alkaline resistances of the HEMA‐grafted and MMA‐grafted silks were clearly improved. Both commercial synthetic dyes, that is, acid and reactive dyes, and a natural dye extracted from turmeric, with potassium aluminum sulfate as a mordant, were used in this study. The results suggested that the dye uptake increased in the presence of poly(2‐hydroxyethyl methacrylate) or poly(methyl methacrylate) in the silk fibroin structures when acid and curcumin dyes were used. The washfastness level of the HEMA‐grafted silk dyed by acid and reactive dyes was similar to that of the degummed silk. However, the colorfastness to washing of the MMA‐grafted silk dyed by an acid dye was improved when the polymer add‐on concentration was 65%. In addition, the washfastness for both grafted silks was improved when they were dyed with natural curcumin dyestuff. The acid and alkaline perspiration fastness properties remained unchanged for the HEMA‐grafted and MMA‐grafted silks when acid, reactive, and curcumin dyes were applied. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Grafting vinyl monomers onto silk (Bombyx mori) using different initiators: Properties of grafted silk

The graft–copolymerization of silk with methacrylamide (MAA), 2‐hydroxyethyl methacrylate (HEMA), and methyl methacrylate (MMA) was studied using three different free‐radical initiators: an inorganic peroxide [ammonium persulfate (APS)] and two azo compounds [2,2′‐azobisisobutyronitrile (AIBN) and 2,2′‐azobis(2‐methylpropionamidine) dihydrochloride (ADC)]. The rate and yield of grafting followed the order: APS > AIBN > ADC. The performance of AIBN was close to that of APS in terms of weight gain attained. The degree of yellowing of grafted silk varied as a function of the initiator–monomer system used. APS induced the highest degree of yellowing, regardless of which monomer was used, whereas silk grafted with the MAA/AIBN system displayed the lowest level of yellowing. Moisture regain of grafted silk changed as a function of the hydrophilic/hydrophobic character of the grafted polymer, regardless of the kind of initiator used. Accordingly, tensile properties showed a tendency to decrease with increasing weight gain of grafted silk, the extent of which was independent of the kind of monomer and initiator used. The different initiators did not induce any appreciable change in the fine structure of silk, as demonstrated by optical measurements. Uneven surface deposition of homopolymer was detected to variable extent with MMA and HEMA grafting, whereas the surface of MAA‐grafted silk was completely free of any foreign deposit, independently of the initiator used. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1401–1409, 2001     

Graft copolymerization of methyl methacrylate onto jute fibers. Studies on vanadium (V)-cyclohexanol redox system

Graft copolymerization of methyl methacrylate (MMA) onto natural jute (chemically modified) was studied using V⁵⁺ -cyclohexanol redox initiator system. The effects of time, concentration of metal ion (V⁵⁺), monomer (MMA), substrate, amount of jute fibers, temperature, and acid concentration on graft yield have been studied. The effects of some organic solvents and inorganic salts on graft yield have also been studied. A grafting mechanism is proposed and an expression has been derived for the reaction rate. Grafting has improved the thermal stability and the light fastness of jute fibers dyed with basic dyes. IR spectra of the natural jute (chemically modified) and grafted jute have been taken. More than 170% graft yield could be achieved with the present system.     

Extraction of natural dyes from Alpinia blepharocalyx K. Schum. for dyeing of silk fabric

Natural dyes were extracted from the leaves and stems of Alpinia blepharocalyx K. Schum. Analysis of the designed experiment revealed that extraction at a plant/water ratio of 1:20 could reach an optimal production of natural dyes when extraction was performed at 80 °C, for 4 h, under 20 min ultrasound, in the presence of 10 g/l sodium hydroxide, and with two extractions. The extracted natural dyes were applied to the dyeing of silk fabrics using different methods, including or excluding a mordant. It was found that mordants had a significant effect on the colour of dyed silk fabrics. The silk fabric dyed with the pre‐mordant method using potassium aluminium sulphate as a mordant showed a bright yellow with a higher colour strength. The optimal dyeing conditions were reached when the extracted natural dyes were pre‐mordanted with 10 g/l potassium aluminium sulphate at pH 6, and for a 20 min dyeing time.     

Grafting of methyl methacrylate onto Antheraea pernyi silk fiber with the assistance of supercritical CO2

Graft copolymerization of methyl methacrylate (MMA) onto Antheraea pernyi silk fibers, initiated by benzoyl peroxide in the supercritical CO₂ was investigated. The grafting degree was determined as a function of impregnating pressure, impregnating time, monomer concentration, initiator concentration, and reaction time. The structural properties of MMA‐grafted fiber were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. Grafted MMA was chemically bonded and/or physically adhered to the surfaces of the fibers. The grafted silk fibers exhibited two steps of weight loss according to the characteristic of each component as demonstrated by the thermogravimetric analysis. The water‐retention values indicated that the hydrophobic nature of the fibers was improved. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1299–1305, 2006     

Investigation of grafting sites of acrylic monomers onto alkyd resins via gHMQC two-dimensional NMR: Part 1

Acrylic monomers were grafted onto alkyds via free radical chemistry. The alkyd was a medium oil soya-based alkyd with glycerol, phthalic anhydride, and tetrahydrophthalic anhydride (THPA) as the other components. To identify the specific graft locations, 1D and 2D NMR spectroscopy techniques were utilized. Gradient heteronuclear multiple quantum coherence (gHMQC) 2D NMR was required to assign the chemical shifts of the 1D carbon and proton NMR spectra. Three acrylic monomers, methyl methacrylate (MMA), butyl acrylate (BA), and methacrylic acid (MAA) were grafted to the alkyd, resulting in either MMA, BA, or MAA modified alkyds. Two-dimensional gHMQC spectra for each system confirm grafting at doubly allylic hydrogens located on the fatty acid chains and the polyol segment of the alkyd backbone. The gHMQC spectra show no evidence of grafting across double bonds on either pendant fatty acid groups or THPA unsaturation sites for any of the monomer choices.     

Reactive dyeing of silk using commercial acid dyes based on a three‐component Mannich‐type reaction

Acid dyes are employed for commercially dyeing silk, which results in ionic bonds between the silk fibroin and the dye. This generally leads to low wet fastness properties for dyed silk fabrics. In this work, three commercial acid dyes with aromatic primary amine structures were selected to dye silk using a Mannich‐type reaction, resulting in improved wet fastness of dyed silk by forming covalent bonds between silk fibroin and dye. The Mannich‐type reactive dyeing was applied to silk fabrics at both 30 and 90°C in trials. Dyeing at 90°C can shorten the dyeing time compared with dyeing at 30°C, even although dye exhaustion and relative fixation at 90°C were a little lower. The dyeing process was optimised when the dyeing temperature was 90°C, dyebath pH 4, dye‐to‐formaldehyde ratio 1:30 and holding dyeing time 60 minutes. The results showed that the dye exhaustion on silk fabrics for the three aromatic primary amine‐containing acid dyes exceeded 94% and their relative fixation was over 80%. Their washing and rubbing fastness reached grade 4 or higher. Hence, the colour fastness properties of dyed silk fabrics using the Mannich‐type reactive dyeing method is superior to the conventional acid dyeing method using the same aromatic primary amine‐containing acid dyes. The Mannich‐type reactive dyeing for silk fabrics at 90°C can be developed into a novel and rapid reactive dyeing method, promising an effective dyeing process with excellent colour fastness.     

Studies on graft copolymerization of methyl methacrylate onto chemically modified tussa silk fibers. Peroxydisulfate-thiourea redox system

The graft copolymerization of methyl methacrylate (MMA) onto chemically modified tussa silk fibers in aqueous media using potassium peroxodisulfate-thiourea redox initiator system was studied at 60°C. The effects of time of reaction, concentrations of oxidant, thiourea (TU), monomer (M), amount of silk fibers on graft yield have been studied. The effects of reaction medium, acid concentration, and some inorganic salts and organic solvents on grafting have also been investigated. A significant increase in percent of grafting was observed with increasing monomer concentration to 65.86 · 10^?2 mol · 1^?1; a further increase of monomer concentration is associated with the decrease of graft yield. The graft yield increases with an increase of thiourea concentration up to 10 · 10^?1 mol · 1^?1, beyond which it decreases very significantly. A measurable increase of the graft yield was also observed with an increase of the oxidant concentration up to 0.08 mol · 1^?1 beyond which the graft yield decreased. The graft yield was medium dependent. The reaction mechanism of the grafting process has been proposed and a rate expression has been derived on the basis of experimental findings. IR spectra of the grafted fiber and original fiber have been taken and their characteristic bands have been identified. The thermal behaviour of the original and grafted silk fibers has been studied by TGA and DTG analysis. Grafting has improved thermal stability as well as the light fastness of silk dyed with Rhodamine B.     

辐射接枝SBS的性能研究

采用旋转流变仪研究了苯乙烯-丁二烯-苯乙烯（sgs）嵌段聚合物接枝α-甲基丙烯酸（MAA）、甲基丙烯酸甲酯（MMA）接枝共聚物（SBS-g-MAA，SBS-g-MMA）的动态流变性能。结果表明：接枝共聚物的黏流活化能降低，温度敏感性降低；比较改性前后的共聚物的主曲线，接枝共聚物的相对分子质量分布变宽，在剪切应力作用下，黏度下降较快；接枝共聚物的相对分子质量分布变宽，接枝共聚物的抗氧化性增强。     

Photoinitiated surface grafting of synthetic fibers,IV. Applications of textile dyes onto surface-photografted synthetic fibers

High-strength polyethylene (HSPE), polypropylene (PP), poly(ethylene terephthalate) (PET), and poly(vinyl alcohol) (PVA) textile yarns have been surface-photografted with various functional monomers, such as acrylic acid (AA), acrylamide (AM), glycidyl acrylate (GA) and 4-vinyl pyridine (VP), by means of the continuous presoaking process developed. The dyeing of these surface-modified yarns with various textile dyes has been investigated. In general, considerable improvements of dyeability have been observed. The dye adsorption of the surface-photografted fibers is influenced by many factors, such as type of fiber, amount and properties of the functional monomer grafted on the surface of the fibers, type of textile dye, etc. The fibers surface-grafted with a monomer containing basic groups, such as acrylamide and 4-vinyl pyridine, are efficiently dyed with an acid dye. Conversely, a fiber surface-grafted with acidic functional monomer is easily dyed to deep shades with basic dyes. The dye adsorption increases monotonically with increasing grafting measured in ESCA spectra as relative intensities of relevant lines. The ungrafted HSPE, PP and PET fibers can be dyed to some extent with certain dyes. In the present work, the dye adsorption increased by 3.4 times for HSPE fiber grafted with GA and dyed with the metal complex dye IO, by 7.9 times for PP fiber grafted with AA and dyed with the basic dye MB, by 6.1 times for PET with AM and with the direct dye SL, and by about 15.3 times for PVA with VP and with the acid dye TE.     

Polydopamine‐coated silk yarn for improving the light fastness of natural dyes

One of the problems occasionally associated with the use of natural dyes in the dyeing of silk is the susceptibility of the dyed yarn to fading in light. While a number of approaches have been used to address this problem, the use of polydopamine (PDA), a known agent with photo‐protective properties, has not been assessed previously. In this study, silk was pretreated with nano‐particulate PDA formed in situ by oxidation of a dopamine solution, then dyed with lac dye or annatto dye as model natural dyes. Photofading rates were significantly reduced in the case of annatto‐dyed, PDA‐coated silk relative to uncoated silk, while wash fastness was unaffected and remained only moderately good. In contrast, no significant change was seen in photofading rates with treated or untreated lac‐dyed silk, and wash fastness was also unaffected. The PDA did not adversely affect resultant colour values if the concentration of the dopamine precursor was kept low. When this was done, acceptable colours were obtained in the dyed silk. Further investigation is warranted of PDA as a photofading protectant and mordant with other natural dyes on silk and other fibres.     

Thermal stability of radiation‐grafted and dyed poly(ethylene terephthalate) fabric

The effect of degree of grafting (GY) and degree of dye uptake on the thermal stability of polyethylene terephthalate (PET) fabric was studied using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and X‐ray diffraction analysis (XDA). TGA showed that the degradation process was composed of three overlapping stages. The first and second stages were studied in detail. Methacrylic acid (MAA)‐grafted PET fabric was dyed using Rhodamine Red (RR) and Astrazonrot Violet (AV) basic dyes. It was found that grafting deteriorated the thermal stability of both stages. The first stage showed the formation of two new steps at low and high temperatures. Both steps are heating rate and graft yield dependent. The deteriorating effect of grafting was followed by the changes in the kinetic parameters. AV dyeing of grafted samples accelerated the degradation of both stages whereas RR dyeing improved the thermal stability to reach that of ungrafted fabric. XDA showed that the crystalline nature of AV dye stuff is responsible for the rapid degradation in both stages via the introduction of highly incompatible crystalline phase in the polymer back bone, which resulted in the formation of internal stresses that enhanced the degradation process. DSC measurements supported TGA results. The improvement in the thermal stability by RR dyeing is attributed to the amorphous nature and the high thermal stability of the RR dye stuff. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101:1007–1020, 2006     

Synthesis of polymer‐grafted natural rubbers by radical photopolymerization of vinyl monomers initiated from the rubber chains

The synthesis of polymer‐grafted natural rubbers (NRs) was considered through photopolymerization of vinyl monomers initiated from N,N‐diethyldithiocarbamate groups previously introduced onto cis 1,4‐polyisoprene units of NR chains. The development of the procedure was made with methyl methacrylate (MMA) as monomer. First, initiation of MMA photopolymerization was tested using a model molecule of the N,N‐diethyldithiocarbamate‐functionalized 1,4‐polyisoprene unit to verify the feasibility of the procedure considered. Then, MMA polymerization was successfully initiated from N,N‐diethyldithiocarbamate‐functionalized NR backbone used as macroinitiator, and the conditions of grafting were optimized. It was shown that MMA grafting could occur either in monomer medium, in solution in toluene, and in latex medium, and that the quantities of homopolymer formed were still low. Thereafter, grafting studies were performed with other vinyl monomers (styrene, methacrylonitrile, acrylamide, acrylic acid) showing that grafting efficiency depends essentially on the nature of the monomer. The method developed here was shown particularly well adapted for the synthesis of polymer‐grafted NR with monomers of low polarity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Elucidation of the nanoparticle effect on the grafting of vinyl monomers onto cotton fabric

The grafting emulsion polymerization of vinyl monomers onto cotton was carried out in the presence of double‐modified montmorillonite clay. The obtained results show that grafting with glycidyl methacrylate/montmorillonite gave a higher rate of grafting than grafting with methyl methacrylate/montmorillonite in all clay percentages, and also, the grafting yield of glycidyl methacrylate monomer onto cotton in the presence of montmorillonite clay had a higher value than that in the absence of the clay for all factors studied. Cotton grafted with glycidyl methacrylate/montmorillonite with a graft yield of about 50% was prepared according to the emulsion polymerization technique and was treated with different concentrations of dibutylamine solutions ranging from 1 to 4%. The obtained samples were characterized according to nitrogen content, thermal stability, scanning electron microscopy, mechanical properties, water absorption, and color strength according to acid, basic, and reactive dyes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Natural rubber‐g‐methyl methacrylate/poly(methyl methacrylate) blends

The grafting of the methyl methacrylate (MMA) monomer onto natural rubber using potassium persulfate as an initiator was carried out by emulsion polymerization. The rubber macroradicals reacted with MMA to form graft copolymers. The morphology of grafted natural rubber (GNR) was determined by transmission electron microscopy and it was confirmed that the graft copolymerization was a surface‐controlled process. The effects of the initiator concentration, reaction temperature, monomer concentration, and reaction time on the monomer conversion and grafting efficiency were investigated. The grafting efficiency of the GNR was determined by a solvent‐extraction technique. The natural rubber‐g‐methyl methacrylate/poly(methyl methacrylate) (NR‐g‐MMA/PMMA) blends were prepared by a melt‐mixing system. The mechanical properties and the fracture behavior of GNR/PMMA blends were evaluated as a function of the graft copolymer composition and the blend ratio. The tensile strength, tear strength, and hardness increased with an increase in PMMA content. The tensile fracture surface examined by scanning electron microscopy disclosed that the graft copolymer acted as an interfacial agent and gave a good adhesion between the two phases of the compatibilized blend. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 428–439, 2001     

天然茶染料用于棉织物浸染工艺研究

以硫酸铜为媒染剂,研究了天然茶染料对棉织物的浸染工艺。结果表明,以硫酸铜为媒染剂,对棉织物进行浸染处理,可以得到较好的染色效果,同时还得到最佳的染色工艺:媒染剂Cu2+的浓度为12 g/L,温度为80℃,时间为100 min;以硫酸铜为媒染剂染色的棉织物经高温焙烘固色后,棉织物的干摩擦牢度和湿摩擦牢度都得到了提高。     

Mordant dye application on cotton: optimisation and combination with natural dyes

It is well known that cotton fibres can be dyed through the formation of coordinate bonds involving cellulose chains, mordants such as alum, and natural dyes such as alizarin. Similarly, synthetic dyes known as mordant acid dyes can be used to dye wool fibres. Unlike mordant dyes on wool, the fastnesses of natural dyes on cotton are often low. Although concerns surrounding textile sustainability have sparked renewed interest in the use of natural dyes, extensive replacement of synthetic dyes with natural dyes is neither practical nor fundamentally possible. However, similarities in dyeing methods using mordant and natural dyes raise the possibility of using mordant dyes as alternatives to natural dyes in the dyeing of cotton. Further, the potential for combining suitable dyes from these two classes to expand the colour gamut currently available from natural dyes on cotton seem worthy of exploration. The results of this study indicate that shades comparable with those produced by natural dyes can be obtained on cotton using select mordant dyes following Fe²⁺ and Al³⁺ pretreatments. The best results were obtained using a two‐step/two‐bath process and dyes such as CI Mordant Blue 13 and CI Mordant Orange 6. In evaluations of mordant and natural dye combinations using the two mordant dyes logwood and Osage orange as prototypes, interesting fabric shades were obtained. However, the fastness properties of these dyes must be improved in order to produce commercially viable dyeings.     

Physical properties of silk fibers grafted with vinyltrimethoxysilane

Silk fibers from Bombyx mori silkworms were grafted using a novel grafting monomer, vinyltrimethoxysilane (VTMSi), with various grafting initiators. The effects of these grafting initiators were evaluated. It was possible to successfully copolymerize VTMSi within the silk fiber matrix without disturbing the fine structure of the fiber matrix, which was shown by FTIR analysis and refractive index measurements. The physical properties of VTMSi grafted silk were analyzed and compared to fibers grafted with conventional monomers such as methyl methacrylate, methacrylamide, and 2‐hydroxyethyl methacrylate. No trend in the tensile strength and elongation at break was observed when grafting silk fibers with VTMSi. Crease recovery in the wet state improved significantly, suggesting that this new grafting technique is important for the production of washable silk fabrics. The thermal stability of VTMSi grafted silk fibers was improved as shown by the shift of the endothermic peak for the thermal decomposition toward higher temperatures. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1764–1770, 2001     

Reinforcement of polypropylene using sisal fibers grafted with poly(methyl methacrylate)

Sisal fiber (SF) surface modification was carried out by grafting with methyl methacrylate (MMA) using cerium and ammonium nitrate as initiator. The effects of reaction time, monomer, and initiator concentration on the grafting parameters were systematically investigated. The results showed that MMA was successfully grafted onto the sisal fiber surface. The PMMA‐grafted sisal fibers were melt blended with polypropylene (PP) and then injection molded. The PP/SF composites were characterized by means of thermal analysis, mechanical testing, wide‐angle X‐ray diffraction, and SEM examination. PMMA grafted onto the surface of SF enhanced the intermolecular interaction between the reinforcing SF and PP matrix, improved the dispersion of SF in the PP matrix, and promoted the formation of β‐crystalline PP. These enhanced the thermal stability and mechanical properties of PP/SF composites. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1055–1064, 2003     

Modification of silk with aminated polyepichlorohydrin to improve dyeability with reactive dyes

Reactive dyes have almost complete exhaustion and ideal fixation on aminated polyepichlorohydrin pretreated silk without addition of salt or alkali. The effects of varying pretreatments and dyeing conditions were studied. The dyeing behaviour of CI Reactive Red 15 on modified silk under pH 6 was investigated. Dyeings of modified silk showed good wash fastness, dry and wet rub fastnesses as well as light fastness. The quality of the dyed silks obtained after pretreatment was shown to be satisfactory and the dyeing effluent was less polluted.