Continuous photografting of HEMA onto polypropylene fabrics with benzophenone Photoinitiator

Continuous photografting onto polypropylene fabrics in the absence of inert gases was carried out to improve hydrophilic property of PP fabrics, which was padded with a formulated solution of 2-hydroxyethyl methacrylate(HEMA) and benzophenone as a monomer and a photoinitiator, respectively. The grafting yield increased with increases in benzophenone concentration up to 30 % on the weight of the monomer and UV energy up to of 38 J/cm², while 30 % HEMA concentration was optimal for the grafting efficiency. The physicochemical properties of the grafted PP fabrics were monitored by FT-IR, SEM, zeta potential, and dyeability to a cationic dye. The grafting increased O_1s/C_1s content and remarkably produced more negative zeta potentials compared with the pristine PP fabric. Also the grafted PP showed the increased dyeability to cationic dyes with increasing graft yield resulting from the enhanced electrostatic interaction between the dyes and negatively charged surface of the grafted PP fiber. In addition, improved hydrophilic property of grafted PP fabrics was ascertained by more rapid water wetting time and higher water absorbency.     

Union dyeing of the photografted PET/wool blend fabrics with dimethylaminopropyl methacrylamide

Dimethylaminopropyl methacrylamide (DMAPMA) was grafted onto PET/wool blend fabrics by continuous UV irradiation. Union dyeing of the photografted fabrics was investigated using three reactive dyes of α-bromoacrylamide reactive groups. The influence of grafting yield, DMAPMA concentration, NaCl amount, pH value, and dyeing temperature on the dyeability was evaluated. The dyeability of both PET and wool components was improved significantly by the DMAPMA photografting and successive reactive dyeing. Although the dyeability of the PET component in the blend substantially was improved with higher grafting, equal dyeability between PET and wool was difficult to achieve due to more facile grafting and higher reactivity of the wool component compared with the modified PET component. However, the color fastness of the PET/wool blend fabric was excellent for all three colors. This study may offer a way to achieve union dyeing of PET/wool blend fabrics.     

Thermal performance and flammability of poly(ethylene terephthalate) fabrics grafted with different monomers followed by electron beam irradiation

Electron beam irradiation grafting of acrylic acid (AAc), acrylamide (AAm), and dimethyl vinylphosphonate (DMVP) onto poly(ethylene terephthalate) (PET) fabrics was performed using a high-energy electron accelerator. Parameters affecting the graft polymerization of PET fabrics, including absorbed dose and monomer concentration, were investigated. Fourier transform infrared spectroscopy analysis confirmed that the monomers were grafted onto the PET fabrics. The thermal behavior of the grafted PET fabrics was investigated with thermogravimetric analysis. Findings showed that grafting with AAm could improve the thermal stability of PET. The limiting oxygen index values and vertical flammability test results showed that PET fabric graft-polymerized with AAc could improve the flammability and prevent melt dripping. Grafting with AAm and DMVP could improve the flame retardation property of PET fabric. Scanning electron micrographs showed that the surface morphology of the PET fabric samples was significantly influenced by graft polymerization, and that grafting with AAc could promote the formation of residual char and impart an anti-dripping quality to PET fabrics.     

UV-grafting coloration of cotton and wool fabrics using bismethacrylated quinizarin dye

A novel bifunctional quinizarin dye possessing two photoactive methacrylate groups was synthesized by the reaction of quinizarin with methacryloyl chloride. The synthesized dye, a low substantive dye under the conventional dyeing process, can be photografted onto cotton and wool fabrics at room temperature without neutral salts, which makes it a novel coloration process of excellent environmental friendliness. The concurrent polymerization and grafting of the synthesized dye onto cotton or wool can be assisted by a photoinitiator and acrylic acid in the case of cotton grafting. Moreover, color yields of the grafted fabrics improved significantly with the photografting of the bifunctional dye. The bifunctional dye can be photopolymerized with the increase in UV energy to 25 J/cm² and the oligomeric dye has a degree of polymerization of 5 or more. Furthermore, the color fastness properties of the grafted fabrics were superior to those of the dyed fabrics via exhaustion.     

Functinalization of poly(ethylene terephthalate) fibers by grafting of maleic acid/methacrylamide monomer mixture

Functionalized poly(ethylene terephthalate) (PET) fibers were synthesized by grafting of maleic acidmethacrylamide (MAA-MAAm) monomer mixtures by using benzoylperoxide as initiator onto PET fibers in an aqueous medium. The functionalized fibers were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimeter, and scanning electron microscopy. The effects of reaction conditions, such as monomer mixture ratio, monomer mixture and initiator concentration, polymerization time, and temperature on grafting were investigated. In alone grafting of MAA, grafting was not observed. However, the use of MAAm as a comonomer increased the amount of MAA inserted to the PET fiber up to 40.7 %. An increase in the temperature between 75 and 95 °C and also, increase in monomer mixture concentration between 0.50 and 1.00 M increased the grafting rate and saturation graft yield. The graft yield has shown an increase up to an initiator concentration of 1.0×10⁻² M and decreased afterwards. The grafting increased the dyeability with disperse, acidic and basic dyes, and water absorption capacity but decreased the thermal stability of the fibers.     

Use of 1,6-diaminohexane-functionalized glycidyl methacrylate-g-poly(ethylene terephthalate) fiber for removal of acidic dye from aqueous solution

In this study, removal of Congo red (CR) from aqueous solution by 1,6-diaminohexane-functionalized glycidyl methacrylate-g-poly(ethylene terephthalate) (HMDA-GMA-g-PET) fiber was investigated. A new aminated fibrous adsorbent was prepared by a reaction between amine and epoxy group in GMA-g-PET fiber prepared by grafting GMA monomer onto poly (ethylene terephthalate) (PET) fiber. Effects of various parameters such as pH, treatment time, initial, dye concentration, and reaction temperature on the adsorption amount of dye onto reactive fiber were investigated. The adsorption rates of CR were much higher on the HMDA-GMA-g-PET fiber than on GMA-g-PET and ungrafted PET fiber. The effective pH was 2.0 for adsorption on grafted PET fiber. It was found that the sufficient time to attain equilibrium was 60 min. The maximum adsorption capacity of the reactive fiber for CR is 16.6 mg/g fiber. The rates of adsorption were found to conform to the pseudo-second order kinetics with good correlation. It was found that the adsorption isotherm of CR fitted Freundlich type isotherm.     

UV-induced coloration of cotton fabrics by photografting of acrylamido dyes using acrylamide as a comonomer

Formulations of acrylamido dyes containing comonomers can be photografted onto cotton fabric upon UV irradiation at room temperature without neutral salts, which makes it a novel coloration process of excellent environmental friendliness. The photografting of the dyes can be assisted by the copolymerization of the acrylamide comonomer which may reduce the steric hindrance of the bulky dyes. About 90 % of the dyes and 94 % of the acrylamide are photopolymerized in the solution and the degree of polymerization is estimated to be 13.2 according to ¹H-NMR and MALDI-TOF mass analyses. The optimal K/S values of the grafted cotton fabrics showed 13.3 and 12.3 for red and yellow dyes, respectively. The optimal UV-grafting coloration can be achieved when a UV energy of 25 J/cm² was irradiated on the padded fabrics with a formulation of 0.65 mole ratio of acrylamide to the dyes, 7 wt% acetophenone photoinitiator (Irgacure 2959) based on the dye weight under pH 6. Furthermore, the color fastness properties of the grafted fabric were superior to those of conventional reactive dyeing of the dyes due to higher molecular weight of the polymerized dyes.     

Reactive dyeing of meta-aramid fabrics photografted with dimethylaminopropyl methacrylamide

Aramid fibers have been known to difficult to dye with conventional dyes and dyeing techniques because of its extremely high crystallinity and compactness. In order to make the aramid fibers dyeable to a bright color in deep shade, meta-aramid fabrics were photografted under continuous UV irradiation with dimethylaminopropyl methacrylamide (DMAPMA) and benzophenone as a monomer and a hydrogen-abstractable photoinitiator respectively. Several factors affecting the photografting treatment of the meta-aramid fabrics were investigated including monomer and photoinitiator concentrations. ATR, ESCA and SEM analysis indicated significant alterations on the chemical structure and atomic composition of the photografted fabric surface and the fabric surface was covered with the grafted polymers. While the pristine meta-aramid fabrics showed no appreciable dyeability to the α-bromoacrylamide type reactive dyes, the grafted aramid fabrics showed the remarkably enhanced dyeability to the reactive dyes, which was proportional to the graft yield indicating the covalent bond formation between the dyes and the secondary amino groups in the grafted DMAPMA. In case of C.I. Reactive Red 84, a K/S value of 14.8 can be obtained with the grafted meta-aramid fabrics with a graft yield of 7.6 % (w/w). Also and the color fastness properties of the dyed fabrics was excellent in the conditions of washing, rubbing and solar irradiation.     

Acrylamide-assisted Photografting of Bisacrylamide Dyes onto Cotton

Dibromopropionamide groups of C.I. Reactive Red 136 were dehydrobrominated to obtain bisbromoacrylamide groups. Photografting yield of the modified dyes onto cotton increased with the addition of acrylamide comonomer, presumably reducing the steric hindrance between the dyes with bulky chromophores. The acrylamide-assisted grafting was more prominent with increasing degree of the functionality. The optimum grafting was obtained with 2.5 molar ratio AAm and 7 % photoinitiator with respect to 0.03 mol/l dye under a UV energy of 25 J/cm². The grafting yield and K/S of the grafted cotton with C.I. Reactive Red 83 was lower than that with the modified Red 136 at the same degree of functionality 2.0, probably because the relatively larger chromophore of the Red 83. In addition, the washing, rubbing and light fastness of the grafted cotton fabrics with the modified Red 136 were higher than the adsorption-based conventional dyeing, which was more pronounced as the degree of functionality increased.     

An efficient,simple and facile strategy to synthesize Polypropylene-g-(acrylic acid-co-acrylamide) nonwovens by suspension grafting polymerization and melt-blown technique

An efficient, simple and facile process, i.e., suspension grafting polymerization combined with melt-blown technique, was employed to synthesize Polypropylene-g-(acrylic acid-co-acrylamide) nonwoven fabrics [PP-g-(AA-co-AM) nonwovens]. In this study, the grafting mechanism and the effect of synthesis parameters on grafting percentage (GP) were investigated. The as-synthesized products were characterized by melt flow rate (MFR), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), water contact angle (WCA) and thermalgravimetric analysis (TGA). Besides, the uptake properties of metal ions (i.e., Ba²⁺, Cu²⁺, Ni²⁺, Mg²⁺, Al3+, Ca²⁺) on the PP-g-(AA-co-AM) nonwovens in dynamic condition were studied. Results of FTIR showed that AA and AM were successfully grafted onto the PP surface. The decrease in WCAs of the grafted nonwovens with the increasing GP indicated that (AA-co-AM) side chains existed as the hydrophilic component. TGA results revealed that no significant change in thermal stability was found in grafted PP samples. The synthesis experiments showed that the highest GP was obtained at grafting time 3 h, water 3 ml/g, xylene 15 wt%, benzoyl peroxide 0.5 wt%, AA, AM 30 wt% and AA: AM 1:1, with a GP of 16.7 %, and a grafting efficiency of 67 %. However, MFR measurement and SEM image demonstrated that PP-g-(AA-co-AM) nonwovens with the highest GP showed almost no mechanical strength existed between filaments resulting in the occurrence of deformation and contraction of nonwovens, and breaking up into small pieces. Comprehensively, the optimal GP was 8.7 %, and the corresponding PP-g-(AA-co-AM) nonwovens exhibited higher metal ions uptake capacity than pristine PP nonwovens in the dynamic adsorption process.     

Surface modification of microporous polypropylene membrane by UV-initiated grafting with poly(ethylene glycol) diacrylate

Poly(ethylene glycol) diacrylate (PEGDA) was grafted, through UV-initiated grafting, onto a microporous polypropylene (PP) membrane in order to develop a moisture-sensitive porous structure. Based on the concentration of the PEGDA grafting solution, as well as other variables, the pores of the membrane were filled to varying degrees with cross-linked PEGDA hydrogel, decreasing the pore sizes. This decrease in pore size was highly dependent on the grafting degree (weight add-on of the grafted polymer) that was dependent upon grafting conditions. Grafting with PEGDA resulted in a microporous polypropylene membrane with increased hydrophilicity and moisture-responsive pores. The functional membrane can be used in biological protective materials to limit the transport of liquid-borne pathogens while maintaining moisture transport properties.     

Durable press finish of cotton via dual curing using UV light and heat

Continuous photografting/crosslinking of polyethyleneglycol dimethacrylate oligomers onto cotton using a water-soluble benzophenone photoinitiator was investigated. Photografting increased with increasing irradiation dose, oligomer concentration and photoinitiator concentration. Maximum grafting efficiency of DM 400 and 600 were 83% and 79%, respectively. The photografting increased the wrinkle resistance of cotton implying surface crosslinking of cotton. Both surface crosslinking and bulk crosslinking of cotton were accomplished via dual curing of a mixed formulation containing both a thermally curable component (BTCA/SHP) and a UV-curable component. The wrinkle resistance of the crosslinked cotton was found to be higher when cured by thermal curing after UV curing rather than by UV curing after thermal curing due to the facile post-polymerization of the UV active component. The presence of crosslinks in the dually crosslinked cotton was verified with FT-IR and thermogravimetric analysis.     

Preparation and use of amine-functionalized glycidyl methacrylate-g-poly(ethylene terephthalate) fibers for removal of chromium(VI) from aqueous solution

Poly(ethylene terephthalate) (PET) fibers were grafted with glycidyl methacrylate (GMA) using benzoyl peroxide as initiator. 1,6-diaminohexane (HMDA) was then covalently attached to this GMA grafted PET fibers. Variations of time, temperature, initiator and monomer concentrations were investigated. HMDA-GMA-g-PET fibers were used as a new sorbent for removal of Cr(VI) ions from aqueous solutions through batch adsorption method. Effects of various parameters such as pH, treatment time, and initial ions concentration on the adsorption amount of ions onto reactive fibers were investigated. The adsorption rates of Cr(VI) ions were much higher on the HMDA-GMA-g-PET fiber than on GMA-g-PET and ungrafted PET fiber. Within 60 min, at pH 3, Cr(VI) was removed by 98 % while the initial concentration of ions was at 25 mg/l and by 94 % at 400 mg/l. The Cr(VI) ions adsorbed were easily desorbed by treating with 1M KOH within 10 min.     

Effect of various parameters on the chemical grafting of amide monomers to poly(lactic acid)

Radical melt graft copolymerizations of poly (lactic acid) (PLA) with amide monomers using benzoyl peroxide as an initiator during reactive extrusion is studied. The effects of two monomer types at various concentrations, reaction temperatures and initiator concentrations on the grafting yield are investigated. The results showed that percentage of grafting was significantly enhanced by increasing benzoyl peroxide concentrations up to 12 mpm and then decreased by an increase in the initiator concentration. Furthermore, increasing each monomer concentration up to 450 mpm, improved the grafting yield significantly. Further increase brings about a marked fall in the grafting yield. Fourier Transform Infrared Spectroscopy (FTIR), back titration and nitrogen analyses confirmed that monomers of acrylamide and methacrylamide were successfully grafted onto PLA. The Gel Permeation Chromatography (GPC) data showed that the molecular weight of the grafted PLA samples under optimum conditions does not show any dramatic drop of PLA molecular weight by thermal degradation or hydrolysis of polyester chains, while the polydispersity index is poorly affected by the chemical modification of PLA. Also, the monomer structures affected the grafting yield as well as polymer chain combination. In addition under the same conditions, the grafting yield of acrylamide was more than that of methacrylamide. Thermal properties, molecular weight, density, moisture regain and tensile properties of the samples were also measured.     

Acrylamide assisted photoinitiator-free photografting of acrylamido dyes onto wool

Upon UV irradiation wool fabrics can be photografted with photoactive acrylamido dyes at room temperature without photoinitiaors, which is eco-friendly coloration process compared with conventional adsorption-based dyeing. Acrylamide addition as a comonomer can improve the photografting probably by reducing the steric hindrance between the bulky dyes during the photocopolymerization. Even without photointiators and neutral salts, the optimal K/S values of the photografted wool reached upto 18.7 and 18.5 for Reactive Red 84 and Yellow 39 dyes respectively. The optimal UV-grafting coloration can be achieved when a UV energy of 25 J/cm² was irradiated on the padded fabrics with 6.3 %owf dye containing 0.65 mole ratio of acrylamide to the dyes. Furthermore, the color fastness of the grafted fabrics was as good as those of conventionally dyed fabrics due to the copolymerization of dyes and comonomers.     

Green and Efficient Synthesis of an Adsorbent Fiber by Plasma-induced Grafting of Glycidyl Methacrylate and Its Cd(II) Adsorption Performance

A new chelating adsorbent for the removal of Cd(II) from aqueous solution, PP-g-GMA-DETA fibers, is prepared by plasma induced grafting of glycidyl methacrylate (GMA) onto the surface of polypropylene (PP) fibers, followed by modification with diethylenetriamine (DETA). The effects of grafting parameters on the grafting degree are investigated. Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy prove the successful grafting of GMA onto the surfaces of PP fibers and the subsequent conversion of epoxy groups of grafted GMA to amine groups, on reaction with DETA. The adsorption performances of Cd(II) by the chelating fibers are evaluated in detail. Kinetic and isothermal parameters are also evaluated. The data fit well with the pseudo-second order and Langmuir isotherm model, respectively. The maximum adsorption capacity of Cd(II) is 46.47 mg g^-1 and the prepared fibers show selective adsorbability towards target Cd(II) in presence of competing Mg(II) ions.     

Silver(I) ions loaded cyclodextrin-grafted-cotton fabric with excellent antimicrobial property

In this study cyclodextrin (CD) has been grafted onto cellulose back-bone of cotton fabric using citric acid as crosslinker. The CD-grafted fabric was characterized by SEM and FTIR analysis. The percent grafting of CD on fabric has been found to increase with concentration of CD, citric acid, and sodium dihydrogen phosphate. The CD-grafted fabric has been loaded with silver(I) ions for the purpose of obtaining a slow release device. The Ag(I) loaded grafted fabric showed fair antibacterial properties against E. Coli. The release of Ag(I) ions from the CD-grafted fabric was observed for a period of seven days.     

Chemically grafting carbon nanotubes onto carbon fibers by poly(acryloyl chloride) for enhancing interfacial strength in carbon fiber/unsaturated polyester composites

We propose a novel method to uniformly graft high density carbon nanotubes (CNTs) onto carbon fiber (CF) using poly (acryloyl chloride) (PACl) as coupling agents. Compared to micromolecule couping agent previously reported in literature [2,3], PACl can supply much more active groups, which is beneficial for grafting high density CNTs onto CF surface. Moreover, in order to further increase the grafting density of CNTs, the solvothermal strategy was used for improving the reactive activity between CF and CNTs. After CNTs grafting treatment, there are still substantial amounts of reactive groups which can further react with various types of molecules to meet different requirements. In order to create chemical bonding between CF and unsaturated polyester (UP), CF-CNT was further grafted with undecylenic alcohol (UA) to get CF-CNT-UA hierarchical reinforcement. The interfacial adhesion of the resulting composites showed a dramatic improvement.     

LED-UV grafting of vinylsulfone dyes onto photo-oxidized wool fabrics

Photografting coloration of wool was carried out under UV-LED irradiation at room temperature using aqueous vinylsulfone dye solution containing vinylsulfonic acid as a comonomer. UV-LED irradiation of the 395 nm emission is more energy efficient, less damaging to the dyes, and much safer to human eyes compared with polychromatic mercury UV lamps. However, in case of the UV-LED lamps, the wool needs to be photo-oxidized either by UV/ozone or polychromatic UV irradiation before the dye photografting. The surface treatments increased the sulfur and oxygen contents in the modified wool surfaces. While the optimally photografted wool fabrics under the UV-LED lamp yielded a K/S value of 9.9, the K/S of the grafted wool increased to 25.2 and 13.6 after the UV/Ozone or polychromatic UV preoxidation at UV energies of 10.6 J/cm² and 25 J/cm² respectively. The color fastness properties of the photografted fabrics were far better than with those of the conventionally reactive-dyed fabrics, implying that the high-molecular-weight photografted dyes seemed to be more durable than the low-molecular dyes.     

Effect of surrounded air atmospheric plasma treatment on polypropylene dyeability using cationic dyestuffs

The dyeing properties of the polypropylene (PP) fabrics using cationic dyestuffs were investigated after surrounded air atmospheric cold-plasma treatment. Surrounded air plasma (SAP) was used to modify fabric surface and to optimize the effects of some discharge parameters on dyeability. Surface morphology and physical-chemical properties of plasma treated fibers were also characterized by Fourier transform infrared attenuated total reflection spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. Activated surfaces by SAP were grafted with different compounds: 6-aminohexanoic acid, acrylic acid, and hexamethyldisiloxane. Dyeing the plasma-induced grafted PP fabric with basic dye was quite satisfactory when high color strength and good fasteness were considered.