Photograft copolymerization of methyl methacrylate on viscose fiber using titanium(III) chloride–potassium persulfate redox initiator in a limited aqueous system

The graft copolymerization of methyl methacrylate (MMA) onto viscose fibers were studied under photoactive conditions with visible light using titanium(III) chloride—potassium persulfate as redox initiator in a limited aqueous system. Polymerization carried out in the dark at 40 ± 1°C produced little graft copolymer whereas that in the presence of light at 40 ± 1°C produced significant grafting. Percent grafting, percent total conversion, and grafting efficiency (%) were studied by varying time, initiator concentration, monomer concentration, solvent composition, and pH of the medium. High percent grafting (～ 200%), high grafting efficiency (～ 98%), and percent total conversion (～ 47%) were obtained with little homopolymer formation. A suitable mechanism for grafting has been discussed and also the characterization of the grafted fibers were studied by Fourier transform infrared (FTIR) spectroscopy, thermogravimetry and scanning electron microscopy (SEM). © 1992 John Wiley & Sons, Inc.     

Grafting vinyl monomers onto silk fibers. X. Graft copolymerization of methyl methacrylate onto silk using hydrogen peroxide–thiourea redox system

The graft copolymerization of methyl methacrylate onto silk fibers initiated by a hydrogen peroxide–thiourea redox system was investigated under various conditions. The effects of monomer, initiator, temperature, acidity of the medium, and solvent on the rate of grafting were studied. The graft yield increases with the increase of monomer and initiator concentration. The graft yield also increases with the increase of acid concentration upto 22.50 × 10^?2M and thereafter it decreases. The effect of some inorganic salts on the rate of grafting has also been investigated, and a suitable mechanism has been suggested.     

Vanadium-cyclohexanone–initiated graft copolymerization of methyl methacrylate onto jute fibers

Graft copolymerization of methyl methacrylate (MMA) was carried out on jute fibers using a V⁵⁺ -cyclohexanone redox initiator system. The effect of the concentration of acid, monomer, and V⁵⁺ on graft yield have been studied. In order to obtain optimum conditions of grafting, the effects of temperature, acid, reaction medium, solvent, and some inorganic salts on graft yield have been investigated. The most remarkable features of the investigation include the proposition of a mechanism and derivation of rate expression for the grafting process. More than 100% grafting could be achieved with the present system.     

Photograft copolymerization of methyl methacrylate on silk fiber using titanium(III) chloride–potassium persulphate redox initiator in a limited aqueous system. I

Graft copolymerization of methyl methacrylate (MMA) onto mulberry silk fibers has been investigated in a limited aqueous system employing titanium(III) chloride–K₂S₂O₈ as the redox initiator under a photoactive condition with visible light. Polymerization in the presence of light at 32 ± 1°C has been found to be more pronounced than in the dark under identical conditions. The percentage of grafting, the percentage of total conversion, and the percentage of grafting efficiency have been studied by varying the reaction time, concentration of monomer, initiator concentration, solvent composition, and pH of the medium. A high percentage of grafting (∼ 93%), high grafting efficiency (∼ 97%), and the percentage of total conversion (∼ 25%) have been obtained with little homopolymer formation. Characterization of the grafted fibers has been investigated by Fourier transform infrared spectroscopy and scanning electron microscopy. Finally, the reaction mechanism has been discussed by considering hydrogen bonding. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2187–2193, 1999     

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.     

Graft copolymerization of methyl methacrylate on silk fiber using mohr's salt—potassium persulfate as redox initiator under visible light in a limited aqueous medium

Graft copolymerization of methylmethacrylate onto mulberry silk fibers was studied under photoactive conditions with visible light using the Mohr's salt-potassium persulfate as the redox initiator in a limited aqueous medium. Polymerization in the presence of light at 40±1°C was found to be more pronounced than that in the dark at 40±1°C. Percent grafting, percent total conversion, and grafting efficiency under different sets of conditions were studied, and the mechanisms of polymerization and graft copolymer formation were discussed. Characterization of the grafted fibers was done by Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry, and thermogravimetry. © 1996 John Wiley & Sons, Inc.     

Microwave promoted synthesis of chitosan‐graft‐poly(acrylonitrile)

Using microwave (MW) irradiation, polyacrylonitrile was grafted onto chitosan with 170% grafting yield under homogeneous conditions in 1.5 min in the absence of any radical initiator or catalyst. Under similar conditions a maximum grafting of 105% could be achieved when the K₂S₂O₈/ascorbic acid redox system was used as radical initiator in a thermostatic water bath at 35 ± 2°C. The representative graft copolymer was characterized by Fourier transform infrared spectra, thermogravimetric analysis, and X‐ray diffraction measurement, taking chitosan as a reference. The effects of such reaction variables as monomer/chitosan concentration, MW power, and exposure time on the graft co polymerization were studied. A probable mechanism for grafting without the redox system under microwaves was proposed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 820–825, 2005     

Factors affecting polymerization of 2-methyl-5-vinylpyridine in poly(ethylene terephthalate) fibers using benzoyl peroxide as initiator

Polymerization of 2-methyl-5-vinylpyridine (MVP) in the presence of poly(ethylene terephthalate) fibers (PET) using benzoyl peroxide (BP) as initiator caused a substantial increase in the weight of fibers. The mechanism of this polymerization is believed to be grafting by vinyl addition to PET radical formed under the influence of BP. Increasing the BP concentration up to 4.26 × 10^?3 mole/l. causes a significant enhancement in grafting, while further increase brings about a marked fall in the graft yield. Increasing the MVP concentration up to 10% also improves significantly the graft yield, but the latter, particularly in the later stages of the reaction, shows lower values at higher MVP concentrations. Raising the reaction temperature from 65° to 95°C causes a significant enhancement in the rate of grafting, though the maximum graft yield obtained at 95°C is much lower than at 85°C. Incorporation of Cu²⁺ ion in the polymerization system enhances the graft yield outstandingly. The same holds true for Fe³⁺ and Li ions, but the enhancement is much less than for Cu²⁺ ion. Addition of acetic or oxalic acid to the reaction decreases the magnitude of grafting. The same situation is encountered when a water/solvent mixture is used as reaction medium. Solvents employed were methanol, ethanol, propanol, and butanol. Also studied was the polymerization reaction with respect to homopolymer, total conversion, and graft efficiency.     

Grafting vinyl monomers onto silk fibers. VIII. Graft copolymerization of methyl methacrylate onto silk using tetravalent manganese–oxalic acid redox system

The graft copolymerization of methyl methacrylate onto silk fibers was investigated in aqueous solution using the Mn(IV)–oxalic acid redox system. The copolymerization reaction was carried out under a variety of conditions such as different monomer, initiator, oxalic acid, acid concentrations, and temperatures. The graft yield increases with increasing initiator concentration up to 5 × 10^?2M, and with further increase of the initiator concentration it decreases. The graft yield also increases with increasing sulfuric acid concentration up to 15 × 10^?2M, and decreases thereafter. The rate of grafting also increases with increase in oxalic acid concentration up to 1.5 × 10^?2M and 84.592 × 10^?2M, respectively, and thereafter the rate of grafting shows down. The effect of temperature, solvents, and salts on graft yield has also been investigated and a plausible rate expression has been derived.     

Hydrogen peroxide initiated grafting of acrylamide onto poly(ethylene terephthalate) fibers in benzyl alcohol

The grafting of acrylamide onto poly(ethylene terephthalate) fibers using hydrogen peroxide as the redox initiator was investigated. Benzyl alcohol was found to be the favorite medium for this grafting. Maximum graft yield (7.6%) was reached at 95°C; the graft yield decreased at higher temperatures, and finally grafting was inhibited at 120°C. The effect of monomer and initiator concentration on grafting was also studied. © 1996 John Wiley & Sons, Inc.     

Graft copolymerization with a new class of acidic peroxo salts as initiator. V. Grafting of methyl methacrylate onto jute fiber using potassium monopersulfate catalyzed by Fe(II)

Graft copolymerization of methyl methacrylate (MMA) onto jute fibers was studied in an aqueous solution using a new class of acidic peroxo salt, potassium monopersulfate, as initiator, under the catalytic influence of Fe(II) under nitrogen atmosphere. The grafting reaction was influenced by the reaction time, temperature, and concentrations of monomer, initiator, and jute fibers. The grafting reactions have also been studied in the presence of various salts and solvents. The maximum grafting percent (385.4%) has been observed at 35°C for the concentration of monomer (1.4082M), initiator (12.9 × 10^?3M), catalyst (2.5 × 10^?4M), and solvent (acetic acid) composition of (40:60) for a reaction time of 6 h. From the experimental results a suitable mechanism for the graft initiation and termination has been put forth. The graft copolymers have been characterized, and their improved properties such as tensil strength tested.     

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.     

Optimized conditions for the grafting reaction of poly(methyl methacrylate) onto oil‐palm empty fruit bunch fibers

This article describes the graft copolymerization of poly(methyl methacrylate) (PMMA) onto oil‐palm empty fruit bunches (OPEFBs) with a fiber length of less than 75 μm. The graft copolymerization was carried out under a nitrogen atmosphere by a free‐radical initiation technique in an aqueous medium. Hydrogen peroxide and ferrous ions were used as a redox initiator/cocatalyst system. The PMMA homopolymer that formed during the reaction was removed from the grafted copolymers by Soxhlet extraction. Determining the effects of the reaction period, reaction temperature, and monomer concentration on the grafting percentage was the main objective, and they were investigated systematically. The optimum reaction period, reaction temperature, monomer concentration, and initiator concentration were 60 min, 50°C, 47.15 × 10^?3 mol, and 3.92 × 10^?3 mol, respectively. The maximum percentage of grafting achieved under these optimum conditions was 173%. The presence of PMMA functional groups on OPEFB and the enormous reduction of the hydroxyl‐group absorption band in PMMA‐g‐OPEFB spectra provided evidence of the successful grafting reaction. The improvement of the thermal stability of PMMA‐g‐OPEFB also showed the optimal achievement of the grafting reaction of PMMA onto OPEFB. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effect of graft copolymerization of 2-hydroxyethyl methacrylate on the properties of polyester fibers and fabric

Graft copolymerization of hydroxyethyl methacrylate (HEMA) onto poly(ethylene terephthalate) (PET) fibers using benzoyl peroxide (BP) as initiator was carried out in water and in water/organic solvent as a reaction medium. The effect of initiator concentration, reaction time, temperature, and reaction medium as well as addition of FeSO₄ to the polymerization medium was studied. Percent grafting was enhanced significantly by increasing BP concentration up to 0.016 mol/L and then decreased upon further increase in initiator concentration. Increasing the monomer (HEMA) concentration up to 0.48 mol/L improves significantly the graft yield. Raising the polymerization temperature up to 85°C causes a significant increase in grafting yield; further increase in temperature leads to decrease in graft yield. Incorporation of Fe⁺² ions in the polymerization system decrease the graft yield. The same situation is encountered when water/solvent mixture is used as reaction medium. Solvent employed were methanol, toluene, and benzene.     

Graft copolymerization of methyl methacrylate upon gelatin initiated by benzoyl peroxide in aqueous medium

The graft copolymerization of methyl methacrylate upon gelatin was studied using benzoyl peroxide as an organic initiator in aqueous medium. The grafting reactions were carried out within the 65–90°C temperature range, and the effect of monomer and initiator concentrations on the graft yield were also investigated. The maximum graft yield was obtained at a benzoyl peroxide concentration of 0.20 × 10⁻² mol/L and the optimum temperature was 80°C. Thermogravimetric analysis showed that the thermal stability of gelatin increased as a result of grafting. Further, such changes in the properties of methyl methacrylate‐grafted gelatin as density, moisture regain, and water uptake were also determined. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1547–1556, 1999     

Graft copolymerization of an itaconic acid/acrylamide monomer mixture onto poly(ethylene terephthalate) fibers with benzoyl peroxide

A mixture of acrylamide (AAm) and itaconic acid (IA) was grafted onto poly(ethylene terephthalate) (PET) fibers with benzoyl peroxide in aqueous media. The effects of polymerization conditions such as the temperature, polymerization time, initiator concentration, and monomer mixture ratio on grafting were investigated. The maximum graft yield was 76.1% with an AAm/IA mixture ratio of 90/10 (mol/mol). The graft yield was as low as 3% in the single grafting of IA, whereas the use of AAm as a comonomer increased the amount of IA that entered the fiber structure to 33.5%. An increase in the temperature from 65 to 85°C increased the grafting rate and saturation graft yield. However, an increase in the temperature above 85°C decreased the saturation graft yield. The graft yield increased up to an initiator concentration of 1.0 × 10^?2 M and decreased afterwards. The grafting rate was 0.65th‐ and 0.74th‐order with respect to the initiator and AAm concentrations, respectively. The densities, diameters, and moisture‐regain values of the AAm/IA‐grafted PET fibers increased with the graft yield. Similarly, there was an increase in the dyeability of the AAm/IA‐grafted fibers with acidic and basic dyes. The grafted fibers were characterized with Fourier transform infrared and thermogravimetric analysis, and their morphologies were examined with scanning electron microscopy. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1795–1803, 2005     

Surface modification of coir fibers. II. Cu(II)‐ IO initiated graft copolymerization of acrylonitrile onto chemically modified coir fibers

A study of the graft copolymerization of acrylonitrile (AN) onto chemically modified coir fibers was carried out using a CuSO₄ and NaIO₄ combination as the initiator in an aqueous medium in a temperature range of 50–70°C. The graft yield was influenced by the reaction time, temperature, concentration of CuSO₄, concentration of NaIO₄, and monomer concentration. Grafting was also carried out in the presence of inorganic salts and organic solvents. A combination of copper(II) and sodium periodate (Cu²⁺‐IO) in an aqueous medium with an IO concentration of 0.005 mol L^?1 and a Cu²⁺ concentration of 0.004 mol L^?1 produced optimum grafting. The chemically modified and AN grafted fibers were characterized by FTIR and scanning electron microscopy (SEM). The SEM studies revealed that grafting not only takes place on the surface of the fibers but also penetrates the fiber matrix. The tensile properties like the maximum stress at break and extension at break of untreated, chemically modified, and AN grafted coir fibers were evaluated and compared. The extent of absorption of water of untreated, chemically modified, and grafted coir fibers was determined. It was found that grafting of AN imparts hydrophobicity onto coir fibers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 75–82, 2002; DOI 10.1002/app.10221     

Synthesis and characterization of PET fibers grafted with binary mixture of 2-methylpropenoic acid and acrylonitrile by free radical: its application in removal of cationic dye

Grafting of binary vinyl monomer mixtures such as 2-methylpropenoic acid (MPA) and acrylonitrile (AN) onto poly (ethylene terephthalate) fibers (PET) was achieved in an aqueous medium with using benzoyl peroxide like free radical initiator. A new reactively fibrous adsorbent was used for removal of dye such as methylene blue (MB) from aqueous media through batch sorption method. Fibers adsorbent was swelled in solution to support the graft and the subsequent polymerization of MPA/AN onto polyester fibers. Optimum conditions for grafting were discovered and reactive fiber were characterized. Variations of graft yield with time, temperature, initiator concentration and monomer mixture ratio were investigated. The optimum initiator concentration was found to be 8 × 10^?3 mol/L. The percentage of grafting rose steadily with the vinyl monomer mixture monomer concentration (50 %). The optimum temperature and polymerization time were found to be 80 °C and 120 min, respectively. The use of AN and MPA monomers together in grafting produce a significant increased in the graft yield. Experimental studies showed that the percentage removal of MB was a great higher on the MPA/AN grafted PET (MPA/AN-g-PET) fibers than on the original PET fibers. The adsorbed quantity of MB improved with pH and basic pH was appropriate for the elimination of MB. MPA/AN-g-PET fibers removed 98 % of cationic dye when initial concentration diverse from 10 to 80 mg L^?1 at pH 9.0. Almost all of the adsorbed cationic dye was eluted by ethanoic acid in methanol. Ten removal–desorption cycles indicated that the reactive fibers were favorable for repetitive use without notable change in removal capacity. Consequently, the MPA/AN-g-PET fibers have demonstrated potential as an effective adsorbent for the extremely effective removal of cationic dyes from aqueous media.     

Modified chitosan. I. Optimized cerium ammonium nitrate‐induced synthesis of chitosan‐graft‐polyacrylonitrile

Chitin was extracted from shrimp shells and then deacetylated to obtain chitosan. The degree of deacetylation of the chitosan was determined to be 0.76 using pH‐metric titration. A large number of cyanide functional groups were introduced onto chitosan by grafting with polyacrylonitrile as an efficient way of modification. The graft copolymerization reactions were carried out under argon atmosphere in a homogeneous aqueous phase (containing a small portion of acetic acid) by using ceric ammonium nitrate as an initiator. Evidence of grafting was obtained by comparing FTIR spectra of chitosan and the graft copolymer as well as solubility characteristics of the products. The synthetic conditions were systematically optimized through studying the influential factors, including temperature and concentrations of the initiator, acrylonitrile monomer (AN), acetic acid, and chitosan. The effect of individual factors was investigated by calculating and monitoring the variations of the grafting parameters [i.e., grafting ratio (Gr), grafting efficiency (Ge), add‐on value (Ad), homopolymer content (Hp), and total conversion (Ct)]. Under optimum conditions, the grafting parameters were achieved as 535, 98, 81, 2, and 102%, respectively. A mechanism for the free‐radical grafting was proposed. As empirical rates of polymerization and graft copolymerization were plotted against [AN] and [Ce⁴⁺]^1/2, the experimental kinetic data displayed a good match to a reported rate statement. The overall activation energy for the graft copolymerization was determined to be 44.9 kJ/mol. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2048–2054, 2003     

Chemical grafting of aniline and o‐toluidine onto poly(ethylene terephthalate) fiber

Graft copolymerization of poly(aniline) and poly(o‐toluidine) onto poly(ethylene terephthalate) fiber was conducted by using peroxydisulfate as a lone initiator under nitrogen atmosphere at various experimental conditions in aqueous hydrochloric acid medium. The grafting of poly(aniline) and poly(o‐toluidine) onto poly(ethylene terephthalate) fiber was verified by recording cyclic voltammetry of the grafted fiber, conductivity measurements, and thermal analysis. Graft parameters—such as % grafting, % efficiency, and the rate of grafting—were followed. Grafting was always accompanied by homopolymerization. The rate of homopolymerization was also followed in all experimental conditions. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 121–128, 1999