Graft copolymerization of itaconic acid-methacrylamide comonomers onto poly(ethylene terephthalate) fibers

The graft copolymerization of itaconic acid-methacrylamide (IA-MAAm) comonomers was carried out using benzoyl peroxide as initiator onto poly(ethylene terephthalate) (PET) fibers in an aqueous medium. The grafted fibers were characterized by FTIR, TGA, DSC and SEM analysis. Effect of various parameters on graft yield such as feed composition, feed and initiator concentration, reaction time and temperature were investigated. The graft yield in the presence of MAAm increased because of the synergistic effect of MAAm comonomer. While, the graft yield alone with the IA onto PET fiber was 2.2%, the use of MAAm as a comonomer increased the amount of IA introduced to the PET fiber up to 13.7%. The reactivity ratios for both monomers were determined by using a Fineman-Ross plot. The grafting rate and saturation graft yield was increased upon increasing the temperature between 65 °C and 85 °C. When the temperature increased further than 85 °C, the saturation graft yield decreased. The graft yield has shown an increase up to an initiator concentration of 1.0 × 10⁻² M and slightly decreased. The grafting increased the dyeability with acidic and basic dyes, and moisture absorption capacity but decreased the thermal stability of the fibers.     

Graft Copolymerization of Acrylamide on Swollen poly (Ethylene Terephthalate) Fibers Using Cerium Ammonium Nitrate Initiator

Abstract

In this study the graft copolymerization of acrylamide (AAm) on swollen poly(ethylene terephthalate) (PET) fibers using cerium ammonium nitrate (CeAN) initiator was investigated. Five organic solvents, dimethylsulfoxide (DMSO), morpholine, acetic acid (HAc), n-butanol, and 1,2-dichloroethane (DCE), were used as swelling agents. DMSO was found to be the most suitable swelling agent. Solvent diffusion into the fibers was observed to increase with treatment time and temperature. The optimum graft yield was obtained when fibers were grafted after having been swollen in DMSO for a period of 1 hour at 140°C. Variation of graft yield with polymerization time and temperature, and monomer, initiator, and acid concentrations were investigated. Graft yields were observed to increase initially with polymerization time, then to level off, and were found to increase up to a certain monomer and Ce⁴⁺ concentration, then to decrease slightly. The effect of grafting on such fiber properties as diameter, viscosity, and moisture gain were also investigated.     

Graft Copolymerization of 2‐Acrylamido‐2‐methyl Propane Sulfonic Acid on Dimethyl Sulfoxide Pretreated Poly(Ethylene Terephthalate) Films Using Cerium Ammonium Nitrate as Initiator

Abstract

In this study, graft polymerization of 2‐acrylamido‐2‐methyl propane sulfonic acid (AMPS) on poly(ethylene terephthalate) (PET) films using cerium ammonium nitrate (CeAN) as an initiator was investigated. Before the polymerization reaction was carried out, films were swelled in dimethyl sulfoxide (DMSO) at 140°C for 1 h. The effect of polymerization temperature, time, initiator, and monomer concentrations on the graft yield were investigated. It was observed that the graft yield was initially increased with increasing temperature, monomer, and initiator concentrations; and then decreased. Graft yield was found to increase with increasing polymerization time up to 5 h, then remain constant. The effects of monomer and initiator inclusions on the grafting yield were also examined. Optimum conditions for grafting were found to be [AMPS] = 1.0 M, [Ce⁴⁺] = 1.5 × 10^?2 M, T = 85°C and t = 5 h. The rate of grafting was found to be proportional to the 0.1 and 0.4 powers of monomer and initiator concentrations, respectively. The overall activation energy for the grafting was calculated to be 11.4 kcal mol^?1. The effect of grafting on PET film properties such as intrinsic viscosity and water absorption capacity were determined. The grafted PET films were characterized with FTIR spectroscopy and scanning electron microscopy (SEM).     

Characterization and Studies on Grafting of Methyl Methacrylate onto PAN Fibers

The graft copolymerization of methyl methacrylate (MMA) onto commercial acrylic fibers (PAN) has been studied using Azobis(isobutyro)nitrile (AIBN) as an initiator. MMA grafting initiated by radicals formed from thermal decomposition of AIBN. In this study, the effects of monomer and initiator concentration, time and temperature reaction on the grafting yield have been investigated.

The optimum conditions for this grafting reaction were obtained with an MMA concentration of 0.7 M, an AIBN concentration of 0.0073 M, a reaction temperature of T=85°C and with a 60 min reaction time.

The fiber structure has been investigated by different experimental techniques of characterization such as Fourier transform infrared spectroscopy (FT‐IR), calorimetric analysis (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), water absorption and the physical and mechanical properties has also been investigated in this study. The thermal analysis data showed that by increasing grafting yield, little changes have occurred in fibers samples up to 13.5% of grafting yield and the thermal transitions of grafted fibers have approximately the same behavior compared with the raw fibers sample. Grafting also slightly affected the fiber morphology. The experimental data of mechanical properties clearly show that by increasing grafting yield, max extension will decrease but this change up to 13.5% grafting yield is barely noticeable. Grafting of poly MMA improved water absorption.     

Grafting of Acrylamide On 1, 1, 2, 2-Tetra-Chloroethane Preswelled Polyethylene Terephthalate) Films Using Azobisisobutyronitrile Initiator

Abstract

Graft polymerization of acrylamide (AAm) on 1, 1, 2, 2 tetrachloro-ethane (TCE) preswelled poly(ethylene terephthalate) (PET) films were performed with chemical initiation method using asobisiso-butyronitrile (AIBN) initiator. Temperature was found to have a greater effect on the swelling then the swelling time. Variation of the graft yield with polymerization temperature, time, AIBN concentration, AAm concentration, AIBN and AAm inclusion times were investigated. The optimum temperature for grafting was found to be 70°CC. The graft yield was observed to increase with polymerization time, AAm concentration, initiator and monomer diffusion time up to a saturation graft yield and then leveled off. An increase in AIBN concentration first enhanced the percent grafting then showed a decrease. The addition of some salts (Ni²⁺, Cr³⁺, Co²⁺, Cu²⁺) on the rate of grafting was also investigated. From the temperature dependence of the initial rate of grafting, the overall activation energy was found to be 4. 1 kcal/mol and relevant rate equation have been derived. The effect of grafting on film propities, such as water absorption capacity, intrinsic viscosity were determined. Grafted films were characterized by FTIR spectros-copy and scanning electron microscopy (SEM).     

Grafting Vinyl Monomers onto Silk Fibers. XIII. Graft Copolymerization of Methyl Methacrylate onto Silk Using Fe3+−Cysteine Redox System

The graft copolymerization of methyl methacrylate onto silk fibers initiated by the ferric chloride-eysteine redox system has been investigated in aqueous medium. The rate of grafting was calculated by varying the concentrations of monomer, initiator, acidity of the medium, cysteine, and temperature. The percentage of grafting increases with an increase of Fe³⁺ concentration up to 2,5 × 10^?3 mol/L and thereafter it decreases. The graft yield increases steadily upon increasing the monomer concentration. The graft yield also increases with increasing cysteine concentration up to 0.5 × 10^?3 mol/L and then decreases. The effect of the perchloric acid concentration, temperature, solvents, and certain neutral salts on graft yield has also been investigated and a suitable reaction scheme has been proposed.     

On the Modification of Chitosan Through Grafting

Abstract

The feasibility of grafting poly(methyl acrylate) and poly[1-(methoxycarbonyl) ethylene] onto chitosan, poly-β(1←-4)-2-amino-2-deoxy-d-glucose, was investigated. The grafting reaction was carried out in aqueous solution by using ferrous ammonium sulfate (FAS) in combination with H₂O₂ as redox initiator. The effects of such reaction variables as chitosan, monomer and initiator concentrations, reaction time, and reaction temperature were determined. Through this study the grafting reaction could be optimized. The grafting yield reached its maximum value of 332% when 0.3 g chitosan was copolymerized with 3 mL monomer at 70°C for 120 minutes with [FAS] = 6 × 10^?5 M, [H₂O₂] = 6 × 10^?3 M, and 8 mL water. The grafted chitosan was found to be insoluble in solvents for chitosan and solvents for poly(methyl acrylate), but did show swelling in dilute acetic acid, methanol, acetone, and in an ethanol/2% acetic acid 1:1 mixture. The thermal stability of chitosan and grafted chitosan were studied by dynamic thermogravimetric analysis. The results show that the graft copolymer is thermally more stable than pure chitosan. The overall activation energy for graft copolymerization was estimated to be 32.8 kcal/mol.     

Solvent “Goodness” in Polymer Separation by Flow

The graft copolymerization of methyl methacrylate onto silk fibers was investigated in aqueous solution using the V⁵⁺?thiourea redox system. The rate of grafting was determined by varying monomer, thiourea, acidity of the medium, temperature, initiator concentration, and reaction medium. The percentage of graft yield increases significantly by increasing the initiator concentration up to 0.01 M and thereafter decreases with a further increase of initiator concentration. The graft yield increases with an increase of thiourea concentration up to 10.0 × 10^?4 and then decreases with a further increase of thiourea concentration. The effect of increasing the monomer concentration brings about a significant enhancement in the graft yield. A suitable kinetic scheme has been proposed and the rate equation has been evaluated.     

Graft Copolymerization of Methyl Methacrylate onto Nylon 6 Using Thallium(III) Ions as Initiator

Abstract

Graft copolymerization of methyl methacrylate onto nylon 6 was investigated in aqueous perchloric acid medium using thallium(III) ions as initiator. The rate of grafting was evaluated by varying the concentrations of monomer, initiator, acid, and temperature. The rate of grafting was found to increase with an increase of both monomer and initiator concentrations. The graft yield was found to increase with an increase in the acid concentration up to 0.49 mL^?1, and beyond this concentration of perchloric acid the graft yield was found to decrease. It also increased with an increase of temperature. From the Arrhenius plot the overall activation energy was found to be 3.9 kcal/mol. The effects of inhibitors, various solvents, inorganic salts, and swelling agents on graft yield were studied. A suitable kinetic scheme has been proposed and a rate equation has been derived.     

Vibration damping materials based on interpenetrating polymer networks of carboxylated nitrile rubber and poly(methyl methacrylate)

Interpenetrating polymer networks (IPNs) based on carboxylated nitrile rubber (XNBR) and poly(methyl methacrylate)s were synthesized. Crosslinked XNBR was swollen in methyl methacrylate containing benzoyl peroxide as initiator and tetraethylene glycol dimethacrylate as crosslinking agent. The compositions of the IPNs were varied by changing the swelling time of the rubber in the methacrylate monomer. The dynamic mechanical properties of the IPNs were studied. The dynamic mechanical properties in the range 1–10⁵ Hz were obtained by the time‐temperature superposition of the data under multifrequency mode, which indicated high tan δ with good storage modulus in the entire frequency range. This indicates the suitability of these IPNs as vibration and acoustic dampers. Copyright © 2002 John Wiley & Sons, Ltd.     

Functional Polymers. XVII. Radical Grafting of Methyl 5-Vinylsalicylate onto Polybutadienes

Abstract

Methyl 5-vinylsalicylate was successfully grafted onto 1, 2-and cis-1,4-polybutadiene. When the grafting reaction was carried out in benzene at 60°C with azobisisobutyronitrile or benzoyl peroxide as the initiator, methyl 5-vinylsalicylate was transformed into grafted poly(methyl 5-vinylsalicylate) with a grafting efficiency of 5–22%. It was very important to carry out the grafting reaction under carefully controlled conditions and at relatively low concentration of polybutadienes, otherwise utilization of methyl 5-vinylsalicylate was low and cross-linking of polybutadiene occurred.     

Grafting Vinyl Monomers onto Wool Fibers. VII. Graft Copolymerization of Methyl Methacrylate onto Wool Using Peroxydiphosphate-Thiourea Redox System

Graft copolymerization of methyl methacrylate onto wool was investigated in aqueous solution using the potassium peroxy-diphosphate-thiourea redox system as the initiator. The rate of grafting was determined by varying the monomer, peroxydi-phosphate ion, temperature, and solvent. The graft yield increases with increasing peroxydiphosphate ion up to 80 × 10^?-⁴ mol/L, and with further increase of peroxydiphosphate ion the graft yield decreases. The graft yield increases with increasing monomer concentration. The percentage of grafting decreases with increasing thiourea concentration. The rate of grafting increases with an increase of temperature. The effect of acid and water-soluble solvent and certain salts on graft yield has been investigated and a suitable rate expression has been derived.     

Controlled grafting of MMA onto cellulose and cellulose acetate

Homogeneous graft copolymerization of methyl methacrylate onto cellulose and cellulose acetate was carried out in various solvents and solvent systems taking ceric ammonium nitrate, tin (II) 2-ethyl hexanoate [Sn(Oct)₂] and benzoyl peroxide as initiators. The effect of solvents, initiators, initiator and monomer concentration, on graft yield, grafting efficiency and total conversion of monomer to polymer were studied. Formation of Ce³⁺ ion during grafting in presence of CAN enhances the grafting efficiency. Methylene blue was used as a homopolymer inhibitor and controlled the molecular weight of the grafted polymer and its effect on grafting was also studied. In presence of MB, amount of PMMA homopolymer formation reduced and consequently grafting efficiency increased. The number average molecular weights and polydispersity indices of the grafted PMMA were found out by gel permeation chromatography. The products were characterized by FTIR and ¹H-NMR analyses and possible reaction mechanisms were deduced. Finally, thermal degradation of the grafted products was also studied by thermo-gravimetric and differential thermo-gravimetric analyses.     

Grafting Vinyl Monomers onto Silk Fibers: Graft Copolymerization of Vinyl Monomers onto Silk Using the Vanadyl Acetylacetonate Complex

Abstract

The graft copolymerization of methyl methacrylate (MMA) onto mulberry silk fibers was studied in aqueous solution using the acetylacetonate oxovanadium (IV) complex. The rate of grafting was investigated by varying the concentration of the monomer and the complex, the acidity of the medium, the solvent composition of the reaction medium, the surfactants, and the inhibitors. The graft yield increases with increasing concentration of the initiator up to 8.75 × 10^?5 mol/L, of the monomer up to 0.5634 mol/L, and thereafter it decreases. Among the various vinyl monomers studied, MMA was found to be most suitable for grafting. Grafting increases with increasing concentration of HCIO₄ and with increasing temperature. Inhibitors like picryl chloride and hydroquinone significantly decrease the extent of grafting. Alcoholic solvents at a solvents/water ration of 10:90 seem to constitute the most favorable medium for grafting. A suitable reaction scheme has been proposed, and the activation energy calculated from the Arrhenius plots.     

Preparation of Poly(ethylene terephthalate)‐g‐Methacrylamide Copolymers Initiated by Azobisizobutyronitrile: Characterization and Investigation of Some Properties

Poly(ethylene terephthalate)‐g‐methacrylamide (PET‐g‐MAAm) copolymer was prepared by graft copolymerization in organic solvent/water mixtures by using azobisizobutyronitrile (AIBN) as an initiator. The highest graft yield was obtained in 20/80 (v/v) acetonitrile/water mixture as 30.0%. The effect of polymerization parameters such as the ratio of solvent/water mixture, concentrations of initiator and monomer, temperature and time on the graft yield was studied. The moisture regain of the PET fiber increased with grafting from 0.42% to 3.01%. Thermogravimetric data showed that the thermal stability of PET fibers decreased with grafting and 85% of total weight of 29.7% grafted fiber was lost at 500°C. On the other hand, fiber density decreased with increasing graft yield. At SEM micrographs, the layers oriented in the direction of fiber length were observed on the surface of PET fiber as a result of grafting.     

Ascorbic Acid/Hydrogen Peroxide–Initiated Graft Copolymerization of MMA onto Bombyx mori Silk Fibroin

Graft copolymerization of methyl methacrylate (MMA) onto Bombyx mori silk fibroin was investigated using ascorbic acid and hydrogen peroxide as redox system. The effect of different reaction parameters such as reaction time, temperature, and initiator and monomer concentrations on graft yield were determined. The optimum grafting conditions were found to be temperature = 65°C, time = 120 min, monomer concentration = 2.82 × 10^?1 mol/L, ascorbic acid concentration = 2.83 × 10^?2 mol/L, and H₂O₂ concentration = 1.58 × 10^?1 mol/L. The structural properties of the fibers were studied with the help of FT-IR, scanning electron microscopy (SEM), X-ray diffraction, and TGA techniques.     

Synthesis of double hydrophilic graft copolymer containing poly(ethylene glycol) and poly(methacrylic acid) side chains via successive ATRP

A well‐defined double hydrophilic graft copolymer, with polyacrylate as backbone, hydrophilic poly(ethylene glycol) and poly(methacrylic acid) as side chains, was synthesized via successive atom transfer radical polymerization followed by the selective hydrolysis of poly(methoxymethyl methacrylate) side chains. The grafting‐through strategy was first used to prepare poly[poly(ethylene glycol) methyl ether acrylate] comb copolymer. The obtained comb copolymer was transformed into macroinitiator by reacting with lithium diisopropylamine and 2‐bromopropionyl chloride. Afterwards, grafting‐from route was employed for the synthesis of poly[poly(ethylene glycol) methyl ether acrylate]‐g‐poly(methoxymethyl methacrylate) amphiphilic graft copolymer. The molecular weight distribution of this amphiphilic graft copolymer was narrow. Poly(methoxymethyl methacrylate) side chains were connected to polyacrylate backbone through stable C? C bonds instead of ester connections. The final product, poly[poly(ethylene glycol) methyl ether acrylate]‐g‐poly(methacrylate acid), was obtained by selective hydrolysis of poly(methoxymethyl methacrylate) side chains under mild conditions without affecting the polyacrylate backbone. This double hydrophilic graft copolymer was found be stimuli‐responsive to pH and ionic strength. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4056–4069, 2008     

Characterization and Evaluation of Thermal,Morphological, and Physicochemical Properties of Chemically Modified Lignocellulosic Biomass

A novel redox system, ascorbic acid-hydrogen peroxide, was employed to initiate graft copolymerization of ethyl acrylate and methyl methacrylate binary monomer mixtures onto Abelmoschus esculentus fibers at a temperature of 45°C for 90 min in an aqueous medium. Factors affecting grafting such as feed molarity and comonomer composition were investigated. Contrary to the lower affinity of methyl methacrylate for grafting on Abelmoschus fibers, a synergistic effect of ethyl acrylate on methyl methacrylate was observed when graft copolymers were prepared using different feed compositions (f_MMA). The percentage of grafting increased from 40.2% to 89.74% at 0.4 mole fraction of f_MMA. The graft copolymers were characterized by FT-IR, TGA, and SEM techniques.     

Ferrocenyl-containing iron(ii) clathrochelate-benzoyl peroxide, a new initiating system for radical polymerization of methyl methacrylate

Radical polymerization of methyl methacrylate initiated by the benzoyl peroxide — macrobicyclic bis-ferrocenylboron-capped iron(ii) tris-1,2-cyclohexanedione dioximate system was studied. The ferrocenyl-containing macrobicyclic complex and benzoyl peroxide forms an efficient initiating system that allows one to perform the polymerization process at a high rate with substantially reduced amounts of the initiator and the metal complex component at 30–75 °C and to influence the molecular-weight characteristics of poly(methyl methacrylate) produced.     

Chemical initiation of graft copolymerization of methyl methacrylate onto styrene–butadiene block copolymer

When a solution containing both styrene–butadiene block copolymer (SBS) and methyl methacrylate is treated with an initiator both homopolymerization of the methyl methacrylate and graft copolymerization of the methyl methacrylate onto the SBS occur. The amount of graft copolymerization depends upon the time and temperature of the reaction, the concentrations of all species, and the identity of the solvent and initiator. The combination of benzoyl peroxide in chloroform gives the highest graft yield and the reaction occurs by removal of an allylic hydrogen from the SBS by the initiator radical and subsequent addition of monomer units to that site; there is a significant solvent effect. Both AIBN and BPO function by the removal of an allylic hydrogen atom from SBS; BPO is able to effect this reaction relatively easily while AIBN can remove the hydrogen atom only with great difficulty and to a limited extent. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 965–974, 1997