Graft copolymerization onto jute fiber: Ceric ion-initiated graft copolymerization of methyl methacrylate

Graft copolymerization of methyl methacrylate (MMA) was carried out on both defatted and bleached jute fibers using ceric ammonium sulfate (CAS) as the initiator. In order to obtain the optimum condition for grafting, the effects of initiator concentrations, temperature, time of reaction, lignin content of jute, and the monomer concentration were studied. The maximum percent grafting and grafting efficiency were found to be 132% and 0.71, respectively. Kinetic studies showed that at 0.03M CAS, the reaction appeared to obey the second-order process. The activation energies were found to be 7.74 and 5.12 kcal/mole for defatted (lignin content, 15.7%) and chlorite-bleached jute (lignin content 10%), respectively. The activation energies of graft copolymerization of MMA onto jute fiber are compared with the energies of activation of graft copolymerization of acrylonitrile (AN).     

Photo-induced Synthesis and Characterization of Poly（methyl methacrylate） Grafted Sodium Salt of Partially Carboxymethylated Guar Gum

Photo-induced graft copolymerization of methyl methacrylate（MMA） onto sodium salt of partially carboxymethylated guar gum（Na-PCMGG, DS = 0.291） was carried out in an aqueous medium using ceric ammonium nitrate（CAN） as photoinitiator to synthesize a novel graft copolymer, Na-PCMGG-g-PMMA, which may find its potential application as a metal adsorbent. The influences of synthesis variables such as concentrations of photoinitiator（CAN）, nitric acid and monomer（MMA） as well as reaction time, temperature and amount of substrate on the grafting yields were studied and the reaction conditions for optimum photo-grafting were evaluated. At optimum concentration, the maximum values of the grafting yields achieved were G = 271.61% and GE = 63.89%. The experimental results were found to be in very good agreement with the proposed kinetic scheme. The photo-graft copolymerization of MMA onto Na-PCMGG（ DS = 0.291） was also carried out in the presence and absence of ultraviolet radiation for studying the efficiency of the photoinitiator. The influence of carboxymethyl groups introduced onto the guar gum molecules with regard to its behavior towards ultra-violet radiation induced grafting with MMA was also investigated. Photo-grafting process was confirmed and the products were characterized with the help of the spectroscopic（1H-NMR and FTIR） and SEM techniques.     

Effect of dimethylaminoethyl methacrylate on the graft copolymerization of ethyl acrylate onto hydroxypropyl methylcellulose in aqueous medium

Graft copolymerization of an ethyl acrylate (EA) and dimethylaminoethyl methacrylate (DMAEMA) monomer mixture onto water-soluble hydroxypropyl methylcellulose was investigated with potassium persulfate (KPS) as the initiator in an aqueous medium. The effects of introducing DMAEMA onto the graft copolymerization and the properties of the resulting latex that was produced were studied systematically. The optimum conditions for the graft copolymerization in terms of percentage of grafting and grafting efficiency were determined. The graft copolymer was characterized by Fourier transform infrared spectra, elemental analyses, nuclear magnetic resonance, transmission electron microscopy, and dynamic light scattering methods. The results suggest that the introduction of the DMAEMA monomer clearly accelerates the initial rate of the graft copolymerization, whereas the grafting parameters decrease significantly with increasing amounts of DMAEMA. These results can be attributed to the relatively large size of the DMAEMA molecule, its redox reaction with KPS, its hydrophilicity in water, and its chain transfer effect. The equilibrium humidity adsorption behavior and acid solubility of graft the copolymer films were also studied.     

Graft Copolymerization of Methyl Methacrylate onto Chitosan Initiated by Potassium Ditelluratocuprate(III)

A novel redox system, potassium ditelluratocuprate(III) (DTC)–chitosan, was employed to initiate the graft copolymerization of methyl methacrylate (MMA) onto chitosan in alkali medium. The effects of reaction variables, such as the initiator concentration, ratio of monomer to chitosan, the pH value, as well as reaction temperature and time were investigated, and the grafting conditions were optimized. Graft copolymers with both high grafting efficiency (>90%) and percentage of grafting were obtained, and the rate of polymerization is higher, which indicated that the DTC–chitosan redox system is an efficient initiator for this graft copolymerization. The structures and the thermal property of chitosan and chitosan–g–PMMA were characterized by infrared spectroscopy (IR), X‐ray diffraction and thermogravimetric analysis (TGA). A mechanism is proposed to explain the generation of radicals and the initiation. The graft copolymer was used as the compatibilizer in blends of terpolyamide and chitosan. The scanning electron microscope (SEM) photographs indicated that the graft copolymer improved the compatibility of the blend.     

Effect of Toluene on the Kinetics of Ce(IV)-Ion-Initiated Grafting of Methyl Methacrylate onto Chemically Modified Jute Fibers

A study of the graft copolymerization of methyl methacrylate onto jute fiber using Ce(IV) and toluene has been carried out. The effects of concentration of monomer, Ce(IV), and toluene on graft yield have been studied. The effects of time, temperature, acid, amount of jute fiber, and some inorganic salts and organic solvents on graft yield have also been investigated. The investigation includes characterization of the grafted fiber by infrared and thermo-gravimetric studies. Grafting improves the thermal stability of jute fibers. More than 200% graft yield was achieved in the present investigation.     

Graft Copolymerization of Methyl Methacrylate on Potato Starch Using Potassium Trioxalatomanganate,K3[Mn(C2O4)3], as Initiator

Graft copolymerization of methyl methacrylate on potato starch was carried out in methanol-water medium at 35°C in the dark using potassium trioxalatomanganate, K₃[Mn(C₂O₄)₃], as initiator. The effect of different methanol-water ratios (v/v), the temperature of polymerization, the initiator concentration, the monomer concentration, the starch content, and the time of polymerization were studied. Percent total conversion, % grafting, and grafting efficiency (%) under different conditions were evaluated and compared. High grafting efficiency (～80%), high % total conversion (～85%), and high % grafting (-95%) were readily obtained. The reaction mechanism for graft copolymer formation is discussed.     

采用ATRP合成天然橡胶接枝共聚物——Ⅲ.NR-g-PMMA的制备

N-溴代丁二酰亚胺与天然橡胶(NR)反应合成了大分子引发剂——溴代天然橡胶[NR-Br(1)].通过原子转移自由基聚合(ATRP),以CuBr/PMDTA为催化体系,1引发甲基丙烯酸甲酯(MMA)接枝共聚制得新型天然橡胶-g-聚甲基丙烯酸甲酯[NR-g-PMMA(2)],其结构经1H NMR和IR表征.初步聚合反应动力学研究结果表明,NBS与NR在高温下反应容易伴随双键加成和环化反应,于室温反应所得1具有较高的引发活性;接枝聚合符合一级动力学反应,即2的分子量随MMA单体转化率的提高而增加.     

Grafting acrylonitrile and methyl methacrylate on holocellulosic materials

Graft copolymers of acrylonitrile and methyl methacrylate on bleached holocellulose and thiolated holocellulose were obtained by the use of ceric ions in aqueous medium at 29°C. The level and efficiency of grafting on the bleached holocellulose were significantly higher than on the thiolated holocellulse, but the molecular weights and number of grafted copolymer chains on both the unmodified and thiolated holocellulose were similar. The graft level and molecular weight of acrylonitrile graft copolymer were significantly lower than those for methyl methacrylate at comparable ceric ion and monomer concentrations. These results indicate the significance of the influence of the polarity of monomer on the extent of graft copolymer formation and lead to the suggestion that graft copolymerization may not result entirely from radicals generated on the cellulose substrate.     

Monomer reactivity ratios in graft copolymerization

This paper discusses monomer reactivity ratios in various radiation- and redox-initiated graft copolymerizations. The polymers studied were polyethylene, cellulose acetate, poly(vinyl chloride), polytetrafluoroethylene, poly(vinyl alcohol), and poly(methyl methacrylate); the comonomer mixtures were styrene–acrylonitrile, methyl acrylate–styrene, acrylonitrile–methyl acrylate, and vinyl acetate–acrylonitrile. The polymer–comonomer mixture systems were so chosen as to permit study of both homogeneous and heterogeneous systems. The homogeneous systems included systems of low and high viscosity. The heterogeneous systems included both polymers swollen by the comonomer mixture and polymers not swollen by the comonomer mixture. None of the homogeneous grafting systems studied showed deviations from the normal copolymerization behavior under a variety of experimental conditions. Monomer reactivity ratios in graft copolymerization were the same as the values in nongraft copolymerization. The heterogeneous systems in which the polymer was swollen by the comonomer mixture yielded grafted copolymer compositions which were the same as those in nongraft copolymerization. The heterogeneous grafting system polytetrafluoroethylene/styrene–acrylonitrile showed deviations from normal copolymerization behavior at low degrees of grafting when the reaction was only on the polymer surface. The behavior became normal at higher degrees of grafting when the system approaches that in which the polymer is swollen by the comonomers. In all reaction systems, it was found that the use of radiation to initiate the reaction does not in any way affect the copolymerization behavior of the two monomers in a comonomer pair.     

原生态聚丙烯等离子体处理接枝甲基丙烯酸甲酯

将等离子体接枝技术，用于原生态聚丙烯接枝甲基丙烯酸甲酯共聚物的合成。ＦＴ－ＩＲ证明所得产物为接枝共聚物，研究了不同等离子体处理功率、时间，不同接枝聚合反应时间、温度对接枝的影响，以及稀释剂、聚丙烯粒度对接枝的影响。结果表明，接枝过程中有自动加速现象，稀释剂亦使接枝有加速效应。接枝过程为扩散控制过程。     

Grafting of polymers onto a carbon‐fiber surface by ligand‐exchange reaction of poly(vinyl ferrocene‐co‐vinyl monomer) with polycondensed aromatic rings of the surface

To improve the surface of carbon fiber, the grafting reaction of copolymer containing vinyl ferrocene (VFE) onto a carbon‐fiber surface by a ligand‐exchange reaction between ferrocene moieties of the copolymer and polycondensed aromatic rings of carbon fiber was investigated. The copolymer containing VFE was prepared by the radical copolymerization of VFE with vinyl monomers, such as methyl methacrylate (MMA) and styrene, using 2,2′‐azobisisobutyronitrile as an initiator. By heating the carbon fiber with poly(VFE‐co‐MMA) (number‐average molecular weight: 2.1 × 10⁴) in the presence of aluminum chloride and aluminum powder, the copolymer was grafted onto the surface. The percentage of grafting reached 46.1%. On the contrary, in the absence of aluminum chloride, no grafting of the copolymer was observed. Therefore, it is considered that the copolymer was grafted onto the carbon‐fiber surface by a ligand‐exchange reaction between ferrocene moieties of the copolymer and polycondensed aromatic rings of carbon fiber. The molar number of grafted polymer chain on the carbon‐fiber surface decreased with increasing molecular weight of poly(VFE‐co‐MMA) because the steric hindrance of grafted copolymer on the carbon‐fiber surface increases with increasing molecular weight of poly(VFE‐co‐MMA). © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1868–1875, 2002     

Synthesis and Characterization of Bagasse Poly(methyl methacrylate) Graft Copolymer

Summary: Graft copolymerization of methyl methacrylate (MMA) was carried out on bagasse fibers in an aqueous medium using ceric ammonium nitrate (CAN) as initiator under a neutral atmosphere. In order to obtain the optimum condition for graft copolymerization, the effects of initiator concentration, temperature, time of reaction, and monomer concentration were studied. The maximum grafting percent was found to be 122%. The bagasse grafted poly(methyl methacrylate) was characterized by FTIR and its thermal behavior was characterized by TGA.     

Graft copolymerization of methyl methacrylate onto lignosulfonate by H2O2–Fe(II) redox system. I. Preparation and characterization of the graft copolymer

Graft copolymerization of methyl methacrylate onto lignosulfonate in aqueous medium was investigated. It was found that the H₂O₂–Fe(II) redox system is very effective for the grafting (E_a = 4.4 kcal/mole). The H₂O₂/Fe²⁺ ratio was the most important factor in the graft copolymerization and characteristics of the resultant graft copolymers. In most cases, polymerization for 100 min at 30°C was enough to obtain 80% conversion and 50–60% grafting efficiency. The resultant polymer mixture was subjected to extraction alternately with acetone and water, and the graft copolymer was isolated free from homopolymer and unreacted lignosulfonate. With increasing H₂O₂/Fe²⁺ ratio, the grafting ratio showed a maximum at 4, whereas the yield of graft copolymer and number of poly(methyl methacrylate) branches for every building unit of lignosulfonate increased up to a ratio of 4, both values, however, remaining constant above 4. The graft copolymer obtained for the case H₂O₂/Fe²⁺ = 4 consisted of one part of lignosulfonate and five parts of poly(methyl methacrylate). The number of branches in the graft copolymer was 6 × 10^?3/OCH³ or one every 167 guaiacyl nuclei.     

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.     

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.     

Grafting onto wool. XXV. Effect of acids on γ-radiation-induced graft copolymerization of methyl methacrylate onto wool fiber

Graft copolymerization of methyl methacrylate (MMA) onto Himachali wool fiber has been investigated in aqueous medium by using γ irradiation from a 2100 Ci⁶⁰CO source as means of initiation. Graft copolymerization was carried out by the mutual method in nitrogen atmosphere as well as in air. Effect of mineral acids and acetic acid on percentage of grafting was studied. Percentage of grafting was determined as functions of total dose, concentration of monomer, and concentration of acids. Maximum percentage of grafting in the presence of acids occurred in nitrogen atmosphere at a total dose of 1.05 MR. All the acids were found to influence grafting and the reactivity of different acids towards graft copolymerization was found to follow the order: H₂SO₄ > HCl > HNO₃ > HC1O₄ > HOAc. An attempt has been made to explain the reactivity order of different acids in the light of the mechanism proposed for γ-irradiation-induced graft copolymerization of vinyl monomer onto wool fiber.     

Grafting Vinyl Monomers onto Wool Fibers. X. Graft Copolymerization of Methyl Methacrylate onto Wool Using Acetylacetonato Complex of Manganese(lII)

The graft copolymerization of methyl methacrylate onto wool fibers was investigated in aqueous solution using the acetylacetonato complex of manganese(III). The rate of grafting was determined by varying the monomer, the complex, the temperature, the acidity of the medium, the nature of the wool, and the reaction medium. The graft yield increases with increasing monomer and complex concentrations. The graft yield also increases with increasing temperature. The grafting is considerably influenced by chemical modification of wool prior to grafting. A suitable mechanism has been proposed and a rate equation has been derived.     

Graft copolymerization onto rubber. V. Graft copolymerization of methyl methacrylate onto rubber using potassium peroxydiphosphate as initiator

The graft copolymerization of methyl methacrylate onto natural rubber (NR) is investigated using potassium peroxydiphosphate as the initiator. The rate of grafting is determined by varying monomer concentration, peroxydiphosphate concentration, and temperature. The graft yield increased with an increase in monomer concentration up to 1.4082M/L and thereafter the graft yield decreases. The graft yield increases significantly with an increase of peroxydiphosphate concentration up to 150 X 10^-1M/L and thereafter the graft yield decreases. The grafting reaction is temperature dependent. A suitable kinetic scheme is proposed and the rate equation is evaluated.     

Degradation behaviour of poly (methyl methacrylate-g-3-hydroxybutyrate) polymer films

Poly(methyl methacrylate-g-3-hydroxybutyrate) films were prepared from new graft polymers synthesised by an anionic grafting reaction of 3-butyrolactone (3-BL) on poly(methyl methacrylate) (PMMA). The resulting graft polymers form a transparent film of a one phase system, as revealed by DSC measurements. A plasticisation effect was observed for film samples containing the PBL grafted chains. This effect increased with increasing amount of PBL in the graft copolymer. The mechanical properties of the films were investigated, and thermal, hydrolytic and enzymatic degradation behaviours were evaluated. Disintegration of the films was observed during their hydrolytic degradation in phosphate buffer.     

Self‐emulsification and surface modification effect of fluorinated amphiphilic acrylate graft copolymers

We report on self‐emulsification and surface modification effect of novel fluorinated amphiphilic graft copolymers prepared with perfluoroalkyl acrylate and 2‐dimethylaminoethyl methacrylate using simple macromonomer technique and radical copolymerization. The interfacial properties of amphiphilic graft copolymers were characterized with light scattering, contact angle measurement, and X‐ray photoelectron spectroscopy. The preparation of fluorinated amphiphilic graft copolymer was verified using nuclear magnetic resonance and Fourier transform infrared spectroscopy. It was observed that the fluorinated amphiphilic graft copolymer has both strong hydrophobic and hydrophilic properties and shows self‐emulsification ability without addition of external surfactants. The graft copolymer shows very low surface energy even though the copolymer has low content of hydrophobic segment and better performance than random copolymer for low‐energy surface modification. The addition of small amount of the graft copolymer (0.1 wt %) into the base poly(methyl methacrylate) was sufficient to lower the surface energy less than that of poly(tetrafluoroethylene). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010