A novel method for vinyl grafting onto cotton fabric using ceric-cellulose thiocarbonate redox system

Treatment of cotton fabric with carbon disulphide in presence of NaOH resulted in cellulose thiocarbonate. The latter formed a complex when treated with ceric ammonium nitrate (CAN). After being thoroughly washed, the Ce^IV cellulose thiocarbonate was capable of initiating vinyl graft polymerization onto cotton fabric without homopolymer formation. The graft yield obtained with methyl methacrylate was found to increase by increasing CAN from zero to 50 mmol/l at temperatures from 60 to 80°C. Grafting was greatly favoured at pH 2; alkaline pH offset grafting. Incorporation of up to 7% of methanol, ethanol, or isopropanol in the aqueous polymerization medium enhanced grafting significantly with the certainty that the highest graft yield was obtained with isopropanol; using higher alcohol percentages decreased grafting. The rate of grafting showed an initial fast rate followed by a slower rate; 60 minutes reaction time proved appropriate for grafting irrespective of the condition used. In addition to methyl methacrylate the ability of Ce^IV-cellulose thiocarbonate to induce grafting of acrylonitrile and acrylamide was also examined. The rate of grafting followed the order methyl methacrylate > acrylonitrile > acrylamide.     

Polymer–montmorillonite nanocomposites: Chemical grafting of polyvinyl acetate onto Cloisite 20A

This paper is an account of the experiments on grafting polyvinyl acetate onto organophilic montmorillonite. Cloisite 20A was reacted with vinyltrichlorosilane to replace the edge hydroxyl groups of the clay with a vinyl moiety. Because the reaction liberates HCl, it was performed in the presence of sodium hydrogencarbonate to prevent the exchange of quaternary alkylammonium cations with H⁺ ions. Only the silanol groups on the edge of the clay react with vinyltrichlorosilane. After the reaction, the product maintained the same basal spacing as the precursor. The radical polymerization of the product with vinyl acetate as a vinyl monomer leads to chemical grafting of polyvinyl acetate onto montmorillonite surface. The homopolymer formed during polymerization was separated from the grafted organoclay by Soxhelt extraction. Chemical grafting of the polymer onto Cloisite 20A was confirmed by infrared spectroscopy. The prepared nanocomposite materials and the grafted nano‐particles were studied by XRD, SEM, and TEM. Exfoliated nanocomposite was obtained for 0.5% clay content. Nanocomposites with 1% and 3% clay contents showed significant intercalation and agglomeration occurred at higher clay loadings. The nanocomposites were studied by thermogravimertic analysis (TGA) and dynamic mechanical analysis (DMTA). Improved thermo‐mechanical properties were observed for nanocomposite with 0.5% clay content. POLYM. COMPOS., © 2011 Society of Plastics Engineers.     

Synthesis and characterization of poly(glycidyl methacrylate)/Na‐montmorillonite nanocomposites

Poly(glycidyl methacrylate)/Na–montmorillonite nanocomposites were synthesized by free‐radical polymerization of glycidyl methacrylate containing dispersed montmorillonite. By changing the concentration of glycidyl methacrylate several polymer–clay nanocomposites were prepared and the resulting nanocomposites were characterized by X‐ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The results indicated that the properties of the composite were significantly improved. The thermogravimetric analysis results revealed that the degradation temperatures of nanocomposites were higher than that of pure polymer and the thermal degradation rates decreased. Examination of these materials by scanning electron microscopy showed that the clay layers are dispersed homogenously in the polymer matrix and the formation of intercalation nanostructure. Furthermore, adsorptive, moisture regain, and water uptake properties of nanocomposites were also investigated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1532–1538, 2004     

Graft copolymerization of vinyl monomers onto modified cottons. VIII. Dimethylaniline–benzyl chloride-induced grafting of methyl methacrylate onto partially carboxymethylated cotton

The feasibility of dimethylaniline (DMA)–benzyl chloride (BC) mixture to initiate graft polymerization of methyl methacrylate (MMA) onto partially carboxymethylated cotton was examined. The graft yield depends on the nature of the solvent used along with water; ethanol proved to be the best at a water;ethanol ratio of 90:10. Considerable grafting occurred in the presence of acetic acid at a concentration of 200 mmol/l. Higher concentrations of this acid decrease grafting significantly. The graft yield obtained in the presence of formic acid was much lower than that obtained in the presence of acetic acid. Inclusion of hydrochloric or sulfuric acid in the graft polymerization system prevent grafting. A DMA–BC mixture at a concentration of 0.08:0.087 mole/l. constitutes the optimal concentration for grafting. This contrasts with 0.32:0.35 mole/l. for total conversion. The rate of grafting increases by raising the polymerization temperature; it follows the order 50°>60°>65°>70°>75°C. Furthermore, increasing the monomer concentration caused a significant enhancement in the graft yield and total conversion.     

Preparation of poly(glycidyl methacrylate) grafted sulfonamide based polystyrene resin with tertiary amine for the removal of dye from water

Poly(glycidyl methacrylate) was grafted onto crosslinked poly(styrene) beads through the 2-chloroethyl sulphonamide (CSA) groups present in the resin using ATRP polymerization method. A beaded polymer with a poly(glycidyl methacrylate) surface shell was prepared in three steps, starting from poly(styrene-DVB) (10% crosslinking) based beads with a particle size of 420–590 μm, according to the synthetic protocol; chlorosulfonation, sulfamidation with 2-chloroethylamine hydrochloride and grafting reaction of poly(glycidyl methacrylate).The polymeric resin was prepared with 147.8% of grafted glycidyl methacrylate and subsequent modified with diethyl amine to introduce tertiary amine groups. This resin has also been demonstrated to be an efficient dye sorbent, able to remove dye from water even at ppm levels. The dye sorption capacity under non-buffered conditions is around 0.90 g dye/g resin.     

Surface functionalization of Si3N4 nanoparticles by graft polymerization of glycidyl methacrylate and styrene

To improve dispersibility and interfacial interaction of nano‐Si₃N₄ particles in epoxy‐based composites, graft of glycidyl methacrylate (GMA) and styrene (St)/GMA onto the nanoparticles' surface was carried out in terms of emulsion polymerization method. The grafting polymers proved to be chemically attached to the nanoparticles via the double bonds introduced during the coupling agent pretreatment. The factors affecting the graft parameters, such as monomer concentration, initiator consumption, reaction time, etc., were investigated. It was shown that higher concentrations of monomer and initiator are favorable for the graft polymerization. When St/GMA was employed as the grafting monomer, the nanoparticles were found to play the role of polymerization loci. The grafted nanoparticles exhibit greatly improved dispersibility in cured epoxy. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 992–999, 2006     

GMA功能化聚合物及其在共混改性中的应用

通过熔融接枝、乳液聚合、溶液聚合、悬浮聚合等方法可以制得甲基丙烯酸缩水甘油脂功能化的共聚物，这些接枝、嵌段、核壳结构共聚物可以用作增韧剂和增容剂，通过“原位”反应增韧聚合物和增容聚合物共混物，提高聚合物的韧性和改善改善共混物的相容性。     

Nanocomposite materials based on isosorbide methacrylate/Cloisite 20A

This paper reports experiments on grafting of a new polymerizable monomer onto organophilic montmorillonite. The monomer, 5‐methacryloyloxy‐1,4:36‐D ‐anhydrosorbitol (MAS), was synthesized by reacting methacryloyl chloride and isosorbide in the presence of Et₃N as base. Then, Cloisite 20A was reacted with vinyltrichlorosilane to replace the edge hydroxyl groups of the clay with a vinyl moiety. Because the reaction liberates HCl, it was performed in the presence of sodium hydrogen carbonate to prevent the exchange of quaternary alkylammonium cations with H⁺ ions. Only the silanol groups on the edge of the clay react with vinyltrichlorosilane. After the reaction, the product maintained the same basal spacing as the precursor. The radical polymerization of the product with MAS as a vinyl monomer led to chemical grafting of the polymer onto the montmorillonite surface. The homopolymer formed during polymerization was separated from the grafted organoclay by Soxhlet extraction. Chemical grafting of the polymer onto Cloisite 20A was confirmed using infrared spectroscopy. The prepared nanocomposite materials and the grafted nanoparticles were studied using X‐ray diffraction and scanning and transmission electron microscopy. Exfoliated nanocomposite was obtained for 1 wt% clay loadings. The nanocomposites were studied using thermogravimetric and dynamic mechanical analyses. Improved thermal properties were observed for nanocomposites with 1–5 wt% clay content. © 2012 Society of Chemical Industry     

RAFT‐mediated graft polymerization of glycidyl methacrylate in emulsion from polyethylene/polypropylene initiated with γ‐radiation

The successful reversible addition‐fragmentation (RAFT)‐mediated graft polymerization of glycidyl methacrylate (GMA) in emulsion phase from polyethylene/polypropylene nonwoven fabric using 4‐cyano‐4‐[(phenylcarbonothioyl)thio]pentanoic acid under γ‐irradiation at ambient condition is reported. While conventional graft polymerization in emulsion phase yielded grafted materials with low of grafting (Dg) values [<7.5% at 10% (wt/wt) GMA], addition of RAFT agent to the graft polymerization system allowed the synthesis of polyethylene/polypropylene‐g‐poly(GMA) with more tunable Dg (8% ≤ Dg ≤ 94%) by controlling the grafting parameters. Relatively good control (PDI ～1.2 for selected grafting conditions) during polymerization was attained at 100:1 monomer‐to‐RAFT agent molar ratio. The number average molecular weight of free poly(glycidyl methacrylate) (PGMA) increased as a function of monomer conversion. NMR analyses of the free PGMA homopolymers indicate the presence of dithiobenzoate group from 4‐cyano‐4‐((phenylcarbonothioyl)thio) pentanoic acid on the polymer chain. The reactive pendant oxirane group of the grafted GMA can be modified for various environmental and industrial applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45270.     

Preirradiation‐induced emulsion graft polymerization of glycidyl methacrylate onto poly(vinylidene fluoride) powder

An epoxy‐group‐containing monomer, glycidyl methacrylate (GMA), was grafted onto poly(vinylidene fluoride) powder via preirradiation‐induced emulsion graft polymerization. The existence of graft chains was proven by chemical structure characterization with Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy analysis. The degree of grafting was calculated by means of fluorine content analysis. A kinetic study indicated that, with the emulsion graft polymerization system, the GMA conversion rate was high, exceeding 80%. The variation in the molecular weight of the grafted polymer was measured by gel permeation chromatography, and its crystallinity was investigated with differential scanning calorimetry. The epoxy groups in graft chains were found to be suitable for further chemical modification. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Pentavalent vanadium ion–cellulose thiocarbonate redox-system induced grafting of methyl methacrylate and other vinyl monomers onto cotton fabric

Cellulose thiocarbonate was prepared by reacting cotton cellulose fabric with carbon disulphide in the presence of sodium hydroxide. The treated fabric formed, with pentavalent vanadium ion, an effective redox system capable of initiating grafting of methyl methacrylate (MMA) and other monomers no+o the cotton fabric. The dependence of grafting on vanadium concentration, pH of the polymerization medium, temperature and duration of grafting, nature and concentration of monomer, and solvent/water ratio was studied. The results indicated that increasing the pentavalent vanadium (V^v) concentration up to 60 mmol/L was accompanied by enhancement in the rate of grafting; the latter was not affected by further increase in V^v concentration. Maximum grafting yield was achieved at pH 2; grafting fell greatly at higher pH. The rate of grafting followed the order: 70° > 60° > 50°C. The graft yield increased significantly by increasing the MMA concentration from 0.5 to 5%. Of the solvents studied, n-propanol and isopropanol enhanced the grafting rate provided that a solvent/water ratio of 5 : 95 was used; a higher solvent ratio decreased the magnitude of grafting. Other solvents, namely, methanol, ethanol, n-butanol, and acetone, in any proportion, decreased the rate of grafting. With the monomer used, the graft yield followed the order: methyl methacrylate > methyl acrylate > methacrylic acid > ethyl methacrylate > acrylic acid. Also reported was a tentative mechanism for vinyl-graft copolymerization onto cotton fabric using cellulose thiocarbonate-V^v. © 1993 John Wiley & Sons, Inc.     

Interaction between a tertiary amine methacrylate based polyelectrolyte and a sodium montmorillonite dispersion and its rheological and colloidal properties

The rheological and colloidal properties of sodium montmorillonite dispersions were investigated in the presence of a special type of cationic polymer [modified poly(ethylene glycol)]. 2‐(Dimethylamino) ethyl methacrylate was polymerized with monomethoxy‐capped oligo(ethylene glycol) via aqueous atom transfer radical polymerization. The tertiary amine residues of the resulting polymer were then quaternized with methyl iodide to obtain a cationic polyelectrolyte. The rheology and ζ‐potential experiments showed that the cationic polymer adsorbed onto the sodium montmorillonite surface strongly. The rheological parameters (plastic viscosity and yield value) were obtained with a rotational low‐shear rheometer. The results indicated a gradual increase in gelation with the addition of the cationic polymer, which reached a maximum at a cationic polymer concentration of 0.4–0.8 g/L. This gel‐like dispersion showed pronounced thixotropy. A further increase in the polymer concentration resulted in a reduction in this gelation. The adsorption of the cationic polymer onto the clay surface reduced the ζ potential to small values, but no isoelectric point was observed. The basal‐spacing measurements showed that the cationic polymer strongly adsorbed onto the sodium montmorillonite instead of entering the montmorillonite layers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 300–306, 2005     

Preparation and characterization of poly(styrene‐b‐butadiene‐b‐styrene)/montmorillonite nanocomposites

With some polymerizable small molecules grafting onto the montmorillonite surface, we disposed the clay through in‐situ emulsion polymerization, and the structure of the modified montmorillonites were studied through Fourier transform infrared spectroscopy (FTIR) and X‐ray diffraction (XRD). The nanocomposites of poly(styrene‐b‐butadiene‐b‐styrene) (SBS)/montmorillonite with excellent mechanical properties were prepared by mixing SBS and the modified montmorillonite on the double rollers at 150°C. The exfoliation of the layered silicates was confirmed by XRD analysis and transmission electron microscopy (TEM) observation. After mechanical kneading of the molten nanocomposites, the exfoliation structure of the silicates is still stable for polystyrene macromolecules grafting onto the silicates. Upon the addition of the modified montmorillonite, the tensile strength, elongation at break and tear strength of the nanocomposites increased from 22.6 MPa to 31.1 MPa, from 608% to 948%, from 45.32 N/mm to 55.27 N/mm, respectively. The low‐temperature point of glass‐transition temperature (T_g) of the products was about −77°C, almost constant, but the high‐temperature point increased from 97°C to 106°C. In addition, the nanocomposites of SBS and modified montmorillonites showed good resistance to thermal oxidation and aging. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Investigation of styrene‐assisted free‐radical grafting of glycidyl methacrylate onto high‐density polyethylene using response surface method

In this study, the free‐radical grafting of glycidyl methacrylate (GMA) onto high‐density polyethylene (HDPE) in the presence of styrene, as a comonomer, is investigated using a Brabender internal mixer. To optimize grafting level of GMA onto HDPE, response surface method (RSM) was exploited. Using RSM method of experimental design, it was possible to investigate the individual effects of various variables including dicumyl peroxide (DCP) concentration, GMA content, as well as reaction time, and their interactions on grafting efficiency. The fitted quadratic model obtained from statistical analysis is expressed by an approximating function to investigate the final torque as a responding variable over the experimental range of the independent variables. The grafting yield of GMA onto HDPE for the prepared samples was determined using titration/back‐titration technique and Fourier transform infrared spectroscopy (FTIR). According to the torque–time diagrams, increasing the DCP content led to an increase in GMA grafting yield. Also, it was found that the reaction time imparts minor effect on the final processing torque, and there exists an interaction between DCP and GMA content. The results of melt flow index (MFI) test showed that increasing the reaction time at constant DCP and GMA content enhances the MFI values of the samples, due to the more probability of chain scission phenomenon. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of clay type on morphology and thermal stability of PMMA-clay nanocomposites prepared by heterocoagulation method

Poly(methyl methacrylate) (PMMA)-clay nanocomposites were prepared by a heterocoagulation method. A cationic PMMA emulsion was prepared by emulsion polymerization using a cationic initiator in the presence of free surfactant, cetyl trimethylammonium bromide (CTABr), followed by mixing with an aqueous clay slurry. Clays used in present research included montmorillonite (MMT), synthetic hectorites and fluorohectorites (with two different sizes). WAXD results and TEM images indicate that the morphologies of these nanocomposites depend on clay colloid stability as well as clay loadings. WAXD and TEM results also indicate the good morphology preservation of the nanocomposites during solution and melt processing. Thermal stability of these nanocomposites was studied by TG-DTG analyses; the mechanism of thermal stability improvement is discussed based on experimental results.     

Copolymerization of styrene with N‐phenyl maleimide in the presence of montmorillonite

The copolymerization of styrene with N‐phenyl maleimide in the presence of organomodified montmorillonite or Na⁺ montmorillonite was investigated. The conversion of the monomer was determined dilatometrically or gravimetrically. The copolymerization rate was accelerated and the polymerization activation energy in bulk and solution copolymerization decreased in the presence of montmorillonite. The tendency of alter‐copolymerization was enhanced for bulk and solution polymerization, but not affected for emulsion polymerization, by the addition of organomodified montmorillonite or Na⁺ montmorillonite. X‐ray diffraction studies showed that the methods of emulsion and bulk intercalative polymerization were more appropriate techniques for preparing nanocomposites with good dispersibility of clay. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1932–1937, 2005     

Effect of aqueous comonomer solubility on the surfactant-free emulsion copolymerization of methyl methacrylate

Surfactant-free emulsion copolymerization was used to prepare methyl methacrylate-hydroxyethyl methacrylate (MMA-HEA) and methyl methacrylate-hydroxypropyl methacrylate (MMA-HPMA) latex particles. Also, glycidyl methacrylate (GMA) was grafted onto the surface of the preformed MMA-HPMA latex particles by seeded surfactant-free emulsion copolymerization. The copolymerization reactions were conducted at 75 °C using a water-soluble initiator, potassium persulfate (KPS). The morphologies of copolymer latex particles were observed using Scanning electron microscopy (SEM). The influence of different reactions parameters (the MMA saturation concentration (Sr), the KPS concentration and the aqueous solubility of the comonomers (HEA or HPMA)) on the particles average diameter and particles size dispersity was investigated. The experimental results showed that the increase of initiator concentration induces in all investigated cases the increase of particles average diameter, while the presence of HEA or HPMA as comonomers in the copolymerization reaction of MMA (1,000% Sr) lead to a decrease of particles average diameter. At small KPS concentration the latex is monodisperse, the increase of the initiator concentration leading to the formation of polydisperse latex. In the case of grafting reaction of GMA onto the monodisperse preformed MMA-HEA latex particles, although the average diameter of the final particles doubles the latex remains quasi-monodisperse.     

The grafting of methyl methacrylate onto cotton by tri-n-butylborane

Methyl Methacrylate was grafted onto cotton by tri-n-butylborane in the presence of water. No graft was obtained in organic solvents, i.e., in the absence of water. The percentage of grafting increased with increases in reaction time, cotton amount, and initiator concentration. Pretreatment of cotton with pyridine also enhanced the percentage of grafting. Glycidyl methacrylate and ethyl acrylate were grafted onto cotton by tri-n-butylborane, while no grafting occurred when vinyl acetate and 4-vinyl pyridine were used. Usual radical initiators, such as azobisisobutyronitrile and benzoyl peroxide/dimethyl-p-toluidine, were not effective under the same conditions.     

Graft copolymerization of vinyl monomers on modified cottons. VI. Vinyl graft copolymerization initiated by manganese (IV)

The ability of potassium permanganate in the presence of different acids to induce grafting of methyl methacrylate and acrylonitrile onto sodium hydroxide-treated cotton, partially carboxymethylated cotton, partially cyanoethylated cotton, and partially acetylated cotton was investigated. The copolymerization reaction was carried out under a variety of conditions. The graft yields are greatly enhanced by increasing concentration of monomer, reaction time, and temperature. The opposite holds true for initiator at higher concentrations. The effectiveness of the acids was: nitric acid > sulfuric acid > perchloric acid > hydrochloric acid. The change in the physical and/or chemical structure of cellulose by its modification via etherification reaction or esterification reaction had a significant effect on the susceptibility of cellulose toward grafting. While partial carboxymethylation or partial cyanoethylation of cellulose prior to grafting increased the graft yield, partial acetylation caused a decrease.     

Thermal behavior and the determination of the polymer-polymer interaction parameter of polycarbonate and a thermotropic liquid crystalline polymer blends

Summary The surface modification of low-density polyethylene(PE) by liquid phase photograft polymerization with acrylic acid(AA), acrylamide(AM) and glycidyl methacrylate(GMA) was described. The grafting of AA and AM was proved and characterized by electron spectroscopy for chemical analysis(ESCA). It was found that fully hydrophilic surface can be obtained in very short irradiation time. With ESCA and attenuated total reflection infrared spectroscopy(ATR-IR), it can be confirmed that bifunctional monomer GMA was grafted onto the PE film surface. Through further reaction with GMA grafted film, heparin and protamine were immobilized onto the grafted film surface.