Graft polymerization of vinyl acetate onto silica

A method is reported for the surface grafting of polyvinyl acetate (PVAc) onto modified, nonporous silica. The silica surface was modified by silylation with vinyl(triethoxy) silane followed by graft polymerization of vinyl acetate. The graft yield was measured by thermogravimetric analysis and the monomer conversion was monitored by UV spectral analysis. The rate of the graft polymerization and the graft yield were proportional to the initial monomer concentration. Vinyl acetate conversion followed first-order kinetics and displayed a trend of increasing initial rate with increasing monomer concentration.     

Investigation of radiation grafting of vinyl acetate onto (tetrafluoroethylene–perfluorovinyl ether) copolymer films

A study has been made of radiation-induced grafting of vinyl acetate (VAc) on to (tetrafluoroethylene–perfluorovinyl ether) copolymer (PFA). Effects of grafting conditions such as inhibitor and monomer concentrations and irradiation dose on the grafting yield were investigated. In this grafting system, ammonium ferrous sulphate (Mohr′s salt) was added to the monomer-solvent mixture to minimize the homopolymerization of VAc and the most suitable concentration was found to be 2.0 wt%. It was found that the dependence of the initial grafting rate on monomer concentration is of the order 1.5. The degree of grafting tends to level off at high irradiation doses due to the recombination of formed free radicals without initiating graft polymerization. Some properties of the prepared graft copolymer such as swelling behaviour, electrical conductivity, thermal and mechanical properties were also investigated. The electrical conductivity was improved by hydrolysis of poly(vinyl acetate) in the grafted chains to their respective vinyl alcohols. The tensile properties were improved by grafting; however, the elongation percent decreased. The DTA data showed thermal stability of such graft copolymers for temperatures up to 300°C, but stability decreased at higher temperatures.     

Preparation of high PMMA grafted particle SiO2 using surface initiated free radical polymerization

In this work, a convenient surface-initiated free radical graft-polymerization method, by which polymethacrylic acid (PMAA) with a high grafting density was grafted on silica gel particles, was put forward, and it was feasible and effective. The coupling agent γ-aminopropyltrimethoxysilane (AMPS) was first bound onto the surfaces of silica gel particles, obtaining the modified particles AMPS-SiO₂. So a redox initiation system was constituted with the amino groups on the surfaces of AMPS-SiO₂ particles and ammonium persulphate in the solution. A great deal of primary free radicals on the surfaces of AMPS-SiO₂ particles is produced via the redox initiating reaction, so that the surface-initiated free radical graft- polymerization of methacrylic acid (MAA) on the silica gel particles was realized, giving the grafted particles PMAA/SiO₂ with a high grafting degree (about 30 g/100 g) of PMAA. The effects of the main factors on the surface initiated graft polymerization were examined and the corresponding mechanism was investigated in depth. The experimental results show that for this surface-initiated free radical graft-polymerization of MAA, the suitable temperature is 40 °C. If the temperature is over 40 °C, the graft polymerization will be affected negatively, and the grafting degree of PMAA will decline because of the intense heat decomposition of ammonium persulphate. During the graft polymerization, the grafted polymer layer that has formed is a hindrance to the subsequent graft polymerization. The used amount of initiator and the monomer concentration affect the graft polymerization greatly. The appropriate reaction conditions are as follows: reaction time of 10 h, initiator persulphate amount of 1.1% (it implies the mass percent of the monomer), and monomer MAA concentration of about 5% (it drives at the mass percent of the solution).     

Chemical Functionalization of Graphene Oxide by Poly(styrene sulfonate) Using Atom Transfer Radical and Free Radical Polymerization: A Comparative Study

Poly(sodium styrenesulfonate)-functionalized graphene was prepared from graphene oxide, using atom transfer radical polymerization and free radical polymerization. In atom transfer radical polymerization route, the amine-functionalized GO was synthesized through hydroxyl group reaction of GO with 3-amino propyltriethoxysilane. Atom transfer radical polymerization initiator was grafted onto modified GO (GO-NH₂) by reaction of 2-bromo-2-methylpropionyl bromide with amine groups, then styrene sulfonate monomers were polymerized on the surface of GO sheets by in situ atom transfer radical polymerization. In free radical polymerization route, the poly(sodium 4-styrenesulfonate) chains were grafted on GO sheets in presence of Azobis-Isobutyronitrile as an initiator and styrene sulfonate monomer in water medium. The resulting modified GO was characterized using range of techniques. Thermal gravimetric analysis, scanning electron microscopy, transmission electron microscopy, and atomic force microscopy results indicated the successful graft of polymer chains on GO sheets. Thermogravimetric analysis showed that the amount of grafted polymer was 22.5 and 31?wt% in the free radical polymerization and atom transfer radical polymerization methods, respectively. The thickness of polymer grafted on GO sheets was 2.1?nm (free radical polymerization method) and 6?nm (atom transfer radical polymerization method) that was measured by atomic force microscopy analysis. X-ray diffractometer and transmission electron microscopy indicated that after grafting of poly(sodium 4-styrenesulfonate), the modified GO sheets still retained isolated and exfoliated, and also the dispersibility was enhanced.     

Graft polymerization of vinyl monomers initiated by peroxycarbonate groups introduced onto silica surface by Michael addition

The introduction of peroxycarbonate groups onto a silica surface and the graft polymerization of vinyl monomers initiated by peroxycarbonate groups introduced onto a silica surface were investigated. The introduction of peroxycarbonate groups onto a silica surface was achieved by Michael addition of amino groups introduced onto the silica surface to t‐butylperoxy‐2‐methacryloyloxyethylcarbonate (HEPO). The amount of peroxycarbonate groups was determined to be 0.17 mmol/g. The graft polymerization of various vinyl monomers such as styrene (St), N‐vinyl‐2‐pyrrolidinone (NVPD), and 2‐hydroxyethyl methacrylate (HEMA) was initiated by peroxycarbonate groups introduced onto the silica surface to give the corresponding polymer‐grafted silicas. The percentage of poly(St)‐grafting reached about 120% after 5 h. This means that 1.20 g of poly(St) is grafted onto 1.0 g of silica. The surface of poly(St)‐grafted silica shows a hydrophobic nature, but the surfaces of poly(NVPD) and poly(HEMA)‐grafted silica show a hydrophilic nature. Furthermore, the poly(St)‐grafted silica was found to give a stable colloidal dispersion in a good solvent for the grafted polymer. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1491–1497, 1999     

Modification of polyolefin surfaces by plasma-induced grafting

Polar monomers have been grafted onto polyolefin surfaces with the aid of inert gas plasma. In the first stage, an inert gas plasma (argon plasma) was used to generate free radicals on the polyolefin surface. In the second stage, the plasma generator was turned off and a vinyl monomer introduced as a vapor. Monomer was surface grafted by free radical polymerization. After cleaning and drying, the samples were analyzed by XPS, IR, and contact angle. LD–PE was successfully grafted with acrylic acid, glycidyl methacrylate, methyl acrylate, and 2-hydroxy ethylacrylate. The grafting of acrylic acid was studied in more detail, and the rate of grafting was observed to increase with increasing monomer pressure and to decrease with time. The increasing of grafting temperature was found to reduce the degree of grafting. This last factor can be explained by the reduced concentration of monomer at the polymer surface or by a deactivation of surface radicals. © 1996 John Wiley & Sons, Inc.     

Graft polymerization of vinyl acetate onto starch. Saponification to starch–g–poly(vinyl alcohol)

Graft polymerizations of vinyl acetate onto granular corn starch were initiated by cobalt-60 irradiation of starch-monomer-water mixtures, and ungrafted poly(vinylacetate) was separated from the graft copolymer by benzene extraction. Conversions of monomer to polymer were quantitative at a radiation dose of 1.0 Mrad. However, over half of the polymer was present as ungrafted poly-(vinyl acetate) (grafting efficiency less than 50%), and the graft copolymer contained only 34% grafted synthetic polymer (34% add-on). Lower irradiation doses produced lower conversions of monomer to polymer and gave graft copolymers with lower % add-on. Addition of minor amounts of acrylamide, methyl acrylate, and methacrylic acid as comonomers produced only small increases in % add-on and grafting efficiency. However, grafting efficiency was increased to 70% when a monomer mixture containing about 10% methyl methacrylate was used. Grafting efficiency could be increased to over 90% if the graft polymerization of vinyl acetate-methyl methacrylate was carried out near 0°C, although conversion of monomers to polymer was low and grafted polymer contained 40-50% poly(methyl methacrylate). Selected graft copolymers were treated with methanolic sodium hydroxide to convert starch–g–poly(vinyl acetate) to starch–g–poly(vinyl alcohol). The molecular weight of the poly(vinyl alcohol) moiety was about 30,000. The solubility of starch–g–poly(vinyl alcohol) in hot water was less than 50%; however, solubility could be increased by substituting either acid-modified or hypochlorite-oxidized starch for unmodified starch in the graft polymerization reaction. Vinyl acetate was also graft polymerized onto acid-modified starch which had been dispersed and partially solubilized by heating in water. A total irradiation dose of either 1.0 or 0.5 Mrad gave starch–g–poly(vinyl acetate) with about 35% add-on, and a grafting efficiency of about 40% was obtained. A film cast from a starch–g–poly(vinyl alcohol) copolymer in which homopolymer was not removed exhibited a higher ultimate tensile strength than a comparable physical mixture of starch and poly(vinyl alcohol).     

Preparation,characterization, and properties of cellulose–polyacrylamide graft copolymers

Graft copolymers of acrylamide on cellulose materials (α‐cellulose 55.8%, DP 287.3) obtained from Terminalia superba wood meal and its carboxymethylated derivative (DS 0.438) were prepared using a ceric ion initiator and batch polymerization and modified batch polymerization processes. The extent of graft polymer formation was measured in graft level, grafting efficiency, molecular weight of grafted polymer chains, frequency of grafting as a function of the polymerization medium, and initiator and monomer concentrations. It was found that the modified batch polymerization process yielded greater graft polymer formation and that graft copolymerization in aqueous alcohol medium resulted in enhanced levels of grafting and formation of many short grafted polymer chains. Viscosity measurements in aqueous solutions of carboxymethyl cellulose‐g‐polyacrylamide copolymer samples showed that interpositioning of polyacrylamide chains markedly increased the specific viscosity and resistance to biodegradation of the graft copolymers. The flocculation characteristics of the graft copolymers were determined with kaolin suspension. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 913–923, 2003     

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.     

Surface grafting modification of fibrous silicates with polyvinylpyrrolidone and its application in nanocomposites

Chemical surface modification of fibrous silicate with polyvinylpyrrolidone (PVP) or its derivates via grafting‐from and grafting‐to methods was investigated. The grafting‐from method was based on the immobilization of reactive end functional groups of silane coupling agents on silicate surface, followed by chain growth via radical polymerization of N‐vinylpyrrolidone (NVP) to form grafted polymers with different molecular weight. In the grafting‐to method, a novel copolymer PVP‐171 with side functionalized groups and designed molecular weight was synthesized by radical polymerization of NVP and vinyltrimethoxysilane (DB171) and then bonded to the surface of fibrous silicates. Evidences from FTIR, XPS, TGA, and BET test indicate that there are ～ 68,000 reactive sites per square meters on the surface with the grafted vinyl concentration of 59 mequiv per 100 g of clay. XRD patterns and SEM images demonstrate that grafting modification was bound on the silicate surface and make the surface rough with the increase of graft‐loading quantity. In contrast with grafting‐to approach, grafting‐from approach facilitates the dispersion of silicates in PET composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Plasma‐graft polymerization of a monomer with double bonds onto the surface of carbon fiber and its adhesion to a vinyl ester resin

Double bonds reactive with active radical species were introduced onto the surface of carbon yarn by the plasma‐graft polymerization of adipic acid divinyl ester and ethylene glycol dimethacrylate monomers to increase the adhesive strength in the interface between the carbon yarn and a vinyl ester resin. The degree of grafting increased with increasing polymerization time and polymerization temperature. The degree of grafting depended on both the solvent and the monomer species used in the polymerization, and a high degree was obtained with ethylene glycol dimethacrylate as the conjugated monomer and in a mixture of methyl isobutyrate and water. The grafted yarn, whose surface layer contained double bonds, was reacted with a vinyl ester resin containing benzoyl peroxide and N,N‐dimethylaniline. The pull‐out force of the yarn embedded in the resin increased with increasing degree of grafting. The failure in pulling out the yarn was cohesive. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2415–2419, 2003     

Functionalization of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) films via surface‐initiated atom transfer radical polymerization: Comparison with the conventional free‐radical grafting procedure

We modified hydrophobic poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBHV) films with hydrophilic chains to control their surface properties. We designed and investigated surface‐initiated atom transfer radical polymerization (SI‐ATRP) to modify the PHBHV films by grafting poly(2‐hydroxyethyl methacrylate) (PHEMA) from the surface. This method consisted of two steps. In the first step, amino functions were formed on the surface by aminolysis; this was followed by the immobilization of an atom transfer radical polymerization initiator, 2‐bromoisobutyryl bromide. In the second step, the PHEMA chains were grafted to the substrate by a polymerization process initiated by the surface‐bound initiator. The SI‐ATRP technique was expected to favor a polymerization process with a controlled manner. The experimental results demonstrate that the grafting density was controlled by the reaction conditions in the first step. The grafted films were analyzed by Fourier transform infrared spectroscopy, contact angle testing, scanning electron microscopy, and energy‐dispersive X‐ray spectroscopy. The results show that grafted chains under the SI‐ATRP method were preferentially located on the surface for surface grafting and in the bulk for conventional free‐radical polymerization initiated by benzoyl peroxide. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

A study of radical graft copolymerization on polypropylene during extrusion using two peroxide initiators

Functionalization of polypropylene (PP) during melt extrusion has been explored extensively. In this study, two different radical initiators were employed and compared in grafting acyclic halamine precursors to PP. 2,4‐Diamino‐6‐diallylamino‐1,3,5‐triazine (NDAM) was grafted onto PP during a melt‐extrusion process using either 2,5‐dimethyl‐2,5‐(tert‐butylperoxy)hexyne (DTBHY) or dicumyl peroxide (DCP) as initiator. The results confirmed the radical graft copolymerization of the monomer onto the PP backbone during the reactive extrusion process. It was revealed that, at low monomer concentration, when peroxide initiator concentration was increased, polymer chain scission became dominant. DCP was more efficient than DTBHY as an initiator in the graft polymerization. After exposure to chlorine bleach, the grafted structures could be easily transformed into N‐halamines, which provided powerful, durable and regenerable antibacterial activities against Escherichia coli and Staphylococcus aureus. It is concluded that both DCP and DTBHY could be used as radical initiators in reactive extrusion to graft certain vinyl monomers to PP. The NDAM‐grafted PP could provide expected antibacterial function after chlorination of the grafted product in a chlorine bleach solution. The modified PP showed great potential for use in medical devices and non‐woven textiles. Copyright © 2009 Society of Chemical Industry     

Functional biohybrid materials synthesized via surface-initiated MADIX/RAFT polymerization from renewable natural wood fiber: Grafting of polymer as non leaching preservative

Crude wood fibers represent a wide class of renewable resources. The surface modification of such materials via covalent grafting of polymer offers new surface properties with non-leaching coating. The grafting of the polymer chains was achieved by surface-initiated controlled radical polymerization through a grafted xanthate chain transfer agent. Macromolecular design via interchange of xanthate (MADIX) technique was chosen to graft poly(vinyl acetate), polystyrene, poly(n-butyl acrylate) and poly(4-vinylbenzyl chloride)-polystyrene amphiphilic cationic copolymers. Water contact angle measurements highlighted the hydrophobization of the wood fiber surface with a nanoscaled polymer monolayer indicating the appropriate coverage of the fiber. X-ray photoelectron spectroscopy showed the successful grafting of the polymer after drastic washing procedure. The quaternization of the grafted polystyrene-co-poly(4-vinyl benzyl chloride) copolymers with tertiary amine allows the introduction of biocide quaternary ammonium functions while preserving the hydrophobic character of the modified wood fiber when introducing a long alkyl chain in the statistical copolymer. Finally, the cationic copolymer was subjected to Coniophora Puteana to evaluate its propensity to limit the fungi expansion.     

Radical polymerization of vinyl monomers in the presence of carbon black initiated by 2,2'‐azobisisobutyronitrile and benzoyl peroxide in ionic liquid

The radical polymerization behavior of vinyl monomers, such as styrene, methyl methacrylate (MMA), and vinyl acetate (VAc), in the presence of carbon black initiated by benzoyl peroxide (BPO) and 2,2'‐azobisisobutyronitrile (AIBN) in ionic liquid (IL) was compared with those in toluene. 1‐Butyl‐3‐methylimidazolium hexafluorophosphate was used as IL. The radical polymerization of vinyl monomers initiated by BPO and AIBN in the presence of carbon black was remarkably retarded in toluene. On the contrary, the retardation of the polymerization by carbon black was considerably reduced in IL. During the radical polymerization in the presence of carbon black, a part of polymer formed was grafted onto carbon black surface based on the termination reaction of the growing polymer radicals with carbon black surface. The percentage of grafting and molecular weight of polymer in IL were much higher than those in toluene. This may be due to the fact that lifetime of the growing polymer radical is prolonged because of high viscosity of IL. Therefore, the growing polymer radicals with higher molecular weight were trapped by carbon black surface, because of stabilization of polymer radicals. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Semicontinuous emulsion polymerization of vinyl acetate: Effect of ethoxylation degree of nonionic emulsifiers

Poly(vinyl acetate) latices were prepared in the presence of an ammonium persulfate initiator, 10–50 mol of an ethoxylated nonylphenol nonionic emulsifier, and a poly(vinyl alcohol) colloid stabilizer by applying semicontinuous emulsion polymerization (delayed monomer and initiator addition process) in a laboratory scale similar to industrial practice. Two approaches were applied: the molar concentration of the nonionic emulsifier was kept constant and the weight ratios in the polymerization recipe varied or the weight ratios were kept constant. The effects of the change in the ethoxylation degree of the emulsifier to the final latex viscosity, average polymer molecular weight, polymer grafting degree, surface tension of the latex, and the surface free energy of the dried films were investigated. It was determined that the resultant latex viscosity decreases and the viscosity‐average polymer molecular weight increases with increase of the nonionic emulsifier ethoxylation degree. The increase of the ethoxylation degree does not seriously affect the surface tension of the resultant latex or the surface free energy of the dried poly(vinyl acetate) films. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 844–851, 2002     

Studies on the grafting of acryloylated potato starch with styrene

An investigation of graft polymerization to determine the potential of a starch‐bonded acryloyl group as a suitable coupling agent with vinyl monomers was carried out. In this case, potassium persulfate was used as a free‐radical initiator using water as the reaction solvent for further graft polymerization. This work revealed the ability of water as a reaction medium; perhydroxyl and hydroxyl radicals were easily formed from persulfate to produce free radicals to activate the styrene monomer towards grafting with acryloylated potato starch. The graft copolymers were characterized by FT‐IR spectroscopy and further confirmed using saponification. The analysis results showed the grafted potato starch with the styryl chain afforded protection to the ester bond, which resisted the alkaline hydrolysis. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 452–459, 2005     

Functional polymers supported on porous silica. II.Radical polymerization of vinylbenzyl chloride from grafted precursors

Vinylbenzyl chloride was chosen as a model monomer for grafting a functional polymer onto silica carrying radical active precursors, such as monomer, transfer agent or initiator, previously grafted onto silica via a suitable coupling agent. The grafting efficiency was studied as a function of the texture of the initial silica, the nature of the active precursor and the polymerization conditions. Evidence for grafting was obtained from FTIR and ²⁹Si CP-MAS NMR spectra, and the thickness of the grafted layer was estimated from surface area and porosimetry measurements. From molecular weight measurements of nongrafted polymer it can be deduced that there is a trend toward the elongated conformation of the grafted polymer. Attempts to separate the grafted polymer through digestion of the silica with HF, failed to give a soluble linear polymer except when the active precursor was a transfer agent; in the two other cases a crosslinked polymer with a low crosslink density was obtained, which kept the morphology of the initial silica.     

Location of some typical vinyl polymers within radiation-grafted cotton fibers: An electron microscopical survey

Electron microscopical observations of radiation-induced rayon–styrene graft copolymers were published by Kaeppner and Huang in 1965. The present paper reports electron microscopical investigations on the relationship of the structure of vinyl–cotton graft polymers to the original morphology of the cotton fiber and into the distribution of the grafted vinyl polymer in the cotton fiber structure. The grafted vinyl monomers investigated in this study were acrylonitrile, styrene, methyl methacrylate, and vinyl acetate. Two radiation-induced procedures were used: simultaneous irradiation grafting and post-irradiation grafting. Ceric ion grafting of acrylonitrile to cotton was included for purposes of comparison. Distribution of the vinyl polymer within the cotton fiber is illustrated by a series of electron micrographs, selected as typical of the particular grafted species under consideration. Results indicate that the diffusion rate of monomer into the cellulose fiber plays an important role in the final distribution of polyacrylonitrile grafts within the fiber. Uniform distribution of polyacrylonitrile in the fiber was achieved by simultaneous irradiation grafting of acrylonitrile on a highly substituted cyanoethylated cotton. In samples of low degree of cyanoethylation the distribution of graft polymer was non-uniform. In grafting initiated by ceric ion the acrylonitrile graft polymer was evenly distributed. Polystyrene–cotton copolymers from grafts, made by simultaneous irradiation of cotton in methanol solutions of the styrene monomer, were uniform throughout the fiber but showed opening of structure associated with the amount of graft formed. Grafting of methyl methacrylate occurred only in the peripheral regions of the fiber; by contrast, grafting of vinyl acetate was uniform throughout the fiber wall. Important factors governing the successful irradiation grafting in cotton fibers are choice of solvent, ratio of monomer to cellulose, nature of prior chemical modification of the cellulose, and total irradiation dosage.     

A comparative study on effects of two kinds of polymerization methods on grafting of polymer onto silica surface

In this article we present the result of a comparative study of two kinds of polymerization methods—solution polymerization (sol. poly.) and dispersion polymerization (dis. poly.) for grafting polymer onto silica. As a model for the grafting polymerization reaction, styrene was chosen as the monomer and azo diisobutyronitrile (AIBN) as the initiator. The study aims at supplying theoretical reference for better selecting polymerization method to graft polymer on the silica particle surface. First, monolayers of 3‐methacryloylpropyl trimethoxysilane were chemically bonded onto the surfaces of micrometer‐sized silica gel particles, and so double bonds were immobilized onto the silica surface. Second, the copolymerizations between the immobilized double bonds and the monomer styrene were carried out, homopolymerizations of styrene followed, and finally polystyrene was grafted to the silica surfaces. Two kinds of polymerization methods, sol. poly. and dis. poly., were adopted respectively, and the effects of polymerization methods on grafting process were examined mainly. At the same time, the effects of different polymerization conditions on the grafting degree were researched. It was found that in the dis. poly. system the grafting degree is obviously higher than that in the sol. poly. system under the same polymerization conditions, and the grafting degree can go up to 47%, i.e. 47g/100g. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5808–5817, 2006