Preparing polymer brushes on poly(vinylidene fluoride) films by free radical polymerization

Grafting of polymer brushes on the poly(vinylidene fluoride) (PVDF) films was carried out by the surface‐initiated free radical polymerization. Surface‐initiators were immobilized on the PVDF films by surface hydroxylation and esterification of the surface‐tethered hydroxyl groups with 4,4′‐azobis(4‐cyanopentanoic acid) (ACP). Homopolymer brushes of methyl methacrylate (MMA) were prepared by free radical polymerization from the azofunctionalized PVDF surface. The chemical composition and topography of the graft‐functionalized PVDF surfaces were characterized by X‐ray photoelectron spectroscopy (XPS), attenuated total reflectance (ATR) FTIR spectroscopy, and atomic force microscopy (AFM). Kinetics study revealed an exponential increase in the graft concentration of polymer brushes with the reaction time, indicating that the chain growth from the surface was consistence with a chain polymerization. Water contact angles on PVDF films were reduced by surface grafting of MMA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 857–862, 2006     

Controlled grafting of polymer brushes on poly(vinylidene fluoride) films by surface‐initiated atom transfer radical polymerization

Controlled grafting of well‐defined polymer brushes on the poly(vinylidene fluoride) (PVDF) films was carried out by the surface‐initiated atom transfer radical polymerization (ATRP). Surface‐initiators were immobilized on the PVDF films by surface hydroxylation and esterification of the hydroxyl groups covalently linked to the surface with 2‐bromoisobutyrate bromide. Homopolymer brushes of methyl methacrylate (MMA) and poly(ethylene glycol) monomethacrylate (PEGMA) were prepared by ATRP from the α‐bromoester‐functionalized PVDF surface. The chemical composition of the graft‐functionalized PVDF surfaces was characterized by X‐ray photoelectron spectroscopy (XPS) and attenuated total reflectance (ATR)–FTIR spectroscopy. Kinetics study revealed a linear increase in the graft concentration of PMMA and PEGMA with the reaction time, indicating that the chain growth from the surface was consistent with a “controlled” or “living” process. The “living” chain ends were used as the macroinitiator for the synthesis of diblock copolymer brushes. Water contact angles on PVDF films were reduced by surface grafting of PEGMA and MMA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3704–3712, 2006     

Synthesis of graft copolymers of binary vinyl monomer mixtures onto acetylated Saccharum spontaneum L and characterization

Methylmethacrylate (MMA) + acrylamide (AAm), MMA + acrylonitrile (AN), and MMA + acrylic acid (AA) binary vinyl monomer mixtures were graft copolymerization onto acetylated Saccharum spontaneum L, was carried out and maximum graft yield (185.6 %) was found with MMA+AAm binary mixture. Synthesized graft co‐polymers were characterized with FT‐IR spectrophotometry, scanning electron microscopy (SEM), thermal analysis TGA/DTA/DTG, and X‐ray diffraction (XRD) techniques. Thermal stability of Ss‐g‐poly(MMA + AAm) was found to be more than that of natural, acetylated S. spontaneum fiber and other graft copolymers. Although on grafting, percentage crystallinity and crystallinity index were found to decrease but graft copolymers were found to exhibit more moisture, chemical, and thermal resistance. Also, it can be observed that the surface of the grafted fibers is highly rough in comparison with the ungrafted fiber. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Development of antimicrobial polypropylene sutures by graft polymerization. I. Influence of grafting conditions and characterization

Modification of polypropylene monofilament was carried out by the graft polymerization of 1‐vinylimidazole (VIm) using simultaneous radiation grafting method. The effect of radiation dose, monomer concentration, and the grafting medium on the degree of grafting was evaluated. It was observed that the presence of organics as additives in the reaction medium had significant influence on the graft levels. These grafted sutures were characterized using several techniques, such as infrared spectroscopy (IR), X‐ray diffraction, and differential scanning calorimetry (DSC). It was found that the grafts are confined to the amorphous region of the monofilament and the crystalline regions remain intact. The surface morphology of sutures was evaluated by scanning electron microscopy. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3895–3901, 2006     

Preparation of antimicrobial sutures by preirradiation grafting of acrylonitrile onto polypropylene monofilament. II. Mechanical,physical, and thermal characteristics

Polypropylene‐g‐polyacrylonitrile sutures were prepared by graft polymerization of acrylonitrile onto polypropylene monofilament by preirradiation method. Sutures with various graft levels were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Density, Birefriengence, X‐ray Diffraction, Scanning Electron Microscopy (SEM), and Differential Scanning Calorimetry (DSC). Mechanical properties of the unmodified and grafted sutures were also evaluated. The physical characteristics of sutures were markedly affected by the graft levels. Density of the polypropylene sutures increased with an increased in the degree of grafting. The heat of fusion and heat of crystallization decreased with the increase in the degree of grafting. X‐ray diffraction also revealed decrease in crystallinity with the increase in the graft levels. Tenacity of the monofilament improved, whereas the elongation at break decreased in grafted samples. Scanning electron microscopy showed significant variation in surface morphology in the grafted samples. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1224–1229, 2004     

Surface modification of low‐density polyethylene films by UV‐induced graft copolymerization with a fluorescent monomer

Surface modification of argon plasma–pretreated low‐density polyethylene (LDPE) film via UV‐induced graft copolymerization with a fluorescent monomer, (pyrenyl)methyl methacrylate (Py)MMA, was carried out. The chemical composition and morphology of the (Py)MMA‐graft‐copolymerized LDPE [(Py)MMA‐g‐LDPE] surfaces were characterized, respectively, by X‐ray photoelectron spectroscopy (XPS) and by atomic force microscopy (AFM). The concentration of the surface‐grafted (Py)MMA polymer increased with Ar plasma pretreatment time and UV graft copolymerization time. The photophysical properties of the (Py)MMA‐g‐LDPE surfaces were measured by fluorescence spectroscopy. After graft copolymerization with the fluorescent monomer, the surface of the LDPE film was found to have incorporated new and unique functionalities. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1526–1534, 2001     

Alkali‐responsive membrane prepared by grafting dimethylaminoethyl methacrylate onto ethylene vinyl alcohol copolymer membrane

An alkali‐responsive membrane was prepared by grafting dimethylaminoethyl methacrylate (DMAEMA) onto ethylene vinyl alcohol copolymer (EVAL) membrane using ultraviolet (UV) irradiation graft polymerization. A subtranslucent state of EVAL membrane swelling in the DMAEMA solution was observed, and such a state enabled the passage of UV light through all the pores, inducing graft polymerization inside the pores and on the back. Attenuated total reflectance Fourier‐transform infrared spectrometer (ATR‐FTIR), X‐ray photoelectron spectroscopy (XPS), field‐emission scanning electron microscopy (FESEM), and energy‐dispersive X‐ray spectroscope (EDX) confirmed that the poly(DMAEMA)‐grafted chains existed not only on the top surface, but also inside the pores and on the back. Atomic force microscopy (AFM) and nitrogen adsorption analysis confirmed that the grafted chains collapsed in air, and decreased the surface roughness, surface area, and pore size of the grafted membranes. Alkali‐responsive properties of the poly(DMAEMA)‐grafted EVAL membrane (i.e., contact angle, permeability, and selectivity) were observed in the pH range of 9–10. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41775.     

Initiation of surface graft polymerization by ceric ions on polymer microspheres

The surface graft polymerization of acrylamide on poly(styrene‐co‐acrylonitrile) copolymer microspheres by the initiation of ceric ions was studied. The grafting was verified by IR spectra and X‐ray photoelectron spectroscopy measurements. The resultant microspheres with surface‐grafted polymer chains were employed in the preparation of polymer‐microsphere‐supported palladium composite particles. The composite particles were then studied by transmission electron microscopy and X‐ray diffraction. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 936–940, 2003     

Surface grafting of poly(vinylamine) onto poly(ethylene) film by corona discharge‐induced grafting

Poly(vinylamine) (PVAm) was grafted on a poly(ethylene) (PE) film surface via the surface graft polymerization of N‐vinylformamide (NVF) and N‐vinylacetamide (NVA) and the subsequent hydrolysis of those grafted polymers. The surface was characterized by X‐ray photoelectron spectroscopy (XPS), contact angle, moisture absorption, and the leakage of electrostatic charge from the films. PNVF and PNVA were introduced onto the surface of the PE film successfully, in spite of the fact that the initiator for polymerization was a peroxide group. The grafted amounts of PNVF and PNVA were dependent on the grafting time. A PVAm‐grafted surface was obtained via the hydrolysis of the grafted PNVF. The grafted‐PNVA was not hydrolyzed under mild hydrolysis. The obtained PVAm‐grafted surface appeared to be useful for various applications, such as protein immobilization or chemical modification. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1583–1587, 1999     

Temperature‐sensitive membranes prepared by the plasma‐induced graft polymerization of N‐Isopropylacrylamide into porous polyethylene membranes

A temperature‐responsive polymer, poly(N‐isopropylacrylamide) (PNIPAAm), was grafted onto porous polyethylene membranes by a plasma‐induced graft polymerization technique. A wide range of grafting was achieved through variations in the grafting conditions, including the postpolymerization temperature, time, monomer concentration, and graft‐reaction medium. The active species induced by plasma treatment was proven to be long‐living via a postpolymerization time of 95 h. Different solvent compositions, that is, water, methanol, benzene, and water/methanol, were used as reaction media, and water showed a much higher polymerization rate than the organic solvents. Based on the hydrophilicity of the active species, a mechanism explaining the solvent effect in plasma‐induced graft polymerization was examined. Characterizations by scanning electron microscopy, X‐ray photoelectron spectroscopy (XPS), and micro Fourier transform infrared showed that the grafted polymers were located on both the outer surface and inside pores of the membranes. The XPS analysis also confirmed that the polar amide groups tended to distribute more outward when grafted PNIPAAm was in its expanding state than when it was in its shrinking state. Water permeation experiments showed that the permeability of the grafted membranes varied dramatically with a slight temperature change in the vicinity of the lower critical solution temperature (LCST) of PNIPAAm. The effective pore radii of the grafted membranes above and below the LCST could be depicted by Hagen‐Poiseuille's law. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3180–3187, 2003     

Surface graft copolymerization of poly(methyl methacrylate) onto waste tire rubber powder through ozonization

Grinding of tires offers a promising opportunity for recycling waste rubber because fine waste tire rubber particle may be used as fillers and property modifiers in thermoplastic, elastomer, and thermoset blends. However, due to the lack of reactive sites on the WTR surface, the adhesion between WTR powder and matrix is poor. In this article, ozonization of waste tire rubber (WTR) powder was performed to produce some “immobile” reactive points (hydroperoxide groups) on the WTR surface. The free radical generated by the decomposition of hydroperoxide groups on WTR surface, was used to initiate graft polymerization of methyl methacrylate (MMA) onto the surface of WTR powder. The experimental results showed that MMA was successfully grafted onto the surface of WTR. The hydrophilicity of the MMA grafted WTR (MMA‐g‐WTR) was improved. The concentration of hydroperoxide groups and the graft degree were both increased with ozonization time. With increasing of polymerization time and polymerization temperature, the grafting degree increased. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation of poly(methyl methacrylate)‐grafted attapulgite by surface‐Initiated radical polymerization

Poly(methyl methacrylate) (PMMA) was bonded on the surface of attapulgite (ATP) by using an ammonium persulfate amine redox initiation system via grafting from approach. ATP was modified with (3‐aminopropyl)triethoxysilane to anchor amine groups on the surface, and then the amine‐functionalized ATP was further treated with methacryloyl chloride and 4,4′‐azobis(4‐cyanovaleric acid) to give methacryl‐ and azo‐functionalized ATP, respectively. Subsequently, surface‐initiated graft polymerization of MMA in a soap‐free emulsion was performed to afford ATP/PMMA hybrids. Meanwhile, graft polymerizations on the surface of methacryl‐ and azo‐functionalized ATP were carried out for comparison. The grafting of PMMA on the surface of ATP was characterized by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and thermogravimetric analysis (TGA). The crystal structure of hybrids was characterized by X‐ray diffraction analysis. The morphology of hybrids was observed by scanning electron microscopy and transmission electron microscopy. The degree of grafting obtained from surface‐initiated graft polymerization in a soap‐free emulsion was found to be the greatest (29.4%) estimated from TGA. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41062.     

Preparation of a poly(3‐hexylthiophene)‐grafted indium tin oxide/poly(3‐hexylthiopene) composite and its conductivity–temperature characteristics

The temperature–conductivity characteristics of poly(3‐hexylthiophene) (P3HT) composites filled with P3HT‐grafted indium tin oxide (ITO) particles were investigated in this work. The ITO particles were first treated with a silane coupling reagent of 3‐aminopropyltriethoxysilane (APS), and then thiophene rings were introduced through a condensation reaction between the ending amino groups of APS and the carboxylic groups of thiophene‐3‐acetic acid. The composites were prepared by the polymerization filling of the 3‐hexylthiophene (3HT) monomer with the thiophene‐ring‐introduced ITO particles. Elemental analysis, Fourier transform infrared, and X‐ray photoelectron spectroscopy were used to confirm the grafting reaction on the ITO surface. The longer the polymerization time was or the higher the 3HT/ITO feeding ratio was, the more P3HT was grafted. The influence of the grafted amount on the electrical properties of ITO particles was attributed to the wrapping effect formed by the grafted P3HT on the surface of the ITO particles. The conductivity change of the P3HT‐grafted ITO/P3HT composites was proved to be subject to the change in the average gap width of ITO interparticles, which was determined by the filling ratio of P3HT to ITO in the polymerization and the volume expansion effect of a P3HT thin film between neighboring ITO particles during the heating process. In comparison with the ungrafted ITO/P3HT composites, the grafting treatment enhanced the interaction between the particles and polymer matrix, and this was helpful for obtaining a more homogeneous dispersion structure for the composites and thus afforded a higher positive temperature coefficient intensity and better reproducibility. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1881–1888, 2006     

Synthesis of two‐end‐functionalized copolymer of styrene and methyl methacrylate via living radical polymerization

The random copolymers (HO‐P(St‐r‐MMA)‐COOH) of styrene (St) and methyl methacrylate (MMA) with hydroxyl group at one end and carboxyl group at another end were synthesized by nitroxide‐mediated living radical polymerization initiated by 4,4′‐azobis(4‐cyanovaleric acid) (ACVA) and 4‐hydroxyl‐2,2,6,6–tetramethylpiperidineoxyl (TEMPO‐OH). The experimental results have shown that all synthesized copolymers have narrow molecular weight distribution. The conversion of monomers and the molecular weight of copolymer increase with polymerization time. Thus, a copolymerization mechanism containing living radical polymerization is suggested. The use of this method permits the copolymer with two functional chain ends and controllable molecular weight as well as low molecular weight distribution. X‐ray photoelectron spectroscopy result shows that the synthesized copolymers can be tethered on the surface of silicon wafer through the reaction between the hydroxyl end of the copolymer and native oxide layer on the wafer. In addition, an organic/inorganic hybrid surface has achieved by treating copolymer tethered Si‐substrates with SiCl₄ vapor. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3118–3122, 2006     

Synthesis and characterization of submicron PMMA particles containing rare earth ions on the surface

Emulsifier‐free emulsion polymerization was adopted to synthesize rare earth containing submicron polymer particles under microwave irradiation. To control the size and distribution of the particle, the relationship between reaction time, monomer content, and particle radius was studied for the polymerization of methyl methacrylate (MMA) in the absence and presence of rare earth ions, in which water was used as solvent, and potassium persulfate was used as initiator. In the latter polymerization, the solution of MMA and europium octanoate (EOA) was used instead of MMA itself as EOA can be dissolved in MMA within certain concentrations, and the result shows that the polymerization process is affected by existence of EOA except when the amount of MMA is 2 ml. For particles containing rare earth ions, characterization shows that mole percentage of Eu(III) ion in the surface layer with a thickness of 5 nm, which is estimated from X‐ray photo electron spectroscopy (XPS), is always larger than the value estimated by inductively coupled plasma atomic emission spectrometer (ICP‐AES) for the whole particle, indicating that surface enrichment of rare earth ions took place during the polymerization. Further characterization by XPS depth measurement after Ar⁺ sputtering shows the same result. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1124–1131, 2003     

Surface‐initiated atom‐transfer radical polymerization (SI‐ATRP) of methyl methacrylate from carbon fibre

Surface modification of carbon fibre (CF) by well‐defined polymer brushes was carried out using the ‘grafting from’ method. Poly(methyl methacrylate)‐grafted carbon fibre (CF‐PMMA) was successfully prepared by surface‐initiated atom‐transfer radical polymerization (SI‐ATRP) of methyl methacrylate (MMA) from the macro‐initiator, bromo‐acetic ester‐modified carbon fibre (CF‐BrA), with the complex of 1,10‐phenanthroline and Cu(I)Br as catalyst. The percentage of grafting (PG%) and the conversion of monomer (C%) increased linearly with increasing of polymerization time, and reached 24.0 % and 6.7 %, respectively, after a polymerization time of 6 h, calculated from the elemental analyses (EA). The structural and surface morphological analyses were conducted with Fourier‐transform infrared (FTIR) spectroscopy, X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Copyright © 2005 Society of Chemical Industry     

Surface modification of polyethylene by plasma pretreatment and UV‐induced graft polymerization for improvement of antithrombogenicity

The purpose of this study was to enhance blood compatibility of polyethylene (PE) films. Glycidyl methacrylate (GMA) was grafted onto the surface of PE by Ar plasma pretreatment and UV‐induced graft polymerization without photo‐initiator, then heparin was immobilized onto the poly (glycidyl methacrylate) segments. The surface compositions and microstructure of GMA graft polymerized PE films were studied by X‐ray photoelectron spectroscopy (XPS) and Attenuated Total Reflectance Fourier Transfer Infrared (ATR‐FTIR) spectroscopy. It was confirmed that heparin was successfully immobilized onto the surface of PE films by XPS analysis. The antithrombogenicity of the samples was determined by the activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), and plasma recalcification time (PRT) tests and platelet adhesion experiment. Results indicated that the antithrombogenicity of modified PE was improved remarkably. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2014–2018, 2004     

Effects of functionalized MWNTs with GMA on the properties of PMMA nanocomposites

The acid modification of multiwall carbon nanotubes (MWNTs) was performed by an HNO₃/H₂SO₄ solution. The glycidyl methacrylate (GMA) undergoing an opening‐ring was grafted onto the surface of acid‐modified MWNTs. The surface properties of MWNTs were investigated by Fourier transform infrared spectrometer (FTIR), Raman spectra, transmission electron microscopy (TEM), X‐ray diffraction, and thermogravimeric analysis. Then the MWNTs/ poly(methyl methacrylate) (PMMA) nanocomposites were prepared by in situ polymerization. The tribological and dielectric properties of nanocomposites were studied. As a result, GMA was grafted on the surface of MWNTs. The tribological and dielectric properties of MWNTs/ PMMA nanocomposites were improved as the content of the surface‐modified MWNT increased. The marked improvement in tribological and dielectric properties were attributed to the good dispersion of MWNTs that were bonded with C?C on the surface that participated in the polymerization of MMA. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Atom transfer radical polymerization of graft chains onto polyethylene film initiated at tribromomethyl unit introduced by electron beam irradiation

A novel process for graft polymerization onto a polyethylene (PE) film using atom transfer radical polymerization (ATRP) was examined. First, a PE film irradiated with an electron beam was treated with carbon tetrabromide, thereby introducing tribromomethyl groups. The number of tribromomethyl groups introduced onto the film could be controlled by adjusting the electron beam irradiation dose. Methyl methacrylate (MMA) was then graft‐polymerized by ATRP in the initiator‐introduced PE film in the presence of a copper catalyst. Based on FTIR spectra from the PMMA grafted films, the behavior of graft polymerization reactions on the film surface and inside the film are discussed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

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