Graft Polymerization Of 2-hydroxyethyl Methacrylate Research Articles

Free radical graft polymerization of 2-hydroxyethyl methacrylate and acrylic acid on the polysulfone membrane surface through circulation of reaction media to improve its performance and hemocompatibility properties

In this study, a new facile and cost effective method is used to modify polysulfone membrane surface in order to improve the hydrophilicity, antifouling, and blood compatibility. This modification was performed by adding two functional monomers on the dialysis membrane. Polysulfone (PSF) membranes containing polyvinylpyrrolidone were prepared via phase inversion technique. In the next step, free radical polymerization combined with surface polymerization was used to introduce acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) onto the polysulfone membrane surface via circulation of initiator and monomer solutions across the membrane surface, respectively. Various monomer concentrations were selected to obtain an optimum condition. Field emission scanning electron microscope (FE-SEM), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and atomic force microscopy (AFM) confirmed that monomers were successfully grafted on the membrane surface. Water contact angle (WCA) results represented the enhancement of membrane hydrophilicity, which effectively improved water flux and alleviated protein fouling resistance. WCA decreased from 71 °C to 45 °C which corresponds to the negative charge of the membrane surfaces. When the AA concentration was 1 M, the flux recovery ratio reached up to 66% and total protein fouling resistance noticeably decreased to 38%. Nevertheless, urea, creatinine, and vitamin B12 clearance experienced a slight increase. Biocompatibility of membranes was evaluated via activated partial thromboplastin time (APTT), prothrombin time (PT), and cytotoxicity experiments. The presented results indicated that APTT was enhanced by 35% for the best blood compatible sample.

Прищеплені кополімери полівінілпіролідону та м’які контактні лінзи на їхній основі

The graft polymerization of 2-hydroxyethyl methacrylate in presence of polyvinylpyrrolidone, which occurs through a stage of complex formation between the reactants, was investigated. The basic performance properties of hydrogel copolymers depending on their composition were investigated. A hydrogel polymeric material “Akrylan-LPI” for soft contact lenses was developed. Clinical testing confirmed the effectiveness of using of such lenses for vision correction as well as for eye injuries and burns treating.

Graft polymerization of 2-hydroxyethyl methacrylate via ATRP with poly(acrylonitrile-co-p-chloromethyl styrene) as a macroinitiator

Amphiphilic graft copolymers are excellent additives for the development of antifouling membranes by nonsolvent induced phase separation. We report a convenient approach to the synthesis of novel graft copolymers with hydrophobic polyacrylonitrile (PAN) backbones and hydrophilic poly(2-hydroxyethyl methacrylate) (PHEMA) side chains. Atom transfer radical polymerization (ATRP) of 2-hydroxyethyl methacrylate was carried out with poly(acrylonitrile-co-p-chloromethyl styrene) (PAN-co-PCMS) as a macroinitiator in the presence of CuCl/2,2′-bipyridine at 50 °C in dimethyl sulfoxide. Kinetics of the graft polymerization was also evaluated. The synthesis of poly(acrylonitrile-co-p-chloromethyl styrene-g-2-hydroxyethyl methacrylate) (PAN-co-(PCMS-g-PHEMA)) can be relatively controlled when CMS (the ATRP sites) unit in the macroinitiator is around 5 mol%. Both the macroinitiators and graft copolymers were characterized by FTIR, NMR and GPC. The surface morphology and wettability of the copolymer films were studied by AFM and water contact angle measurement, respectively. We demonstrate that phase segregation between the PAN-co-PCMS backbones and the PHEMA side chains takes place and the surface hydrophilicity of the graft copolymers increases with the length of the PHEMA side chains. Because these amphiphilic graft copolymers can be synthesized in mass, they will be useful as latent additives for the fabrication of advanced PAN separation membranes.

Construction of comb-like poly( N-isopropylacrylamide) layers on microporous polypropylene membrane by surface-initiated atom transfer radical polymerization

In this paper, we describe a thermo-responsive membrane based on microporous polypropylene membrane (MPPM). Comb-like poly( N-isopropylacrylamide) (PNIPAM) was grafted onto the MPPM surface using surface-initiated atom transfer radical polymerization (ATRP). Hydroxyl groups were firstly introduced onto the membrane surface by the ultraviolet-induced graft polymerization of 2-hydroxyethyl methacrylate. Then ATRP initiators were immobilized through the reaction between the tethered hydroxyl groups and 2-bromoisobutyryl bromide, which initiated the ATRP of NIPAM on the membrane surface. Attenuated total reflectance Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and field emission scanning electron microscopy were used to characterize the chemical composition and surface morphologies of the modified membranes. The thermo-response of the modified membranes was evaluated by water contact angle and water permeation measurements. It is found that both water contact angles and water fluxes have obvious response to the environmental temperature. This type of membrane with controlled PNIPAM graft layer can be applied in many fields including smart separation.

Functionalization of three-dimensionally ordered macroporous cross-linked polystyrene by atom-transfer radical polymerization of hydroxyethyl methacrylate and subsequent derivatization

The surface-initiated atom-transfer radical polymerization (ATRP) technique was applied to the graft polymerization of 2-hydroxyethyl methacrylate (HEMA) from three-dimensionally ordered macroporous crosslinked polystyrene (3DOM CLPS) on which the initiator (benzyl chloride) was immobilized onto the pore wall of 3DOM CLPS by chloromethylation of benzene ring. By the adjustment of the monomer concentration or graft polymerization time, the thickness of grafted polymer layers can be controlled. FTIR analysis confirms that the graft polymerization of HEMA via ATRP had been taken place at the pore wall of 3DOM CLPS. SEM images of PHEMA-grafted 3DOM CLPS show that the ordered structure is well preserved after graft polymerization and the grafted layers are dense and homogeneous. The maximum thickness of grafted layer is up to 35 nm and the corresponding percent weight increase is 102.8% in this study. Moreover, the PHEMA layers were further functionalized in high yield via their reactive hydroxyl groups under gentle condition. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7950–7959, 2008

Surface Mobility of Grafted Hydrogels

Solid-supported hydrogels were prepared by ozone-induced graft polymerization of 2-hydroxyethyl methacrylate (HEMA), diethylene glycol methacrylate (DEGMA), and triethylene glycol methacrylate (TEGMA) onto polypropylene substrates. Angle-dependent ESCA showed a gradient in chemical composition in the near-surface region (thickness 55 A). The various shapes of the C 1s peaks collected at a takeoff angle of 45° corresponded to what could be expected from the chemical composition of polyHEMA, polyDEGMA, and polyTEGMA, respectively. At a takeoff angle of 15°, all grafted polymers showed a more hydrophobic character with respect to the shape of the C 1s peak. During dynamic contact angle measurements, HEMA-grafted fibers showed the largest contact angle hysteresis, with an advancing contact angle of about 90° and receding contact angle close to zero. A less pronounced contact angle hysteresis for both DEGMA and TEGMA-grafted fibers was explained by a hindered reorientation as a consequence of an increased side chain length of the grafted polymers. A suppressed contact angle hysteresis was also obtained for fibers grafted in a HEMA monomer mixture containing 5% cross-linker (EDMA). Such surfaces also showed good reproducibility when sequential wetting cycles were performed during the dynamic contact angle measurements.

Laser surface modification of polymers to improve biocompatibility: HEMA grafted PDMS, in vitro assay—III

Polydimethylsiloxane (PDMS) surface modifications were carried out using CO2-pulsed laser, without photosensitizer at ambient condition, to introduce peroxide groups onto the PDMS surface. Such peroxides were capable of initiating graft polymerization of 2-hydroxyethyl methacrylate (HEMA) onto the PDMS. The modified surfaces were characterized using a variety of techniques including scanning electron microscopy (SEM), attenuated total reflectance infrared (ATR-FTIR) and the water drop contact angle measurements. Data from in vitro assays indicated a significant reduction of the platelet adhesion and aggregation for the modified surfaces.

Characterization of plasma‐induced graft polymerization of 2‐hydroxyethyl methacrylate onto silicone rubber

AbstractGraft copolymerization of 2‐hydroxyethyl methacrylate (HEMA) as attempted onto the surface of silicone rubber membrane, which was pretreated by Ar‐plasma, then exposed in oxygen to introduce a peroxide group. The effect of the amount of HEMA grafted on Arplasma‐treated and graft copolymerization was examined for various parameters of power, pressure, time, reaction time, and concentration of HEMA aqueous solution. The surfaces were characterized by ATR–FTIR, ESCA, contact angle, and SEM. PHEMA was indicated by ATR–FTIR and ESCA analysis to be present successfully onto the grafted surface of silicone rubber membrane. The stable wettability, as demonstrated once the PHEMA grafted films, indicated contact with a hydrated environment by the study of contact angle. © 1994 John Wiley & Sons, Inc.

Reduction of nonselective adsorption of proteins by hydrophilization of microfiltration membranes by radiation-induced grafting.

Alcoholic hydroxyl groups were introduced into a polyethylene microfiltration (MF) membrane by radiation-induced graft polymerization of 2-hydroxyethyl methacrylate (HEMA), vinyl acetate (VAc), and glycidyl methacrylate (GMA). Subsequently, the VAc- and GMA-grafted membranes were quantitatively hydrolyzed into monool (single hydroxyl) and diol groups, respectively. The pure water flux of the modified membrane and the saturation capacity of bovine gamma-globulin onto the membrane were determined as a function of alcoholic hydroxyl group density. The threshold value for hydrophilization ranged between 5 and 7 mol of alcoholic hydroxyl group per kilogram of original MF membrane. Masking of the polyethylene surface with grafted polymer branches containing the diol groups was effective because approximately 70% of the pure water flux of the original MF membrane was maintained. Irrespective of the pore diameter of the original MF membrane, saturation capacities on the modified membrane correlated well with the diol group density. Saturation capacities of bovine gamma-globulin and bovine serum albumin were reduced to 1 mg/m2 of the membrane. In addition, the binding interaction changed from irreversible to reversible.

Graft Polymerization of 2-Hydroxyethyl Methacrylate onto Plasma Pretreated Cotton, Silk, and Polyester Fibers

Abstract Graft polymerization of 2-hydroxyethyl methacrylate was made onto plasma pretreated fabrics of cotton, silk, and polyester. Homopolymerization also took place during the graft polymerization, but the percent of the homopolymer formation was comparatively small. Therefore, kinetic analyses of graft polymerization were undertaken based on the first-order reaction of the monomer. Through a comparison of the rate constants which were obtained from the rate equation of the graft polymerization of 2-hydroxyethyl methacrylate, the dependence of plasma pretreatment on various factors and the resulting polymerization were clarified. Polymerizability was compared to that obtained with the Ce(IV) catalyst and without catalysts.

Radiation grafting of methacrylates onto silicone rubber: Prototype burn wound dressing

The radiation-induced graft polymerization of 2-hydroxyethyl methacrylate (HEMA) and ethylene glycol dimethacrylate (EGDMA) to silicone rubber (Silastic) sheeting has been investigated with the aim of developing an elastomeric composite for use as a burn dressing material. Polymerization is initiated by 60Co γ-ray irradiation of the elastomer immersed in an aqueous solution of monomer. Some of the physical parameters associated with grafting from aqueous solution are characterized. Factors influencing the depth and morphology of the grafts include dose, dose rate, monomer concentration and purity, and the extent of the competing homopolymerization reactions.