Showing papers on "Glycidyl methacrylate published in 2015"

A facile controllable coating of carbonyl iron particles with poly(glycidyl methacrylate): a tool for adjusting MR response and stability properties

Abstract: This study is focused on the controllable coating of the carbonyl iron (CI) particles widely applied in magnetorheology. These particles were grafted with poly(glycidyl methacrylate) (PGMA) with narrow polydispersity via surface-initiated atom transfer radical polymerization. Two types of core–shell particles differing in molecular weights of grafted polymer chains were synthesized. The effect of shell thickness on the thermo-oxidation stability of particles as well as the sedimentation stability of their silicone oil suspensions was evaluated. The successful coating process was confirmed by Fourier transform infrared spectroscopy and energy-dispersive spectrometry. The differences in the magnetic properties of bare and coated CI particles were clarified through vibrating sample magnetometry. Due to the controllable length of the PGMA grafts, the magnetic properties remain almost the same as those for bare CI. The magnetorheological (MR) behavior of silicone oil suspensions containing 60 wt% of bare CI particles as well as PGMA-coated analogues was investigated in the absence and in the presence of various magnetic field strengths, demonstrating the negligible impact of surface modification on final MR performance. Thus, the grafting of the particles with PGMA negligibly affected magnetic properties but considerably enhanced thermo-oxidation and sedimentation stabilities. Finally, a novel tensiometric method for sedimentation stability measurements of MR suspensions was successfully implemented.

Effect of lithium bis(trifluoromethylsulfonyl)imide salt-doped UV-cured glycidyl methacrylate

Abstract: A study is carried out on solid polymer electrolytes (SPEs) based on UV-curable glycidyl methacrylate (GMA) reactive mixtures to determine the lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) effect at different weight percentages. These polymeric systems are discussed considering several factors such as chemical interaction, structural and thermal properties, ionic conductivity, and lithium transference number. Samples are prepared using solution casting technique and are analyzed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and electrochemical impedance spectroscopy (EIS) characterization methodologies. FTIR spectra show that interaction occurs between electronegative atoms in polymer host and TFSI− ions. XRD diffractogram indicates the amorphous aspect of SPEs, without the presence of LiTFSI peaks. Doping with LiTFSI salt reduces the glass transition temperature of SPEs and increased their ionic conductivity. Identified as the ideal salt concentration for poly(glycidyl methacrylate) (PGMA)-LiTFSI SPE system is 30 wt.% LiTFSI doping level, thus achieving a ionic conductivity of 3.69 × 10−8 S cm−1 at ambient temperature and 1.23 × 10−4 S cm−1 at 373 K. The ionic conductivity behavior obeys the Vogel–Tamman–Fulcher equation with an activation energy of 0.054 eV.

Multi-arm carriers composed of an antioxidant lignin core and poly(glycidyl methacrylate-co-poly(ethylene glycol)methacrylate) derivative arms for highly efficient gene delivery

Abstract: A lignin-based copolymer with good biocompability was successfully prepared via atom transfer radical polymerization (ATRP) for efficient gene delivery. Kraft lignin was modified into lignin-based macroinitiators and then poly(glycidyl methacrylate)-co-poly(ethylene glycol)methacrylate (PGMA–PEGMA) side chains were prepared via ATRP grafting onto lignin. Ethanolamine was sequentially functionalized onto lignin–PGMA–PEGMA and a cationic lignin–PGEA–PEGMA copolymer consisting of a lignin core and different-length PGEA–PEGMA side chains was produced. Lignin–PGEA–PEGMA copolymers could efficiently compact pDNA into nanoparticles with sizes ranging from 150 to 250 nm at N/P ratios of 10 or higher. The gene transfection efficiency depends greatly on the mass percentage of PGEA units and the N/P ratio. The lignin–PGEA–PEGMA with 46.9% (mass%) of PGEA units (i.e. LG100) has highest transfection efficiency in comparison with the copolymers with a lower amount of PGEA units. In addition, LG100 has high transfection efficiency under serum conditions, which is comparable to or much higher than PEI control in HEK 293T and Hep G2 cell lines. More importantly, lignin–PGEA–PEGMA copolymers have excellent antioxidant activity. The novel cationic lignin–PGEA–PEGMA copolymers can be promising gene carriers for gene delivery.

Photoreactive Polymers Bearing a Zwitterionic Phosphorylcholine Group for Surface Modification of Biomaterials

Abstract: Photoreactive polymers bearing zwitterionic phosphorylcholine and benzophenone groups on the side chain were synthesized and used as surface modification reagents for biomaterials. A photoreactive methacrylate containing the benzophenone group, 3-methacryloyloxy-2-hydroxypropyl-4-oxybenzophenone (MHPBP), was synthesized via a ring-opening and addition reaction between glycidyl methacrylate and 4-hydroxybenzophenone. Then, water-soluble, amphiphilic polymers poly(2-methacryloyloxyethyl phosphorylcholine (MPC)-co-MHPBP) (PMH) and poly(MPC-co-n-butyl methacrylate-co-MHPBP), with different monomer unit compositions, were synthesized through radical polymerization. Ultraviolet–visible (UV/vis) absorption spectra of these polymer solutions showed that these polymers have maximum absorption peaks at 254 and 289 nm that can be attributed to the benzophenone unit. The intensity of UV adsorption at 289 nm was decreased with increased UV irradiation time, and it was saturated within a few minutes, indicating that th...

In Situ Synthesis of Monodisperse Silver Nanoparticles on Sulfhydryl-Functionalized Poly(glycidyl methacrylate) Microspheres for Catalytic Reduction of 4-Nitrophenol

Abstract: Immobilization of silver nanoparticles (Ag NPs) to improve monodispersity and recyclability is crucial for applications in nanocatalysts. Herein, a novel protocol for stabilizer-free, effective, and in situ synthesis of Ag NPs on sulfhydryl-functionalized poly(glycidyl methacrylate) microspheres (PGMA-SH) was proposed. Ag NPs of 16.97 ± 3.15 nm were successfully grown on PGMA-SH, and remained monodisperse and stable even after sonication, washing, and long-term storage. Moreover, the Ag NPs on PGMA-SH (Ag NPs@PGMA-SH) composite exhibited excellent catalytic activity with an average normalized activity parameter of 4.38 × 10–3 L·mg–1·s–1 toward the reduction of 4-nitrophenol, which was 1.3–132 times higher than reported in literature. The composite can be easily recycled and showed excellent reusability as a conversion higher than 92% was achieved after 10 cycles. Thus, the preparation of Ag NPs@PGMA-SH has been proven a feasible, straightforward, and effective protocol, which would facilitate the applicat...

Melt free radical grafting of glycidyl methacrylate (GMA) onto fully biodegradable poly(lactic) acid films: effect of cellulose nanocrystals and a masterbatch process

Abstract: This article reports the preparation, by means of a masterbatch procedure, of poly (lactic acid) (PLA)/cellulose nanocrystal (CNC) films via premixing 1% wt of CNC into PLA or glycidyl methacrylate (GMA) grafted PLA (g-PLA). These films were obtained by reactive extrusion and subsequent film processing. In this study, 10% wt of GMA with respect to neat PLA was used in the extrusion phase, after that a final grafting degree of 5.69% was obtained. The film obtained by using the masterbatch steps were compared with the system obtained by a direct extrusion of 1% wt of CNC in PLA/g-PLA. Thermogravimetric, crystallization and mechanical properties, as well as morphology of CNC reinforced PLA nanocomposites were characterized. Differential scanning calorimetry and thermogravimetric analysis showed enhanced crystallization ability and an improved heat resistance for the resulting nanocomposites obtained after the use of masterbatches, for example field emission scanning electron microscopy confirmed that the masterbatch preparation procedure was beneficial to the dispersion of CNC in the final nanocomposites. Furthermore, different mechanical performance was obtained when using different masterbatches, which were considered to contribute to extend the applications of PLA based composites as food packaging materials in different sectors.

A glucose sensor via stable immobilization of the GOx enzyme on an organic transistor using a polymer brush

Abstract: Recently, there has been significant research in the area of organic electrochemical transistors (OECTs) because of their superior aptitude of chemical and biological sensing. Here it is shown for the first time the incorporation of polymer brushes to a transistor. Polymer brushes were chosen for their biocompatible properties and their ability to covalently tether enzymes and other biomolecules to different surfaces. OECTs were fabricated from the conducting polymer poly(3,4-ethyle- nedioxythiophene) doped with poly(styrene sulfonate), PEDOT:PSS, and polymerized from the surface a mixed poly- mer brush of poly(glycidyl methacrylate) and poly(2-hydrox- yethyl methacrylate). The brushes were functionalized with glucose oxidase and measured in terms of electrical perform- ance and long-term stability. V C 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 00, 000-000

Generalized Approach for Fabricating Monodisperse Anisotropic Microparticles via Single-Hole Swelling PGMA Seed Particles

Abstract: A unique phenomenon—a single hole appeared gradually on the surface of the seed particles and grew with the proceeding of swelling—has been observed during swelling poly(glycidyl methacrylate) (PGMA) particles. PGMA particles suffer the function of the swelling agent and styrene monomer and form a single hole on their surface. SEM and TEM were utilized to observe and demonstrate the forming process. Inconceivably, monodisperse poly(glycidyl methacrylate)/polystyrene (PGMA/PS) anisotropic microparticles, including Janus, raspberry-shaped, acorn-shaped, and hollow with open mouth, have been fabricated by the seed polymerization of these single-hole microparticles as a generalized approach. The morphology evolution of PGMA/PS is investigated by regulating the amount of monomer and monomer/seed weight ratio. Moreover, the surface of PGMA/PS microparticles are rich in epoxy groups, which has bright prospects in application in biomacromolecule immobilization and superhydrophilic/superhydrophobic coating.

Synthesis of Reactive Comb Polymers and Their Applications as a Highly Efficient Compatibilizer in Immiscible Polymer Blends

Abstract: Reactive comb (RC) polymers were synthesized by copolymerizing methyl methacrylate (MMA) with glycidyl methacrylate (GMA) and a kind of MMA macromer. The obtained molecules had both epoxide groups and long PMMA side chains distributed randomly along the PMMA backbone. The synthesized RC polymers were applied as compatibilizers in an immiscible poly(l-lactic acid)/poly(vinylidene fluoride) (PLLA/PVDF) system. Compared to their linear counterparts, only 1 wt % of RC polymers with appropriate length of side chains significantly reduced the size and enhanced the uniformity of the PVDF dispersed phase in PLLA matrix and the RC-compatibilized blends exhibited a significant improvement in fracture strain. The higher compatibilization efficiency of RC polymers was ascribed to the existence of PMMA side chains, which improved the stability of RC polymers at the interface of immiscible blend, and this was demonstrated by transmission electron microscopy.

Core-shell structured poly(glycidyl methacrylate)/BaTiO3nanocomposites prepared by surface-initiated atom transfer radical polymerization: A novel material for high energy density dielectric storage

Abstract: Core-shell structured barium titanate-poly(glycidyl methacrylate) (BaTiO3-PGMA) nanocomposites were prepared by surface-initiated atom transfer radical polymerization of GMA from the surface of BaTiO3 nanoparticles. Fourier transform infrared spectroscopy confirmed the grafting of the PGMA shell on the surface of the BaTiO3 nanoparticles cores. Transmission Electron Microscopy results revealed that BaTiO3 nanoparticles are covered by thin brushes (∼20 nm) of PGMA forming a core-shell structure and thermogravimetric analysis results showed that the grafted BaTiO3-PGMA nanoparticles consist of ∼13.7% PGMA by weight. Upon incorporating these grafted nanoparticles into 20 μm-thick films, the resultant BaTiO3-PGMA nanocomposites have shown an improved dielectric constant (e = 54), a high breakdown field strength (∼3 MV/cm) and high-energy storage density ∼21.51 J/cm3. AC conductivity measurements were in good agreement with Jonscher's universal power law and low leakage current behavior was observed before the electrical breakdown field of the films. Improved dielectric and electrical properties of core-shell structured BaTiO3-PGMA nanocomposite were attributed to good nanoparticle dispersion and enhanced interfacial polarization. Furthermore, only the surface grafted BaTiO3 yielded homogenous films that were mechanically stable. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 719–728

Preparation of Chemically-Tailored Copolymer Membranes with Tunable Ion Transport Properties.

Abstract: Membranes derived from copolymer materials are a promising platform due to their straightforward fabrication and small yet tunable pore structures. However, most current applications of these membranes are limited to the size-selective filtration of solutes. In this study, to advance the utility of copolymer membranes beyond size-selective filtrations, a poly(acrylonitrile-r-oligo(ethylene glycol) methyl ether methacrylate-r-glycidyl methacrylate) (P(AN-r-OEGMA-r-GMA)) copolymer is used to fabricate membranes that can be chemically modified via straightforward schemes. The P(AN-r-OEGMA-r-GMA) copolymer is cast into asymmetric membranes using a nonsolvent induced phase separation technique. Then, the surface charge of the membrane is modified to tailor its performance for nanofiltration applications. The oxirane groups of the glycidyl methacrylate (GMA) moiety that line the pore walls of the membrane allows for both positively charged and negatively charged moieties to be introduced directly without any prior activation. Notably, the highly size-selective nanostructure of the copolymer materials is retained throughout the functionalization processes. Specifically, amine moieties are attached to the pore walls using the aminolysis of the oxirane groups. The resulting amine-functionalized membrane is positively charged and rejects up to 87% of the salt dissolved in a 10 mM magnesium chloride feed solution. Further modification of the amine-functionalized membrane with 4-sulfophenyl isothiocyanate results in pore walls lined by sulfonic acid moieties. These negatively charged membranes reject up to 90% of a 10 mM sodium sulfate feed solution. Throughout the modification scheme, the membrane permeability remains equal to 1.5 L m(-2) h(-1) bar(-1) and the rejection of neutral solutes (i.e., sucrose and poly(ethylene oxide)) is consistent with the membrane having a single well-defined pore diameter of ∼5 nm. The performance of the membrane as a function of ion valence number, solution pH, and ionic strength is investigated.

Acid-Labile Poly(glycidyl methacrylate)-Based Star Gene Vectors.

Abstract: It was recently reported that ethanolamine-functionalized poly(glycidyl methacrylate) (PGEA) possesses great potential applications in gene therapy due to its good biocompatibility and high transfection efficiency Importing responsivity into PGEA vectors would further improve their performances Herein, a series of responsive star-shaped vectors, acetaled β-cyclodextrin-PGEAs (A-CD-PGEAs) consisting of a β-CD core and five PGEA arms linked by acid-labile acetal groups, were proposed and characterized as therapeutic pDNA vectors The A-CD-PGEAs owned abundant hydroxyl groups to shield extra positive charges of A-CD-PGEAs/pDNA complexes, and the star structure could decrease charge density The incorporation of acetal linkers endowed A-CD-PGEAs with pH responsivity and degradation In weakly acidic endosome, the broken acetal linkers resulted in decomposition of A-CD-PGEAs and morphological transformation of A-CD-PGEAs/pDNA complexes, lowering cytotoxicity and accelerating release of pDNA In comparison wi

Fabrication of cross-linked fluorescent polymer nanoparticles and their cell imaging applications

Abstract: Novel aggregation induced emission (AIE) dye based cross-linked amphiphilic fluorescent polymers have been prepared facilely by a one pot method. This was carried out first by free radical polymerization between the AIE monomer (PhE) and glycidyl methacrylate (GM), then by the ring-opening reaction between GM and polyethyleneimine (PEI) to obtain the cross-linked polymer. The resultant cross-linked amphiphilic polymer was prone to self-assemble into stable nanoparticles with high water dispersibility due to the surplus amino groups and hydroxyl groups covered on the surface, which can also be further functionalized. The thus obtained nanoparticles demonstrated strong orange fluorescent emission with a quantum yield of about 41% owing to the AIE dyes in the cores of the nanoparticles. Biocompatibility evaluation and cell uptake behaviour of the nanoparticles were further investigated to explore their potential biomedical applications and the demonstrated excellent biocompatibility made them promising for cell imaging.

Mechanical property characterization of carbon nanofiber/epoxy nanocomposites reinforced by GMA-grafted UHMWPE fibers

Abstract: Carbon nanofibers (CNFs) dispersed epoxy resin was reinforced with unidirectional glycidyl methacrylate (GMA) grafted ultra-high molecular weight polyethylene (UHMWPE) fibers. Tensile tests were performed on unfilled, and CNF filled epoxy to identify the effect of adding CNFs on the mechanical properties of epoxy. The highest improvement in strength was obtained with 1 wt% of CNF. Tensile and flexural properties improvements in three-component nanocomposites were confirmed by obtained results. The combined use of CNFs and GMA-grafted UHMWPE fibers leads to a significant synergy in the mechanical properties of nanocomposites. The mechanisms of such synergism were analyzed by fracture studies using scanning electron microscopy.

Trametes versicolor laccase immobilized poly(glycidyl methacrylate) based cryogels for phenol degradation from aqueous media

Abstract: This study aims removal of phenols in wastewater by enzymatic oxidation method. In this study, Trametes versicolor laccase was covalently immobilized onto a cryogel matrix by the nucleophilic attack of amino groups of laccase to epoxy groups of matrix. Glycidyl methacrylate was chosen as functional monomer to prepare poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) [p(HEMA-co-GMA)] cryogels. The enzyme immobilized matrix was characterized by FTIR, SEM, and swelling tests. The effect of pH, reaction time, temperature, substrate concentration, enzyme concentration, and storage period on immobilized enzyme activity was determined and compared with those of free enzyme. The model substrate was 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS). Lineweaver-Burk plots were used to calculate Km and Vm values. Km values were 165.1 and 156.0 µM while Vm values were 55.2 µM min−1 and 1.57 µM min−1 for free and immobilized laccase, respectively. Immobilized enzyme was determined to retain 82.5% and 72.0% of the original activity, respectively, after 6 consecutive use and storage period of 4 weeks. The free enzyme retained only 24.0% of its original activity following the same storage period. Lastly, decomposition products resulting from enzymatic oxidation of a model phenolic compound (3,5-dinitrosalicylic acid) in aqueous solution were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41981.

The chemical stability and cytotoxicity of carbonyl iron particles grafted with poly(glycidyl methacrylate) and the magnetorheological activity of their suspensions

Abstract: Carbonyl iron (CI) particles were grafted with poly(glycidyl methacrylate) (PGMA) using atom transfer radical polymerization. Compact coating of PGMA largely improved the chemical stability of the particles in an acid environment and thus reduced the common drawback of bare CI particles. Furthermore, due to possible medical applications of CI-polymer systems for magnetic drug targeting, an in vitro cytotoxicity test was performed using an NIH/3T3 cell line. The cell viability was evaluated by spectrometric assay (MTT). The results show that the prepared particles are not cytotoxic. Moreover, bare CI particles as well as synthesized core–shell particles were suspended in silicone oil, and the rheological behavior of MR suspensions was investigated in controlled shear rate mode under various magnetic field strengths. Dynamic yield stress as a measure of the rigidity of the created internal structures of the suspensions was determined using the Herschel–Bulkley model, which provided a reasonably good fit for rheological data. MR suspensions of PGMA-coated particles exhibited only slightly decreased yield stresses due to their negligibly-affected magnetic performance.