Simultaneous Polymerization Research Articles

Novel bio‐based IPNs obtained by simultaneous thermal polymerization of flexible methacrylate network based on a vegetable oil and a rigid epoxy

A series of novel vegetable oil‐based interpenetrating polymer networks (IPNs) have been successfully prepared: on one hand, methacrylated camelina oil (MCO) and a polyethyleneglycol dimethacrylate (PEG, MW 750 g/mol) and on the other hand, diglycidylether of bisphenol A (DER), in various blend ratios (75/25, 50/50, and 25/75 wt). Hence the appealing innovative direction of the current work was to build oil‐based poly(methacrylate) network using PEG macromonomer which is able to modulate adequately the crosslinking degree of the oil‐based network.These innovative combinations of cross‐linkable resins in terms of flexible methacrylate network based on camelina oil (CO) and PEG and a rigid epoxy (DER) were simultaneously polymerized using two independent non‐interfering curing reactions: free‐radical process for MCO and anionic polymerization of epoxy resin in the presence of a tertiary amine. The effect of the IPNs composition compositional characteristics on the reactivity of methacrylate or epoxy groups was studied using differential scanning calorimetry. The influence of the MCO‐PEG bio‐based polymer on the system properties was evaluated after curing by dynamic mechanical and thermogravimetric analyses. In addition mechanical and morphological studies were also carried out. The results suggested that blending of MCO and DER gave synergistic effects on the overall properties of the developed oil‐based IPNs and a dependence on the methacrylate/epoxy ratio was clearly noticed. Copyright © 2014 John Wiley & Sons, Ltd.

Hydrogenation of nitro-compounds over rhodium catalysts supported on poly[acrylic acid]/Al2O3 composites

In this report, poly[acrylic acid] gels containing Al2O3 were prepared by simultaneous free-radical polymerization and sol–gel chemistry using different amounts of 3-(trimethoxysilyl)propyl methacrylate (TMPM) as a compatibilizer. The hybrid materials were used as supports for a rhodium catalyst in the chemoselective hydrogenation of 3-substituted aromatic nitro-compounds. The supported rhodium catalyst was prepared by an ion-exchange process. In situ H2 flux was used to produce active species of the catalysts. The resulting materials were characterized by infrared spectroscopy, thermogravimetric analysis, solid-state 29Si and 13C NMR, X-ray diffraction, transmission/scanning electron microscopy, and X-ray photoelectron spectroscopy. All materials exhibited simultaneous interpenetrating hybrid network structures (SIHNs). The morphologies and physicochemical properties depended on the amount of TMPM used. The catalysts were found to be effective for the reduction of nitrobenzene in ethanol at room temperature and a hydrogen pressure of 20atm. The most active and selective catalyst was used in the hydrogenation of different 3-substituted aromatic nitro-compounds. The hydrogenation reactions displayed high conversion levels and promoted exclusive –NO2 group reduction, resulting in the sole formation of the corresponding amino-compound, with the exception of 1,3-dinitrobenzene, in which over-hydrogenation was detected. The presence of electron-donating/electron-withdrawing substituents at the 3-position resulted in different rates of –NO2group hydrogenation. This effect was quantified in terms of the Hammett relationship, in which the catalyst displayed a linear correlation between the substituent constant (σi) and the hydrogenation rate, with the exception of –OH, –NH2, and –OCH3 groups. One explanation for this behavior is a proposed support-substrate hydrogen bond interaction during the catalytic reaction.

One-Step Synthesis of Triblock Copolymers via Simultaneous Reversible-Addition Fragmentation Chain Transfer (RAFT) and Ring-Opening Polymerization Using a Novel Difunctional Macro-RAFT Agent Based on Polyethylene Glycol

One-step synthesis of the triblock copolymers was carried out by reversible addition–fragmentation chain transfer (RAFT) polymerization of methyl methacrylate (MMA) and ring-opening polymerization (ROP) of β-butyrolactone (BL) or ϵ-caprolactone (CL) using a novel difunctional macro-RAFT agent. For this purpose, primarily PEG-Br (polyethylene glycol bromine) was obtained by using 3-bromopropanoyl chloride and PEGs (polyethylene glycols) with different molecular weights. Then, macro-RAFT agent was synthesized by the reaction of potassium ethyl xanthogenate and PEG-Br. By using macro-RAFT agent, poly(MMA-b-EG-b-BL), and poly(MMA-b-EG-b-CL) triblock copolymers were synthesized by changing some polymerization conditions such as monomer/initiator concentration, polymerization time. The effect of the reaction conditions on the polydispersity and molecular weights were also investigated. The block lengths of the triblock copolymers were calculated by using 1H-nuclear magnetic resonance (1H-NMR) spectra. It was observed that the block length could be altered by varying the monomer and initiator concentrations. The characterization of the products were achieved using 1H-NMR, Fourier-transform infrared spectroscopy (FTIR), gel-permeation chromatography (GPC), thermogravimetric analysis (TGA), and fractional precipitation (γ) techniques.

Synthesis and electrochemical performance of porous carbon by carbonizing PF/PMMA interpenetrating polymer networks

Porous carbon was synthesized by the direct carbonization of full interpenetrating polymer networks (IPNs) of phenol-formaldehyde resin (PF) and poly(methyl methacrylate) (PMMA). The PF/PMMA IPNs were prepared by simultaneous polymerization of PF prepolymer as well as methyl methacrylate and ethylene glycol dimethacrylate monomers in dimethylformamide. During the followed carbonization process, the PF polymeric networks tended to form carbon matrix (carbon precursor) while the PMMA decomposed into gaseous products, leaving pores in carbon matrix (pore-former). The obtained porous carbon has an interconnected pore structure with a high BET surface area of 865m2g−1 and an average pore size of 4.4nm. Such porous carbon shows outstanding capacitive performance (252F g−1), good rate capacitive behavior, and excellent cycling stability. Due to its unique pore structure, the as-prepared porous carbon shows promise as an electrode material for supercapacitors.

Bioactive organic-inorganic poly(CLMA-co-HEA)/silica nanocomposites.

A series of novel poly(CLMA-co-HEA)/silica nanocomposites is synthesized from caprolactone 2-(methacryloyloxy)ethyl ester (CLMA) and 2-hydroxyethyl acrylate (HEA) as organic comonomers and the simultaneous sol-gel polymerization of tetraethyloxysilane (TEOS) as silica precursor, in different mass ratios up to a 30 wt% of silica. The nanocomposites are characterized as to their mechanical and thermal properties, water sorption, bioactivity and biocompatibility, reflecting the effect on the organic matrix provided by the silica network formation. The nanocomposites nucleate the growth of hydroxyapatite (HAp) on their surfaces when immersed in the simulated body fluid of the composition used in this work. Proliferation of the MC3T3 osteoblast-like cells on the materials was assessed with the MTS assay showing their biocompatibility. Immunocytochemistry reveals osteocalcin and type I collagen production, indicating that osteoblast differentiation was promoted by the materials, and calcium deposition was confirmed by von Kossa staining. The results indicate that these poly(CLMA-co-HEA)/silica nanocomposites could be a promising biomaterial for bone tissue engineering.

Bioactive nanoparticles stimulate bone tissue formation in bioprinted three‐dimensional scaffold and human mesenchymal stem cells

Bioprinting based on thermal inkjet printing is a promising but unexplored approach in bone tissue engineering. Appropriate cell types and suitable biomaterial scaffolds are two critical factors to generate successful bioprinted tissue. This study was undertaken in order to evaluate bioactive ceramic nanoparticles in stimulating osteogenesis of printed bone marrow-derived human mesenchymal stem cells (hMSCs) in poly(ethylene glycol)dimethacrylate (PEGDMA) scaffold. hMSCs suspended in PEGDMA were co-printed with nanoparticles of bioactive glass (BG) and hydroxyapatite (HA) under simultaneous polymerization so the printed substrates were delivered with highly accurate placement in three-dimensional (3D) locations. hMSCs interacted with HA showed the highest cell viability (86.62 ± 6.02%) and increased compressive modulus (358.91 ± 48.05 kPa) after 21 days in culture among all groups. Biochemical analysis showed the most collagen production and highest alkaline phosphatase activity in PEG-HA group, which is consistent with gene expression determined by quantitative PCR. Masson's trichrome staining also showed the most collagen deposition in PEG-HA scaffold. Therefore, HA is more effective comparing to BG for hMSCs osteogenesis in bioprinted bone constructs. Combining with our previous experience in vasculature, cartilage, and muscle bioprinting, this technology demonstrates the capacity for both soft and hard tissue engineering with biomimetic structures.

동시-기상중합법을 이용한 Poly(3,4-ethylenedioxythiophene)(PEDOT)-TiO2하이브리드 박막 제조

PEDOT-TiO2 hybrid conductive thin film including semiconductive metal oxide was successfully prepared via simultaneous vapor phase polymerization (VPP). The mechanical properties such as pencil hardness and antiscratch property as well as optoelectrical properties of PEDOT-TiO2 hybrid thin film could be improved as compared with pristine PEDOT thin film. Physicochemically stable crosslinked TiO2 layer derived from a sol-gel process by FTS was generated in the PEDOT thin film layer by simultaneous VPP, resulting in improving mechanical properties of the hybrid thin films without any deterioration of their original optoelectrical properties. PEDOT-TiO2 hybrid thin film showed better electrical conductivity as compared with PEDOT film. It might be due to the fact that the surface morphology of hybrid thin film prepared by simultaneous VPP showed smoother than that of pristine PEDOT thin film.

Facile chemical route to copper/polymer composite: Simultaneous reduction and polymerization

The oxidation of 6-aminoquinoline (AQ) with the cupric sulphate solution yielded the formation of core-shell organic-inorganic composite, consisting of copper particles and poly(6-aminoquinoline) (PAQ) matrix. The resulting composite (PAQ/Cu) was characterized by UV–Vis, FT-IR, SEM, TEM, X-RD, XPS, cyclic voltammetry (CV), thermogravimetry (TG), fluorescence and solid state conductivity measurements. Optic band gap (Eopt) of composite determined by Tauch equality was 3.98eV. From fluorescence analysis, it was revealed the presence of a solvatochromic phenomenon. Current–voltage (I–V) characteristics of PAQ/Cu were determined. As a novel photocatalytic material, photocatalytic performance of composite was also investigated for degradation of methylene blue (MB) under UV irradiation.

A Polymerizable Bioionic Liquid Based Nanogel: A New Nanocarrier for an Anticancer Drug

Nanogels (NGs) are considered as one of the most suitable nanocarrier matrices for drug, gene and protein delivery. There are many methods of synthesis of NGs but polymerizable bioionic liquids are not being applied so far for the synthesis of such nanocarriers. The synthesis of a stimuli‐responsive NG system having average hydrodynamic size of 41 ± 15 nm is reported here, obtained by the simultaneous polymerization and crosslinking of a polymerizable biobased ionic liquid. The NG thus obtained shows prolonged drug delivery for 5‐fluorouracil, an anticancer drug, at pH 1.2 (stomach pH) for 10 days at physiological human body temperature (37 °C). However, no substantial drug delivery is observed at pH 5 and 7.4. Such a prolonged drug release profilemakes the reported NG system a potential candidate in the formulation of a pH‐sensitive drug nanocarrier vehicle for in vivo delivery of stomach‐specific therapeutic agents. image

A non-aqueous procedure to synthesize amino group bearing nanostructured organic-inorganic hybrid materials.

Amino-functionalized organic-inorganic hybrid materials with a narrow distributed nanostructure of 2-4 nm in size were obtained by means of a template-free and non-aqueous procedure. Simultaneous twin polymerization of novel amino group containing twin monomers with 2,2'-spirobi[4H-1,3,2-benzodioxasiline] has been applied for this purpose. The amino groups of the organic-inorganic hybrid material are useful for post derivatization.

Mechanical properties of tough hydrogels synthesized with a facile simultaneous radiation polymerization and cross-linking method

Radiation-induced polymerization and cross-linking method has been applied to hydrogel preparations for decades, but less attention has been paid to the mechanical properties of the hydrogels. In this work, we provide a systematic study on the mechanical properties of hydrogels synthesized with the simultaneous radiation polymerization and cross-linking method. The prepared polyacrylamide (PAAm) had very good mechanical properties, namely high compressive strengths (several to more than 10MPa), high tensile strengths (up to 260kPa), high fracture strains (up to 12) and high fracture energies (10–160J/m2). Absorbed dose and monomer concentration were the two important factors affecting the mechanical properties of the gels. The compressive strength and elastic modulus of the gels increased with increasing absorbed dose and monomer concentration, while the tensile strength, fracture strain and fracture energy of the gels decreased with increasing absorbed dose. The gels also showed excellent elastic recovery property, as indicated by the low stress–strain hysteresis ratios in cyclic tensile tests as well as the small loss factors measured with dynamic mechanical analysis (DMA).

Systematic study of the growth and morphology of vapor deposited porous polymer membranes

In this paper, the authors systematically study the growth and morphology of porous polymer membranes fabricated via initiated chemical vapor deposition. The porous polymer membranes are formed by simultaneous solid monomer deposition and polymerization. The authors demonstrate that the solid monomer serves as both a porogen and a template for the polymerization, and therefore, the final structure of the membrane can be tuned by controlling the physical deposition of the monomer. The results show that the mass of the deposited monomer has a large dependence on the monomer flow rate and a small dependence on the substrate temperature, whereas the thickness has a large dependence on both parameters. The large dependence of the monomer thickness on the substrate temperature is due to significant differences in the morphologies, ranging from three-dimensional growth of pillared microstructures at low substrate temperatures to two-dimensional and weblike growth as the substrate temperature is increased. The authors also demonstrate that the location of membrane formation can be controlled by patterning the surface energy of the underlying substrate. These results can be used to fabricate polymer membranes of controllable morphology and thickness for a variety of applications in filtration, tissue scaffolding, and catalytic supports. In addition, the principles of the technique can be extended to other vapor phase polymerization and chemical vapor deposition processes.

Nanofiltration hollow fiber membranes with high charge density prepared by simultaneous electron beam radiation-induced graft polymerization for removal of Cr(VI)

A novel kind of nanofiltration (NF) hollow fiber membranes with high density of negative charges and relative high permeate flux was prepared by grafting of 2-acrylamido-2-methylpropanesulfonic acid (AMPS) onto a polysulfone (PSf) ultrafiltration hollow fiber membrane using the simultaneous electron beam radiation-induced method. ATR-FTIR and FESEM analyses revealed that the monomer was grafted on both the outer and inner surfaces of the membrane. The effects of irradiation dose and monomer concentration on the mean pore size and performance of the membranes were investigated. The prepared NF membranes were used for removal of Cr(VI) from aqueous solution under varying conditions such as pH value, initial Cr(VI) concentration and coexisting ions. The experimental results showed that Cr(VI) could be effectively removed by the resulting NF membranes when the pH of the solution was higher than 8 and the performance of Cr(VI) removal was nearly not affected by the presence of Na2SO4 and NaCl in the experimental range. It was indicated that the high negative charge density resulting from the high degree of grafting made the grafted membranes achieve nanofiltration performance at a relative large pore size.

Synthesis of carbon with bimodal porosity by simultaneous polymerization of furfuryl alcohol and phloroglucinol

Carbon materials with bimodal porosity have shown enhanced performance in a wide variety of applications including catalysis, energy storage and fluid separation. Presence of mesoporosity is essential to lower the mass transfer limitation imposed by the microporous nature of the carbons. The synthesis approaches used to prepare bimodal carbons with controlled micro/mesopore size and narrow pore size distribution, usually involve multi step processes and the use of harsh chemicals and solvents. Herein, we present a simple one step method that can be used to synthesize carbon with bimodal pore size distribution. Simultaneous polymerization of furfuryl alcohol and phloroglucinol-formaldehyde in the presence of a structure-directing agent (Pluronic F-127) was carried out and the resultant polymer was pyrolyzed to yield the bimodal carbon. Effect of polymerization conditions such as concentrations of monomer, initiator and surfactant on the bimodal pore size distribution of the carbon was studied in detail. Pyrolyzed precursors form carbons with narrow mean micropore size of 0.5nm and mean mesopores ranging from 3.5 to 6nm. The range of the mesopore size could be altered by varying the polymerization parameters (acid and surfactant concentration) as well as selective oxidation using CO2 gas.

Synthesis of Poly(vinyl pyrrolidone)/Silver Nanoprism Composites through Simultaneous Photoinduced Polymerization and Electron Transfer Processes

An investigation into the in situ preparation of polymer/silver nanoprism composites is described. Photoinitiated polymerizations of N-vinyl pyrrolidone (NVP) in water using 2-hydroxy-2-methyl-1-phenyl propanone as photoinitiator under nitrogen and simultaneous redox reactions of AgNO3 resulted in the formation of poly(N-vinyl pyrrolidone) (PNVP)/silver nanocomposites. Prolonged irradiations at low photoinitiator concentration and equimolar concentrations of AgNO3 and NVP produced only spherical silver nanoparticles. The nanocomposites produced at high silver and photoiniatiator concentrations with short irradiation times e.g. 5 min contain polygonal (mainly triangular) silver nanoprisms as evidenced by spectral and TEM analysis.

Anion exchange membrane prepared from simultaneous polymerization and quaternization of 4-vinyl pyridine for non-aqueous vanadium redox flow battery applications

A simple, single step and environmentally friendly process is developed for the synthesis of anion exchange membrane (AEM) by simultaneous polymerization and quaternization, unlike the conventional membrane synthesis which consists of separate polymerization and quaternization step. The membrane synthesis is carried out by dissolving polyvinyl chloride (PVC) in cyclohexanone along with 4-vinyl pyridine (4VP) and 1,4-dibromobutane (DBB) in the presence of thermal initiator benzoyl peroxide, followed by film casting to get thin and flexible AEMs. The membrane properties such as ion exchange capacity, ionic conductivity and swelling behaviour are tuned by varying the degree of crosslinking. These AEMs exhibit low vanadium permeability, while retaining good dimensional and chemical stability in an electrolyte solution, making them appropriate candidates for non-aqueous vanadium acetylacetonate redox flow battery (VRFB) applications. The optimized membrane displays ion exchange capacity and ionic conductivity of 2.0 mequiv g−1 and 0.105 mS cm−1, respectively, whereas the efficiency of 91.7%, 95.7% and 87.7% for coulombic, voltage and energy parameter in non-aqueous VRFB, respectively. This study reveals that the non-aqueous VRFB performance is greatly influenced by membrane properties; therefore the optimal control over the membrane properties is advantageous for the improved performance.

Facile synthesis of thiol-functionalized amphiphilic polylactide–methacrylic diblock copolymers

Biodegradable amphiphilic diblock copolymers based on an aliphatic ester block and various hydrophilic methacrylic monomers were synthesized using a novel hydroxyl-functionalized trithiocarbonate-based chain transfer agent. One protocol involved the one-pot simultaneous ring-opening polymerization (ROP) of the biodegradable monomer (3S)-cis-3,6-dimethyl-1,4-dioxane-2,5-dione (L-lactide, LA) and reversible addition–fragmentation chain transfer (RAFT) polymerization of 2-(dimethylamino)ethyl methacrylate (DMA) or oligo(ethylene glycol) methacrylate (OEGMA) monomer, with 4-dimethylaminopyridine being used as the ROP catalyst and 2,2′-azobis(isobutyronitrile) as the initiator for the RAFT polymerization. Alternatively, a two-step protocol involving the initial polymerization of LA followed by the polymerization of DMA, glycerol monomethacrylate or 2-(methacryloyloxy)ethyl phosphorylcholine using 4,4′-azobis(4-cyanovaleric acid) as a RAFT initiator was also explored. Using a solvent switch processing step, these amphiphilic diblock copolymers self-assemble in dilute aqueous solution. Their self-assembly provides various copolymer morphologies depending on the block compositions, as judged by transmission electron microscopy and dynamic light scattering. Two novel disulfide-functionalized PLA-branched block copolymers were also synthesized using simultaneous ROP of LA and RAFT copolymerization of OEGMA or DMA with a disulfide-based dimethacrylate. The disulfide bonds were reductively cleaved using tributyl phosphine to generate reactive thiol groups. Thiol–ene chemistry was utilized for further derivatization with thiol-based biologically important molecules and heavy metals for tissue engineering or bioimaging applications, respectively.

Radiation-grafting of thermo- and pH-responsive poly(N-vinylcaprolactam-co-acrylic acid) onto silicone rubber and polypropylene films for biomedical purposes

This work focuses on the effects of gamma-ray irradiation conditions on the stimuli-responsiveness of polypropylene (PP) films and silicone (SR) rubber substrates grafted with N-vinylcaprolactam (NVCL) and acrylic acid (AAc). PP films and SR rubber were modified by simultaneous polymerization and grafting of NVCL and AAc, using pre-irradiation oxidative method at a dose rate of 12.23kGyh−1 and doses ranging from 5 to 70kGy. NVCL and AAc solutions (1/1, v/v) at 50% monomer concentration (v/v) in toluene were added to the sample substrates, degassed, sealed and heated at 60 and 70°C for 12h. After grafting, the samples were soaked in ethanol and distilled water for 24h successively, followed by drying under vacuum. Samples were characterized by FTIR-ATR, DSC and swelling measurements. Critical points (pH critical or LCST) of grafts were obtained in a pH-environment (pH ranges from 2.2 to 9) and in a thermo-environment (temperature ranges from 22 to 50°C). Cytotoxicity evaluation was performed using fibroblast BALB/c 3T3 cells. The relationship between NVCL-co-AAc grafting and radiation dose was different for each substrate, PP and SR. At 50% NVCL/AAc concentration in toluene, grafting values were higher for SR than for PP. Despite the fact that PP-g-(NVCL-co-AAc) membrane presented a cytotoxic profile at the highest experimental concentration assayed, cytotoxicity evaluation revealed noncytotoxic profiles for the membranes synthesized highlighting their applications for biomedical purposes.

Synthesis and characterization of diblock and statistical copolymers based on hydrolyzable siloxy silylester methacrylate monomers

Statistical and diblock copolymers of bis(trimethylsiloxy)methylsilyl methacrylate (MATM2), a hydrolyzable monomer containing a silylester and a siloxane group, and methyl methacrylate (MMA) were synthesized by the RAFT process. The controlled character of the MATM2 RAFT polymerization using 2-cyanoprop-2-yl-dithiobenzoate (CPDB) or S-(2-cyanoprop-2-yl)-S-dodecyltrithiocarbonate as chain transfer agents was assessed by linear pseudo-first-order kinetics, linear molar mass growth with monomer conversion and low molar-mass dispersity. The hydrolysis kinetics of pMATM2 homopolymers was investigated by in situ1H-NMR and compared to several methacrylic homopolymers bearing hydrolyzable tri-alkylsilylester side groups. pMATM2-block-pMMA diblock copolymers were synthesized by in situ chain extension with methyl methacrylate, using pMATM2-CPDB as a macro-CTA. p(MATM2-stat-MMA) statistical copolymers were synthesized by simultaneous polymerization of MATM2 and MMA by the RAFT process. The monomer reactivity ratios for MATM2 (r1 = 1.29) and MMA (r2 = 0.62) were obtained from the Mayo Lewis equation using the least-squares method. All the copolymers synthesized by the RAFT process had molar masses close to the targeted values and low dispersities (ĐM < 1.15). DSC analysis and contact angle measurements revealed the influence of the copolymer microstructure (statistical or diblock) on their glass transition temperature and surface energy.

Straightforward Synthesis of Symmetrical Multiblock Copolymers by Simultaneous Block Extension and Radical Coupling Reactions

In situ combination of a polymerization step with a coupling reaction is demonstrated to accelerate the synthesis protocols for symmetrical multiblock copolymers. Predici simulations and experiments prove on the example of cobalt-mediated radical polymerization and coupling (CMRP/C) reactions that such synthesis strategy can be very effective and easy to conduct. Treatment of a cobalt-terminated poly(acrylonitrile) precursor with a mixture of acrylate and isoprene led to the rapid polymerization of the acrylate before isoprene-assisted radical coupling of the macroradical chains forming a well-defined poly(acrylonitrile)-b-poly(acrylate)-b-poly(acrylonitrile) triblock. The degree of polymerization of the central block, resulting from the balance between propagation and coupling, could be tuned by adjusting the relative concentration and varying the structure of the acrylate and diene. The same convergent strategy also permits the synthesis of ABCBA-type pentablock copolymer starting from a cobalt-functional diblock. Simultaneous radical polymerization and coupling is thus a powerful macromolecular engineering approach for the straightforward design of symmetrical multiblock copolymers.