Synthesis of hollow crosslinked miktoarm polymer using miniemulsion as templates

Hollow crosslinked polymers (HCPs) were synthesized using arm first method via atom transfer radical polymerization. The polymerization process was performed in miniemulsion system, in which the macroinitiator, PEG‐Br, was in the water phase, whereas the vinyl‐monomer, 4‐vinylpyridine (4VP), and the crosslinker, DVB, were in the butanone phase. TEM images and light scattering characterization showed that the resultant polymer contained a hollow space, and the volume of the hollow space could be adjusted by changing the ratio of water to butanone. Also, hollow crosslinked Miktoarm polymers (HCMPs) were synthesized through this method when two different macroinitiators, PEG‐Br and PNIPAM‐Br, were used to coinitiate the polymerization of the vinyl‐monomer, 4VP and DVB. The ¹H NMR spectra showed that the hollow polymers contained both PEG arms and PNIPAM arms. The hollow morphologies of the resultant Miktoarm polymers were the same as the HCPs. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1651–1660, 2009     

Synthesis of patterned polymer brushes from flexible polymeric films

Surface-initiated polymerizations were carried out from polymeric surfaces of commercially important polyester films, poly(ethylene terephthalate) (PET) and poly(ethylene naphthalate) (PEN). These plastic films were modified prior to polymerization by plasma oxidation, exposing surface hydroxyl groups, in order to immobilise patterned self assembled monolayers (SAMs) of trichlorosilane initiator, through the soft lithographic method of microcontact printing (μCP). Subsequently, polymerizations were initiated from the surface via controlled atom transfer radical polymerization (ATRP), under aqueous conditions, to create patterned brushes of the thermo-responsive polymer poly(N-isopropyl acrylamide) (PNIPAM). By creating patterned, rather than homogeneous brushes characterization was made possible by atomic force microscopy (AFM).     

A facile and environment-friendly method for fabrication of polymer brush

A novel environment-friendly system is proposed tofabricate polymer brush, which has the advantages including non-toxic and inexpensive initiator(eosin Y), visible-light exposure(λ= 515 nm), water medium and ambient environment. The experimental results from UV-Vis spectroscopy, AFM-based single molecule force spectroscopy(SMFS) and other measurements indicate thata polymer brush with a living nature is fabricated via free radical polymerization. This polymer brush may find applications incoatings, bio-interfaces and so forth.     

Synthesis characterizations and properties of a new fluoro-maleimide polymer

Novel 4-(4-trifluoromethyl)phenoxy N-phenyl-maleimide (FPMI) was synthesized. The free radical-initiated polymerization of FPMI was carried out in 1,4-dioxane solution using azobisisobutyronitrile as initiator. The monomer was investigated by FTIR, ¹H NMR, ¹³C NMR and elemental analysis, while the polymer was investigated by FTIR, ¹H NMR and ¹³C NMR. The effect of the monomer concentration, initiator concentration and temperature on the rate of polymerization (R_p) was studied. The activation energy of the polymerization was calculated (ΔE = 48.94 kJ/mol). The molecular weight of PFPMI and polydispersity index of the polymer were determined by gel permeation chromatography and were equal to 73,500, 16,700 and 2.27, respectively. The properties of PFPMI, including thermal behavior, thermal stability, the glass transition temperature (T_g = 236 °C), photo-stability, solubility and solution viscosity were studied.     

Preparation of reactive polymeric nanoparticles (RPNPs)

A series of reactive polymeric nanoparticles (RPNPs) was prepared by free radical nonlinear copolymerization of mono (M ₁) and trivinyl acrylic (M ₂) monomers in miniemulsion. The crosslinking density was determined by the mole ratio of the trivinyl component. It was found that the unswelled latex nanoparticles showed a narrower dispersity than in the organic solution of macromolecules. In latex, the size increased with the ratio of M ₂ monomer due to its higher polarity in the aqueous medium. However, the swollen nanoparticles, dissolved or dispersed in organic solvent, showed a higher dispersity as a function of composition and the crosslinking density. The residual vinyl groups adjacent to the nanoparticles were subjected to further crosslinking reactions. The reactive vinyl groups were detected by nuclear magnetic resonance spectroscopy (NMR). The size of particles in swollen state was determined by dynamic laser light scattering (DLS) method and the dried form by scanning electron microscopy (SEM). It was found that size of RPNPs is in the range of 50 to 500 nm. These particles possess properties that may allow their application in areas as disparate as dental filling material and as a component in industrial powder-based coatings.     

Formation of homogeneous nanocomposite films at ambient temperature via miniemulsion polymerization using graphene oxide as surfactant

A convenient and industrially scalable method for synthesis of homogeneous nanocomposite films comprising poly(styrene‐stat‐butyl acrylate) and nanodimensional graphene oxide (GO) or reduced GO (rGO) is presented. Importantly, the nanocomposite latex undergoes film formation at ambient temperature, thus alleviating any need for high temperature or high pressure methods such as compression molding. The method entails synthesis of an aqueous nanocomposite latex via miniemulsion copolymerization relying on nanodimensional GO sheets as sole surfactant, followed by ambient temperature film formation resulting in homogeneous film. For comparison, a similar latex obtained by physical mixing of a polymer latex with an aqueous GO dispersion results in severe phase separation, illustrating that the miniemulsion approach using GO as surfactant is key to obtaining homogeneous nanocomposite films. Finally, it is demonstrated that the GO sheets can be readily reduced to rGO in situ by heat treatment of the film. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2289–2297     

Synthesis of nitroxide‐containing block copolymers for the formation of organic cathodes

This contribution describes the polymerization of 2,2,6,6‐tetramethylpiperidin‐4‐yl methacrylate by atom transfer radical polymerization (ATRP). Different catalytic systems are compared. The CuCl/4,4′‐dinonyl‐2,2′‐dipyridyl catalytic system allows a good control over the polymerization and provides polymers with a polydispersity index below 1.2. The successful polymerization of styrene from PTMPM‐Cl macroinitiators by ATRP is then demonstrated. Successful quantitative oxidation of PTMPM‐b‐PS block copolymers leads to poly(2,2,6,6‐tetramethylpiperidinyloxy‐4‐yl‐methacrylate)‐b‐poly(styrene) (PTMA‐b‐PS). The cyclic voltammogram of PTMA‐b‐PS indicates a reversible redox reaction at 3.6 V (vs. Li⁺/Li). Such block copolymers open new opportunities for the formation of functional organic cathode materials. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Uniform molecularly imprinted microspheres and nanoparticles prepared by precipitation polymerization: the control of particle size suitable for different analytical applications

Molecularly imprinted polymers (MIPs) are being increasingly used as selective adsorbents in different analytical applications. To satisfy the different application purposes, MIPs with well controlled physical forms in different size ranges are highly desirable. For examples, MIP nanoparticles are very suitable to be used to develop binding assays and for microfluidic separations, whereas MIP beads with diameter of 1.5-3 μm can be more appropriate to use in new analytical liquid chromatography systems. Previous studies have demonstrated that imprinted microspheres and nanoparticles can be synthesized using a simple precipitation polymerization method. Despite that the synthetic method is straightforward, the final particle size obtained has been difficult to adjust for a given template. In this work, we initiated to study new synthetic conditions to obtain MIP beads with controllable size in the nano- to micro-meter range, using racemic propranolol as a model template. Varying the composition of the cross-linking monomer allowed the particle size of the MIP beads to be altered in the range of 130 nm to 2.4 μm, whereas the favorable binding property of the imprinted beads remained intact. The chiral recognition sites were further characterized with equilibrium binding analysis using tritium-labeled (S)-propranolol as a tracer. In general, the imprinted sites displayed a high chiral selectivity: the apparent affinity of the (S)-imprinted sites for (S)-propranolol was 20 times that of for (R)-propranolol. Compared to previously reported irregular particles, the chiral selectivity of competitive radioligand binding assays developed from the present imprinted beads has been increased by six to seven folds in an optimized aqueous solvent.     

Synthesis of 4-arm methyl methacrylate star polymer by atom transfer radical polymerization

The synthesis of 4-arm methyl methacrylate star polymer had been achieved successfully by atom transfer radical polymerization using CuCl as catalyst, 2, 2′-bipyridyl as ligand and pentaerythritol tetrakis (2-bromoisobutyrate) as the initiator. The star polymer was characterized by ¹H-NMR and GPC, by which the precise 4-arm structure of the PMMA was confirmed. __________ Translated from Journal of Shaanxi Normal University (Natural Science Edition), 2008, 36(2) (in Chinese)     

Synthesis of novel core‐crosslinked graft copolymers from crosslinked poly(mercapto‐thiourethane)

Crosslinked poly(mercapto‐thiourethane) was employed as a precursor for graft copolymer synthesis. The crosslinked stem polymer ( 1 ) was easily prepared by polyaddition of a bifunctional dithiocarbonate and piperazine under air atmosphere via oxidative coupling of mercapto group. Polymerization of styrene and methyl methacrylate in the presence of 1 yielded the corresponding crosslinked graft copolymers with high grafting weight percentages (>1800%). © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5097–5102, 2005     

Synthesis of molecularly imprinted polymer nanoparticles for the fast and highly selective adsorption of sunset yellow

Novel molecularly imprinted polymer nanoparticles were synthesized by precipitation polymerization with sunset yellow as the template and [2‐(methacryloyloxy)ethyl] trimethylammonium chloride as the functional monomer. The molecularly imprinted polymer nanoparticles were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and their specific surface area and thermal stability were measured. The molecularly imprinted polymer nanoparticles had a high adsorption capacity in wide pH range (pH 1–8) for sunset yellow. The adsorption equilibrium only needed 5 min, and the quantitative desorption was very fast (1 min) by using 10.0 mol/L HCl as the eluant. The maximum adsorption capacity of the molecularly imprinted polymer nanoparticles for sunset yellow was 144.6 mg/g. The adsorption isotherm and kinetic were well consistent with Langmuir adsorption model and pseudo‐second‐order kinetic model, respectively. The relative selectivity coefficients of the molecularly imprinted polymer nanoparticles for tartrazine and carmine were 9.766 and 12.64, respectively. The prepared molecularly imprinted polymer nanoparticles were repeatedly used and regenerated ten times without significant absorption capacity decrease.     

Porous sol gel silica films doped with crystalline NiO nanoparticles for gas sensing applications

A reliable sol gel route to synthesize NiO doped SiO₂ films with different NiO content is here described. The films showed detectable and reversible changes in both optical and electrical properties when exposed to some reducing/oxidizing gaseous species at temperatures in the 250°C–350°C range. A functional characterization protocol has been designed and some of the sensing properties of the materials have been investigated for detecting NO₂, CH₄, CO and H₂. An optical transmittance increase up to 2% has been detected for 1% CO in dry air atmospheres, while relative resistance response (R _R = R _gas/R _air) values up to 4.97 for 850 ppm H₂/air mixtures have been registered for conductometric gas sensing. Films at all NiO molar concentrations in the 10% NiO - 40% range showed an optical response to the target gas, while only 30% and 40% NiO films provided a detectable gas induced resistance change.     

Synthesis,characterization and impregnation of lead sulphide semiconductor nanoparticles on polymer matrix

Lead sulphide nanoparticles were prepared using a precursor and dual sources methods. The composites were fabricated by stabilizing chemically synthesized semiconductor PbS nanocrystals into laurylmethacrylate and ethyleneglycol dimethacrylate matrix in the presence of tri-n-octylphosphine. PbS nanocrystals were dispersed in toluene as a compatible medium for the polymerization and cross-linking of poly laurylmethacrylate networks. The nano-sized particles and polymer composites were characterized by XRD and TEM. Possible formulations and incorporation of these PbS nanoparticles in polymer matrix have been discussed. The reported lead sulphide nanoparticles into tailered polymeric system show greater uniformity and stability.     

Synthesis of highly crosslinked monodisperse polymer particles: Effect of reaction parameters on the size and size distribution

Monodisperse polystyrene particles crosslinked with different concentrations of divinylbenzene were synthesized in the 3.2–9.1 μm size range by dispersion polymerization in an isopropyl alcohol/toluene mixed‐dispersion medium with poly(N‐vinylpyrrolidone) as a steric stabilizer and 2,2′‐azobisisobutyronitrile as a radical initiator. The effects of the reaction parameters such as the crosslinking agent concentration, media solvency (controlled by varying the amount of toluene addition), the initiator concentration, and the stabilizer concentration on the particle size and size distribution were investigated with reference particles with a monodisperse size distribution and crosslinked by 1.5 wt % divinylbenzene. The appropriate increase in media solvency was a prerequisite for preparing crosslinked particles without coagulated and/or odd‐shaped particles. The investigation of the effects of the polymerization parameters also shows that only specific sets of conditions produce particles with a monodisperse size distribution. The glass‐transition temperatures of the particles increased with increasing divinylbenzene concentration. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4368–4377, 2002     

Synthesis of functional polymer particles by dispersion polymerization in organic media: A tool toward stable electrophoretic inks

In this article, a simple route to obtain particles in one step from functional ionizable monomers in organic media by the use of acrylate‐based macroinitiator synthesized by nitroxide‐mediated radical polymerization is presented. Different positively ionizable monomers like 4‐vinylpyridine, (dimethylamino)ethyl methacrylate, or negatively ionizable ones like methacrylic acid and acrylic acid were tested. Several parameters were studied to control the particles size, their stability in different organic media, and the possibility to crosslink them. Finally, well‐defined, depending of conditions, functional latexes in organic media were produced in a simple way. This synthetic process constitutes the first step to produce electrophoretic inks for display applications such as electronic paper. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4608–4617     

Mechanical properties of films from polymer latices

The mechanical behavior of latex films is governed by their macromolecular nature as well as by their origin from particles dispersed in an aqueous medium. When monomers of different polarity are copolymerized in emulsion copolymerization, a heterogeneous distribution of the polar groups in the latex and the film can occur, owing to the different water solubilities of the comonomers. Films from these latices in many cases show a two-phase morphology, first, consisting of the main polymer within the particles and, second, a phase which is concentrated in the interphase between the original particles and which has a strong influence on the mechanical properties of the films. Films from latices with crosslinked particles behave like homogeneous networks in the linear viscoelastic range, i.e. at small strains. Structured networks are found when latex films are interparticularly crosslinked during or after film formation, e.g. by polar bifunctional monomers or metal salts. Tensile tests of films show that the mechanical strength of latex films develops in the last stage of film formation by interdiffusion and entaglement formation across particle boundaries.     

Synthesis and properties of crosslinked chiral nanoparticles via RAFT miniemulsion polymerization

Crosslinked chiral nanoparticles were successfully synthesized via reversible addition‐fragmentation chain transfer (RAFT) miniemulsion polymerization of 6‐O‐p‐vinylbenzyl‐1,2:3,4‐di‐O‐isopropylidene‐D ‐galactopyranose (VBPG) using linear poly(VBPG) as the macro‐RAFT agent. The polymerization of VBPG in the absence of crosslinker was first studied and the kinetic results showed that the molecular weights of the obtained poly(VBPG) increased linearly with the monomer conversion and was in good consistency with the corresponding theoretical ones while there remained a relative narrow polydispersity. The effect of the amount of crosslinker, divinylbenzene, on the nanoparticle size and chiral separation properties of the obtained nanoparticles were investigated in detail using four racemates ±‐3‐Amino‐1,2‐propanediol, D ,L ‐arabinose, D ,L ‐tartaric acid, and D ,L ‐mandelic acid. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1324–1331, 2010     

Chitosan nanoparticles crosslinked by glycidoxypropyltrimethoxysilane for pH triggered release of protein

pH-responsive-chitosan nanoparticles for the control release of protein drug were prepared by combining two-step crosslinking method,in which chitosan was subsequently crosslinked by sodium tripolyphosphate(TPP)and glycidoxypropyltrimethoxysilane (GPTMS).Compared with TPP crosslinked chitosan particles,the two-step crosslinked nanoparticles were not only pH-responsive but also more stable in wide pH range.Fluorescein isothiocyanate(FITC)labeled anti-human-IgG antibody was used as a model protein drug for...     

Synthesis of methacrylate polymer bearing cyanate groups and its chemoselective reaction with amines

A novel reactive polymer containing cyanate groups in the side chain was prepared by free radical polymerization of a cyanate‐containing monomer, 2‐(4‐cyanatophenyl)ethyl methacrylate ( 1 ). The monomer 1 and its polymer, poly[2‐(4‐cyanatophenyl)ethyl methacrylate] (PCPMA), were stable under the air for a long period. The copolymerization of 1 and methyl methacrylate provided the corresponding copolymers with various cyanate contents. The availability of the cyanate‐containing polymers as a reactive polymer was investigated. Model reaction using 4‐cyanatotoluene revealed that a cyanate group reacted with aliphatic amines, whereas no reaction occurred in the presence of water, alcohols, and aromatic amines under mild conditions. Post‐functionalization of PCPMA was demonstrated using aliphatic amines or diamines. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 699–706     

Synthesis of Liquid Crystalline Polymers with Side Chains

The present paper covers the synthesis and characterization of several intermediate products, monomer, and polymers. 3-{ 2-[ 4-( 4-Nitrophenylazo ) phenoxy] ethyloxycarbonyl} propanoyloxy (2-hydroxy) propyl acrylate (4) was prepared by the ring-opening reaction of glycidyl acrylate with the monoester of succinic acid (3). The polymers (5) with different molecular weights were prepared by the free-radical polymerization. The polymers (5) had liquid crystalline behavior without decomposition as revealed by DSC, optical microscope.