PEO Macromonomer Research Articles

PCEs containing C5 and C6 based PEO side chains: A comparison on the synthesized polymers and the resulting dispersing effectivenesss

The reactivity of C5 and C6 based PEO macromonomers in the synthesis of PCE superplasticizers, followed by the dispersing abilities of such PCEs on cement pastes were analysed and compared in this study. It was found that free radical compolymerisation of C5 macromonomers and acrylic acid (AA) produced PCEs with less controlled block compolymers characteristics, which were highly sensitive to reaction conditions such as the rate of polymer additions, etc. This can be attributed to the difference in reactivity constants of the monomers, where AA was highly reactive. The orderness became more dominant when the temperature of synthesis was suitably controlled. The ease in adapting the molecular architecture of C6 based PCEs as compared to C5 based PCEs enabled better prediction of cement dispersing ability, as confirmed by the slump flow tests performed. It was thus shown through this study that using C6 macromonmers, PCE with tailormade acrhitecture could be developed easier than with C5 macromonomers, potentially to adapt to different types of cement on the market.

Polyelectrolyte stabilized nanodiamond dispersions

Colloidal stability of negatively charged nanodiamonds (ND) has been realized with the help of double hydrophilic block copolymers poly(ethylene oxide)-block-poly(dimethylaminoethyl methacrylate)-dodecyl (PEO-b-PDMAEMA-C12). The polymers were synthesized through RAFT polymerization of DMAEMA with a PEO macromonomer carrying trithiocarbonate and dodecyl end-groups. The NDs and the polymers were complexed by mixing them in different ratios. In addition to the amount of polymers, the effect of the detailed structure of the polymer was of interest and thus, also polymers with different lengths of the PEO-block were synthesized, as well as a block copolymer without the dodecyl end-group. The composition of the polymer, as well as the complexation conditions were varied to find the route to stable nanoparticles. The optimized complexation method gave colloidally stable ND particles with positively charged PDMAEMA coronas. The colloids were stable at room temperature and also in saline solutions up to 0.154 M NaCl.

Living Anionic Polymerization – Part II: Further Expanding the Synthetic Versatility for Novel Polymer Architectures

Living Anionic Polymerization – Part II: Further Expanding the Synthetic Versatility for Novel Polymer Architectures

Acrylamide monomers and polymers that contain phosphonate ions

Alkylacrylamide phosphonate monomers were synthesized by aza-Michael addition of an alkylamine onto the double bond of diethyl vinylphosphonate, then reaction with acryloyl chloride. Free radical copolymerization of n-butylacrylamide phosphonate with an acrylate-functional PEO macromonomer, then removal of the ethyl groups from the phosphonates led to poly(n-butylacrylamide phosphonic acid)-g-PEO copolymers. The copolymer comprising 56 wt% of the backbone and 44 wt% of PEO grafts was soluble in DMF, DMSO, methanol and water at pH 7.4. This copolymer formed aggregates in DMF and DMSO with only a few aggregates in methanol or water. Interaction of the phosphonic acid derivative (0.11 mmol) of n-butylacrylamide phosphonate with hydroxyapatite (0.15 or 0.30 mmol calcium ions) showed 80 and 95% extent of binding of the phosphonic acid whereas those values for acrylic acid were 47 and 64%. The hydrolytically stable polyacrylamide phosphonates with their excellent binding properties to hydroxyapatite make them potential candidates for adhesives.

Precise synthesis of undecenyl poly(ethylene oxide) macromonomers as heterofunctional building blocks for the synthesis of linear diblocks or of branched materials

Heterofunctional α-undecenyl-ω-hydroxy poly(ethylene oxide) (PEO) macromonomers could be designed by initiation. For their synthesis via Anionic Ring-Opening Polymerization (AROP) of ethylene oxide, a potassium alcoholate, prepared in situ by reaction of 10-undecene-1-ol with a stoichiometric amount of diphenylmethyl potassium (DPMK), was used. The applicability of the same initiator but in powder form was evaluated for the polymerization of ethylene oxide. This initiator is well-suited for, e.g., automated high-throughput screening approaches by simply weighing in the amount of initiator needed. The macromonomers were characterized by SEC, 1H NMR, MALDI-TOF MS and light scattering. Independent from the applied approach, well-defined heterobifunctional PEO macromonomers could be obtained. Their solution behavior was investigated in water and methanol by Dynamic Light Scattering (DLS) and in water by critical micelle concentration (cmc) measurements. Chemical modification of the hydroxyl end-group by methyl methacrylate or by propargyl bromide could be achieved leading to heterobifunctional PEO macromonomers. These PEOs offer a great potential as building blocks in macromolecular engineering. PI-b-PEO diblocks or comb-shaped PEOs represent typical examples.

Easy and effective method to produce functionalized particles for cellular uptake

In this contribution, a versatile approach for the synthesis of functionalized particles for drug delivery is presented, using two nonaggressive standardized procedures. The first procedure considered is the functionalization of an azido-terminated α-norbornenyl poly(ethylene oxide) (PEO) macromonomer with an alkyne-containing active molecule via the copper catalyzed azide alkyne cycloaddition, click type reaction. The functionalized macromonomer is then polymerized by Ring-Opening Metathesis Polymerization (ROMP) in dispersion to form functionalized particles. The second procedure consists in synthesizing particles by ROMP in dispersed media of norbornene with azido-terminated α-norbornenyl PEO macromonomer. The ROMP was initiated by the first generation Grubbs catalyst. Such functionalized core-shell particles have stealthy properties due to their PEO shell and can be viewed as universal nanocarriers on which any alkyne-modified active molecule can be grafted by click chemistry. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013

Uniform PEO Star Polymers Synthesized in Water via Free Radical Polymerization or Atom Transfer Radical Polymerization

Amphiphilic star shaped polymers with poly(ethylene oxide) (PEO) arms and cross-linked hydrophobic core were synthesized in water via either conventional free radical polymerization (FRP) or atom transfer radical polymerization (ATRP) techniques using a simple "arm-first" method. In FRP, PEO based macromonomers (MM) were used as arm precursors, which were then cross-linked by divinylbenzene (DVB) using 2,2'-azoisobutyronitrile (AIBN). Uniform star polymers (Mw/Mn < 1.2) were achieved through adjustment of the ratio of PEO MM, DVB, and AIBN. While in case of ATRP, both PEO MM, and PEO based macroinitiator (MI) were used as arm precursors with ethylene glycol diacrylate as cross-linker. Even more uniform star polymers with less contamination by low MW polymers were obtained, as compared to the products synthesized by FRP.

Pearl Necklace Architecture: New Threaded Star-Shaped Copolymers

The synthesis of star-shaped polymers, which are threaded regularly along a common backbone, is described. Thus, two different approaches for preparation of so-called pearl necklace polymers (synonyms: multigraft copolymers, barbwire or centipedes polymers, multiple dumbbells or star-oligomers) are presented. Poly(ethylene oxide) (PEO) was used as a thread and poly(dimethylaminoethyl methacrylate) (PDMAEMA) stars were used as pearls. In the first approach, a polycondensation reaction of PEO macromonomers with partly protected dipentaerythritol leads first to a multiblock PEO. Afterward, the protected hydroxy groups of dipentaerythritol, which is situated at the junction points of the blocks, can be released for the anchoring of PDMAEMA chains. In the second approach, anionic polymerization of ethylene oxide leads directly to a diblock PEO with an interior dipentaerythritol unit. The chain ends can be modified with further dipentaerythritols, giving access after selective deprotection to either star dimers...

An all ATRP route to PMMA–PEO–PS and PMAA–PEO–PS miktoarm ABC star terpolymer

An all Atom Transfer Radical Polymerization (ATRP) route to synthesize miktoarm ABC star terpolymer, μ-(poly(methyl methacrylate)–poly(ethylene oxide)–polystyrene) (μ-(PMMA–PEO–PS)), was demonstrated. Poly(methyl methacrylate) (PMMA) with a halide end group was first prepared by ATRP of MMA. It was then activated under ATRP conditions at 30°C to add a styrenic-terminated PEO macromonomer, resulting in the formation of PMMA-b-PEO. Finally, the active halide at the junction point of the diblock copolymer was used to initiate the ATRP of St at higher temperature. By a similar approach, μ-(poly(phenyl methacrylate)–poly(ethylene oxide)–polystyrene) (μ-(PhMA–PEO–PS)) was synthesized, hydrolysis of which in basic medium gave μ-(PMAA–PEO–PS). The polymers were characterized by 1H NMR spectroscopy and gel permeation chromatography.

Copolymer of poly(4-vinylpyridine)- g-poly(ethylene oxide) respond sharply to temperature, pH and ionic strength

The stimuli-responsive copolymers with poly(ethylene oxide) (PEO) as side chain were prepared by free-radical copolymerization of methacrylamide end-capped PEO macromonomer and 4-vinylpyridine (4VP). Phase transition behavior of these copolymers of poly(4-vinylpyridine)- g-poly(ethylene oxide) (P4VP- g-PEO) was investigated as a function of polymer concentration, temperature, pH and ionic strength by monitoring the turbidity of the polymer solutions. The copolymers displayed sharp response to temperature and pH. The LCST of P4VP- g-PEO copolymer increased with the increase of PEO content and decreased with increasing pH due to the deprotonation of the pyridine ring, indicating well-tunable LCST. In addition, the LCST of P4VP- g-PEO9 presented a unique phase transition behavior with varying salt concentration, showing a minimum with 1 M NaCl solution at pH 6.0.

Amphiphilic polymer brushes with alternating PCL and PEO grafts through radical copolymerization of styrenic and maleimidic macromonomers

Synthesis of a novel amphiphilic polymer brush with a sequence of alternating poly(ɛ-caprolactone) (PCL) and poly(ethylene oxide) (PEO) side chains through grafting-through approach is reported. This strategy consists of two steps: first, a PCL macromonomer carrying maleimide functional group (MI-PCL) and a PEO macromonomer with vinylbenzyl group (St-PEO) were prepared; then a conventional radical copolymerization of the MI-PCL and the St-PEO macromonomers was carried out to obtain the proto-type polymer brush. The reactivity ratios of two macromonomers were studied and the alternating sequence structure was proved.

Atom transfer radical copolymerization of N,N′-dimethylacrylamide with methacrylate-functionalized poly(ethylene oxide)

Graft copolymers with poly(ethylene oxide) (PEO) side chains were prepared by atom transfer radical copolymerization (ATRP) of N,N′-dimethylacrylamide (DMAA) with PEO macromonomer functionalized by methacrylate group (PEOMA). The reactions were initiated by alkyl halides in the presence of CuBr/HMTETA or CuCl/Me6TREN catalyst/ligand complexes in organic solvents at 70 or 30°C. The well-defined graft copolymers with polymerization degree up to 100 repeating units in the backbone and molecular weight distribution in the range 1.1–1.4 were obtained. Reactivity ratio of PEO methacrylate was higher in comparison to DMAA yielding copolymers with spontaneous gradient. Amorphous morphology was observed for DMAA/PEO copolymers with shorter PEO chains (nEO=5), whereas introduction of macromonomer having longer chain of PEO (nEO=23) generated crystalline properties.

Synthesis and Characteristics of Poly(macromonomers) and Graft Copolymers Composed of Poly(phenylacetylene) Main Chain and Poly(ethylene oxide) Side Chains

New amphiphilic water-soluble poly(macromonomers), poly(1) and poly(2), consisting of a poly(phenylacetylene) [poly(3)] main chain and poly(ethylene oxide) (PEO) side chains, were synthesized by the homopolymerization of PEO macromonomers, while poly(3)-based graft copolymers, poly(1-co-3) and poly(2-co-3), with PEO side chains were prepared by the copolymerization of the PEO macromonomers with phenylacetylene (3). Two PEO macromonomers 1 (DPPEO ∼ 16) and 2 (DPPEO ∼ 45) possessing 3 as an end group were prepared by the esterfication of p-ethynylbenzoic acid with commercial PEO monomethyl ethers. The macromonomers 1 and 2 homopolymerized in the presence of a binary Rh catalyst to yield poly(1) (DPs up to 55) and poly(2) (DPs up to 18), respectively. They also copolymerized with 3 to give graft copolymers poly(1-co-3) (Mn 37 500−93 800, 1 0.3−22 mol %) and poly(2-co-3) (Mn 44 900−177 800, 2 0.5−13 mol %). Poly(1) and poly(2) were a brown liquid and solid, respectively, while poly(1-co-3) and poly(2-co-3) were yellow solids. These polymers were soluble not only in relatively nonpolar solvents such as toluene and CHCl3 but also in polar solvents such as DMSO and MeOH. The side-chain crystallinity was observed in the solid state in poly(2-co-3) with PEO contents above 9 mol % according to DSC analysis.

Synthesis of Amphiphilic Copolymers of Poly(ethylene oxide) and Poly(ϵ‐caprolactone) with Different Architectures, and Their Role in the Preparation of Stealthy Nanoparticles

AbstractWell‐defined copolymers of biocompatible poly(ϵ‐caprolactone) (PCL) and poly(ethylene oxide) (PEO) are synthesized by two methods. Graft copolymers with a gradient structure are prepared by ring‐opening copolymerization of ϵ‐caprolactone (ϵCL) with a PEO macromonomer of the ϵCL‐type. The ϵCL polymerization is initiated by a PEO macroinitiator to prepare diblock copolymers. These amphiphilic copolymers are used as stabilizers for biodegradable poly(D,L‐lactide) (PLA) nanoparticles prepared by a nanoprecipitation technique. The effect of the copolymer characteristic features (architecture, composition, and amount) on the nanoparticle formation and structure is investigated. The average size, size distribution, and stability of aqueous suspensions of the nanoparticles is measured by dynamic light scattering. For comparison, an amphiphilic random copolymer, poly(methyl methacrylate‐co‐methacrylic acid) (P(MMA‐co‐MA)), is synthesized. The stealthiness of the nanoparticles is analyzed in relation to the copolymer used as stabilizer. For this purpose, the activation of the complement system by nanoparticles is investigated in vitro using human serum. This activation is much less important whenever the nanoparticles are stabilized by a PEO‐containing copolymer rather than by the P(MMA‐co‐MA) amphiphile. The graft copolymers with a gradient structure and the diblock copolymers with similar macromolecular characteristics (molecular weight and hydrophilicity) are compared on the basis of their capacity to coat PLA nanoparticles and to make them stealthy.

Preparation and retention of poly(ethylene oxide)‐grafted cationic polyacrylamide microparticles

AbstractNovel microparticles of poly(ethylene oxide) (PEO)‐grafted cationic polyacrylamide were prepared through the free‐radical tetrapolymerization of acrylamide, acryloyloxyethyl trimethylammonium chloride (DAC), PEO macromonomer, and N,N′‐methylene bisacrylamide in an inverse microemulsion. The effects of the DAC content and the PEO chain length and content on the diameter and distribution of the microparticles were studied. Highly effective retention aids were obtained in retention experiments with fibers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 359–363, 2006

Preparation and ionic conductivity of solid polymer electrolyte based on polyacrylonitrile‐polyethylene oxide

AbstractThe transparent and flexible solid polymer electrolytes (SPEs) were fabricated from polyacrylonitrile‐polyethylene oxide (PAN‐PEO) copolymer which was synthesized by methacrylate‐headed PEO macromonomer and acrylonitrile. The formation of copolymer is confirmed by Fourier‐transform infrared spectroscopy (FTIR) measurements. The ionic conductivity was measured by alternating current (AC) impedance spectroscopy. Ionic conductivity of PAN‐PEO‐LiClO4 complexes was investigated with various salt concentration, temperatures and molecular weight of PEO (Mn). And the maximum ionic conductivity at room temperature was measured to be 3.54 × 10−4 S/cm with an [Li+]/[EO] mole ratio of about 0.1. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 461–464, 2006

Thermo-induced formation of physical “cross-linking points” of PNIPAM- g-PEO in semidilute aqueous solutions

Linear poly( N-isopropylacrylamide) chains grafted with short poly(ethylene oxide) chains (PNIPAM- g-PEO) were prepared by free radical copolymerization of NIPAM and PEO macromonomers ( M w = 5000 g / mol ) end-capped with methacrylate in water. Temperature effects on the solution viscosity of thermally sensitive copolymer were studied in different aqueous concentrations. A specific transition was observed during the measurement of the reduced viscosities of PNIPAM- g-PEO copolymer at a certain concentration ( C 0 ) in semidilute aqueous solutions: the reduced viscosities increased sharply (namely, thermothickening behavior) at LCST when concentrations were higher than C 0 , or decreased sharply at LCST when concentrations lower than C 0 . A plateau was also found near C 0 when temperature was closing to LCST from low temperature, showing there is no change in reduced viscosity under this circumstance. The inverse increase of the viscosities at higher temperatures in higher concentration ( > ∼ 3 g / L ) is attributed to the forming of physical “cross-linking points” composed of collapsed PNIPAM core and expanded PEO shell. The sharp decrease of the viscosities at higher temperatures in lower concentration ( < ∼ 3 g / L ) is attributed to the forming of independent globules. The plateau could be attributed to the equilibrium competition between forming of physical “cross-linking points” and independent globules depending on the copolymer solution concentrations.

Gradient graft copolymers derived from PEO‐based macromonomers

AbstractAtom transfer radical polymerization (ATRP) of two poly(ethylene oxide) (PEO) macromonomers, with different polymerization degrees (DPn) and different end groups, was conducted in solution via the grafting through method. Selection of a PEO methacrylate with a methyl end‐group (PEOMeMA, DPPEO = 23) and a PEO acrylate end‐capped by a phenyl ring (PEOPhA, DPPEO = 4) for the copolymerization led to a spontaneous gradient of PEO grafts along the copolymer backbone. Such a composition was formed because of significantly different reactivities of the two PEO macromonomers. The resulting copolymer has PEOMeMA at one end of the polymer chain, gradually changing through hetero‐sequences of PEOPhA at the other chain end. An increase in the initial feed ratio of PEO acrylate reduced the rate of change in the shape of the gradient. Amorphous–crystalline structure in the copolymers was demonstrated by DSC and WAXS. The mechanical measurements of copolymers consisting of an amorphous PEOPhA and crystallizable PEOMeMA segments indicated elastomeric properties in the range of a soft rubber (G′ ∼ 104 Pa, G′ ≫ G″). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1347–1356, 2006

Synthesis of polyethylene oxide end-capped with perfluoroalkyl groups/polystyrene prototype brushes

Polystyrene (PS)/poly(ethylene oxide) (PEO) prototype brushes were prepared by alternating free-radical copolymerization of methacryloyl-terminated PS and α-vinylbenzyl-ω-hydroxy or α-vinylbenzyl-ω-perfluoroalkyl (Rf) PEO macromonomers with the addition of Lewis acid (SnCl4). It was found from their dilute-solution properties that PS/PEO end-capped with Rf (PBRf), and PS/PEO having OH groups at terminal ends (PBOH) prototype brushes formed a single molecule in benzene and aggregates in chloroform, respectively. However, the brush PBOH formed a single molecule in N,N-dimethylformamide. Such aggregation behaviors seemed to be caused by the interaction between hydroxy groups of PEO chain ends. The brush PBOH was also converted into PBRf-type brush by chemical modification, using corresponding acid chloride. The substitution of Rf groups was ∼70% due to slipping of terminal hydroxy groups into PEO internal domains. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 772–778, 2006

Synthesis and Liquid Crystalline Behavior of Random Copolymer of Poly(ethylene oxide) Macromonomer and Liquid Crystalline Monomer by the Photon Transmission Technique

Random copolymers of poly(ethylene oxide) macromonomer with p‐vinylbenzyl end‐functional group (PEOVB) and liquid crystalline monomer, namely 6‐(4‐cyanobiphenyl‐4′‐oxy)hexyl acrylate (COA), were prepared by conventional free radical polymerization. A living anionic polymerization technique was employed for the synthesis of PEO macromonomers bearing p‐vinylbenzyl moiety at one end. The photon transmission method was also applied to study the phase transitions of COA monomer and its random copolymer with PEO. It was found that, for both samples, the nematic‐smectic A transition is continuous, but the critical fluctuation regions do not allow to obtain 3D XY values. Instead, we have obtained the values close to mean field regime. Scaling of thermal hystersis for random copolymer sample near the nematic‐isotropic transition was studied as well. Thermal hysteresis loops were produced under linearly varying temperature. It was shown that the areas of the hysteresis loops scale with the temperature scanning rate with an exponent being equal to 0.614 which is in good agreement with the field‐theoretical value.