Ester Copolymers Research Articles

Regular trends in synthesis of sorption-active granular copolymers of methacrylic acid esters with polyvinylpyrrolidone

Granular copolymerization of compounds of 2-hydroxyethyl methacrylate and glycidyl methacrylate with polyvinylpyrrolidone in inert solvents was studied. The copolymers synthesized show promise as polymer systems for prolonged and controlled drug release.

Dielectric studies of epoxy/polyester powder coatings containing titanium dioxide, silica, and zinc oxide pigments

Dielectric measurements are reported covering a frequency range from 10−3 to 105 Hz and a temperature range from ~355 to 410 K for a pigmented epoxy/polyester resin powder coating system. A large low frequency ohmic conduction was observed in all these systems and the electrical modulus representation was used to aid analysis. A space charge relaxation indicative of heterogeneity in the matrix was observed in the pure resin and the pigmented coatings. In the pure resin, the heterogeneity is associated with nanoscale phase separation. A study with the resin modified with Modaflow, an ester copolymer dispersion agent, shows that the dipole relaxation is more ideal and the activation energy for dipole relaxation is reduced compared with that observed in the pure resin. The introduction of titanium dioxide pigment reduces the activation energy but also increases the magnitude of the ohmic conductivity and space charge contributions to the dielectric permittivity. All the systems exhibit heterogeneity and in the case of a pigmented system charge carriers can be introduced into the system by the pigment. Clear differences are observed between TiO2 produced via the chloride and sulfate routes, reflecting different levels of charge carriers and ion mobile in the resin system. High levels of mobile ions were also observed when zinc oxide and silica were used as pigments.

Controlled radical (co)polymerization of (meth)acrylic esters via the reversible addition-fragmentation chain-transfer mechanism

The homopolymerization of acrylic and fluoroacrylic esters mediated by benzyl dithiobenzoate and dibenzyl trithiocarbonate proceeds in the controlled mode via the reversible addition-fragmentation chain-transfer mechanism, while the controlled radical polymerization of methacrylic esters is not effected under these conditions. The molecular-mass characteristics of the copolymers of acrylic and methacrylic esters may be satisfactorily controlled by benzyl dithiobenzoate-mediated copolymerization when the content of acrylic esters is no less than 50 mol %. If a reversible addition-fragmentation chain-transfer agent active with respect to only one of the monomers is used, compositionally homogeneous narrowly dispersed copolymers are formed via the azeotropic copolymerization of the monomers up to high conversions. The controlled copolymerization of N-vinylpyrrolidone and fluoroacrylates allows the synthesis of alternating narrowly dispersed amphiphilic copolymers with properties different from those of alternating copolymers with a broad molecular-mass distribution.

Preparação de nanopartículas poliméricas a partir da polimerização de monômeros: parte I

Nanopartículas poliméricas produzidas a partir de polímeros sintéticos, como copolímeros do ácido metacrílico, ésteres acrílicos ou metacrílicos, têm sido amplamente utilizadas na área farmacêutica para encapsulação de princípios ativos. Essas nanopartículas apresentam as vantagens de proteção, liberação controlada, melhor biodisponibilidade e menor toxicidade, proporcionando maior conforto aos pacientes e adesão ao tratamento. A produção das nanopartículas (nanocápsulas e nanosferas) por polimerização de monômeros é revisada e descrita neste artigo, evidenciando os parâmetros tecnológicos que interferem nas características físico-químicas das nanopartículas, como a solubilidade do princípio ativo, o volume e pH do meio de polimerização, a massa molar e concentração do monômero e a natureza e concentração do tensoativo.

Analysis of Dispersion Behavior of Silane Coupling Agent in Acrylic Ester Copolymer

感圧接着剤（粘着剤）でガラス等の無機物に貼付するような用途では，高温高湿の環境下においても長期間高い粘着性，耐久性，耐湿性が求められ，シランカップリング剤が添加される場合がある。例えば，建物や車両などの開口部におけるガラスへの機能性フィルム貼付用粘着剤，光学機能性部材を液晶セルのガラス基板に接着するための粘着剤などである。そのため，シランカップリング剤の分散状態を解析し，粘着特性との関係を明らかにする事により，効果的なシランカップリング剤の利用による，界面接着強度の制御が可能になると考える。しかし，これまでに粘着剤中のシランカップリング剤分散状態を具体的に数値化した例はほとんどない。本報では，アクリル酸エステル共重合体中のシランカップリング剤添加量を変化させた時の分散状態解析及びガラスに対する粘着力を評価し，シランカップリング剤分散状態との関係を考察した。ブチルアクリレート，2－ヒドロキシエチルメタアクリレートからなるアクリル酸エステル共重合体に架橋剤及びシランカップリング剤を添加し，酢酸エチルにて希釈後，ポリエステルフィルム上に塗布することで粘着シートを作製した。シランカツプリング剤の分散状態をX線光電子分光法(XPS)及びC60イオンスパッタリングを用いて解析した結果，シランカップリング剤は粘着シート表面に偏在し，添加量の増加に伴い表面存在量も増加する傾向を示した。また，粘着シート､表面のシランカップリング剤量が，粘着力制御に重要であることが示された。

Chemical modification of poly(ethylene‐co‐methyl acrylate‐co‐maleic anhydride) for cathodic electrodepositions

AbstractThis study is concerned with the development of new polymers that could be deposited via cathodic electrocoating methods on metal surfaces. The synthetic strategy is based on the incorporation of cationic functionalities into commercial polymers. Polyalkyl acrylic or methacrylic ester copolymers were reacted with primary or secondary amines and aminoalkanols or their mixtures. Depending on the proportion of the acrylic or methacrylic ester in the starting material and the extent of the chemical modification, the resulting amide functionalized polymers are soluble or dispersible in water and could be used as aqueous dispersions for cathodic electrodepositions. Hindered amine catalysts, such as diazabicyclo[2.2.2]octane, accelerate the chemical transformation leading to higher level of functionalization. Among different amines screened, mixtures of oleylamine and ethanolamine proved to produce the best results. A poly(ethylene‐co‐methyl acrylate‐co‐maleic anhydride) [poly(E‐co‐MA‐co‐MAH)] was aminolyzed in solution with a mixture of 50/50 (mol % ratio) of oleylamine/ethanolamine and used to generate aqueous dispersions via phase inversion from methyl isobutyl ketone solutions. These dispersions exhibit particle sizes in the submicron range and zeta potential values indicating a good stability. They could be electrodeposited to give films of high elasticity according to the nanomechanical tests. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

New vinyl ester copolymers as stabilisers for dispersion polymerisation in scCO 2

In this paper we demonstrate new poly vinyl alkylate homopolymers and copolymers with excellent solubility in scCO 2 that can be used as stabilisers for dispersion polymerisation in scCO 2. Poly (vinyl acetate) (PVAc) was combined in various ratios with poly (vinyl butyrate) (PVBu) and poly (vinyl octanoate) (PVOc) to both tune the scCO 2-solubility and provide adequate steric stabilisation. The polymer cloud points observed were found to be dependent on the ratio of the different blocks and the molecular weights and polydispersities (PDI) of the polymers. The effectiveness of these new polymeric stabilisers for dispersion polymerisation of N-vinyl pyrrolidone ( N-VP) in scCO 2 is presented.

Influence of Ethylene Acrylic Alkyl Ester Copolymer Wax Dispersants on the Rhological Behavior of Egyptian Crude Oil

A variety of techniques have been employed in order to reduce problems caused by the crystallization of paraffin during the production and/or transportation of paraffin oils and derivatives. Ethylene acrylic acid copolymer, PEAA, was esterified with 1-docosanol, DcA, in the presence of p-toluene sulfonic acid, PTSA, as a catalyst and xylene as a solvent. The produced ester was characterized by FTIR and 1H NMR. The polymeric additive was added at different doses ranged from 1000 to 5000 ppm to crude oil to reduce its pour point and viscosity. The copolymer achieved a large reduction in the pour point and the viscosity of samples of Egyptian wax crude oils. The polymer was show good reduction of pour point temperature and viscosity of the crude oil tested depending on the composition of crude oil.

Block copolymerization of vinyl ester monomers via RAFT/MADIX under microwave irradiation

Well-defined homopolymers and block copolymers of vinyl esters were synthesized under microwave irradiation via reversible addition-fragmentation chain transfer (RAFT)/macromolecular design via interchange of xanthates (MADIX) polymerization without the significant inhibition or retardation often observed under conventional heating conditions. Poly(vinyl acetate) (PVAc) with molecular weights of 1000−10 000 g/mol was prepared in less than 15 min under microwave irradiation at an apparent temperature of 70 °C in the presence of the commercially available chain transfer agent ethylxanthogenacetic acid. The polymerizations were well-controlled, leading to polymers with narrow molecular weight distributions and excellent agreement between theoretical and experimental number average molecular weights. Despite the high rates of polymerization, the resulting PVAc homopolymers retained a high degree of thiocarbonylthio end group functionality that allowed the synthesis of block copolymers by chain extension with vinyl benzoate and vinyl pivalate. The rates of polymerization during the addition of the second blocks were also high, and the resulting block copolymers were obtained in good yield with excellent blocking efficiencies.

The influence of casting solvent composition on structure and permeability of acrylic-methacrylic ester copolymer films.

Decrease in the solvation of polymer by inclusion of ethanol in the acetone casting solution resulted in greater permeability to urea of cast acrylate-methacrylate film. The greater permeability was accompanied particularly by a decrease in pore size and increase in pore number, despite the absence of change in pore area. A decrease in cohesiveness in the film was suggested by the decrease in tortuosity of the pores as seen by scanning electron microscopy; also, water uptake was increased when the film was cast from an ethanolic solution. The results support the view that, in practice, the composition of the solvent, by its effect on microstructure, can affect the function of the film cast from it.

A versatile kit of additives to lubricating oils

Various mixtures of imidazolines, copolymers of methacrylic acid esters, and trithiolanes were examined as additives to motor oils for diesel fuels or to cutting fluids.

Adsorption of surfactant-rich stickies onto mineral surfaces

"Stickies" are tacky species, present in recycled paper and coated broke, derived from coating formulations, adhesives etc. They impact negatively on paper quality and cause web runnability problems by deposit build-up. To sustain recycling, stickies are controlled by adsorbing them onto minerals added to the recycled stock. We report isotherms for a fatty acid ester defoamer and an acrylic acid ester copolymer adsorbing from colloidal suspension onto various talcs and modified calcium carbonates. We used commercial preparations of the fatty acid ester defoamer and acrylic acid ester copolymer to provide a simple analogue to the industrial process. The modified calcium carbonates are hydrophilic with anionic and cationic sites present. Adsorption isotherms for low surface area modified calcium carbonate conform to the Langmuir model, while those for high surface area modified calcium carbonate reflect a two stage process involving the formation of a monolayer over the mineral surface and subsequent partial aggregation. Talc platelets display hydrophilic edges and hydrophobic surfaces. Adsorption onto them appears to involve three stages; specifically, a hydrophilic interaction between hydrophilic groups on the molecules and the talc edges, followed by hydrophobic interactions between the molecules and the talc surfaces, and finally by formation of multilayers.

Development of controlled release formulations of azadirachtin-A employing poly(ethylene glycol) based amphiphilic copolymers

Controlled release (CR) formulations of azadirachtin-A, a bioactive constituent derived from the seed of Azadirachta indica A. Juss (Meliaceae), have been prepared using commercially available polyvinyl chloride, polyethylene glycol (PEG) and laboratory synthesized poly ethylene glycol–based amphiphilic copolymers. Copolymers of polyethylene glycol and various dimethyl esters, which self assemble into nano micellar aggregates in aqueous media, have been synthesized. The kinetics of azadirachtin-A, release in water from the different formulations was studied. Release from the commercial polyethylene glycol (PEG) formulation was faster than the other CR formulations. The rate of release of encapsulated azadirachtin-A from nano micellar aggregates is reduced by increasing the molecular weight of PEG. The diffusion exponent (n value) of azadirachtin-A, in water ranged from 0.47 to 1.18 in the tested formulations. The release was diffusion controlled with a half release time (t1/2) of 3.05 to 42.80 days in water from different matrices. The results suggest that depending upon the polymer matrix used, the application rate of azadirachtin-A can be optimized to achieve insect control at the desired level and period.

Development of Poly(ethylene glycol) Based Amphiphilic Copolymers for Controlled Release Delivery of Carbofuran

The formation of micelles in a solvent that is selective for one of the blocks is one of the most important and useful properties of block copolymers. We had synthesized copolymers of polyethylene glycol and various dimethyl esters, which self assemble into nano micellar aggregates in aqueous media. In the present work, we have utilized these nano micelles for the encapsulation of carbofuran, [2,3–dihydro-2,2-dimethylbenzofuran-7-yl methylcarbamate], a systemic insecticide-nematicide, for the development of controlled release formulation.

Solvent-Free Polymerization of l-Aspartic Acid in the Presence of d-Sorbitol to Obtain Water Soluble or Network Copolymers

l-Aspartic acid was thermally polymerized in the presence of d-sorbitol with the goal of synthesizing new, higher molecular weight water soluble and absorbent copolymers. No reaction occurred when aspartic acid alone was heated at 170 or 200 °C. In contrast, heating sorbitol and aspartic acid neat or with ammonium hydroxide gave a mixture of water soluble and insoluble copolymers of polysuccinimide and sorbitol. In the presence of phosphoric acid, sorbitol aspartate ester copolymers having both water soluble and highly swollen gel components were formed. These results indicate that polysaccharides such as sorbitol can readily react to form copolymer ester/amides with aspartic acid and such copolymers may have utility as biodegradable water soluble and swellable polyampholytes.

Function of styrene-acrylic ester copolymer latex in cement mortar

This paper focuses on the effect of the styrene-acrylic ester copolymer (SAE) latex on the performance of cement mortar, through studying on the water-reduction and water-retention effects of the SAE latex in the mortar, and the influence of the SAE latex on the air-content and the bulk density of the fresh mortar and the bulk density, compressive and flexural strengths, shrinkage rate, water capillary adsorption and anti-penetration capacity of the hardened mortar. The experimental results show that the SAE latex has good water-reduction and water-retention effects in mortar. The SAE latex has also air entrainment effect, increasing the air content and reducing the bulk density of the fresh mortar. The apparent bulk density and dry bulk density of the hardened mortars decrease with the increase of the SAE latex/cement-ratio (mp/mc) and the change is in accordance with that for the bulk density of the fresh mortar. The SAE latex influences the development of the compressive strength but slightly on the flexural strength, and improves the toughness, shrinkage property, waterproofing quality and anti-penetration capacity of the mortar significantly.

Effectiveness of Polycarboxylate Superplasticizers in Ultra-High Strength Concrete: The Importance of PCE Compatibility with Silica Fume

Methacrylate ester as well as allylether based polycarboxylates (PCEs) were synthesized to plasticize pastes of cement and silica fume having a water/cement ratio of 0.22. Methacrylate ester copolymers were found to disperse cement well, whereas allylether copolymers are more effective with silica fume. Mechanistic investigations revealed that in cement pore solution, the surface charge of silica fume becomes positive by adsorption of Ca 2+ onto negatively charged silanolate groups present on the silica surface. This way, polycarboxylate copolymers adsorb to and disperse silica fume grains. Thus, mixtures of both copolymers were tested in cement-silica fume pastes. These blends provide significantly better dispersion than using only one polymer. Apparently, the surfaces of hydrating cement (here mainly ettringite) and silica fume are quite different with respect to their chemical composition. Therefore, PCEs with different molecular architectures are required to provide maximum coordination with calcium atoms present on these surfaces.

Synthesis and performance of methacrylic ester based polycarboxylate superplasticizers possessing hydroxy terminated poly(ethylene glycol) side chains

The synthesis and performance of new methacrylate ester based polycarboxylate superplasticizers is shown. These new superplasticizers possess hydroxy termination of the poly(ethylene glycol) side chains instead of conventional methoxy termination. Properties of the new superplasticizers in cement paste were compared to those of conventional ones. For this comparison, methacrylic acid–poly(ethylene glycol) methacrylate ester copolymers having three different side chain lengths and either hydroxyl or methoxy terminated graft chains were synthesized. For characterization of the superplasticizers, gel permeation chromatography (GPC) as well as anionic charge density determination was carried out. The performance of the polymers in cement was tested by measuring paste flow, adsorption as well as zeta potential. Additionally, retardation of the copolymers possessing side chains of 45 ethylene oxide units was investigated by heat calorimetry. According to the data, macromonomers based on hydroxy terminated poly(ethylene glycol) methacrylate ester chemistry allow to produce superplasticizers of high quality.

Characterization of acrylic copolymers applied in negative‐type photoresist via a ternary composition diagram

AbstractThree‐component acrylic copolymers used as a binder for negative‐type photoresists were synthesized and characterized. First, free radical polymerization was employed to synthesize two‐component binders, i.e., acrylic ester copolymers with different ratios of benzyl methacrylate (BZMA) and methacrylic acid (MAA). Thermal behavior, viscosity and molecular weight of the prepared two‐component binders were studied. Then, a series of three‐component binders were prepared through incorporation of another monomer, 2‐hydroxyethyl methacrylate (2‐HEMA). FTIR was used to examine the evolution of chemical bonds at various stages of the synthetic process. Thermal analyses, TGA and DSC, were used to evaluate the level of enhancement on thermal stabilities of the prepared three‐component binders. Finally, an optimal region in the ternary composition diagram of BZMA, MAA, and 2‐HEMA can be identified by comparing the results of acid value, viscosity, and molecular weight of the binder. A negative‐type photoresist was prepared using an optimized composition, for which resolution of the circuit could reach the level of 6 μm. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Synthesis and Characterization of Phosphonate Ester/Phosphonic Acid Grafted Styrene−Divinylbenzene Copolymer Microbeads and Their Utility in Adsorption of Divalent Metal Ions in Aqueous Solutions

In this paper the preparation and characterization of some chelating resins, phosphonate grafted on polystyrene−divinylbenzene supports, are reported. The resins were prepared by an Arbuzov-type reaction between chloromethyl polystyrene−divinylbenzene copolymers and triethylphosphite, yielding the phosphonate ester copolymer (resin A). This can be hydrolyzed by HCl to yield the phosphonate/phosphonic acid copolymer (resin B). The phosphonate resins A and B were characterized by determination of the phosphorus content, infrared spectrometry, and thermal analysis. The total sorption capacity of the phosphonate ester functionalized resin (A) and phosphonate/phosphonic acid functionalized resin (B) for divalent metal ions such as Ca2+, Cu2+, and Ni2+ was studied in aqueous solutions. Resin A retains ∼3.25 mg of Ca2+/g of copolymer and 2.75 mg of Cu2+/g of copolymer, but retains no Ni2+ at pH 1. On the other hand, resin B retains 8.46 mg of Ca2+/g of copolymer, 7.17 mg of Cu2+/g of copolymer, and no Ni2+ at pH 1. Efficient Ni2+ retention was observed at pH 7 only for the phosphonate/phosphonic acid functionalized resin (B) at the level of 19 mg of Ni2+/g of polymer B. Polymer A was incapable of retaining Ni2+ at pH 7.