Ethylene-acrylic Copolymer Research Articles

A ToF‐SIMS investigation of a buried polymer/polymer interface exposed by ultra‐low‐angle microtomy

AbstractThe interfacial region of a model multilayer coating system on an aluminium substrate has been investigated by high‐resolution time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS). Employing ultra‐low‐angle microtomy (ULAM), the interface between a poly(vinylidene difluoride) (PVdF)‐based topcoat and a poly(urethane) (PU)‐based primer ‘buried’ >20 µm below the PVdF topcoat's air/coating surface was exposed. Imaging ToF‐SIMS and subsequent post‐processing extraction of mass spectra of the ULAM‐exposed interface region and of the PVdF topcoat and PU primer bulks indicates that the material composition of the polymer/polymer interface region is substantially different to that of the bulk PVdF and PU coatings. Analysis of the negative ion mass spectra obtained from the PVdF/PU interface reveals the presence of a methacrylate‐based component or additive at the interface region. Reviewing the topcoat and primer coating formulations reveals that the PVdF topcoat formulation contains methyl methacrylate (MMA)–ethyl acrylate (EA) acrylic co‐polymer components. Negative ion ToF‐SIMS analysis of an acrylic co‐polymer confirms that it is these components that are observed at the PVdF/PU interface. Post‐processing extraction of ToF‐SIMS images based on the major ions of the MMA–EA co‐polymers reveals that these components are observed in high concentration at the extremities of the PVdF coating, i.e. at the polymer/polymer interface, but are also observed to be distributed evenly throughout the bulk of the PVdF topcoat. These findings confirm that a fraction of the MMA–EA acrylic co‐polymers in the formulation segregate to the topcoat/primer interface where they enhance the adhesive properties exhibited by the PVdF topcoat towards the underlying PU primer substrate. Copyright © 2004 John Wiley & Sons, Ltd.

Binding of Dodecyltrimethylammonium Bromide to pH-Responsive Nanocolloids Containing Cross-Linked Methacrylic Acid−Ethyl Acrylate Copolymers

The binding of dodecyltrimethylammonium bromide (DoTab) to cross-linked methacrylic acid-ethyl acrylate (MAA-EA) copolymers with various MAA/EA molar ratios at different degrees of neutralization (alpha) was quantitatively studied using isothermal titration calorimetry, dynamic light scattering, surfactant selective electrode, and electrophoresis techniques. The surfactant binds to the polymers at all degrees of neutralization, but via different mechanisms. When alpha is sufficiently high, the binding is primarily electrostatic interaction between the surfactant and ionized polymer chains, which is reinforced by the micellization of electrostatically bound surfactant molecules. The saturation takes place at charge ratio ([DoTa(+)]/[ approximately COO(-)]) close to 1, indicating that the binding is a one-to-one charge neutralization between the cationic surfactant headgroups and anionic carboxylate sites of the polymers. When alpha is low, the binding of DoTab to the unneutralized polymers is driven by the hydrophobic interaction. The onset of hydrophobic binding takes place at DoTab concentration as low as 0.01 mM in 0.05 wt % polymer solution, where the saturation occurs at C(DoTab) approximately 0.19 mM and the amount of bound surfactant is approximately 0.09 mmol of DoTab/(g of polymer) at saturation concentration. The binding results in the formation of the polymer-surfactant complex. For the polymer with low MAA/EA molar ratio, the complex coagulates at a higher DoTab concentration that leads to phase separation; however, for polymers with high MAA/EA molar ratio, the complex remains dispersed and the mixture is stable even at high DoTab concentration.

PH-independent release of a basic drug from pellets coated with the extended release polymer dispersion Kollicoat ® SR 30 D and the enteric polymer dispersion Kollicoat ® MAE 30 DP

The objective of this study was to obtain pH-independent release profiles from coated pellets containing drugs with pH-dependent solubility. pH-independent release of the basic model drug verapamil HCl was achieved by coating with a combination of the neutral polymer dispersions Kollicoat ® SR 30 D (aqueous dispersion of polyvinyl acetate) and the enteric polymer dispersion Kollicoat ® MAE 30 DP (aqueous dispersion of methacrylic acid and ethyl acrylate copolymer; methacrylic acid copolymer type C). The two polymers where applied either as separate layers (enteric polymer+extended release polymer or vice versa) or as a polymer blend. A careful balance of the ratios of the polymers allowed the achievement of a pH-independent release. Higher amounts of the enteric polymer in the polymer blend resulted in a reversal of the pH-dependency, e.g. a faster release at pH 6.8 than in 0.1 N HCl.

Small‐angle neutron scattering of poly(styrene)/poly(acrylic acid–ethyl acrylate) copolymers: The effect of the degree of hydrolysis of the poly(acrylic acid–ethyl acrylate) block

AbstractWe report the results of systems based on polystyrene‐poly(ethyl acrylate) (PEA) diblocks, which self‐assemble in aqueous solutions to form spherical micelles. Previous work has shown that the rheological properties of these solutions, in particular the gel–liquid transition, can be tuned through the use of a simple hydrolysis reaction to convert PEA to poly(acrylic acid) (PAA). We studied the effect of the extent of hydrolysis on the self‐assembly and micellar interactions. Small‐angle neutron scattering (SANS) spectra were fit with a variety of models to determine the micelle structure. As more PEA was converted to PAA (i.e., as the corona became more charged and more hydrophilic), the micellar aggregation number decreased, analogous to observations of other polymeric micelles. This effect could impact the gel–liquid transition and rheology in this system and in similar micellar block copolymer gels. Finally, our SANS spectra qualitatively agreed with predictions for attractive colloidal glasses, confirming the idea that the elasticity of these gels arises from the jamming of micelles. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 490–497, 2004

Novel Functionalised Ethylene Acrylate Copolymers as Polymer Modifiers

A novel reactive functionalised polymer modifier system based on ethylene acrylate copolymers produced by a tubular reactor polymerisation process is discussed. The tubular copolymers are unique due to the heterogeneous distribution of acrylate comonomer in the polymer chain making them more compatible with a variety of polymer systems. Because of this feature they can be used as modifiers and universal masterbatch carrier resins for a variety of polymer systems in a more appropriate way than their autoclave based homologues. The new reactive modifiers have excellent compatibility with both polar and non-polar polymers. The incorporation of a reactive functional group, such as maleic anhydride, is used to provide optimal morphology for polymer modification. Impact modification of polyamides using the new acrylate modifier is discussed. Besidessuperior impact properties, the functionalised ethylene acrylate modifier provides improved gloss in moulded parts and flow in polyamide blends compared to conventional reactive modifiers. Another feature of the finished compounds is their high elongation at break. Furthermore, the morphology of the new modifier in PA is discussed. Apart from the modification of polyamides, other applications such as coupling of mineral fillers to polymer matrices is conceivable.

Synthesis and Aggregation Behavior of Amphiphilic Block Copolymers in Aqueous Solution: Di- and Triblock Copolymers of Poly(ethylene oxide) and Poly(ethyl acrylate)

Di- and triblock copolymers of ethylene oxide (EO) and ethyl acrylate (EA) were synthesized by the atom transfer radical polymerization technique. The chemical compositions of the di- and triblock copolymers as determined by NMR and gel permeation chromatography are represented by [EO114EA10] and [EA10EO445EA10], respectively. The aggregation behaviors of these polymers in aqueous solutions were studied using a combination of static light scattering (SLS), dynamic light scattering, steady fluorescence, time-resolved fluorescence quenching (TRFQ), and surface tension techniques. The hydrodynamic radii (Rh) of PEO-b-PEA and PEA-b-PEO-b-PEA, where PEO is poly(ethylene oxide) and PEA, poly(ethylene acrylate), in an aqueous solution possess values of 15.3 and 25.5 nm, respectively, and they are independent of the polymer concentrations, which suggest that these micelles are formed via the closed association model. The critical micelle concentration (cmc) for the di- and triblock copolymers as determined from t...

Evaluation of Hypromellose Acetate Succinate (HPMCAS) as a Carrier in Solid Dispersions

The utility of hypromellose acetate succinate (HPMCAS), a cellulosic enteric coating agent, as a carrier in a solid dispersion of nifedipine (NP) was evaluated in comparison with other polymers, including hypromellose (HPMC), hypromellose phthalate (HPMCP), methacrylic acid ethyl acrylate copolymer (MAEA), and povidone (PVP). An X‐ray diffraction study showed that the minimum amount of HPMCAS required to make the drug completely amorphous was the same as that of other cellulosic polymers, and less than that in dispersions using non‐cellulosic polymers. Hypromellose acetate succinate showed the highest drug dissolution level from its solid dispersion in a dissolution study using a buffer of pH 6.8. This characteristic was unchanged after a storage test at high temperature and high humidity. The inhibitory effect of HPMCAS on recrystallization of NP from a supersaturated solution was the greatest among all the polymers examined. Further, the drug release pattern could be modulated by altering the ratio of succinoyl and acetyl moieties in the polymer chain. Our results indicate that HPMCAS is an attractive candidate for use as a carrier in solid dispersions.

Thermal properties of hydrophobically modified methacrylic acid-ethyl acrylate copolymer solutions

The thermal behavior of a water-soluble associating polymer system, hydrophobically modified alkali-soluble emulsion (HASE) polymer, was investigated. This polymer contains a methacrylic acid–ethyl acrylate copolymer backbone with 1 mol % of pendant hydrophobic groups grafted to it. The thermal behavior of the HASE polymer exhibits different trends compared to the hydrophobic ethoxylated urethane (HEUR) system. The lifetime of the hydrophobic junction of the HASE polymer increases with temperature due to the increase in the entropy of the system. However, the structural relaxation time decreases with temperature, caused by the enhanced Brownian dynamics of polymer chains. The relaxation behavior of HASE polymers is either governed by the lifetime of the hydrophobic junction, the structural relaxation time, or a combination of both, depending on the degree of network formation and temperature. Temperature studies indicated that the transient network theory proposed by Tanaka and Edwards is inadequate for describing the activation process of hydrophobic junctions in the HASE associative polymer. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 604–612, 2004

Ion‐exchange resins. II. Acrylamide crosslinked copolymers as precursors for some ion exchangers

AbstractCrosslinked copolymers of acrylamide (AA) and ethylacrylate and some ion exchangers derived from them containing either primary amine groups, obtained by the Hofmann degradation of the amide groups, or carboxylic groups, obtained by the alkaline hydrolysis of the ester groups, were studied. Divinylbenzene and N,N′‐methylenebisacrylamide were used as crosslinkers. The starting copolymers and the corresponding ion exchangers were characterized by IR spectroscopy, swelling behavior, and thermogravimetric analysis. The ion‐exchanger properties were correlated with the crosslinker nature and the chemical reactions performed on the AA copolymers. The average molecular weight between two crosslinks, determined from the swelling data in water, was compared with that calculated on the basis of the copolymerization stoichiometry only for the carboxylic cation exchangers. In this way, the preservation of the crosslink density after the hydrolysis was revealed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2701–2707, 2003

Molar mass characterization of cationic methyl methacrylate–ethyl acrylate copolymers using size-exclusion chromatography with online multi-angle light scattering and refractometric detection

Size-exclusion chromatography (SEC) combined with online multi-angle light scattering (MALS) and refractometric (RI) detection has been employed for the molar mass characterisation of water-insoluble cationic methyl methacrylate–ethyl acrylate copolymers (Eudragit RS and RL). Due to their positive charge, cationic polymers are particularly difficult to separate on a SEC column, in worst cases being completely adsorbed on the oppositely charged packing material. This work has examined how a careful addition of salt (LiCl) to the copolymer solution in ethanol decreases the electrostatic interactions, clearly seen as a decrease in elution volume from the SEC column as well as an improved recovery. At a certain level of ionic strength, typically about 50 m M, the copolymer recovery from the SEC column reached 100% and molar mass distributions corresponding to the complete sample could be obtained. The combined MALS/RI detection gives the opportunity to measure the absolute molar mass independent of recovery and retention. Thus, in this study, it turned out to be a favourable tool for tracing the changes in elution behaviour of the charged copolymer as the ionic strength was increased.

The flame retardant mechanism of polyolefins modified with chalk and silicone elastomer

AbstractThis paper presents the current understanding of the flame retardant mechanism of Casico™. The study includes the flame retardant effect of each individual component: ethylene–acrylate copolymer, chalk and silicone elastomer, as well as the formation of an intumescent structure during heating. The flame retardant properties were investigated by cone calorimetry and oxygen index tests. To obtain insight into the flame retardant mechanism, heat treatment under different conditions has also been performed. The results indicate that the flame retardant mechanism of Casico is complex and is related to a number of reactions, e.g. ester pyrolysis of acrylate groups, formation of carbon dioxide by reaction between carboxylic acid and chalk, ionomer formation and formation of an intumescent structure stabilized by a protecting char. Special emphasis is given to the formation of the intumescent structure and its molecular structure as evaluated from 13C MAS‐NMR and 29Si MAS‐NMR, ESCA and XRD analysis. After treatment at 500°C the intumescent structure consists mainly of silicon oxides and calcium carbonate and after treatment at 1000°C the intumescent structure consists of calcium silicate, calcium oxide and calcium hydroxide. Copyright © 2003 John Wiley & Sons, Ltd.

Laccase-catalyzed oxidation of naphthol in the presence of soluble polymers

The oxidation of 1-naphthol and 2-naphthol was studied in presence of recombinant laccases (benzenediol:oxygen oxidoreductase, EC 1.10.3.2) from Polyporus pinsitus (rPpL), Myceliophthora thermophila (rMtL), Coprinus cinereus (rCcL) and Rhizoctonia solani (rRsL). During 1-naphthol oxidation a violet colored insoluble product was formed. The product of 2-naphthol oxidation was a white insoluble precipitate. Almost two moles of 1-naphthol was oxidized by one mole of oxygen. Kinetic measurements of oxygen consumption showed that laccases have been inactivated during naphthols oxidation. Water soluble polymers and albumins changed oxidation profile. The polymers investigated were divided into three groups. The first group includes polymers which increase total oxygen consumption without changing an initial rate: polyvinyl alcohol, ficoll, a copolymer of acrylamide, N-vinylpyrrolidone and ethyl acrylate, hydroxyethyl cellulose, dextrans 500, 110 and 20, polyvinylpyrrolidone, polyethylene glycol and albumins. These polymers intermediately bound hydrophobic naphtholic radicals preventing inactivation of laccases. Cationic polymers such as diethylaminoethyl-dextran, poly- l-lysine and protasan that inhibited the initial oxidation rate, but did not change total oxygen consumption, were attributed to the second group. The inhibition was associated with complexation of positively charged polymers with negatively charged laccases since isoelectric points of rPpL and of rMtL were 3.5 and 4.2, respectively. The polymers such as alginic acid, polyacrylic acid and heparin were attributed to the third group. These polymers carried negative charges and formed random coil in solution due to electrostatic repulsion. They did not interact with laccases and did not combine intermediates. Therefore, they practically did not change total oxygen consumption and initial rate of naphthol oxidation.

Testing the Durability of Polymyxin B Immobilization on a Polymer Showing Antimicrobial Activity: A Novel Approach with the Ion-Step Method

A polymyxin B (PMB) modified copolymer of ethyl acrylate and 2-hydroxyethyl methacrylate is reported that shows antibacterial activity towards E. coli. The polymer is designed for biosensor interfaces to provide protection against microbial contamination. However, leaching of a biomolecule from its solid support is a well-known problem in immobilization chemistry. It has been proposed that antimicrobial activity results from release of the antibiotic from the polymer matrix, but in the work reported here, bactericidal action was seen for tresyl activated polymers even when no polymyxin B could be detected in the supernatant and where covalent attachment of PMB was indicated. Further evidence for the in situ action of PMB on the polymer was provided using a novel method of investigation, subjecting the polymer, deposited on an Ion-Sensitive Field-Effect Transistor (ISFET) to a step change in ion-concentration (Ion-step). With the ion-step method activation of the polymer and the grafting of Polymyxin-B were followed. A comparison of absorbed PMB on a nonactivated polymer and PMB on the tresyl activated polymer suggested that if leaching of PMB from the latter occurred, it was below the detection limit and well below the minimum inhibitory concentration (MIC) for antimicrobial action. Bactericidal action was thus attributed to PMB attached to the polymer.

Thickening of acrylic lattices with dispersions of crosslinked ethyl acrylate–methacrylic acid copolymers

Thickening of three model lattices of copolymers of ethyl acrylate and 0–2 wt.% of acrylic acid using dispersions of ethyl acrylate–methacrylic acid copolymer crosslinked with 0.25–5 wt.% of N, N′-methylenebisacrylamide was investigated. Measurement of the static light scattering revealed that the highest thickening effect occurred when, after alkalinisation, a sufficient amount of highly swollen crosslinked particles arose from the thickener. Viscoelastic properties of this basic matrix are a decisive factor for the rheological behaviour of thickening material.

Effect of crosslinking on the positive temperature coefficient stability of carbon black‐filled HDPE/ethylene‐ethylacrylate copolymer blend system

AbstractCarbon black‐filled high‐density polyethylene (HDPE)/ethylene ethylacrylate copolymer (EEA) blends were prepared and the effect of crosslinking of the blends on the positive temperature coefficient (PTC) stability was investigated. By irradiation and silane‐crosslinking methods, crosslinked composites with various degrees of crosslinking were obtained. Crosslinking of the matrix polymer led to the disappearance of the negative temperature coefficient (NTC) phenomenon. Also, the PTC intensity increased with an increasing degree of crosslinking. The PTC stability of silane‐crosslinked samples was notably improved at heat cycles of 140°C. This was sufficiently improved by both the silane‐ and radiation‐crosslinking methods when they were treated at 85°C. Therefore, the limiting temperature of self‐regulating heat is about 85°C. Both radiation‐ and silane‐crosslinked samples are thought to be of use to the industry.

Modifier offers low cost alternative for plastics

DuPont has developed a new range of economically-priced ethylene-acrylate copolymers, manufactured through tubular technology. This technology produces copolymers with a different molecular structure, yielding features and properties different from those made by the conventional high-pressure autoclave route.These differences point to new cost-effective ways for compounders and processors to modify engineering plastics and to prepare masterbatches. Dr. K Hausmann, Bernard Rioux and Coreen Y Lee of DuPont describe how the company has introduced the new resins as Elvaloy® AC ethylene-acrylate copolymers, which are available as methyl, ethyl and butyl acrylates.

高速液体クロマトグラフィー（ＨＰＬＣ）によるアクリル酸ブチル‐アクリル酸エチル共重合体の組成分布解析

Copolymers of butyl acrylate (BA) and ethyl acrylate (EA) were prepared. Their conversion was kept below 10% for obtaining samples with a narrow chemical composition distribution. The composition of each sample was determined by 1H nuclear magnetic resonance (NMR). The mixture of the copolymers was separated depending on composition by normal and reversed phase high performance liquid chromatography (HPLC) using cross-linked acrylamide and styrene beads, respectively. Samples with higher BA content eluted earlier with normal phase HPLC, while opposite order with reversed phase HPLC, indicating that BA unit is less polar than EA unit. Observed composition distribution of copolymers was broader than the calculated one assuming copolymerization theory. The difference between them can mainly be explained by the peak broadening in the column and tailing.

Synthesis of poly(2‐oxo‐1,3‐dioxolane‐4‐yl) methyl methacrylate by polymer reaction of carbon dioxide and miscibility of its blends with copolymers of methyl methacrylate and ethyl acrylate

Synthesis of poly(2‐oxo‐1,3‐dioxolane‐4‐yl) methyl methacrylate by polymer reaction of carbon dioxide and miscibility of its blends with copolymers of methyl methacrylate and ethyl acrylate

Synthesis of poly(2‐oxo‐1,3‐dioxolane‐4‐yl) methyl methacrylate by polymer reaction of carbon dioxide and miscibility of its blends with copolymers of methyl methacrylate and ethyl acrylate

AbstractPolymeric epoxides were converted to corresponding five‐membered cyclic carbonates in an effective manner. Poly(glycidyl methacrylate) (PGMA) was converted to a poly(2‐oxo‐1,3‐dioxolane‐4‐yl) methyl methacrylate (PDOMMA) by the polymer reaction with carbon dioxide using tetraoctylammonium chloride (TOAC) as a catalyst. The miscibility of blends of PGMA or PDOMMA with copolymers of MMA and ethyl acrylate (MMA‐EA) of two different EA compositions (2 and 5 wt %) was investigated by differential scanning calorimetry (DSC). The films of PGMA or PDOMMA and MMA‐EA (2 and 5 wt %) blends were cast from N,N‐dimethylformamide solution. An optical clarity test and DSC analysis showed that PDOMMA blends were miscible over the entire composition range, but PGMA was immiscible with the MMA‐EA copolymers. It was also found that the miscibility of PDOMMA with 2 wt % MMA‐EA copolymer was better than that of DOMMA with 5 wt % MMA‐EA copolymer. The different miscibility behaviors were investigated in terms of Fourier transform IR spectra and interaction parameters based on the binary interaction model. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2161–2169, 2001

Synthesis, characterization, and properties of amphiphilic poly(ethyl acrylate) with uniform polyoxyethylene grafts

AbstractAmphiphilic copolymers of ethyl acrylate (EA) with uniform polyoxyethylene (PEO) grafts were synthesized by copolymerization of EA with methacrylate terminated PEO macromer in benzene using azobisisobutyronitrile as the initiator. The effects of the molecular weight of the macromers, the charging weight ratio of the macromer to EA, the total monomer concentration, and the amount of initiator on the grafting efficiency (GE) were reported as was the molecular weight of the copolymers. The highest GE reached to above 90% and the molecular weight of the copolymers varied from (5–15) × 104. The reactivity ratio of EA with the macromer was determined to be 0.83. The graft copolymers were purified with extractions and the purified products were characterized with IR, 1H‐NMR, gel permeation chromatography, differential scanning calorimetry, and membrane osmometry. The average grafting number of the copolymer varied from 2 to 11. The glass‐transition temperature of the poly(EA) in the copolymer was increased because of the partial compatibility of the two components. The crystalline property, emulsifying property, and dilute solution viscosity of the graft copolymers, as well as ionic conductivity of their complexes with alkali metal salts, were studied. The emulsifying volume decreased with the increasing molecular weight of the PEO grafts. The addition of NaOH to the emulsion affected the emulsifying volume only slightly, whereas the addition of HCl changed the oil in water type emulsion into a water in oil type. The conductivity of the LiClO4 complex of the copolymer with an oxyethylene/Li ratio of 20 reached 3.7 × 10−5 S/cm at 27°C. The lower the crystallinity of the complex, the higher was the conductivity. The dilute solution viscosity showed the existence of intramolecular microphase separation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 903–912, 2001