Acrylate Random Copolymers Research Articles

Random Copolymers Based on 2-Ethylhexyl Acrylate Exhibit Unusual Glass Transition Breadth and Facile Autonomous Self-Healing over a Broad Composition Range.

Statistical copolymers are commercially important because their properties can be tuned by comonomer selection and composition. Rubbery-state styrene (S)/n-butyl acrylate (nBA) copolymers have previously been reported to exhibit facile, autonomous self-healing over a narrow composition band (47/53 to 53/47 mol%). The need for a narrow composition band is explained by alternating comonomer sequences that accommodate interchain secondary bonding. It is hypothesized that copolymers that achieve interchain secondary bonding without alternating sequences can exhibit facile self-healing over a broad composition range. 2-ethylhexyl acrylate (EHA) is identified as yielding sequence-independent secondary bonding interactions. For these interactions it is tested experimentally by glass transition breadth in rubbery-state S/EHA copolymers, with S/n-hexyl acrylate (nHA) and S/nBA copolymers as controls. The n-alkyl acrylate random copolymers exhibit enhanced glass transition breadths over narrow composition bands that correspond to autonomous self-healing. In contrast, S/EHA copolymers exhibit much greater glass transition breadths than S/nHA and S/nBA copolymers at all compositions tested as well as self-healing of damage over a broad composition range with full tensile-property recovery, often in 3-10h. Characterization of glass transition breadth may serve as a simple screening tool for identifying copolymers that exhibit broad-composition-range, facile, autonomous self-healing and contribute to polymer resilience and sustainability.

Synthesis of a Vinyl Chloride-Methyl Acrylate Random Copolymer with Controllable Copolymer Composition and Its Processing Features in Rigid PVC

Synthesis of a Vinyl Chloride-Methyl Acrylate Random Copolymer with Controllable Copolymer Composition and Its Processing Features in Rigid PVC

Effect of compatibilizer addition on the surface nucleation of dispersed polyethylene droplets in a self-nucleated polypropylene matrix

A significant portion of the global plastics market encompasses the production of polyolefin materials and especially polypropylene (PP) and polyethylene (PE), as commodity polymers with a wide range of applications. However, the increase in the generation of unsustainable plastic waste requires a close technological look-up to address this challenge adequately. In this context, mechanical recycling is part of the strategies expected to contribute to the solution. Nevertheless, the melt blending process presents a challenge due to the immiscibility between PP and PE. Therefore, compatibilization strategies are meant to solve the problem effectively. In this paper, we employ a commercial ethylene-ran-methyl acrylate random copolymer as a compatibilizer for PP/PE blends. With the addition of the compatibilizer, it was possible to obtain a 44% reduction in PE domain size, while ductility increased by around ∼40% with respect to uncompatibilized blends. Interesting results were obtained concerning the crystallization behavior of the blends. The overall isothermal crystallization kinetics of the different blend components was studied, and a synergistic nucleation effect of the PP and the compatibilizer toward the PE phase was found. For the first time, the effect of the compatibilizer on the surface nucleation of PE in a self-nucleated PP matrix phase is reported. An enhancement in the crystallization rate of PE was found when the self-nucleation protocol was applied to the polypropylene matrix phase for neat and compatibilized blends. The nucleation efficiency was in the range of 120–124%, indicating a supernucleation behavior. The induced crystallization at the interface by the self-nucleated polypropylene is the reason for such high nucleation efficiencies. Surprisingly, a higher amount of compatibilizer decreases the overall crystallization rate of PE droplets. The compatibilizer segregates at the interface between both polymers, reducing the surface nucleation of the PE droplets on the PP matrix phase. The results presented in this paper lead the way toward improving the use of post-consumer recycled materials.

In situ crosslinkable acrylic random copolymer binders for silicon anodes in lithium‐ion batteries

Silicon is in the spotlight as a promising anode material for next-generation Li-ion batteries. However, its practical application is limited by a rapid decay in capacity due to considerable volume changes. Rational design of binders that can exhibit strong adhesion and robust mechanical properties is crucial for overcoming such challenges. Herein, we synthesize a series of multifunctional acrylic random copolymers comprising various ratios of acrylic acid and glyceryl groups by free-radical polymerization. The adhesive and mechanical properties of the binders are systematically modulated, and their impact on the electrochemical properties of a Si-nanoparticle anode are investigated. Owing to the presence of both acrylic acid and hydroxyl groups, the copolymers containing 7 mol% and 25 mol% glyceryl group undergo in situ crosslinking under mild thermal treatment (70°C for 24 h). In particular, the copolymer containing 7 mol% glyceryl group exhibits the highest specific capacity and capacity retention (1170 mAh g−1 and 54% after 100 cycles at 0.5 A g−1, respectively), which is superior to those of a conventional poly(acrylic acid) binder (880 mAh g−1 and 52% after 100 cycles at 0.5 A g−1). The enhanced electrochemical properties attribute to the improved adhesive and mechanical properties enabled by the network structure.

Study on Preparation of Fluorinated Photosensitive Copolymer and Surface Wettability Light Regulation

Low surface energy and micro/nano structure are two key factors affecting the construction of hydrophobic surfaces. In this paper, a series of tetrafluoropropyl methacrylate (TFPMA) and 6- [4- [2- [4- (trifluoromethoxy) phenyl] diazenyl] phenoxy] hexyl acrylate (FAzo) random copolymer [P(TFPMA-co-FAzo)] of different monomer molar ratios were prepared by free radical solution polymerization; and the chemical structure of the copolymer was characterized in detail using FTIR and 1HNMR. The introduction of long-chain flexible acrylate components with high fluorine content can effectively reduce the surface energy of the material. When the molar ratio of TFPMA is increased to 70%, the static water contact angle on the surface of the copolymer film is increased to 90°. By doping 10 wt% micron-sized PTFE particles, the water contact angle on the surface of the copolymer film can be further increased to 105°; Meanwhile, based on the cis-trans isomerization reaction of the azobenzene component in the copolymer, light irradiation with different wavelengths can realize the rapid and reversible regulation of hydrophobic/hydrophilic properties on the surface of copolymer film. This method of combining low surface energy fluorine-containing component with photosensitive azobenzene to construct light-responsive hydrophobic surface has a good research prospect.

A photo-crosslinkable bis-triarylamine side-chain polymer as a hole-transport material for stable perovskite solar cells

A crosslinkable acrylate random copolymer with both bis(triarylamine) and photocrosslinkable cinnamate side chains is compared to the widely used poly(4-butyl-triphenylamine-4′,4′′-diyl) as a hole-transport material in perovskite solar cells.

Tailoring the temperature-dependent viscoelastic behavior of acrylic copolymers by introducing hydrogen bonding interactions

A great challenge of toner design is to improve the storage stability and energy saving. The reciprocal characteristics of endowing high glass transition temperature (Tg) while low fusing temperature (Tf) are essential. In this study, we investigate the influence of hydrogen bonding interactions on Tg and temperature-dependent viscoelastic of styrene/ethyl acrylate random copolymers [P(St-co-EA)] with different ratios of St/EA by the incorporation of small molecule 4,4′-thio-bis(6-tert-butyl-m-methyl phenol) (AO300). The results of FTIR spectra confirm the intermolecular hydrogen bonding between the carbonyl groups of acrylic copolymers and hydroxyl groups of AO300 small molecules. With increasing AO300 content, Tg of the hybrids increases due to the increased number of hydrogen bonding. The universal scaling law of temperature-dependent viscoelastic behavior is indeed valid for pure acrylic copolymers in both the Arrhenius and non-Arrhenius regions. However, the temperature-dependent viscoelastic behaviors of the hybrids are strongly influenced by the ratio of St/EA and AO300 content, showing positive or negative deviations from the universal plot for high and low ratio of St/EA copolymer based hybrids, respectively. The systematic deviations are greater with increasing small molecule content. Such irregular deviations can be attributed to either the disassociation of hydrogen bonding or plasticizing effect by the introduction of AO300. The P(St-co-EA)/AO300 hybrids possessing high Tg and low Tf provides a promising candidate of toner binder resin to realize the storage stability and energy efficient.

Novel petroleum demulsifiers based on acrylic random copolymers

Although normally the copolymers used to remove water from crude oil have a block structure, two series of random acrylic copolymers were evaluated as petroleum demulsifiers. These acrylic copolymers, with two different butyl acrylate (BuA) and 2-ethylhexyl acrylate (2-EHA) contents, were synthesized by semi-continuous emulsion polymerization. Their weight-average molar mass () was varied by modifying the amount of chain transfer agent relative to the monomers from 0 to 8 wt%. FTIR and 13C-NMR spectroscopies confirmed that the conversion of the monomers was complete. The synthesized acrylic copolymers were subsequently evaluated as demulsifier agents in a Mexican heavy crude oil (10.24°API). Copolymers with 70 wt% butyl acrylate monomer and a weight-average molar mass above of 11 000 g mol−1 presented the greatest ability to remove emulsified water from the system. The demulsifying capability of the copolymer was evidenced to be strongly dependent on their molecular mass.HighlightsSynthesis of random acrylic copolymers (BuA-co-2-EHA) of different average molar mass ().Evaluation of random acrylic copolymers as demulsifiers of heavy crude oil.Weight-average molar mass () and monomer composition play an important role on the performance of random acrylic copolymers as demulsifiers.

Acrylate-Selective Transesterification of Methacrylate/Acrylate Copolymers: Postfunctionalization with Common Acrylates and Alcohols.

Acrylate-selective transesterification of methacrylate/acrylate copolymers with alcohols was developed for a site-selective postfunctionalization technique of polymers without using specific monomers. Importantly, a common methyl acrylate efficiently works as a selective modification unit via transesterification coupled with a titanium alkoxide catalyst. The acrylate-selective transesterification is achieved owing to less steric hindrance of the carbonyl groups that are attached to the main chain without an α-methyl group. Typically, the acrylate pendants of dodecyl methacrylate/methyl acrylate (MA) random copolymers were selectively transesterified with benzyl alcohol (BzOH). The conversion of the pendent esters into benzyl esters proportionally increased with MA contents. Additionally, various alcohols were applicable to this MA-selective transesterification system.

Viscoelastic Behavior of Poly(Methyl Methacrylate-Co-Methyl Acrylate) Random Copolymer Studied by Dynamic Mechanical Analysis and Nanoindentation

The viscoelastic behavior of poly(methyl methacrylate) (PMMA) homopolymer and poly(methyl methacrylate-co-methyl acrylate) random copolymers was characterized by dynamic mechanical analysis and nanoindentation. Differential scanning calorimetric results showed only one glass transition, indicating the random distribution of comonomers in the copolymers. The α relaxation temperature (Tα) and activation energy (Hα) decreased with increasing content of methyl acrylate monomers (CMA%). The β relaxation temperature (Tβ) also decreased whereas the activation energy (Hβ) showed only small variations compared with Hα. Moreover, the indention displacement and creep compliance strongly depended on CMA%. Two creep stages were found in the creep compliance curves.

Molecular View of Polymer/Water Interfaces in Latex Paint

To obtain a molecular level view of the interface of a latex particle with water solvent, atomistic simulations using two different force fields were performed for a slab of methyl methacrylate (MMA)/n-butyl acrylate (BA) random copolymer in water. The carbonyl groups at the polymer/water interface were found to orient significantly toward the water phase. We calculated the copolymer/water and the copolymer/vacuum interfacial tensions, and predict a contact angle for water on copolymer of 77°, consistent with experimental values. We also calculated bulk densities of MMA/BA copolymer, and PMMA and PBA homopolymers, which compare well with experiment, and the structure factor for PMMA, which agrees with neutron scattering results. The simulated Tg of PMMA is not far from its experimental value, despite the much shorter chains and faster cooling rates of simulations versus experiments, because these two effects tend to cancel each other. When we correct for these effects, the predicted Tg is within 5 K of th...

Effect of Restricted Phase Segregation and Resultant Nanostructural Heterogeneity on Glass Transition of Nonuniform Acrylic Random Copolymers

The glass transition behavior of emulsion polymerized butyl acrylate (BA)−methyl methacrylate (MMA) copolymers was related to their microstructural features. Broad transition regions composed of tw...

Polymer blend emulsion stabilization using carbon nanotubes interfacial confinement

The present study demonstrates the effect of unfunctionalized MultiWalled Carbon Nanotubes (MWNTs) interfacial confinement on coalescence suppression in an immiscible polymer blend exhibiting a sea-island morphology. The effect of carbon nanotubes on morphological stabilization in polyamide (PA)/ethylene–methyl acrylate random copolymer (EA) blends is studied using electronic microscopy techniques. Owing to their interfacial localization, MWNTs are shown to enhance both phase dispersion and stability of the dispersed phase for long mixing time (at least 60 min) and very low filler content (0.5 wt.-% MWNTs) compared to what was previously observed in literature. MWNTs also produce a more uniform distribution of droplets size. The main stabilization mechanism proposed is the formation of a deformable barrier network providing a mechanical barrier against coalescence. Blends stabilized by solid anisotropic nanoparticles, like MWNTs, could therefore offer an interesting alternative to blends compatibilized by block-copolymers.

QSPR Analysis of Copolymers by Recursive Neural Networks: Prediction of the Glass Transition Temperature of (Meth)acrylic Random Copolymers.

The glass transition temperature (Tg ) of acrylic and methacrylic random copolymers was investigated by means of Quantitative Structure-Property Relationship (QSPR) methodology based on Recursive Neural Networks (RNN). This method can directly take molecular structures as input, in the form of labelled trees, without needing predefined descriptors. It was applied to three data sets containing up to 615 polymers (340 homopolymers and 275 copolymers). The adopted representation was able to account for the structure of the repeating unit as well as average macromolecular characteristics, such as stereoregularity and molar composition. The best result, obtained on a data set focused on copolymers, showed a Mean Average Residual (MAR) of 4.9 K, a standard error of prediction (S) of 6.1 K and a squared correlation coefficient (R(2) ) of 0.98 for the test set, with an optimal rate with respect to the training error. Through the treatment of homopolymers and copolymers both as separated and merged data sets, we also showed that the proposed approach is particularly suited for generalizing prediction of polymer properties to various types of chemical structures in a uniform setting.

Vibration damping and electrical conductivity of styrene–butyl acrylate random copolymers filled with carbon black

AbstractEmulsion‐polymerized poly(styrene‐rand‐butyl acrylate) (St–BA) copolymers exhibit damping capabilities over a wide temperature range with changes in the monomer ratio. Blending copolymers of different compositions results in a multidamping peak, further widening the effective damping temperature range. Adding carbon black (CB) reduces the peak damping intensity but enhances damping at higher temperatures. The addition of dodecyl benzene sulfonic acid to an St–BA/CB aqueous dispersion improves the dispersion of CB in the polymer, reducing the percolation threshold and improving the conductivity while slightly affecting the mechanical behavior. The electrical properties of the St–BA/CB system are affected by the copolymer composition, influencing the polymer surface tension. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Effect of acrylic acid neutralization on ‘livingness’ of poly[styrene‐ran‐(acrylic acid)] macro‐initiators for nitroxide‐mediated polymerization of styrene

AbstractBACKGROUND: The effect of acrylic acid neutralization on the degradation of alkoxyamine initiators for nitroxide‐mediated polymerization (NMP) was studied using styrene/acrylic acid and styrene/sodium acrylate random copolymers (20 mol% initial acrylate feed concentration) as macro‐initiators. The random copolymers were re‐initiated with fresh styrene in 1,4‐dioxane at 110 °C at SG1 mediator/BlocBuilder® unimolecular initiator ratios of 5 and 10 mol%.RESULTS: The value of kpK (kp = propagation rate constant, K = equilibrium constant) was not significantly different for styrene/acrylic acid and styrene/sodium acrylate compositions at 110 °C (kpK = 2.4 × 10−6–4.6 × 10−6 s−1) and agreed closely with that for styrene homopolymerization at the same conditions (kpK = 2.7 × 10−6–3.0 × 10−6 s−1). All random copolymers had monomodal, narrow molecular weight distributions (polydispersity index M̄w/M̄n = 1.10–1.22) with similar number‐average molecular weights M̄n = 19.3–22.1 kg mol−1. Re‐initiation of styrene/acrylic acid random copolymers with styrene resulted in block copolymers with broader molecular weight distributions (M̄w/M̄n = 1.37–2.04) compared to chains re‐initiated by styrene/sodium acrylate random copolymers (M̄w/M̄n = 1.33).CONCLUSIONS: Acrylic acid degradation of the alkoxyamines was prevented by neutralization of acrylic acid and allowed more SG1‐terminated chains to re‐initiate the polymerization of a second styrenic block by NMP. Copyright © 2008 Society of Chemical Industry

Styrene/tert-Butyl Acrylate Random Copolymers Synthesized by Nitroxide-Mediated Polymerization: Effect of Free Nitroxide on Kinetics and Copolymer Composition

Styrene/tert-butyl acrylate (S/t-BuA) mixtures were copolymerized using nitroxide-mediated polymerization in bulk at 115 °C using an alkoxyamine unimolecular initiator, 2-[N-tert-butyl-2,2-(dimethylpropyl)aminooxy]propionic acid (BlocBuilder) to observe the effect of additional N-tert-butyl-N-[1-diethylphosphono-(2,2-dimethylpropyl)] nitroxide (SG1) on kinetics and copolymer composition. Polymerizations with 4.5 mol % SG1 relative to BlocBuilder were more controlled with lower polydispersities (from 1.14 to 1.22), and the number-average molecular weight M̄n exhibited linear behavior with conversion up to ∼50%. In contrast, without SG1, apparent rate constants were greater but higher polydispersities were observed, and M̄n vs conversion deviated from the ideal linear relationship at low conversions ∼20%. The value of kpK (kp = propagation rate constant, K = equilibrium constant) for t-BuA at 115 °C was 3.0 × 10-6 s-1 and is lower than other acrylic monomers. The copolymers were richer in t-BuA than the feed composition at low initial t-BuA feed compositions ft-BuA,0 (20 mol %) but became richer in styrene when ft-BuA,0 > 40 mol %. Copolymer reactivity ratios ranged from rt-BuA = 0.09 to 0.12 and rS = 0.40 to 0.49 using Fineman−Ross, Kelen−Tüdos, and nonlinear least-squares fitting methods.

Self-diffusion in Solutions of Carboxylated Acrylic Polymers as Studied by Pulsed Field Gradient NMR. 1. Solvent Diffusion Studies

The diffusion constants of solvent in solutions of carboxylated acrylic random copolymers in isopropanol (IPA) have been investigated using the PFG NMR technique. The copolymers are composed of butyl methacrylate and methacrylic acid with a range of molar ratios (BMA/MAA 100/0 through to 60/40 in 10 mol% steps). It was found that the echo attenuation function depended on the diffusion time, and experiments with short and long diffusion times have been analysed separately. Two questions are addressed: the first concerns the influence of concentration on the polymer aggregation in solution, and the second concerns the influence of the BMA/MAA molar ratio on the diffusion constants of the solvent. The data obtained have been discussed using established physical models for diffusion. Using the model of Wang gave the relative mass of bound solvent per mass of polymer which increased with the mol% of MAA in the copolymer.

Influence of Copolymer Configuration on the Phase Behavior of Ternary Blends

The influence of copolymer configuration on the phase behavior of various ternary polymer blends containing a crystallizable polyester, a noncrystallizable polyether, and an acrylic random copolymer of different chain configuration was investigated. In these ternary blends, the acrylic random copolymer is typically added to control rheological properties at elevated temperatures. In fact, the acrylic random copolymers composed of various compositions of MMA and nBMA were found to have different miscibility with polyester as well as polyether, leading to substantially different phase behavior of ternary blends. Remarkable temperature dependence was also found. The mean-field Flory-Huggins theory for the free energy of mixing, extended to ternary polymer blends, was adopted for predicting phase diagrams where the exact spinodal and binodal boundaries could be calculated. Phase diagrams of ternary blends, predicted by the Flory-Huggins formulations and related calculations, were in good agreement with experimental phase diagrams. The differences observed in the rheological processes of various ternary blends with different acrylic copolymers were directly related to changes in miscibility, associated phase behavior, and chain configuration.

Conjugated effects of the compatibilization and the dynamic vulcanization on the phase inversion behavior in poly(butylene terephthalate)/epoxide-containing rubber reactive polymer blends

The conjugated effects of both reactive compatibilization and dynamic vulcanization on the phase inversion behavior of poly(butylene terephthalate) (PBT)/epoxide-containing rubber blends have been studied in detail. Pure ethylene–methyl acrylate random copolymer (E-MA) and ethylene–methyl acrylate–glycidyl methacrylate random terpolymer (E–MA–GMA) were used as non reactive or reactive rubber phase, respectively. Location of the phase inversion region was studied using several techniques, including transmission electron microscopy (TEM) and dynamical mechanical thermal analysis (DMTA). To evaluate the relative influence of the blend compatibilization and the dynamic vulcanization on the phase inversion behavior, the relative kinetics of the two reactions were modified using different PBT and E–MA–GMA grades. The obtained results show unambiguously that the position and the width of the phase inversion region is essentially governed by the kinetic of the dynamic vulcanization process. The effect of the blend compatibilization remains quite limited even in the case of fast interfacial reaction. The crosslinking of the rubber phase induces an important shift of the phase inversion composition to higher rubber content. For blends containing low molecular weight PBT, up to 60 wt% of rubber can be homogeneously dispersed in the PBT matrix at long mixing time. In this case, development of high performance PBT based thermoplastic vulcanisates can be envisioned.