Radical Polymerization Of Butyl Acrylate Research Articles

Bioinspired Design of High Vibration-Damping Supramolecular Elastomers Based on Multiple Energy-Dissipation Mechanisms.

Suppressing vibrations and noises is essential for our automated society. Here, inspired by the hierarchical dynamic bonds and phase separation of mussel byssal threads, we synthesize high-damping supramolecular elastomers (HDEs) via simple one-pot radical polymerization of butyl acrylate (BA), acrylic acid (AA), and vinylimidazole (VI). Interestingly, AA and VI not only form hydrogen bonds and ionic bonds simultaneously but also segregate into aggregates of different sizes, thereby successfully mimicking the hierarchical structure of mussel byssal threads. When applying external forces, the weak hydrogen bonds are broken at first and then the ionic bonds and aggregates are disrupted progressively from small to large deformations. Such multiple energy-dissipation mechanisms lead to the outstanding damping property of the HDEs. Therefore, the HDEs outperform commercially available rubbers in terms of sound absorption and vibration damping. Furthermore, the multiple energy-dissipation mechanisms impart the HDEs with high toughness (41.1 MJ/m3), tensile strength (21.3 MPa), and self-healing ability.

Photocontrolled reversible-deactivation radical polymerization of butyl acrylate mediated by Salen-type CoII complexes

Salen-type Co II complexes were applied in the photo-OMRP of BA and MA to synthetize a copolymer (poly[MA]– co -poly[BA]) under 390 and 400–800 nm LEDs. • Co II complexes with Schiff-base ligands were prepared. • The Co II complexes were applied in the photo-OMRP of butyl acrylate. • The photosystems proposed showed a living character being able to mediate the copolymerization of poly[MA]- b -[BA]. • Experimental and theoretical data suggest a majority reversible termination pathway for these photo-OMRP reactions. In this study, we synthesized the complex [Co(BuSalen)] using the novel tetradentate BuSalen ligand and analyzed its ability as a controlling agent for the photo-induced organometallic-mediated radical polymerization (photo-OMRP) of butyl acrylate (BA) using diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) as photo-initiator. BA polymerization with [Co(BuSalen)] reached significant control levels using the [BA]/[Co II ]/TPO molar ratio of 600/1/1. The [Co(Salen)] and [Co(Bu 2 Salen)] complexes were also obtained following literature methods aiming a comparison in the mediating ability in photo-OMRP. [Co(BuSalen)] and [Co(Bu 2 Salen)] showed better controlling ability, as observed in the copolymerization study (Đ= 2.64, 1.50, and 1.26 for complexes [Co(Salen)], [Co(BuSalen)] and [Co(Bu 2 Salen)], respectively). Kinetics studies and computational investigations support a reversible termination (RT) mechanism and a tailorable Co II complex reactivity mainly altered by Schiff-base steric factors. Calculated thermodynamic parameters agree with the controlling degree delivered by these complexes, since the polymerization control increases with increasing the ΔG values for the formation of dormant species.

Allylthioketone mediating radical polymerization of butyl acrylate

By combination of high trapping radical efficiency of thioketone with resonance of allylic radicals, a novel mediated agent, 1, 3, 3-triphenylprop-2-ene-1-thione (TPPT) has been successfully synthesized. 1H NMR method was used to trace the TPPT-mediated radical polymerization of butyl acrylate (BA) at 50 °C, we observed that the disappearance rates of BA, TPPT and initiator, dimethyl 2,2′-azobis (2-methylpropionate) (AIBME) have the following order: BA > AIBME > TPPT, monomer conversion increases gradually with proceeding of the polymerization and approximately 84% of conversion was obtained within 24 h of the polymerization. The molecular weights of the obtained PBA are not varied obviously with the conversion, but the molecular weight distributions are narrow. The matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) studies reveal three polymerization mechanisms. The TPPT can efficiently capture the growing PBA radicals to form PBA-TPPT• radicals, and this highly stable radicals are able to be cross-terminated by the growing PBA• radicals or primary radicals to form the dormant chains. Although the reversed reaction of reaction 1 is very slow, the extension polymerization of the PBA can undergo to form block copolymers. The molecular weight of the formed PBA is influenced by the feed molar ratio of BA/TPPT and TPPT/AIBME.

Triple‐functional riboflavin‐based molecule for efficient atom transfer radical polymerization in miniemulsion media

AbstractTriple‐functional riboflavin‐based macromolecule was synthesized providing an efficient activator regeneration by electron transfer atom transfer radical polymerization of butyl acrylate in a miniemulsion media in a fully oxygen tolerant environment. For the first time, the riboflavin‐inspired supramolecular structure fulfilled three primarily roles, acting simultaneously as (a) an initiator due to incorporation of bromine molecules in a ribitol tail by esterification reaction of riboflavin with α‐bromoisobutyryl bromide; (b) a reducing agent caused by the preservation of redox functionality of isoalloxazine ring in this structure; (c) and enables polymerization in air conditions. Electrochemical characterization of the riboflavin‐based molecule was conducted by a series of cyclic voltammetry measurements, determining an activation rate constant (ka = [1.34 ± 0.58] × 103 M−1 s−1) reflecting a reduction of the copper(II) catalytic complex in the presence of the multifunctional initiator. Proposed reaction system allowed to maintain control during polymerization proved by linear kinetics and a clear shift in molecular weights, resulting in the preparation of polymer brushes with narrow molecular weight distribution (Mw/Mn = 1.39) with high initiation efficiency (ƒi = 72%).

Glass surface modification via Cu(0)-mediated living radical polymerization of fluorinated and non-fluorinated acrylates

The glass surface was modified via Cu(0)-mediated living radical polymerization of butyl acrylate and trifluoroethyl methacrylate by using the grafting from and grafting to methodologies.

Visible Light-Induced Living Radical Polymerization of Butyl Acrylate: Photocatalyst-Free, Ultrafast, and Oxygen Tolerance.

Butyl acrylate is polymerized in the living way under the irradiation of purple light-emitting diode (LED) or sunlight without photocatalyst at ambient temperature. 2-((Phenoxycarbonothioyl)thio) ethyl propanoate) is exclusively added and acted as an initiator and a chain transfer agent simultaneously in the current system. Poly(butyl acrylate) with well-regulated molecular weight and relatively narrow molecular weight distribution (Ð < 1.30) is synthesized. High conversion (>95%) can be achieved within several minutes. Polymerization shows oxygen tolerance. Near quantitative end-group fidelity of polymer is demonstrated by 1 H NMR and matrix-assisted laser desorption/ionization time-of-flight mass spectra.

Phase transfer catalyst aided radical polymerization of n-butyl acrylate in two-phase system: a kinetic study

The kinetics of radical polymerization of butyl acrylate initiated by potassium peroxydisulphate and cetyltrimethylammonium bromide as phase transfer catalyst (PTC) was carried out under inert and unstirred conditions at constant temperature of 60 ± 2 °C in ethyl acetate–water biphase media. The polymerization reactions were relatively fast in the two-phase systems with phase transfer agent whereas extremely sluggish in the system without PTC. Use of PTC accelerates the reaction effectively if the reactants located in two phase. The effects of rate of polymerization (R p) on various experimental conditions such as different concentrations of monomer, initiator, phase transfer catalyst, temperature, and different ionic strength of the medium were explored. The order with respect to monomer, initiator and phase transfer catalyst was found to be unity. The R p is independent of ionic strength and pH of the medium. However, an increase in the polarity of solvent has slightly increased the R p value. Based on the results obtained, a plausible mechanism has been proposed for the polymerization reaction. The obtained polymer was confirmed by FT-IR analysis.

Pseudolive radical polymerization of butyl acrylate in the presence of trithiocarbonates: Modeling the kinetics and regulation of the molecular mass characteristics of the polymer

Mathematical modeling of the kinetics of the pseudolive radical polymerization of butyl acrylate initiated by 2,2′-azobis(isobutyronitrile) in the presence of trithiocarbonates was performed. The kinetic scheme of the model includes the specific stages of quadratic breaking of intermediates. The model was shown to be adequate by comparing the theoretical and experimental molecular mass characteristics of the polymer. A computer experiment was performed within the framework of the model to determine the effect of the process-controlling factors on the molecular mass characteristics of poly(butyl acrylate).

Molecular weight properties of poly(butyl acrylate): Computational experiment based on a kinetic model of “living” radical polymerization with reversible addition-fragmentation chain transfer

Based on a kinetic model of “living” radical polymerization of butyl acrylate with reversible chain-transfer, the characteristics of altering the molecular weight properties of the polymer by varying the initial concentrations of the reactants and temperature are established.

Continuous ARGET ATRP of Methyl Methacrylate and Butyl Acrylate in a Stirred Tank Reactor

Activator regenerated by electron transfer atom-transfer radical polymerization of butyl acrylate and methyl methacrylate was successfully adapted from a batch process to a continuous stirred tank reactor (CSTR) with 50 ppm copper. A series of batch polymerizations were first performed to identify a solvent mixture to enhance the polymerization rate, maintain chain livingness, and eliminate unsteady-state behavior caused by the precipitation of copper(II) complexes. The batch formulations were run in a CSTR with mean residence times of 60, 90, and 120 min, with steady-state behavior reached after four residence times. The apparent rate coefficient in the CSTR experiments was higher than that in batch polymerizations, likely because of a higher steady-state reducing agent concentration in the CSTR, which shifted the copper(I)/copper(II) ratio in favor of the activating species. Polymer chain extensions showed good living characteristics, demonstrating CSTRs as a viable platform for industrial-scale control...

A Density Functional Theory Study of Secondary Reactions in n‐Butyl Acrylate Free Radical Polymerization

AbstractIn this work, secondary reactions involved in the free radical polymerization of butyl acrylate are investigated using quantum chemistry. First, various backbiting reactions are studied by adopting a simplified molecular model suitable for treating long polymer chains. The predicted reaction kinetics suggest the possibility of a radical migration along the poly(butyl acrylate) (PBA) chain as a consequence of subsequent j:j + 4 hydrogen abstractions, which are characterized by a low activation energy. Moreover, branching propagation and β‐scission reactions originating from mid‐chain radicals are investigated using a complete PBA model composed of five monomer units. The reaction kinetics involving short‐branch radicals are also examined, and a novel backbiting step leading to the formation of short branches is proposed. magnified image

Kinetic approach to modeling the radical polymerization of butyl acrylate in the presence dibenzyl trithiocarbonate

Kinetic approach to modeling the radical polymerization of butyl acrylate in the presence dibenzyl trithiocarbonate

Free radical polymerization of butyl acrylate in monodispersed droplets: Comparison between two heating strategies

AbstractMonodispersed droplets could be easily generated in coaxial microdevice, and a reaction based upon these discrete droplets is an attractive approach thanks to isolated reaction units, efficient mixing, and precise residence time control. In this work, free radical polymerization of butyl acrylate was conducted in monodispersed droplets of several hundred microns. Two different heating methodologies, microwave heating and conventional heating with oil bath were adopted to initiate polymerization, respectively. The polymerization under conventional heating could be regarded as an isothermal process, while the polymerization under microwave heating gradually underwent a temperature increase. So the poly (butyl acrylate) obtained by microwave heating has larger average molecular weight and higher polydispersity index. Meanwhile, the conversion of butyl acrylate was significantly improved by microwave heating compared with conventional heating, even though the reaction temperature under microwave heating might be lower than the temperature of the oil bath. This remarkable enhancement was a direct proof of the nonthermal effect of the microwave field for free radical polymerization. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Synthesis and Dispersion Property of Poly(Butyl Acrylate-B-Acryl Amide) by Alkaline Reversed Atom Transfer Radical Polymerization in Emulsion: A Novel Amphiphilic Binder

The hydrophilic property of acrylate copolymer is very important for the dispersion and adhesion ability in many fields such as pigment printing and dyeing of textiles. Poly(butyl acrylate-b-acryl amide) was synthesized by successive reversal atom transfer radical polymerization of butyl acrylate and acryl amide in emulsion. The structure of the copolymer was characterized by infrared spectrum and nuclear magnetic resonance. By adding alkaline salt, the molecular weight and its distribution of the block copolymer were controlled. The dispersion ability of acrylic copolymer was improved by acryl amide segment; thus, preparation of a novel amphiphilic binder is expected to be helpful to solve the problems of the current binders.

Transparent and ductile poly(lactic acid)/poly(butyl acrylate) (PBA) blends: Structure and properties

Poly(butyl acrylate) was prepared by the free radical polymerization of butyl acrylate as an initiator in the presence of 2,2′-Azoisobu-tyronitrile (AIBN) and the average molecular weight, polydispersity and thermal stability were evaluated. PLA and PBA were melt blended using a Haake Rheometer, and the light transmission, thermal properties, dynamic rheological properties, mechanical properties, phase morphology of blends and toughening mechanism were investigated. Dynamic rheology, SEM and DSC results show that the PLA is partial miscible with PBA. The PBA component improved the crystallization ability of PLA and the crystallinity of PLA increased with content of PBA (<15 wt.%). With the increase of PBA, the tensile strength and modulus of the blend decreased slightly while the elongation at break and toughness were dramatically increased. With the addition of PBA, the failure mode changes from brittle fracture of neat PLA to ductile fracture of the blend. Rheological results revealed the complex viscosity and melt elasticity of the blends decreased with increasing content of PBA and phase segregation occurred at loading above 11 wt.% PBA. UV–vis light transmittance showed that PLA/PBA blends with a high transparency, and the transmittance decreased with the amount of PBA.

Revisiting Chain Transfer to Polymer and Branching in Controlled Radical Polymerization of Butyl Acrylate

Acrylic monomers undergo chain transfer to polymer during polymerization leading to branched and even gelled polymers. It has been experimentally demonstrated that the extent of branching is higher for conventional free radical polymerization than for controlled radical polymerization (ATRP, RAFT, NMP) and this has been qualitatively explained in terms of the differences in the concentrations of highly reactive short-chain radicals between controlled and conventional radical polymerizations. Contrary to this explanation, in this work, it is quantitatively demonstrated that the short transient lifetime of the radicals, i.e., the time between activation and deactivation of the radical in controlled radical polymerization, is the cause for the low level of branching in these polymerizations.

Surface-initiated atom transfer radical polymerization of butyl acrylate on cellulose microfibrils

Surface-initiated atom transfer radical polymerization (SI-ATRP) of butyl acrylate (BA) on cellulose microfibrils (CMF) was conducted to create controllable hydrophobic chains on CMF. The macroinitiator, CMF-Br, was prepared by the esterification of hydroxyl groups on CMF with 2-bromoisobutyrylbromide (BIBB); followed by the ATRP of BA using two catalyst systems, Cu IBr/2,2′-bipyridine (BPY) and Cu IBr/pentamethyl-diethylenetriamine (PMDETA). The molecular weight (MW) and polydispersity of the grafted PBA cleaved from CMF via hydrolysis was determined using GPC. The results indicated that the PMDETA system exhibited relatively poor control over the ATRP; whereas the BPY system produced the PBA with tailored chain lengths and relatively narrow polydispersities but experienced a rather slow polymerization process. To optimize the polymerization with the CuBr/PMDETA system, several influencing factors were investigated, including the type of solvents, reaction temperature and the use of co-catalyst Cu IIBr 2. The hydrophobic-modified CMF is of great potential as reinforcements biocomposites.

Nitroxide‐Mediated Radical Polymerization of Butyl Acrylate Using TEMPO: Improvement of Control Exploiting Nanoreactors?

AbstractCompartmentalization effects in the nitroxide‐mediated radical polymerization of butyl acrylate in a dispersed system using the nitroxide 2,2,6,6‐tetramethylpiperidine‐N‐oxyl (TEMPO) at 130 °C have been examined by means of modeling and simulations employing modified Smith–Ewart equations that account for compartmentalization effects on both propagating radicals and free nitroxide species. TEMPO‐mediated acrylate polymerization is known to be problematic, speculated to be mainly related to excessive accumulation of free TEMPO with increasing conversion. The present theoretical results indicate that it may be possible to at least partially overcome this difficulty by careful exploitation of compartmentalization effects in nanoreactors.magnified image

Simultaneous continuous, nonchromatographic monitoring and discrete chromatographic monitoring of polymerization reactions

AbstractAutomatic continuous nonchromatographic monitoring and discrete chromatographic monitoring were coupled together for the first time and used to monitor free radical and controlled‐radical polymerization reactions. This was achieved by adding a multidetector Size Exclusion Chromatography (SEC) system (alternatively termed Gel Permeation Chromatography, GPC) to the ACOMP platform (Automatic Continuous Online Monitoring of Polymerization reactions). The fact that the reactor solution is already preconditioned in the ACOMP front‐end to the concentration levels used in SEC makes direct coupling possible. Kinetics from two different types of reactions, Reversible Addition Fragmentation Transfer (RAFT) and free radical polymerization of butyl acrylate were studied, including the production of a bimodal population. Complementary and contrasting features from the continuous and SEC approaches are highlighted. The main advantage of the SEC detection is to follow the evolution of full molecular weight distributions (MWD), especially in ‘living’ type reactions, where polydispersity decreases with monomer conversion, whereas the continuous detection provides a much more detailed characterization of the reaction. Interestingly, in the case where a bimodal molecular weight distribution was produced, the continuous method automatically detected the onset of the second mode in a model independent fashion, whereas SEC could only discern the bimodality by applying preconceived models. The SEC approach will have valuable niche applications, however, such as when reactions are relatively slow, monitoring narrow polydispersity is of primary importance, and also in copolymerization and terpolymerization reactions where complex mixtures of reagents (e.g., RAFT agents, copper ions, etc.) make unfractionated spectroscopic resolution of comonomers difficult. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Self‐directed formation of uniform unsaturated macromolecules from acrylate monomers at high temperatures

An approach to self-directed formation of uniform unsaturated macromonomers (MM) from acrylate monomers at high temperature has been discussed. On the basis of a procedure to generate MM of high purities directly from the monomer without the need for endgroup modification, it was demonstrated that the growing radicals in acrylate polymerization at temperatures well above 120°C undergo a series of transfer and β-scission reactions, which are interconnected through complex dynamic equilibria. High temperature autoinitiated free radical polymerization of butyl acrylate resulted into a highly ordered product that consisted almost quantitatively of uniform macromonomeric structures. Autoinitiation provided a low radical flux aiding the MM synthesis, without requiring any initiator. This self-organized synthesis approach is highly efficient, simple, and cost and time effective as no purification and isolation steps are required, except high temperature.