Reaction Of Acrylate Research Articles

Pd-catalyzed oxidative homo-coupling of acrylates and aromatic alkenes for the conjugated diene synthesis

We developed a bidentate monoanionic nitrogen ligand that was effective in the Pd-catalyzed oxidative homo-coupling reaction of acrylates and aromatic alkenes. In the presence of Pd(OAc)2/ligand several conjugated dienes were obtained in good yields with high stereoselectivities.

Construction compositions based on integrated binding of thermoplastic waste

The paper suggests a solution of the actual problem of processing polymeric municipal waste in building materials with a high complex of decorative and operational properties. The work is aimed at studying the processes of structure formation and hardening in the system “multicomponent thermoplastic binder - mineral filler” in the manufacture of polymer concrete products for construction purposes. During the research methods of infrared spectroscopy, differential thermal analysis, standard methods for determining the structure and properties of building products were used. As a result of the research, compositions of a complex thermoplastic binder including polymeric consumption waste (PET, PP) are proposed taking into account the volumes of their sampling at the waste sorting stations. An additive - a compatibilizer based on an ethylene-vinyl acetate copolymer with grafted reactive polar acrylate and epoxy groups, is also included. It was found that the introduction of a compatibilizer promotes the activation of the physicochemical interaction between the components of the polymer binder and between the polymer matrix and the mineral surface of the fillers. There was also an increase in the density and strength of the resulting artificial stone. The optimal content of the additive in an amount of 5% of the total mass of the complex binder was experimentally determined. With the introduction of a compatibilizer in smaller amounts, the effect of strengthening the flexural strength decreases, and when more compatibilizers are introduced, the strength of the products remains the same at bending, and the compressive strength decreases. Mechanisms of interphase interactions are proposed, taking into account the chemical-mineralogical composition of mineral fillers (based on carbonates and aluminosilicates). The possibility of participation of epoxide and acrylate functional groups in the formation of intramolecular and intermolecular hydrogen bonds with the formation of polyassociates was established. The revealed patterns of interaction make it possible to ensure the compatibility of weakly polar PET with other multitonnage thermoplastics, as well as compatibility of the complex polymer binder with mineral fillers. The management of the processes of structure formation in the studied systems makes it possible to obtain high decorative and operational parameters of the construction products.

Radical-Induced Single-Chain Collapse of Passerini Sequence-Regulated Polymers Assessed by High-Resolution Mass Spectrometry

We assess the versatility of high-resolution Orbitrap electrospray mass spectrometry (HR ESI MS) coupled to size exclusion chromatography (SEC) by challenging it with the to date most complex—for mass spectrometric analysis—single chain nanoparticle (SCNP) collapse system in terms of both precursor complexity and collapse mechanism. Here, sequence-regulated ter- and quaterpolymers prepared by the Passerini multicomponent step-growth polymerization serve as ideal mass spectrometric complex precursor structures to identify critical parameters for successful MS mapping and thus understanding of the radical intrachain compaction process. As Passerini monomers for the terpolymerization, 1,6-diisocyanohexane (1 equiv), HO2C-PEG10–11-CO2H (1 equiv), and 4-formylcoumarin equipped with an acrylate (2 equiv) were utilized for subsequent radical-induced single-chain collapse. We evidence the characteristic mass species indicating successful collapse, confirming the collapse mechanism via bimolecular coupling or propagation. A quaterpolymer containing 1,6-diisocyanohexane (1 equiv), HO2C-PEG10–11-CO2H (1 equiv), benzaldehyde (1.7 equiv), and 4-formylcoumarin acrylate (0.3 equiv) is also collapsed, yet cannot be mapped via SEC-ESI MS, as the number of chains entailing a reactive unit is too small, while diffusion ordered NMR spectroscopy (DOSY) can readily witness the compaction. On the basis of these two precursor systems, we are able to identify criteria that the precursors and the collapse system have to fulfill for their successful SEC-ESI MS characterization. The collapse mechanism can only be elucidated via mass analysis if (i) a minimum of four to five intra SCNP linkages are present and, thus, (ii) the precursor formation needs to lead to a sufficient number of chains that feature reactive coumarin acrylate units. Finally, (iii) a chemically too diverse system such as the quarterpolymer leads to a high repeat unit diversity that challenges the MS analysis given the contemporary resolution limits.

Mechanistic Aspects of Acrylic Acid Formation from CO2–Ethylene Coupling over Palladium‐ and Nickel‐based Catalysts

AbstractThe detailed mechanism of catalytic conversion of CO2 and ethylene to acrylic acid has been investigated through DFT and DLPNO‐CCSD(T) calculations. Four bidentate ligands, dmpe (1,2‐bis(dimethylphosphino)ethane), dcpe (1,2‐bis(dicyclohexylphosphino)ethane), dtbpe (1,2‐bis(di‐tert‐butylphosphino)ethane), and tmeda (tetramethylethylenediamine) were systematically studied to understand the different catalytic behavior of the Pd‐based catalyst and the well‐known Ni‐based catalyst. The energy barrier of Pd‐/Ni‐catalyzed C−C coupling appears to increase with the larger steric hindrance of the ligand, whereas the barrier of the corresponding β‐H elimination shows an opposite tendency. The barrier for C−C coupling is likely higher than the associated barrier for β‐H elimination in both catalytic systems provided that the coordinated ligand is bulky enough. The palladium catalytic center is more effective than the nickel center for the C−C coupling and β‐H elimination steps in the presence of bulky ligands, whereas the nickel catalyst in turn performs better with small ligands. The palladium catalyst tends to be superior to the nickel catalyst during the following hydrogen transfer to the O atom. In general, the diamine ligand (tmeda) is less efficient than the diphosphine ligands for both systems. In the absence of the auxiliaries, a novel chelating carbene ligand was proposed to be quite efficient for Pd‐catalyzed C−C coupling. Two ligands (dcpm, dtbpm) showed relatively better performance towards the palladium‐catalyzed acrylic acid formation reaction among all the investigated ligands.

Fabrication of half-polyimide-less liquid crystal device with fast response using reactive self-aligning amphiphile

ABSTRACTWe propose a new vertical alignment method for fast switching liquid crystal displays (LCDs) without the polyimide alignment layer on one side of a substrate. The key to this new method is the use of the amphoteric 2-carboxyethyl acrylate, which combines reactive acrylate and carboxylic acid groups to allow hydrogen bonding with substrate. The reactive group can achieve pre-tilt for a fast-switching of LC molecule, and the hydrogen bonding allow for vertical alignment of LC. The amphoteric material enables the manufacturing of cost-effective LCDs by reducing the number of steps in the process and fast switching by establishing pre-tilt alignment.

Amine-Reactive Poly(pentafluorophenyl acrylate) Brush Platforms for Cleaner Protein Purification.

Reactive pentafluorophenyl acrylate (PFPA) polymer brushes grafted on silica particles were prepared using surface-initiated reversible addition and fragmentation chain transfer polymerization. The polymer brush was successfully immobilized with antibody, then used for protein separation. The immunoprecipitated proteins showed successful enrichment of target protein, with reduced nonspecific background and less contamination from eluted antibodies. To further improve protein recovery, the hydrophobic poly(PFPA) brush was modified with hydrophilic poly(ethylene glycol) (PEG). The partially PEG-substituted poly(PFPA) brush showed better dispersion in aqueous solution, leading to improved antibody immobilization efficiency. By optimizing both the brush molecular weight and the degree of PEG substitution, an optimal balance between surface hydrophilicity and number of available PFP units was found, leading to efficient target protein purification. This study shows that poly(PFPA) platform offers a versatile approach to prepare biomolecule-activated surfaces with tunable surface property, which has potential applications in protein separation and other areas.

Novel Biocomposites Based on Sunflower Oil and Alfa Fibers as Renewable Resources

The aim of this work is to develop biocomposites based on modified sunflower oil as resin and short natural fibers from Alfa plants (Stipa tenacissima) as reinforcement. Epoxidized sunflower oil (ESFO) was chemically modified via acrylation reaction to obtain acrylated epoxidized sunflower oil resin (AESFO). The AESFO resin was then copolymerized with styrene as co-monomer in the presence of boron trifluoride (BF3) as cationic initiator and cobalt octoate (Co) as catalyst. Experimental conditions of this modification were optimized by varying styrene, Co and BF3 wt%. The styrene was varied from 30, 40 to 50 wt% while the catalyst (Co) was varied from 0, 0.01, 0.02 to 0.03 wt%. Two different percents of BF3 were considered: 0.5 and 1 wt%. The prepared samples were evaluated according to their appearance and then characterized in terms of tensile properties (stress at break, Young’s modulus and elongation at break) to determine the best ratio of styrene/BF3/Co. Alfa fibers, used as bio-reinforcement, were treated with a 5% NaOH solution and characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and thermo gravimetric analysis (TGA). Biocomposites were prepared by using untreated (UAF) and treated Alfa fibers (TAF) at a ratio of 5 wt% and characterized in terms of tensile properties and morphology by SEM. The best results were obtained with TAF. Then, the ratio of TAF was varied (5, 7.5 and 10 wt%) and the tensile and thermal properties of the biocomposites were characterized. The results showed that the best results were obtained with the ratio of 7.5 wt%.

Experimental and Theoretical Study of the Self-Initiation Reaction of Methyl Acrylate in Free-Radical Polymerization

Extensive experimental results (measurements of the monomer conversion in the absence of any external initiators) indicating the occurrence of the self-initiation reaction of methyl acrylate (MA) a...

On the Thermal Self-Initiation Reaction of n-Butyl Acrylate in Free-Radical Polymerization

This experimental and theoretical study deals with the thermal spontaneous polymerization of n-butyl acrylate (n-BA). The polymerization was carried out in solution (n-heptane as the solvent) at 200 and 220 °C without adding any conventional initiators. It was studied with the five different n-BA/n-heptane volume ratios: 50/50, 70/30, 80/20, 90/10, and 100/0. Extensive experimental data presented here show significant monomer conversion at all temperatures and concentrations confirming the occurrence of the thermal self-initiation of the monomer. The order, frequency factor, and activation energy of the thermal self-initiation reaction of n-BA were estimated from n-BA conversion, using a macroscopic mechanistic model. The estimated reaction order agrees well with the order obtained via our quantum chemical calculations. Furthermore, the frequency factor and activation energy estimates agree well with the corresponding values that we already reported for bulk polymerization of n-BA.

Specific and sensitive imaging of basal cysteine over homocysteine in living cells

Biological thiols play important roles in maintaining appropriate redox status of organisms. Accepting the challenge to differentiate structurally similar cysteine (Cys) and homocysteine (Hcy), we have successfully developed a miniature synthetic turn-on fluorescent probe based on 6-(2-benzothiazolyl)-2-naphthalenol for Cys. This probe is able to specifically react with Cys to yield its naphthalenol derivative, accompanied by remarkable green fluorescence enhancement with a detection limit of 14.8 nM. Besides, this probe displays much greater selectivity for Cys over other biological thiols, including homocysteine (Hcy) and glutathione (GSH). Practically, good cell permeability and low cytotoxicity make it suitable for monitoring basal Cys in living cells.

Functionalized magnesium hydroxide fluids/acrylate-coated hybrid cotton fabric with enhanced mechanical, flame retardant and shape-memory properties

Functionalized magnesium hydroxide fluids (MHFs) with both grafting reactive acrylate groups and organic long chain ion are successfully fabricated and then incorporated in poly(ethylene glycol) diacrylate (PEGDA) to produce flexible MHFs/PPEGDA coated hybrid cotton fabric via UV photo-polymerization. The morphology, composition, transparency, rheological behavior, mechanical and flame retardant properties of MHFs/PPEGDA coating are systematically characterized by various techniques. It is found that tensile strength and young’s modulus of MHFs/PPEGDA/cotton composite are as high as 46 and 556 MPa at MHFs loading amount of 40 wt%, respectively, an enhancement of 58.6 and 66.4% in comparison with PPEGDA/cotton composite. What’s more, the addition of MHFs not only reduces the surface energy of PEGDA to improve its film-forming property during polymerization process, but also maintains high transparency over 90%. Besides the above mentioned advantages, MHFs/PPEGDA coating as thermal induced shape memory material could be fixed their shape at − 4 °C and rapidly recover their original shape at 60 °C, which is related to the melting transition temperature of MHFs. More importantly, with the synergistic effect of magnesium hydroxide and surface grafted organic long chain ion molecules, the flame retardant property of MHFs/PPEGDA/cotton is also significantly improved. These functionalized organic/inorganic fluids provide a simple approach to fabricate high performance cellulose fabrics with tunable properties in the textile industry.

Self-assembled vertical alignment layer of bifunctional amphiphiles for fast electro-optical switching of nematic liquid crystals

ABSTRACTWe present a novel homeotropic alignment method that simultaneously improves the ability of vertical alignment and fast switching of liquid crystals (LCs) in the electro-optical performance. The proposed method utilizes dual self-assembly of 4-(4-heptylphenyl)benzoic acid and 2-carboxyethyl acrylate via hydrogen bonding with ITO substrate. The 4-(4-heptylphenyl)benzoic acid composed of aromatic moieties and alkyl chains induce the homeotropic alignment of the LC molecules. Photopolymerization of 2-carboxylethyl acrylate with a reactive acrylate group under UV irradiation gives the LC molecules a fast response. Our proposed alignment method allows for fabrication of LC devices exhibiting fast LC switching without a conventional polyimide layer.

Restoration of Impact Damage in Polymers via a Hybrid Microcapsule–Microvascular Self‐Healing System

AbstractA hybrid microcapsule–microvascular system is introduced to regenerate the multiscale damage that results from impact puncture of vascularized polymeric sheets. Microvascular delivery of a two‐stage healing agent restores lost damage volume (puncture) to recover impact energy absorption, while embedded microcapsules heal microcracks to facilitate sealing. Modulation of the mechanical properties (1.4 GPa to 1.1 MPa stiffness) of the healing agent after curing is achieved by selection of compatible reactive acrylate monomers. Specimens are punctured and the impacted hole and surrounding damaged volume is restored by delivering the two‐stage healing agents to the site of damage via a microvascular network. Rapid gelling of two‐stage healing agents enables their retention in the damage region, while subsequent polymerization recovers structural performance. Impact recovery efficiency is assessed in terms of energy absorption, comparing reimpacted specimens to the initial impact. Recovery of impact energy absorption as high as 100% is observed for the optimal specimen design. Specimens are tested for sealing under static pressurization to monitoring leakage through the restored damage. A hybrid system incorporating both microvascular delivery of the two‐stage healing agents and microcapsules containing solvated epoxy enables sealing of 100% of specimens.

Highly Enantioselective Synthesis of Chiral Cyclopropyl Nucleosides via Catalytic Asymmetric Intermolecular Cyclopropanation.

An efficient route to construct chiral cyclopropyl purine nucleoside analogues has been established via the catalytic asymmetric Michael-initiated ring-closure reactions of α-purine acrylates with α-bromo-carboxylic esters. Using (DHQD)2AQN as the catalyst, various chiral cyclopropyl purine nucleoside analogues with a chiral quaternary stereocenter were obtained in 72-98% yields, excellent diastereoselectivities, and 93-97% ee. Through simple functional group transformations, diverse chiral cyclopropyl purine nucleosides with hydroxymethyl group or carboxyl group were obtained.

Enhancement of the mechanical and thermal properties of injection-molded polylactide parts by the addition of acrylated epoxidized soybean oil

This work reports the effect of acrylated epoxidized soybean oil (AESO) addition on the mechanical, thermal, and thermomechanical properties of polylactide (PLA) parts obtained by injection molding. To this end, AESO, a chemically multi-functionalized vegetable oil, was incorporated into PLA during melt processing. The PLA parts with AESO contents in the 2.5–7.5wt% range showed a remarkable enhancement in both elongation at break and impact-absorbed energy while their tensile and flexural strength as well as thermomechanical properties were maintained or slightly improved. Additionally, the AESO-containing PLA parts presented higher thermal stability and lower crystallinity. The improvement achieved was ascribed to a dual effect of plasticization in combination with a chain-extension and/or cross-linking process of the PLA chains by the highly reactive acrylate and epoxy groups present in AESO. The use of AESO thus represents an environmentally friendly solution to obtain toughened PLA materials of high interest in, for instance, rigid packaging, automotive or building and construction applications.

Physico-chemical characterisation of epoxy acrylate resin from jatropha seed oil

PurposeThis paper aims to demonstrate the synthesis of polyesterification reaction of non-edible jatropha seed oil (JO) and acrylic acid, which leads to the production of acrylated epoxidised-based resin. To understand the physico-chemical characteristics when synthesis the JO-based epoxy acrylate, the effect of temperature on the reaction, concentration of acrylic acid and role of catalyst on reaction time and acid value were studied.Design/methodology/approachFirst, the double bond in JO was functionalised by epoxidation using the solvent-free performic method. The subsequent process was acrylation with acrylic acid using the base catalyst triethylamine and 4-methoxyphenol as an inhibitor respectively. The physico-chemical characteristics during the synthesis of the epoxy acrylate such as acid value was monitored and analysed. The formation of the epoxy and acrylate group was confirmed by a Fourier transform infrared spectroscopy spectra analysis and nuclear magnetic resonance analysis.FindingsThe optimum reaction condition was achieved at a ratio of epoxidised JO to acrylic acid of 1:1.5 and the reaction temperature of 110°C. This was indicated by the acid value reduction from 86 to 15 mg KOH/g sample at 6 hours.Practical implicationsThe JO-based epoxy acrylate synthesised has a potential to be used in formulations the prepolymer resin for UV curable coating applications. The JO which is from natural resources and is sustainable raw materials that possible reduce the dependency on petroleum-based coating.Originality/valueThe epoxidised jatropha seed oil epoxy acrylate was synthesised, as a new type of oligomer resin that contains a reactive acrylate group, which can be alternative to petroleum-based coating and can used further in the formulation of the radiation curable coating.

Palladium catalyzed Heck reaction of 2-iodoanilines under ligand-free conditions in air

ABSTRACTPalladium catalyzed Heck reaction of 2-iodoanilines and acrylate has been developed. The palladium catalyzed Heck reaction of 2-iodoanilines can readily occur in CH3CN using Pd(OAc)2 (5.0 mol%) as catalyst, NEt3 as base under ligand-free conditions. And 2-alkenylanilines were obtained as the cross-coupling products with medium to high yield.

Protective features, durability and biodegration study of acrylic and methacrylic fluorinated polymer coatings for marble protection

Abstract In the present paper, a new fluorine based methacrylic monomer, 1H,1H,2H,2H-Perfluoro-octyl-methacrylate (POMA), was synthesized via esterification reaction from methacryloyl chloride and 1H,1H,2H,2H-Perfluoro-1-octanol. Furthermore, POMA was used to prepare with methyl methacrylate (MMA) via free radical polymerization a novel fluorinated methacrylic polymer (MMA_POMA), in order to overcome the well-known technical problems related to the use of acrylic monomer-based commercial protectives, such as Paraloid B72 ® . Indeed, in Paraloid B72 ® −obtainable from the copolymerization reaction of ethyl methacrylate (EMA) and methyl acrylate (MA)- the presence of an acrylic hydrogen atom in alpha to the carbonyl group can start photo-chemical degradation reactions that are able to promote fungi attack and proliferation. The properties of MMA_POMA and the two references synthesized, EMA_MA and EMA_MA_POMA −in terms of macromolecular structure, molecular weights, thermal features and water repellency- were determined; furthermore, the long-term behavior of these polymeric protective agents was estimated by means of accelerated aging tests exploiting UV radiations. Their behavior over time was checked via Size Exclusion Chromatography (SEC), Fourier Transform Infrared (FT-IR) spectroscopy and biodegradation assay. Lastly, MMA_POMA resin was applied on two marble substrates −Calcite and Dolomite- and its wetting properties were successfully assessed and compared to the same features displayed by the reference polymers. This work demonstrates that a polymer protective prepared starting from methacrylic and fluorinated monomers, i.e. MMA and POMA, is an efficient way to obtain resins with satisfactory water repellent properties and enhanced durability than acrylic based polymers without the use of any photo stabilizer additive.

Effects of crosslinking agent/diluents/thiol on morphology of the polymer matrix and electro-optical properties of polymer-dispersed liquid crystal

ABSTRACTTo study effects of the crosslinking agent/diluents/thiol on morphology of the polymer matrix and the electro-optical properties of polymer-dispersed liquid crystal (PDLC) films, samples were prepared by ultraviolet (UV)-initiated polymerisation. Due to the interaction between thiol–acrylate reaction and acrylate monomers polymerisation, the sample compositions were the foremost determinant to the microstructures which in turn played an essential role on the electro-optical properties of the PDLC films. With the increasing content of the crosslinking agent, the LC droplet size decreased, while the thiol had a contrary effect on the LC droplet size. It was demonstrated that the superior properties of the low-driven voltage (37.2 V), the high contrast ratio (148.2), the short response time (14.9 ms) and the high saturation transmittance (86.6%) could benefit from a novel microstructure which had a dense surface and meshes with microspheres attached. It was of great significance for the optimisation and the potential applications of the PDLC films.

Targeted synthesis and biological activity of polypharmacophoric agents for the treatment of neurodegenerative diseases

Synthetic approaches to the design of new multitarget agents for the treatment of neurodegenerative diseases are surveyed. These approaches are based on the conjugation of the pharmacophoric indole, phenothiazine, and aminoadamantane moieties via 1-oxopropylene and 2-hydroxypropylene spacers using reactions of acrylate- and epoxide-containing pharmacophores with tetrahydro-γ-carbolines, cycloalkaneindoles, carbazoles, and aminoadamantanes. The review considers data on biological activity of the compounds assessed within a complex screening system. This system includes neurotransmitter targets associated with cognitive compensation, such as cholinesterases and glutamate receptors, mitochondria, the influence on which can provide neuroprotective effects, and microtubules, the stabilization of which leads to the improvement of axonal transport. The ability of the compounds to act as free-radical scavengers was evaluated. Types of polypharmacophoric compounds promising for further development are proposed.