Acetoacetoxy Ethyl Methacrylate Research Articles

Acetoacetoxy functionalized natural rubber latex capable of forming cross-linkable film under ambient conditions

This work demonstrates that natural rubber (NR) latex particles containing acetoacetoxy (AcAc) groups are able to undergo cross-linking upon film formation at ambient temperature by reaction with glutaraldehyde (GTA). Natural rubber latex grafted with poly(acetoacetoxyethyl methacrylate) (NR-g-PAAEM) was synthesized by seeded emulsion polymerization, using benzoyl peroxide (BPO) as an initiator in free radical polymerization. The degree of grafting of PAAEM in the graft copolymers was evaluated by 1H NMR technique. Transmission electron microscope (TEM) was used for investigation the particle morphology of the grafted NR latex. Since the AcAc groups are intentionally attached to the NR particles providing sites of cross-linking at ambient temperature, the cross-linking ability of these sites by reaction with GTA was then investigated. The results revealed that the latex film of NR-g-PAAEM with the addition of GTA had a much higher tensile strength in comparison with the film without GTA. The surface morphology of the NR-g-PAAEM latex film formed in the absence and presence of the GTA cross-linker was also investigated using atomic force microscopy (AFM). By GTA addition into the NR-g-PAAEM latex before film formation, an increase in the root-mean-square (RMS) roughness of the surface of the latex film was observed. Moreover, it was also observed that the NR-g-PAAEM films with the addition of GTA had higher activation energy for thermal degradation than that without the cross-linker. This confirms that the cross-linking reaction took place in the NR-g-PAAEM latex film as a result of its reaction with the GTA.

Functionalized polymeric magnetic nanoconstructs for selective capturing and sensitive detection of Salmonella typhimurium

Rapid detection and enumeration of pathogens is essential for monitoring contamination and spoilage of food products to ensure improved quality control management. Functionalized polymeric magnetic nanoconstructs (FPMNCs) were developed as an effective immunomagnetic separator and sensing platform for the selective capturing of Salmonella typhimurium. Novel FPMNCs were prepared in three stages involving synthesis of iron oxide (IO) dispersion, capping with sodium oleate and encapsulation of preformed IO nanoparticles by in-situ free radical emulsion polymerization of styrene (St), methyl methacrylate (MMA) and acetoacetoxy ethylmethacrylate (AAEM). PMMA improves the stability of FPMNCs by bridging extremely hydrophobic PS and hydrophilic PAAEM. Core-shell morphology of hydrophobic core of IO, PS & PMMA and hydrophilic shell of PAAEM was demonstrated by SEM, TEM and FTIR studies. FPMNCs with surface functionalized acetoacetoxy groups were covalently attached with polyclonal antibodies against Salmonella common structural antigen (CSA-1-Ab) without using any linker and catalyst. Colorimetric readout signal was acquired using CSA-1-Ab-HRP as secondary antibody after formation of sandwich immunocomplex with bacteria where the optical density of the samples were recorded using ELISA plate reader at 450 nm. The developed immunoassay was specific and selective which captures only targeted S. typhimurium with a detection limit of 10 cells/mL lower than infectious dose of salmonellosis infection. Minimal interference of food matrix with high signal to noise ratio was shown by various food samples. In addition, the performance of developed FPMNC based immunoassay was superior to commercially available immunomagnetic microbeads demonstrating undisputed advantage for capturing and detecting specific bacteria without any pre-enrichment of sample.

A complete kinetic study of a versatile functional monomer: acetoacetoxyethyl methacrylate (AAEMA)

The current study reports the complete kinetic analysis of acetoacetoxyethyl methacrylate (AAEMA).

Single Monomer for Multiple Tasks: Polymerization Induced Self-Assembly, Functionalization and Cross-Linking, and Nanoparticle Loading.

Efficient preparation of multifunctional nano-objects with controlled morphologies in one step at high concentrations is synthetically challenging, yet is highly desirable, in a broad range of materials applications. Herein, we address this synthetic hurdle by introducing a single commodity monomer 2-(acetoacetoxy)ethyl methacrylate (AEMA) to realize multiple functions. Facile preparation of both nanospheres and vesicles via polymerization induced self-assembly at concentrations of 20-30% provided defined polymeric nanomaterials with reactive handles inherent to the AEMA units. High-yielding keto-alkoxylamine chemistry was utilized to decorate and cross-link the nano-objects. Nanoparticle loading into the designated location within both nano-objects was exemplified with in situ formation of silver nanoparticles. The concept of using a single monomer capable of both morphology control and multifunctionalization is expected to offer significant opportunities in functional nanomaterials.

Tautomeric acetoacetate monomers as building units of functional copolymers

Although synthetic polymers from tautomeric functional monomers have emerged as a new kind of materials due to potential applications their interest needs still to be revealed. In this work we have synthesized two series of tautomeric acetoacetate copolymers, with different composition, microstructure and properties. We have selected allyl acetoacetate (AAA) and 2-(acetoacetoxy)ethyl methacrylate (AEMA) monomers to copolymerize with styrene (St). The bulk copolymerization initiated with azobisisobutyronitrile was carried out at 60°C for different monomer feed compositions and times. The products were characterized by 1H NMR, HSQC NMR and size exclusion chromatography. The calculated monomer reactivity ratio obtained for poly(St-co-AAA) and for poly(St-co-AEMA), show noteworthy differences in the copolymerization behavior; r1r2 take values near 1 and zero for poly(St-co-AAA) and poly(St-co-AEMA), respectively. The glass transition temperature (Tg) values for copolymers were determined by differential scanning calorimetry. Two Tg temperatures were found for poly(St-co-AAA) which were close to the Tg values of corresponding homopolymers. On the other hand, only one Tg values characterized the St-co-AEMA copolymers system. Thermal stability has been studied by thermo gravimetric analysis (TGA). The copolymers St-co-AAA and St-co-AEMA exhibited higher thermal stability than homopolymer AAA and AEMA, respectively. Due to the functional group present in both monomers, they exhibit tautomeric equilibrium; an interesting NMR study in solution allowed us to demonstrate that the displacement of equilibrium depends on composition, microstructure and solvents. In view of future applications as nanomatrices for tissue engineering, these tautomeric copolymers (St-co-AAA), were nanostructured in AAO nanocavities and its morphological and surface characteristics analyzed by SEM.

In situ ultrasonic synthesis and characterization of nanocopper/poly(acetoacetoxyethyl methacrylate–styrene) composites

Nanocopper (nano-Cu)/poly(acetoacetoxyethyl methacrylate (AAEM)–styrene (St)) (P(AAEM-St)) composites were synthesized by reducing copper acetate solution in AAEM and St monomer by ultrasonic technique without adding emulsifier. The morphology, structure, thermal stability, and the interaction between Cu nanoparticles (NPs) and P(AAEM-St) matrix of the composites were characterized using ultraviolet–visible spectroscopy, X-ray diffractometer, transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA), respectively. The results show that Cu NPs possessed face-centered cubic structure, and they were homogeneously dispersed in P(AAEM-St) matrix. XPS and FTIR analyses reveal the interaction between Cu NPs and C=O of the acetoacetoxy in the copolymer of AAEM and St. TGA proves that the thermal stability of the pure P(AAEM-St) is higher than that of the nano-Cu/P(AAEM-St) composites.

Poly (vinylcaprolactam)-based Microgels to Improve Gloss Properties of Different Natural Fibres

Three different thermo-sensitive microgels obtained by the copolymerisation of vinylcaprolactam) (VCL) and various monomers (vinylimidazole(VIm), acetoacetoxyethyl methacrylate (AAEM) and itaconic acid(IA)) are used to coat different fibre surfaces. Two different pHs and two different temperatures, 25°C and 50°C respectively are chosen for the deposition of the microgels. The scanning electron microscopy of the treated fibre shows good distribution of the particles onto the fibres especially at increasing temperatures. The gloss index for the treated fibres has been measured, and showed that it may be controlled for all of the fibres with the treatment parameters (pH and temperature) and the microgel structure.

Anisotropic Nanoparticles with Controllable Morphologies from Non‐Cross‐Linked Seeded Emulsion Polymerization

A simple and elegant approach to fabricate anisotropic P(VC-co-AAEM)/PS nanoparticles with controllable morphologies via emulsifier-free seeded emulsion polymerization is presented. Non-cross-linked P(VC-co-AAEM) seeds with hydrophilic surface are first synthesized through copolymerization of vinyl chloride (VC) and acetoacetoxyethyl methacrylate (AAEM), which are used to prepare P(VC-co-AAEM)/PS NPs with multiple bulges by SEP of styrene. Electron microscopy observation indicates that the content of AAEM in seeds is crucial to control the phase separation and morphology of the composite NPs. Moreover, the thermodynamic immiscibility between PVC and PS is the driving force for the formation of PS bulges onto the P(VC-co-AAEM) seeds. The resultant anisotropic NPs with non-cross-linked feature may promisingly serve as compatibilizers for further polymer processing.

A study of acetoacetoxyethyl methacrylate hydrolysis in acrylic latex polymers as a function of pH

Acetoacetoxyethyl methacrylate (AAEM) is an ambient crosslinking monomer that, when incorporated into architectural coatings binders, provides coatings with improved hardness, scrub, stain, and dirt pick-up resistance. This study details the use of NMR spectroscopy to explore the hydrolysis profile of AAEM as a function of pH, type of neutralizer, and glass transition temperature of the binder. We have determined that AAEM has a hydrolysis profile that is independent of latex polymer pH relevant to coatings (pH 7–10). Lower Tg latex polymers enable the diffusion of ammonia into the binder nanoparticles converting a larger amount of the acetoacetoxy moiety to the enamine form; this approach also allows for measuring the distribution of enamine and AAEM form in the latex polymer particle. The consequence of these findings is that AAEM may be utilized at a lower pH than previously envisioned without consequence to the hydrolysis profile of the acetoacetoxy functionality.

Copolyperoxides of 2-(acetoacetoxy)ethyl methacrylate with methyl methacrylate and styrene; Synthesis, characterization, thermal analysis, and reactivity ratios

Copolyperoxides of 2-(acetoacetoxy)ethyl methacrylate (AEMA) with styrene (St) and methyl methacrylate (MMA) of different compositions have been synthesized in the presence of 2,2′-azobisisobutyronitrile as a free radical initiator under 100 psi oxygen pressure at 50 °C. The rates of oxidative copolymerization reactions are determined from the oxygen consumption (Δp) against time plot. Highly exothermic thermal degradations of these copolyperoxides are studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) and degradation products have been characterised by electron-impact mass spectroscopy (EI-MS). The NMR spectroscopy and EI-MS analysis confirm the alternating peroxy bonds in the main chain. The monomer reactivity ratios are computed by the Fineman–Ross and Kelen–Tüdös methods, using compositions obtained from 1H and 13C NMR analysis. These copolymers can potentially be used as polymeric initiators for the radical polymerization of vinyl monomers, autocombustible fuel. Also, the β-carbonyl moieties along the side chain of the copolyperoxides can be utilized to prepare degradable polyperoxide–metal complexes.

Multiresponsive Polymer Conetworks Capable of Responding to Changes in pH, Temperature, and Magnetic Field: Synthesis, Characterization, and Evaluation of Their Ability for Controlled Uptake and Release of Solutes

This study deals with the preparation of novel multiresponsive (magnetoresponsive, thermoresponsive and pH-responsive) nanocomposite conetworks consisting of oleic acid-coated magnetite nanoparticles (OA·Fe(3)O(4)), hydrophilic/thermoresponsive hexa(ethylene glycol) methyl ether methacrylate (HEGMA), hydrophobic/metal binding 2-(acetoacetoxy)ethyl methacrylate (AEMA), and pH-responsive/thermoresponsive N-diethylaminoethyl methacrylate (DEAEMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) moieties. Conventional free radical copolymerization was employed for the synthesis of random conetworks in the absence and presence of preformed OA·Fe(3)O(4). Further, in characterization of these materials in regards to their swelling behavior in organic and aqueous solvents, thermal/thermoresponsive properties, and composition, assessment of their magnetic characteristics disclosed tunable superparamagnetic behavior. These systems were also evaluated toward their ability to adsorb and release a solute (benzoic acid) in a controlled manner upon varying the pH.

Fabrication and Characterization of Magnetoresponsive Electrospun Nanocomposite Membranes Based on Methacrylic Random Copolymers and Magnetite Nanoparticles

Magnetoresponsive polymer‐based fibrous nanocomposites belonging to the broad category of stimuli‐responsive materials, is a relatively new class of “soft” composite materials, consisting of magnetic nanoparticles embedded within a polymeric fibrous matrix. The presence of an externally applied magnetic field influences the properties of these materials rendering them useful in numerous technological and biomedical applications including sensing, magnetic separation, catalysis and magnetic drug delivery. This study deals with the fabrication and characterization of magnetoresponsive nanocomposite fibrous membranes consisting of methacrylic random copolymers based on methyl methacrylate (MMA) and 2‐(acetoacetoxy)ethyl methacrylate (AEMA) (MMA‐co‐AEMA) and oleic acid‐coated magnetite (OA·Fe3O4) nanoparticles. The AEMA moieties containing β‐ketoester side‐chain functionalities were introduced for the first time in this type of materials, because of their inherent ability to bind effectively onto inorganic surfaces providing an improved stabilization. For membrane fabrication the electrospinning technique was employed and a series of nanocomposite membranes was prepared in which the polymer content was kept constant and only the inorganic (OA·Fe3O4) content varied. Further to the characterization of these materials in regards to their morphology, composition and thermal properties, assessment of their magnetic characteristics disclosed tunable superparamagnetic behaviour at ambient temperature.

Crosslinkable poly(vinyl acetate) emulsions for wood adhesive

PurposeThe purpose of this paper is to enhance the water resistance and the heat resistance of poly(vinyl acetate) (PVAc) emulsion adhesive, by providing the emulsion with controllable thermosetting capability.Design/methodology/approachEmulsion polymerisation was used to synthesise PVAc/VeoVa 10 copolymers with varying proportions of acetoacetoxyethyl methacrylate (AAEM) incorporated in the copolymer chains. The AAEM component provided sites for crosslinking the chains via reaction of diamines with AAEM. The emulsion copolymers formed crosslinked films on addition of a range of diamines, during drying at ambient temperature. Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy were employed to characterise the copolymerisation and crosslinking reaction. Glass transition temperatures of the polymer films were measured using dynamic mechanical thermal analysis to quantify the effects of copolymer composition variation and crosslinker. The performance of the crosslinked emulsions as wood adhesives was evaluated in accordance with the ISO 6238 standard by measuring the maximum shear stress of wood joints.FindingsThe crosslinking reaction between acetoacetoxy groups in the copolymer chains and the added diamines gives enamine structures, and occurs rapidly at ambient temperature. Major changes in the 13C NMR spectrum include the appearance of an enamine signal at 82 ppm, and disappearance of the acetoacetoxy carbonyl signal at 202 ppm. The new vibrational band at 1,597‐1,606 cm−1 in the FTIR spectrum is assigned to the vibrations of the enamine double bond. The experimental results showed substantial increases in Tg and viscosity as the AAEM proportion in the copolymer emulsion increased. The crosslinked adhesives showed superior wood adhesive performance to unmodified PVAc emulsion.Research limitations/implicationsIt was necessary to adjust the pH of the emulsion for extended shelf life.Practical implicationsThe method developed provides a simple and practical route to emulsions with improved water and heat resistance and bonding strength.Originality/valueThe method for enhanced water and heat resistance of PVAc wood adhesive was novel, straightforward and environmental friendly.

Attachment of selenium to a reverse osmosis membrane to inhibit biofilm formation of S. aureus

Previous experiments have shown that when selenium was attached to a surface, biofilm development on the surface was inhibited. Selenium is a catalytic producer of superoxide radicals via oxygen reduction. The superoxide radicals can cause damage to the outer membrane of bacterial cells that frequently results in cell death. Therefore, we propose selenium attachment to an RO membrane surface as a biofouling inhibition technique. Selenium was attached to the surface of RO membranes via monomer (selenocystamine) and polymer (aceto acetoxy ethyl methacrylate) attachment mechanisms. Using confocal microscopy and Staphylococcus aureus cell counting to evaluate S. aureus biofilm growth, the number of attached S. aureus cells was seen to be significantly reduced on RO membranes coated with selenium. While both selenium coatings had similar S. aureus inhibition, the selenium coatings had much different impacts on permeate flux. The selenocystamine attachment method maintained a higher permeate flux compared to the AAEMA attachment method due to AAEMA requiring a harsh attachment procedure. Ultimately, attached selenocystamine showed great potential to serve as a biofouling inhibitor by reducing attached S. aureus growth on RO membranes without excessive permeate flux loss.

Guided self-assembly of microgels: from particle arrays to anisotropic nanostructures

We investigate the guided large scale self-assembly of microgels consisting of N-vinylcaprolactam (VCL), N-isopropylacrylamide (NiPAAm) and acetoacetoxyethyl methacrylate (AAEM) using nanostructured substrates fabricated via controlled wrinkling. Depending on the type of microgel, the arrangement in the grooves of the substrates influences the particle shape and the overall pattern formation. Thus we obtain straight lines composed of single particles as well as zigzag-structures. In an additional processing step, we use the nanostructured substrates as stamps to transfer the formed microgel patterns onto a planar support. Subsequent UV-crosslinking of the microgel strings yields anisotropic particles.

Effect of particle structure on the peel strength and heat resistance properties of vinyl acetate/acrylate latexes laminating adhesives

The concept of using particle structure design to prepare emulsion laminating adhesives (LAs) for improving both the peel strength and heat resistance properties has been investigated. The homogeneous particle latices based on vinyl acetate/acrylate copolymer (samples 1–3) were synthesized by seeded semicontinuous emulsion polymerization with different chain transfer agent (CTA) contents but with no functional monomers, while the core-shell structure crosslinkable latices (samples 4 and 5) were prepared through multistage polymerization technique. The emulsion particle structure was investigated by TEM and particle size analyzer. The results indicate that the average emulsion particle diameter is about 130 nm and the particles grow without secondary nucleation. Samples 1 and 2 prepared with 0.7 and 0.5 phm (per hundred gram monomer) CTA respectively, show high peel strength but poor heat resistance property. On the contrary, the sample 3 prepared with 0.1-phm CTA exhibits low peel strength but relatively good heat resistance. However, sample 4, which was synthesized with 0.5-phm CTA and 0.4-phm acetoacetoxy ethyl methacrylate (AAEM) in core but 0.5-phm CTA and 0.6-phm AAEM in shell stages, shows high peel strength (1032.9 g/in.) and good heat resistance property (524.9 g/in.). In addition, sample 5 also demonstrates high peel strength (987.2 g/in.) and good heat resistance property (643.5 g/in.) when it was synthesized using 0.1-phm CTA but no AAEM in core, 0.36-phm CTA and 0.75-phm AAEM in shell stages. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Synthesis and characterization of a novel in situ forming gel based on hydrogel dispersions

This report describes the synthesis and characterization of hydrogel dispersions for the potential use as an in situ gel-forming wound sealant. A series of polyacrylamide (PAAm) particles (solid content 5-10 wt %) were prepared by dispersion polymerization of acrylamide (AAm) in a solvent mixture of ethanol/water (90/10 w/w). These particles are characterized by the presence of a "core" [ethylene glycol dimethacrylate (EGDMA) crosslinked PAAm] surrounded by a "shell" [acetoacetoxyethyl methacrylate (AAEMA) or 2-aminoethylmethacrylate-containing PAAm, named as AAEMA-xPAAm and NH(2)-xPAAm, respectively; x represents "crosslinked"]. Two "2-in-1" working systems were prepared: (1) AAEMA-xPAAm mixed with NH(2)-xPAAm and (2) AAEMA-xPAAm mixed with 1,6-diaminohexane [AAEMA:NH(2) (1:1 mol/mol in (1) and (2)]. These systems appeared to possess essential characteristics for their potential use as wound sealants. For example, at 37 degrees C (and/or room temperature), both systems (1) and (2) formed transparent films, within 2 min upon applying them to a substrate; a rapid, concomitant crosslinking reaction occurred between AAEMA and -NH(2) on their outer "shells," knitting the EGDMA-crosslinked PAAm micro-"gel" together into a macro one. In contrast to other reported wound sealants, which are in either solution form or powder form, the advantages of hydrogel dispersion-based sealant may include ease of application (sprayable due to its low viscosity), species encapsulation and protection, and so forth. To our best knowledge, this is the first report on designing a wound sealant based on micro-particle dispersions.

The influence of PEG macromonomers on the size and properties of thermosensitive aqueous microgels

We describe the preparation and thermal response of aqueous microgels based on poly(N-vinyl caprolactam) containing grafted poly(ethylene glycol) (PEG) chains. These microgels were synthesized by free radical copolymerization of vinyl caprolactam and acetoacetoxyethyl methacrylate in the presence of methoxy-capped poly(ethylene glycol)methacrylate macromonomers. We show that variation of the amount of PEG macromonomer or the length of the PEG chain provides effective control of the microgel diameter in the range 60–220 nm. The presence of the grafted PEG chains improves the colloidal stability of the microgels. The incorporation of the PEG macromonomers into microgel structure decreases the swelling degree and induces a shift of the volume phase transition to higher temperatures.

Synthesis and properties of electrically‐sensitive poly(acrylic acid‐co‐acetoacetoxy ethyl methacrylate) gels

AbstractA series of electric field sensitive copolymer P(AA‐co‐AAEM) gels of acrylic acid (AA) with acetoacetoxy ethyl methacrylate (AAEM) were prepared by free‐radical copolymerization, with N,N′‐methylene bisacrylamide (MBAAm) and ammounium persulfate (APS) as crosslinking agent and initiator, respectively. The structures and properties of the gels were tunable by changing the monomer feed weighty ratio (R) (R = WAAEM/(WAAEM + WAA) of AAEM and AA. The influences of the NaCl concentration and pH buffer solutions on the equilibrium swelling ratios of the gels were studied in detail. It is shown that both NaCl concentration and pH value of the buffer solution affect the swelling properties of the P(AA‐co‐AAEM) gels greatly. Moreover, the gel deswelling behavior induced by a direct current electric field was investigated and an excellent electric‐sensitivity was found. Among all the samples, the gel with monomer feed weighty ratio (R) = 0.1479 showed the best electrical contraction properties. On the basis of the experimental results, the mechanism of the electricity‐induced deswelling behavior was presented. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Synthesis and characterization of well‐defined block and statistical copolymers based on lauryl methacrylate and 2‐(acetoacetoxy)ethyl methacrylate using RAFT‐controlled radical polymerization

AbstractFour well‐defined diblock copolymers and one statistical copolymer based on lauryl methacrylate (LauMA) and 2‐(acetoacetoxy)ethyl methacrylate (AEMA) were prepared using reversible addition‐fragmentation chain transfer (RAFT) polymerization. The polymers were characterized in terms of molecular weights, polydispersity indices (ranging between 1.12 and 1.23) and compositions by size exclusion chromatography and 1H NMR spectroscopy, respectively. The preparation of the block copolymers was accomplished following a two‐step methodology: First, well‐defined LauMA homopolymers were prepared by RAFT using cumyl dithiobenzoate as the chain transfer agent (CTA). Kinetic studies revealed that the polymerization of LauMA followed first‐order kinetics demonstrating the “livingness” of the RAFT process. The pLauMAs were subsequently used as macro‐CTA for the polymerization of AEMA. The glass transition (Tg) and decomposition temperatures (ranging between 200 and 300 °C) of the copolymers were determined using differential scanning calorimetry and thermal gravimetric analysis, respectively. The Tgs of the LauMA homopolymers were found to be around −53 °C. Block copolymers exhibited two Tgs suggesting microphase separation in the bulk whereas the statistical copolymer presented a single Tg as expected. Furthermore, the micellization behavior of pLauMA‐b‐pAEMA block copolymers was investigated in n‐hexane, a selective solvent for the LauMA block, using dynamic light scattering. pLauMA‐b‐pAEMA block copolymers formed spherical micelles in dilute hexane solutions with hydrodynamic diameters ranging between 30 and 50 nm. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5442–5451, 2008