Acetoacetoxy Ethyl Methacrylate Research Articles

Thermadapt shape memory vitrimeric polymyrcene elastomer

Earlier studies of β-Myrcene (Myr)/ β-ketoester functional (acetoacetoxy)ethyl methacrylate (AAEMA) copolymers exhibited compositional drift, leading to ambiguity in microstructure/thermomechanical property correlations while shape memory recovery times were excessively long ~1 h. The terpene-based 1,3-diene Myr and AAEMA were copolymerized via nitroxide-mediated polymerization (NMP) with an initial Myr molar feed ratio ranging from 0.1 to 0.9. Reactivity ratios estimated by the Meyer-Lowry method were rMyr = 0.20 and rAAEMA = 0.22 with respective 95% confidence intervals of [0.13, 0.37] and [0.15, 0.23], suggesting alternating copolymerization. Bulk terpolymerization with styrene (Sty) afforded linear poly(Myr-stat-Sty-stat-AAEMA) prepolymers designed to modulate glass transition temperature Tg and stiffness. Subsequent cross-linking with isophorone diamine (IPDA) formed catalyst-free vinylogous urethane dynamic linkages. ATR-FTIR, dynamic mechanical analysis (DMA), and tensile measurements confirmed the recyclability of vitrimers through hot pressing at 110 °C, demonstrating minimal changes in rheological and mechanical properties even after four cycles. By heating the vitrimers to above their Tg (to ~45 °C), they exhibited a shape memory effect with high shape fixity and fast shape recovery (< 1 min). The vitrimers could undergo permanent shape reprogramming through reconfiguration of dynamic bonds at ~110 °C. This work shows the adaptability of Myr-based rubbers by vitrification and appropriate copolymerization for the synthesis of more sustainable elastomers with stimuli responsive properties.

Hybrid Dynamic Covalent Network-Based Protecting Layer for Stable Li-Metal Batteries.

Metallic lithium (Li) is considered as the "Holy Grail" anode material for next-generation energy storage systems due to its extremely high theoretical capacity and low electrochemical potential. Before the commercialization of the Li electrode, dendritic Li growth and the unstable solid electrolyte interphase layer should be conquered. Herein, a hybrid covalent adaptable polymer network (HCAPN) is prepared via the random copolymerization of poly(ethylene glycol) methyl ether methacrylate and -acetoacetoxyethyl methacrylate, followed by chemical cross-linking with polyethylenimine (PEI) and amine-modified silicon dioxide (SiO2). Such a hybrid network, where PEI and amine-modified SiO2 formed a vinylogous urethane-based dynamic covalent bond with the copolymer, respectively, shows improved mechanical properties, solvent resistance, and excellent healability/recyclability. As the protecting layer on the Li electrode, the assembled HCAPN@Li||HCAPN@Li symmetric cell shows a long cycle life of 800 h with low overpotential at a current density of 1 mA cm-2, and superior electrochemical performance can be achieved in the HCAPN@Li||LiFePO4 full cell (capacity retention of 77% over 400 cycles at 1.5 C) and HCAPN@Li||NCM811 cell (capacity retention of 79% after 300 cycles). Surface morphology analysis is also performed for physical insight into their role as protecting layer. This work provides a new perspective for constructing a hybrid dynamic covalent network-based polymer protecting layer for inhibiting Li dendrite growth.

The Post-Curing of Waterborne Polyurethane-Acrylate Composite Latex with the Dynamic Disulfide-Bearing Crosslinking Agent.

The development of a dynamic network for commodity polymer systems via feasible methods has been explored in the context of a society-wide focus on the environment and sustainability. Herein, we demonstrate an adaptive post-curing method used to build a self-healable network of waterborne polyurethane-acrylate (WPUA) composite latex. The composite latex was synthesized via the miniemulsion polymerization of acrylates in the dispersion of waterborne polyurethane (PU), with commercial acetoacetoxyethyl methacrylate (AAEM) serving as the functional monomer. Then, a dynamic disulfide (S-S)-bearing diamine was applied as the crosslinking agent for the post-curing of the hybrid latex via keto-amine condensation, which occurred during the evaporation of water for film formation. It was revealed that the microphase separation in the hybrid films was suppressed by the post-curing network. The mechanical performance exhibited a high reliability as regards the contents of the crosslinking agents. The reversible exchange of S-S bonds meant that the film displayed associative covalent-adaptive networks in the range of medium temperature in stress relaxation tests, and ≥95% recovery in both the stress and the strain was achieved after the cut-off films were self-healed at 70 °C for 2 h. The rebuilding of the network was also illustrated by the >80% recovery in the elongation at break of the films after three crushing-hot pressing cycles. These findings offer valuable insights, not only endowing the traditional WPUA with self-healing and reprocessing properties, but broadening the field of study of dynamic networks to polymer hybrid latex.

Preparation and application of diacetone-based functionalized polymeric microspheres

Diacetone is widely used to form chelates with various metals. Polymer materials containing acetylacetone have great potential for catalytic reactions, the separation of heavy metals, and luminescent materials. In this report, we chose 2-(acetoacetoxy)ethyl methacrylate (AAEM) as a functional monomer. We synthesised monodisperse polymethylmethacrylate (PMMA) with diacetone on the surface via one-step RAFT-assisted dispersion photopolymerisation using P(AAEM-co-mPEGA) as a stabiliser. This type of functional microsphere can be used for catalysis after the adsorption of TiO2. Using 2-(acetoxy)ethyl methacrylate (AAEM), methyl methacrylate (MMA), and dipropylene glycol diacrylate (DPGDA) as crosslinking agents and the poly(acrylamide N,N-dimethyl) macromolecular RAFT reagent (P(DMA)-TTC) as a stabiliser, we obtained other functional microspheres using diacetone. These microspheres can be further utilised as magnetic microspheres by swelling in DMF and adsorbing iron and ferrous ions. We also evaluated the magnetic content and thermal stability of microspheres with different AAEM and MMA monomer ratios. Polymer microspheres have great potential in various applications owing to their excellent monodispersibility, superparamagnetism, and easy separation. Our study provides a new, simple, and effective method for preparing surface- and internal-functionalized microspheres.

Delaminasi Perekat Polivinil Asetat Berbasis Air Satu Komponen untuk Aplikasi Kayu Keras Ulin dan Merbau

Water-based adhesive was one of the most important media for bonding substrates to one another because of their environmental friendly character. Previously, in the application of hardwood adhesives such as Ulin and Merbau, the type of adhesive used was a two-component system. For this reason, a one-component water-based adhesive was introduced in this study. The advantage of these was environmental friendly and high durability. In this application, delamination was one of the important parameters to determine whether the adhesive used was well penetrated or not. For this reason, delamination will be the main parameter in this study. This research includes the preparation of tools and materials, manufacture of PVA (polyvinyl alcohol) solution, polymerization of polyvinyl acetate by mixing the main raw material of vinyl acetate monomer and PVOH solution using APS (ammonium persulfate) initiator. The polymerization process was carried out at 1 atm pressure and 75oC – 80oC temperature accompanied by stirring with ±500 rpm rotation rate. Final product is a homopolymer PVAc (polyvinyl acetate) with PVOH Z-210 with AAEM (acetoacetoxy ethyl methacrylate) content having an acetoxy functional group. A delamination test was carried out on the final product with a modified test based on Japanese Agricultural Standard 1152 where the product was immersed in water for 360 minutes, then placed in an oven at 40oC for 18 hours. Samples using PVOH with AAEM content have an average delamination rate of 0.67-1.67% while existing products on the market have an average delamination rate of 45.83-52.08%.

Kinetic study of crosslinking between acetoacetoxy and hexamethylene diamine functionalized waterborne latexes in two-pack systems

A kinetic study of the crosslinking reaction between waterborne polymer particles functionalized with aceto acetoxy ethyl methacrylate (AAEMA) and polymer particles functionalized with hexamethylene diamine (HMDA) is presented. Seeded emulsion polymerization is used to synthesize the polymer particles and the crosslinking reaction is followed during the film formation of the two-pack system. The kinetics of reaction with respect to time and temperature are studied using FTIR spectroscopy and rheological measurements, and the effects of crosslinking are also analysed by tensile strength and water absorption test. It is found that room temperature crosslinking occurs, as previously suggested in the literature, but at relatively slow rates. On the other hand, the annealing at 60 °C enhances considerably such crosslinking reactions, leading to fully interparticle crosslinked systems with improved mechanical and chemical resistance properties.

Preparation and properties of a self-crosslinking styrene acrylic emulsion using amino-functional graphene oxide as a crosslinking agent and anti-corrosion filler

In this paper, we prepared a self-crosslinking amino-functional graphene oxide/styrene acrylic hybrid emulsion (AGO/SA). The styrene acrylic emulsion (SA) was synthesized with acetoacetoxyethyl methacrylate (AAEM) by semicontinuous seeded emulsion polymerization. Then, amino-functionalized graphene oxide (AGO) was prepared via the modification of graphene oxide (GO) with 3-aminopropyltriethoxysilane (APTES) and reacted with the SA emulsion as a crosslinking agent by in situ polymerization. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermal gravity analysis (TGA), and transmission electron microscopy (TEM) were applied to explore the chemical structures and morphologies of the samples. The anti-corrosion performance of the AGO/SA coatings was evaluated by Tafel polarization and electrochemical impedance spectroscopy (EIS). Along with the crosslink between AGO and SA, the micropores in the matrix were reduced, the coating expressed improved corrosion resistance due to the graphene barrier, and the hybrid emulsion with 0.7 wt.% AGO exhibited the best anti-corrosion properties. These results indicate that AGO can act as both a crosslinking agent and an anti-corrosion agent in self-crosslinking hybrid emulsions, which have great potential in the field of environmentally friendly emulsions.

Anchoring Interfacial Nickel Cations by Tunable Coordinative Structure for Highly Stabilized Nickel-Rich Layered Oxide Cathodes

Ni-rich LiNixCoyMn1−x-yO2 (NCM) cathode materials have received extensive attention on account of their high specific capacities and great application prospects in electric vehicles. While increasing Ni content in NCM can greatly increase initial discharge capacities, more highly reactive Ni4+ species in the delithiated state may facilitate irreversible phase transformation and undesirable interfacial reactions, leading to severe capacity degradation. Here we demonstrate an organic surface modification approach to modulate the surface coordinative structure of NCM cathode for enhanced cycling stability. We discover that the highly reactive Ni4+ cations can be anchored by strong electron-donating organic groups, especially under bidentate coordination, which mitigates excessive electrolyte decomposition and Ni dissolution into the electrolyte, inhibits the layered-to-rock salt phase transformation and suppresses the initiation and propagation of microcracks within the NCM cathodes. In consequence, the nickel-rich cathode coated with poly (acetoacetoxyethyl methacrylate) (PAAEM) with multiple ester groups exhibits a remarkable improvement in cycling stability, showing 91.3% retention of the initial capacity after 200 cycles. The present findings demonstrate that regulating surface coordinative structure is an efficient and practical strategy to modify the interfacial reactions for enhanced cyclability in Ni-rich layered oxide cathodes.

Preparation of Block Copolymer Nano-Objects with Embedded β-Ketoester Functional Groups by Photoinitiated RAFT Dispersion Polymerization.

Herein, a photoinitiated reversible addition-fragmentation chain transfer (RAFT) dispersion polymerization of 2-(acetoacetoxy)ethyl methacrylate (AEMA) in ethanol/water at room temperature for in situ preparation of β-ketoester-functionalized block copolymer nano-objects is reported. AEMA is also copolymerized with isobornyl methacrylate (IBOMA) to improve the colloidal stability of PIBOMA-based block copolymer nano-objects prepared by photoinitiated RAFT dispersion polymerization at low temperatures. A series of P(IBOMA-stat-AEMA)-based block copolymer nano-objects are prepared by changing reaction parameters. Finally, lanthanide-doped block copolymer nano-objects with luminescent and magnetic properties are also prepared based on the complexation of various lanthanide ions with the β-ketoester group. It is expected that the current study will provide a facile platform for the in situ preparation of β-ketoester-functionalized block copolymer nano-objects with different morphologies for specific applications.

Rubber-to-steel adhesives based on natural rubber grafted with poly(acetoacetoxyethyl methacrylate)

Abstract The present study aimed to develop adhesives for bonding natural rubber (NR) to steel based on modified NR bearing grafted poly(acetoacetoxyethyl methacrylate), NR-g-PAAEM. Graft copolymers of NR-g-PAAEMs were prepared by emulsion polymerization at 50 °C. A significant increase in the polar component of NR from 1.62 to 6.84 mN/m was observed after grafting modification, indicating an increase in its hydrophilicity. After that, both one-coat and two-coat adhesives (or adhesive/cover-coat system) were then prepared, using polyisocyanate (poly‐HDI) as a bonding agent. The NR/steel joints were made by vulcanization bonding, using the NR-g-PAAEM adhesive in the presence or absence of cover-coat layer. The results reveal that the NR/steel joint bonded using the two-coat system exhibited higher peel strength than that bonded using the one-coat system. For the two-coat system, the peel strength of 874 N/m was attained when the NR-g-PAAEM adhesive was used in combination with the NR cover-coat. The replacement of the NR cover-coat by the NR-g-PAAEM20 cover-coat led to 49% increase in peel strength of the NR/steel joint. Moreover, the X-ray photoelectron spectroscopy analysis also indicated the formation of urethane-like bonding in this adhesive system, as a result of the reaction between the poly‐HDI and metal oxides on the steel surface.

Self-stratifying amphiphobic coating based on functional polyacrylates

Self-stratifying coating is a promising and interesting coating system containing multi-resinous components, which instinctively stratify after coating on the substrate. Here, we have developed a new type of self-stratifying coating based on functional polyacrylate system. In this case a terpolymer of butyl acrylate, acetoacetoxy ethyl methacrylate and hydroxyethyl methacrylate was used as the polymer matrix. The whole coating system consists of a blend of a functional acrylic terpolymer (bearing acetoacetoxy, n-butyl as well as hydroxy ethyl functional group as the pendant group), phenyl methoxy functional siloxanes, hollow glass spheres (HGS) and aerogel particles (AP). 3-aminopropyl triethoxysilane was used as a crosslinker. Hydrophilic hollow glass spheres (of 20 μm average particle size) and hydrophilic aerogel particles (of 5 μm average particle size) were used to generate desirable roughness on the surface. Low quantity of a non-silanated fluorinated surfactant was incorporated, which self-stratifies to the surface during coating film formation and imparts oleophobicity. An oil and water repellent (amphiphobic) surface was developed with high water as well as diiodomethane contact angle (∼130°) by varying the ratio of glass spheres and aerogel to each other and the polymer. Rolling effect of water and oil drops was also prominently visible. The surface showed excellent resistance to polar and non-polar solvents, good resistance to heat (150 °C) and sand impingement after which the water contact angle remains unchanged. The oil repellency was easily restored by spraying or dipping in a dilute solution of the non-silanated fluorinated compound. This coating can be applied by conventional techniques such as spray application and can have potential applications in anti-soiling and self-cleaning coatings.

Investigation of the mechanical and thermal properties of reactive AAEM-co-MMA adhesive

The effect of acetoacetoxyethyl methacrylate (AAEM) comonomer was investigated on the adhesion and thermal and mechanical properties of methyl methacrylate (MMA) reactive adhesive. The free radical bulk copolymerization of AAEM-co-MMA at ambient temperature was carried out in the presence of redox couple of benzoyl peroxide (BPO) and N,N-dimethylaniline (DMA). The glass transition temperature (Tg) and Young’s modulus of different AAEM comonomer compositions were investigated by dynamic mechanical thermal analysis (DMTA) and three-point bending test. The presence of AAEM comonomer resulted in a low Tg and high modulus adhesive. The results from tensile test and lap shear strength showed the usefulness of AAEM in MMA adhesive with an optimum AAEM contribution of 20 wt.%. The improvements in adhesive main properties and thermal stability may be well attributed to the formation of cross-linking bonds which is in agreement with the results of FTIR spectroscopy.

High-Throughput Preparation of Antibacterial Polymers from Natural Product Derivatives via the Hantzsch Reaction.

SummaryThe Hantzsch and free-radical polymerization reactions were combined in a one-pot high-throughput (HTP) system to simultaneously prepare 30 unique polymers in parallel. Six aldehydes derived from natural products were used as the starting materials to rapidly prepare the library of 30 poly(1,4-dihydropyridines). From this library, HTP evaluation methods led to the identification of an antibacterial polymer. Mechanistic studies revealed that the dihydropyridine group in the polymer side-chain structure plays an important role in resisting bacterial attachment to the polymer surface, thus leading to the antibacterial function of this polymer. This research demonstrates the value of multicomponent reactions (MCRs) in interdisciplinary fields by discovering functional polymers for possible practical applications. It also provides insights to further developing new functional polymers using MCRs and HTP methods with important implications in organic chemistry, polymer chemistry, and materials science.

New Thermoplastic Vulcanizate Based on Acetoacetoxy Functionalized Natural Rubber/Polyamide12 Blend Filled with Carbon Black

Thermoplastic vulcanizates (TPVs) based on blends of natural rubber (NR) grafted with poly(acetoacetoxyethyl methacrylate), NR-g-PAAEM, and polyamide12 (PA12) were prepared by the dynamic vulcanization technique. NR-g-PAAEM was first prepared and its surface free energy was evaluated by means of contact angles. Blends of NR-g-PAAEM and PA12 were then prepared at a 60/40 blend ratio (wt%) using a dynamic vulcanization technique. The results revealed that TPVs exhibited a dispersed-phase morphology. However, the TPVs filled with carbon black (CB) showed much smaller dispersed rubber particles when compared to the unfilled TPV. TEM analysis also revealed that the CB appeared to be mainly located within the NR-g-PAAEM phase. The presence of CB generally raised the melt viscosity and increased shear during melt-mixing, resulting in finer dispersion of the rubber particles. Additionally, a significant enhancement in the tensile properties of the TPV was also achieved by the incorporation of CB. The optimum tensile properties were attained by the addition 30 phr of CB. The results also showed that the incorporation of CB into the NR-g-PAAEM/PA12 TPVs improved their stress relaxation properties. Moreover, the effects of reprocessing on the mechanical properties of the TPV filled with CB were also investigated. Although the TPV filled with CB exhibited reprocessing capability, reprocessing at high temperature and shear forces was found to negatively affect its tensile properties, especially after the third reprocessing cycle.

Ambient curable latex films and adhesives based on natural rubber bearing Acetoacetoxy functionality

The study described in this paper first demonstrates that a newly modified form of natural rubber, namely graft copolymers of natural rubber with poly (acetoacetoxyethyl methacrylate), NR‐g‐PAAEM, is able to undergo a cross‐linking reaction at room temperature by reaction with a water dispersible polyisocyanate based on hexamethylene diisocyanate (poly‐HDI). Attenuated total reflectance Fourier transform infrared (ATR‐FTIR) analysis indicated that amide groups were formed by the reaction of the acetoacetyl groups (AcAc) present in the grafted poly (acetoacetoxyethyl methacrylate) (PAAEM) chains with the poly‐HDI. This observation was accompanied by a noticeable increase in the tensile strength of the NR‐g‐PAAEM latex films when adding poly‐HDI to the latex prior to film formation. DMTA analyses also revealed a shift in the tan δ peaks, corresponding to the transitions of both NR‐g‐PAAEM and free PAAEM phases, to higher temperatures. These results provide firm evidence of cross‐linking between NR‐g‐PAAEM chains by reaction with poly‐HDI during film formation under ambient conditions. Adhesives for bonding wood to wood based on the NR‐g‐PAAEM latex were then prepared, using poly‐HDI as the cross‐linker. The lap shear strength of the resulting adhesives exhibited a maximum value of 2657 KPa when a poly‐HDI:AAEM molar ratio of 3:1 was employed. It was also observed that the adhesive attained about approximately 89% of the highest lap shear strength after it was allowed to set at 30°C for 24 hours. Hence, the use of poly‐HDI in cross‐linking NR particles bearing grafted PAAEM offers great potential for developing latex adhesives and coatings capable of curing under ambient conditions.

Preparation of the polymerizable titania oriented to 3D printing and the laser-induced crystallization

PurposeThe titania (titanium dioxide) is one of the important functional additives in the photosensitive resin and encounters the problem of stabilization in the photosensitive resin for 3D printing. This study aims to achieve enhancement in stabilization by preparation of the polymerizable titania and in situ laser-induced crystallization during 3D printing.Design/methodology/approachA type of polymerizable titania (AAEM@TiO2) was designed and prepared from tetrabutyl titanate (TBT) and 2-(acetoacetoxy)ethyl methacrylate (AAEM) via the sol–gel process, which was characterized by Fourier-transform infrared (FTIR) spectra, ultraviolet–visible (UV-Vis) spectra, surface bonding efficiency (SBE) and settling height (H). AAEM acted on both bonding to the titania and polymerization with the monomer in resin for stabilization. The polymerizable titania could be converted to the pigmented titania by means of laser-induced crystallization. The photosensitive resin was then formulated on the basis of optimization and used in a stereolithography apparatus (SLA) for 3D printing.FindingsThe stabilization effect of AAEM on TiO2 was achieved and the mechanism of competition in the light-consuming reactions during photocuring was proposed. The ratio of nAAEM/nTBT in AAEM@TiO2, the concentration of AAEM@TiO2 and photoinitiator (PI) used in the photosensitive resin were optimized. The anatase crystal form was indicated by X-ray diffraction (XRD) and clustering of nanocrystals was revealed by scanning electron microscopy (SEM) after SLA 3D printing.Originality/valueThis investigation provides a novel method of pigmentation by preparation of the polymerizable titania and in situ laser-induced crystallization for SLA 3D printing.

In Situ Growth and Size Regulation of Single Gold Nanoparticles in Composite Microgels.

Herein, a novel method for the in situ growth of single gold nanoparticles (AuNPs) in microgel (MG) networks is presented. The key feature in this approach is the localization of β-diketone groups capable of both complexation and reduction of aurate ions in the MGs' core, which allows localization of the nucleation and growth of single AuNPs. The MG synthesis is carried out via precipitation polymerization in water with N-vinylcaprolactam as the main monomer and with the two comonomers acetoacetoxyethyl methacrylate (AAEM) and acrylic acid (AAc), where AAEM is mainly located in the MGs' core and AAc in their shell. For the synthesis of AuNPs, a certain amount of chloroauric acid (HAuCl4 ) is added to the dispersion, followed by fast reduction with sodium borohydride (NaBH4 ). In situ synthesized AuNPs in MGs possess a spherical shape, with a diameter of 8.1 ± 0.8 nm, being localized in the center of every MG. In addition, these AuNPs embedded into MG networks can be used as seeds that grow in their size after the addition of HAuCl4 up to 46.0 ± 9.5 nm under mild reaction conditions (room temperature, aqueous dispersion) and without the use of any additional reducing and stabilizing agents.

Synthesis of a low‐temperature self‐crosslinking polyacrylate binder with a core‐shell structure and its application in textile pigment printing

A core‐shell acrylate binder for pigment printing containing acetoacetoxyethyl methacrylate (AAEM) in its shell was synthesised via semicontinuous seeded emulsion polymerisation. Self‐crosslinking occurs when curing at low temperatures without releasing formaldehyde. The core‐shell structure of the binder produces prints with a high block resistance and good film‐forming properties, which can avoid clogging the screens during the printing process and help to acquire a soft handle for textiles. Transmission electron microscopy (TEM) analysis demonstrated that the latex particle had a core‐shell structure of size ca. 120 nm. Differential scanning calorimetry (DSC) testing showed that polyacrylate (PA)‐modified AAEM exhibited two apparent Tg, providing further information about the formation of the soft core‐hard shell latex particles. Crosslinking degree tests, thermogravimetric analysis (TGA) and testing of the mechanical properties indicated that self‐crosslinking of AAEM took place at 100 °C, thereby enhancing the thermostability and mechanical properties of the latex films. The softer and non‐stick handle, excellent rubbing fastness, and higher K/S were obtained by further padding the printed fabric with amino silicon softener. The chemical structures of the surfaces of the printed fabrics were studied by Fourier Transform‐infrared (FTIR), and results confirmed that the crosslinking reaction between the amino of the softener and remaining acetoacetoxy functional group (AcAc) of AAEM had taken place.

Effect of nanosilver on the thermal stability and thermal decomposition kinetics of poly(acetoacetoxyethyl methacrylate–styrene)

Nanosilver/poly(acetoacetoxyethyl methacrylate–styrene) (nano-Ag/P(AAEM-St)) composites were synthesized via emulsifier-free emulsion with silver nitrate solution, AAEM, and St monomer copolymerization by ultrasonic. The morphology and structure of the composites were characterized by ultraviolet and visible spectroscopy, X-ray diffractometer, and transmission electron microscopy, respectively. The results show that Ag nanoparticles with face-centered cubic structure are homogeneously dispersed in the P(AAEM-St) matrix. The thermal stability and the thermal degradation kinetics of P(AAEM-St) were investigated using the thermogravimetric analysis and Kissinger and Flynn–Wall–Ozawa method, respectively. The results prove that the thermal stability of the pure P(AAEM-St) is better than that of the nano-Ag/P(AAEM-St) composites.

Synthesis of modified Natural Rubber with grafted poly(acetoacetoxyethyl methacrylate‐co‐methyl methacrylate) and performance of derived adhesives with GTA crosslinker

The main objective of this study is to develop wood adhesives that can be cured at room temperature, based on modified natural rubber (NR) latex. Two types of modified NR, namely poly(acetoacetoxyethyl methacrylate)‐grafted NR, NR‐g‐PAAEM, and poly(acetoacetoxyethyl methacrylate‐co‐methyl methacrylate)‐grafted NR, NR‐g‐P(AAEM‐co‐MMA), were synthesized. Emulsion polymerization technique was exploited to synthesize the graft copolymers. The hydrophilicity of NR after grafting modifications was examined by means of contact angle. These results reveal that the NR become more hydrophilic after being modified with poly(acetoacetoxyethyl methacrylate), PAAEM, and/or poly(methyl methacrylate), PMMA. Adhesion properties in terms of lap shear strength were studied for wood adhesives derived from both types of NR graft copolymers, with glutaraldehyde (GTA) as the crosslinking agent. The results show that adhesives based on the NR graft copolymers gave higher lap shear strength than the NR latex adhesive. For the graft copolymers, the NR‐g‐P(AAEM‐co‐MMA) adhesive exhibited much higher lap shear strength than the NR‐g‐PAAEM adhesive. This indicates that the incorporation of PMMA chains into the NR‐g‐PAAEM molecules significantly increased the cohesive strength of the resulting adhesive, which is probably due to increased modulus and hardness of the adhesive film. POLYM. ENG. SCI., 58:1610–1618, 2018. © 2017 Society of Plastics Engineers