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Epoxy adhesives become very brittle after curing due to their high‐crosslinking degree. For increasing the toughness of epoxy adhesives, the addition of different toughening agents has been proposed. In this study the diglycidyl ether of bisphenol A (DGEBA)/dicyandiamide epoxy network has been modified by adding an emulsion latex containing core–shell rubber particles (CSPs) prepared by means of seeded emulsion polymerization. The CSPs consist of poly (butyl acrylate) (PBA) as core and methyl methacrylate (MMA) copolymerized with glycidyl methacrylate (GMA) as shell. The effects of adding various amounts of the emulsion latex on the mechanical properties, thermal stability, adhesion, and microstructure of the cured epoxy resin were investigated. The CSPs were analyzed by transmission electron microscopy (TEM), Fourier‐transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). The mechanical properties, thermal stability, adhesion to aluminum plates, and microstructure of the cured epoxy resin were investigated by stress–strain, thermal gravimetric analysis (TGA), single lap shear test, and field emission scanning electron microscopy (FESEM), respectively. The addition of 7 wt.% emulsion latex to epoxy enhanced the tensile strength and the toughness of the dumbbell‐shaped samples by 421% and 4388% with respect to neat epoxy, respectively. Furthermore, the single lap shear strength increased in 33% and an increase of 71°C in the initial decomposition temperature of the epoxy was obtained by adding 7 wt.% CSP, without affecting the maximum decomposition temperature. The FESEM micrographs of the fractured surfaces indicated that the major toughening mechanisms were CSP de‐bonding, plastic void growth, and shear bond yielding. [ABSTRACT FROM AUTHOR]

In this study, MIL‐101 (Cr) and NH2‐MIL‐101 (Cr) nanoparticles were synthesized by hydrothermal method. Butyl acrylate‐styrene copolymer was used along with these nanoparticles to improve the mechanical properties of epoxy adhesive. The results of the Fourier Transform Infrared (FTIR) and X‐ray diffraction (XRD) test showed that the synthesis and functionalization of the metal organic framework (MOFs) were successful. The mechanical properties and adhesion features in the lap joint bonding of aluminum foil to the aluminum foil of modified epoxy adhesives were investigated by tensile and lap shear tests. The results of the tensile test showed that by adding 0.3 wt% of NH2‐MIL‐101 (Cr) and 2.5 wt% of poly(butyl acrylate‐block‐styrene) to epoxy adhesive, the tensile strength, modulus and toughness of dumbbell samples were increased up to 34.46%, 31.74% and 58.53%, respectively. Furthermore, based on the lap shear test results, by adding 0.3 wt% NH2‐MIL‐101 (Cr) along with 2.5% poly(butyl acrylate‐block‐styrene) to the epoxy adhesive, the lap shear strength of samples increased from 1.05 ± 0.08 MPa to 5.25 ± 0.06 MPa compared to the neat epoxy adhesive. According to the TGA test, the highest thermal stability is related to the sample containing 0.3 wt% of NH2‐MIL‐101 nanoparticles and 2.5 wt% of the copolymer. The image of the fracture surface of the sample containing 0.3 wt%. NH2‐MIL‐101 (Cr) and 2.5 wt% block copolymer shows that the interface of nanoparticles and the matrix improved due to the chemical reaction of functional groups of nanoparticles and adhesive matrix. [ABSTRACT FROM AUTHOR]

In this study, non‐isothermal curing kinetics of the prepared samples was studied using differential scanning calorimetry (DSC) to evaluate the effect of methyl phenyl silicone resin (MPS), acrylonitrile butadiene styrene (ABS), and graphene oxide (GO) on the cure reaction of epoxy resin. Chemical and microscopic structure of prepared nanocomposites was investigated using Fourier‐transform infrared spectrophotometry (FTIR) and scanning electron microscopy (SEM), respectively. Izod impact strength of modified epoxy resin with 5 phr MPS, 2 phr ABS, and 0.1 phr GO was about 53% higher than pure epoxy resin. Evaluation of activation energy (Ea) by Kissinger, Ozawa, FWO and Friedman methods showed that the presence of GO facilitates the curing reaction by reducing Ea about 30% which is due to the catalytic effect of hydroxyl groups presented on the surface of GO for epoxy ring opening. According to Friedman's plots, curing reaction remained autocatalytic for all of samples. The presence of GO increased the autocatalytic term of the reaction (n) from 0.26 to 0.32. Non‐isothermal DSC diagrams obtained from experimental data fitted well with data obtained from theoretical relations. [ABSTRACT FROM AUTHOR]

Herein the kinetics of network formation (cross‐linking) and network degradation (thermal decomposition) in a complex system based on epoxy resin reinforced with hyperbranched amino polymer‐functionalized nanoparticles (HAPF) were discussed. Five classes of nanoparticles, that is, nano‐SiO2, halloysite nanotubes (HNTs), HNTs@nano‐SiO2 core/shell, HAPF/nano‐SiO2, HAPF/HNTs@nano‐SiO2 core/shell were loaded at 0.5, 1.0, 2.0 (optimal loading among prepared samples), and 5 wt% were examined. Parameters of the cure kinetics and degradation were correlated, and the mechanical properties were interpreted in terms of microstructure and rheological analyses. The isothermal chemorheological cure kinetics study (60, 70, and 80°C) revealed a low activation energy for epoxy/HAPF/HNTs@nano‐SiO2 core/shell nanocomposite (72.21 kJ/mol), compared with the blank epoxy (79.99 kJ/mol). Correspondingly, gel time of the system decreased from 1040 to 515 to 237 s upon isotherms of 60, 70, and 80°C, respectively. Tensile strength was also increased vividly (ca. 32%), possibly due to the strong interfacial adhesion, which reflected in an induced shear yielding. Nitrogen‐mediated thermal decomposition kinetics suggested an average degradation activation energies of ca. 150 and 210 kJ/mol for the assigned nanocomposites and the blank epoxy, respectively. Overall, there was a complete agreement between the kinetics of network formation and network degradation in the studied epoxy nanocomposite. This work enables understanding of structure‐properties‐performance in complex epoxy nanocomposites. [ABSTRACT FROM AUTHOR]

This paper investigates the synthesis of graphene oxide (GO)-incorporated polyamide thin-film nanocomposite (TFN) membranes on polysulfone substrate for forward osmosis applications. The GO nanosheets were embedded into polyamide layer using different concentrations (0.05−0.2 wt%). The results represented the alteration of polyamide surface by GO nanosheets and enhancing the surface hydrophilicity by increasing the GO loading. The results showed that the water flux for 0.1 wt% GO embedded nanocomposite (TFN) membrane was 34.7 L/m2 h, representing 90% improvement compared to the thin-film composite, while the salt reverse diffusion was reduced up to 39%. [ABSTRACT FROM AUTHOR]