Synthesis and characterization of the nano alumina-filled tetraglycidyl-4, 4′-diaminodiphenylmethane epoxy resin

Incorporation of Al2O3, GO, and Al2O3@GO nanoparticles into water-borne epoxy coatings: abrasion and corrosion resistance

Nano-Al₂O₃ particles and graphene oxide (GO) nanosheets were modified by 3-aminopropyltriethoxysilane (KH550), and then dispersed in epoxy resin, and finally modified-Al₂O₃/epoxy, modified-GO/epoxy and modified-Al₂O₃@GO/epoxy composite coatings were prepared on steel sheets by the scraping stick method. The microstructure, phase identification, surface bonding and composition of the nanoparticles were characterized by SEM, XRD, FT-IR, and Raman spectroscopy, respectively. The hardness of the coating was assessed by the pencil hardness method. The abrasion resistance of the coating was tested by a sand washing machine. The corrosion resistance of the coating was assessed using salt spray, a long-period immersion test, potentiodynamic polarization curves and electrochemical impedance spectra. With the addition of a small amount of nanoparticles, the dispersion of nanoparticles in the epoxy resin was good. When the content of nano-Al₂O₃ particles was equal to 1.5 wt%, the particles in the epoxy exhibited the best dispersion and stability. However, the GO and Al₂O₃@GO nanofillers in the epoxy resin exhibited poor dispersion and stability. The hardness, abrasion and corrosion resistance of the composite coatings were improved with the addition of a small amount of nanoparticles, but the performance began to decline after exceeding a certain content range of the nanoparticles. A relatively good abrasion resistance for the coatings was obtained when the content of Al₂O₃, GO and Al₂O₃@GO after modification was 1.5 wt%, 0.2 wt% and 0.4 wt%, respectively. The corrosion resistance of the coatings doped with nano-Al₂O₃ particles was better than that of the coatings incorporating GO nanosheets and Al₂O₃@GO hybrids. The corrosion mechanism of the composite coatings in 3.5 wt% NaCl solution was addressed and studied.

Nano-Al₂O₃ particles and graphene oxide (GO) nanosheets were modified by 3-aminopropyltriethoxysilane (KH550), and then dispersed in epoxy resin, and finally modified-Al₂O₃/epoxy, modified-GO/epoxy and modified-Al₂O₃@GO/epoxy composite coatings were prepared on steel sheets by the scraping stick method.

Green synthesis of nano-Al2O3, recent functionalization, and fabrication of synthetic or natural polymer nanocomposites: various technological applications

Environmentally friendly fabrication of nano-Al₂O₃, recent functionalization, and preparation of polymer nanocomposites including natural and man-made polymers with various industrial applications are reviewed.

Reaction mechanism, cure behavior and properties of a multifunctional epoxy resin, TGDDM, with latent curing agent dicyandiamide

A novel resin system was prepared using the glycidyl amide type multifunctional epoxy resin N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane (TGDDM) and latent curing agent dicyandiamide (DICY). The curing reaction mechanism of the TGDDM/DICY system was studied by Fourier transform infrared (FTIR) spectrometry and the non-isothermal cure behaviors of the mixture were investigated with differential scanning calorimetry (DSC) measurements. The FTIR results demonstrated that there were two main reactions occurring in the curing process of the TGDDM/DICY system. The DSC thermogram of the blend exhibited two different cure regimes in the temperature range of 140-358 °C, and the system experienced two autocatalytic curing processes with α = 0.45 as the boundary; the corresponding average activation energies calculated by the Kissinger method were 69.7 and 88.7 kJ mol-1, respectively. In addition, the correlation between activation energy E a and fractional conversion α was determined by applying model-free isoconversional analysis with Flynn-Wall-Ozawa (FWO) and Starink methods. Results showed that both methods revealed similar trends and possessed approximately the same values at each fractional conversion. Activation energy varied greatly with fractional conversion and the possible causes behind the variations were analyzed in detail. The cured TGDDM/DICY exhibited outstanding mechanical and adhesive properties with tensile and shear strengths of 27.1 MPa at 25 °C and12.6 MPa at 200 °C, good dielectric properties with a low dielectric constant of 3.26 at 1000 kHz and a low water absorption of 0.41%.