Novel layered double hydroxide/epoxy nanocomposites for corrosion protective coatings
Topic(s) : Material science
Co-authors :
Daiva ZELENIAKIENE (LITHUANIA), Rochele PINTO (LITHUANIA), Claudia ROCHA , Stanislav STANKEVICH , Marie NOVAKOVA , Katerina KATERINA ZETKOVA (CZECH REPUBLIC), Andrey ANISKEVICH (LATVIA), Frederico MAIA , Joao TEDIMAbstract :
Eco-friendly Mg-Al/NO3 layered double hydroxides (LDH) represent a unique class of nanomaterials. These compounds are characterised by their layered structure, composed of magnesium and aluminium hydroxide layers, with nitrate anions intercalated between them. Owing to this, LDH have versatile applications in various fields. One of the promising applications is utilising these materials as nanofillers in polymer matrix coatings to protect metals against corrosion [1, 2]. When incorporated into coatings, LDH enhance the barrier properties of the layer, significantly reducing the penetration of corrosive elements. Furthermore, the addition of Mg-Al/NO3 LDH to coatings can improve the adhesion and mechanical strength of the layer, maintaining the integrity of the coating under diverse environmental conditions.
This study was aimed to develop a novel Mg-Al/NO3 LDH and epoxy resin nanocomposite for anti-corrosive steel protection and to comprehensively evaluate both the mechanical and electrochemical properties of this nanocomposite. Two methods were trialled for incorporating LDH particles into epoxy resin. In the first approach, a Mg-Al/NO3 LDH slurry in water (wt.% solids: 15-20) was utilised. A nine-step particle washing procedure was employed, gradually replacing water with ethanol, acetone, and finally xylene. The washed particles were examined using microscopy, atomic force microscopy, X-ray diffraction analysis, and other characterisation tests. These studies revealed that the particles were partially exfoliated. LDH particles in xylene were added to bisphenol A epoxy (CHS 582) in specific volume fractions and mixed with a high shear stirrer. Subsequently, the isophorone diamine hardener (Telalit 0420) was added and epoxy/LDH nanocomposites were obtained. Films and dog-bone samples were prepared for characterisation and mechanical testing. As a second alternative method for particle incorporation into epoxy resin, the introduction of dried LDH powder into the resin was used. Initially, the powder was mixed with the hardener in a certain ratio, additionally introducing a wetting and dispersion additive. LDH/epoxy samples prepared in this way were also thoroughly examined.
Comparative analysis of all sample groups revealed that the mechanical properties of the new nanocomposites, if reduced, were only slightly so, and in some cases, even improved. Furthermore, coatings made using this nanocomposite demonstrated excellent anti-corrosive properties.
Acknowledgements:
The project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 101007430.
This study was aimed to develop a novel Mg-Al/NO3 LDH and epoxy resin nanocomposite for anti-corrosive steel protection and to comprehensively evaluate both the mechanical and electrochemical properties of this nanocomposite. Two methods were trialled for incorporating LDH particles into epoxy resin. In the first approach, a Mg-Al/NO3 LDH slurry in water (wt.% solids: 15-20) was utilised. A nine-step particle washing procedure was employed, gradually replacing water with ethanol, acetone, and finally xylene. The washed particles were examined using microscopy, atomic force microscopy, X-ray diffraction analysis, and other characterisation tests. These studies revealed that the particles were partially exfoliated. LDH particles in xylene were added to bisphenol A epoxy (CHS 582) in specific volume fractions and mixed with a high shear stirrer. Subsequently, the isophorone diamine hardener (Telalit 0420) was added and epoxy/LDH nanocomposites were obtained. Films and dog-bone samples were prepared for characterisation and mechanical testing. As a second alternative method for particle incorporation into epoxy resin, the introduction of dried LDH powder into the resin was used. Initially, the powder was mixed with the hardener in a certain ratio, additionally introducing a wetting and dispersion additive. LDH/epoxy samples prepared in this way were also thoroughly examined.
Comparative analysis of all sample groups revealed that the mechanical properties of the new nanocomposites, if reduced, were only slightly so, and in some cases, even improved. Furthermore, coatings made using this nanocomposite demonstrated excellent anti-corrosive properties.
Acknowledgements:
The project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 101007430.