Chemical modification of Schiff base epoxy resins involves introduction of waste PET degradation products into a synthesis reaction between N,N'-bis(2hydroxybenzylidene)-4,4'-oxydianiline and epichlorohydrin or introduction of a flexibility spacer between the mesogenic units in a reaction with epichlorohydrin. This provides the resins with much lower glass transition temperatures. All used Schiff bases are the derivatives of 2-hydroxybenzaldehyde. Synthesized epoxy resins were used as a component of binder of new organic coatings. Xylene-based solution of polyamide based on dimerized fatty acid and polyamines and poly(oxypropylene diamine) were used as a hardener for the synthesized and commercial epoxy resins at room temperatures. Physical and mechanical properties of coatings based on new epoxy resins were determined. Results were compared with those for one selected commercial epoxy resin. The results of investigations prove that coatings based on new epoxy resins have good elasticity, impact resistance, and their adhesion to the substrate is comparable or even better than that of coatings based on the widely used commercial epoxy resin.

No abstract

Typically, an anticorrosive coating system for long-term protection consists of a primer, one or several intermediate coats, and a topcoat. In such systems, zinc-rich primers are often used as they ensure good adhesion to the substrate and protect it from corrosion. Such coatings are very highly pigmented, which sometimes leads to losses in cohesive strength and deterioration of mechanical properties. Furthermore, Zn is known to be harmful to the environment. In this work we present Zn primers with reduced Zn content and better protective properties than traditional zinc-rich primers. The formulations of different Zn pigments in the epoxy matrix were developed with the concentration of zinc particles reduced to about 50% in the dry coating. To evaluate the distribution of pigments scanning electron microscopy has been employed. The anticorrosive properties were tested using the salt spray test and electrochemical impedance spectroscopy. The mechanical properties of the coatings were also tested.

No abstract

No abstract