Epoxy and epoxy novolac adhesive binders for structural reinforcement systems of building structures

Today, along with the conventional materials and technologies for reinforcement of building structures, structural reinforcement systems based on polymer composites are on the rise. A structural reinforcement system consists of reinforcing filler (normally, carbon fiber fabric or cloth) and adhesive binder. This paper investigated the modification of epoxy nobake adhesive binders to provide a higher thermal resistance and mechanical strength. The influence of epoxy novolac resins on the processing and physical mechanical properties of adhesives, thermal resistance is studied. It is found that the substitution of 20-40 % of epoxy resin for epoxy novolac resin in the binder increases tensile strength by 40-50 %, flexural modulus by 20 %, reduces tensile strain, and increases glass transition temperature. From the processing point of view, it is more reasonable to use liquid epoxy novolac resins with a functionality of f=2.5 than semisolid resins with a functionality of f=3.6.

Study of binders for ecologically safe anhydrous tap-hole clays

Detailed analytical review of the existing tap-hole clays used in the blast furnace production at various metallurgical enterprises is made. It is established that it is necessary to ensure environmental safety when using tap-hole clay. It is clarifi ed that synthetic resins (phenol-formaldehyde and novolac resins) are used instead of harmful coal-tar resin for the production of tap-hole clays. The oxidation of coal-tar resin and pitch occurs up to temperature of 600 °С, which is especially important for large blast furnaces equipped with 2...4 tap-holes.

Laser treatment of high-performance Kynol fibers: An example as alternative tool for coloration and imaging on surfaces of high-performance fibers

Novolac resins are used to prepare high-performance flame-retardant fibers, which are also supplied under the brand name Kynol fibers. In the current study, Kynol fiber materials are treated with a laser beam to introduce dark coloration at distinct areas on the textile surface. By this, imaging and writing on the textile surface is possible. For investigation, two different types of Kynol fiber materials are used - a non-woven fiber felt and a woven fabric. It is shown that a laser treatment of medium intensity can introduce a change to dark coloration with good rubbing fastness. The writing of letters and symbols onto fabrics is possible. However, treatments with strong laser intensity lead to significant fiber damages and low rubbing fastness. Nevertheless, the presented method is a promising tool to apply images onto flame retardant fabrics from high performance fibers, which are difficult to dye using conventional techniques of dyeing and printing.