Kursk Composite Materials Plant
The plant produces composite products by pultrusion on an epoxy compound (resin + ISOMGFTA hardener).
Products are rods of a semicircular shape with a width of 10 to 15 mm, a height of 5 to 8 mm, produced by passing glass molding through a bath of impregnation with an epoxy binder and then forming in a die at a temperature of 150-190 degrees C.
The rods undergo mandatory tests for statistical bending. In the current technological parameters, these requirements are met at the minimum values, while there is no stable result. There is also a request for the resistance of these rods to bending after preheating to 140 degrees. For this reason, technological additives are being searched for in the binder used, which can allow increasing the strength of the rods.
The first results of graphene application
The first trial batch of composite rods using graphene has been made.
At the first stage of the experimental application of the graphene additive, a water-based paste with a graphene content of 15% was used. 35 g of paste was dissolved in 1 kg of ISOMTHFA hardener to obtain a concentrate, but after 30-40 minutes an exothermic reaction began, and after 3 hours the concentrate solidified. The use of the solution has become impossible. Experiments on the addition of graphene to ISOMTHFA were no longer carried out.
At the second stage, 99% graphene powder was used, which was dissolved in an epoxy plasticizer DEG-1. There was no reaction. After that, for three days long rods were produced with the addition of graphene in an amount of 0.02% of the mass of the epoxy compound.
At the third stage, a water-based paste with a graphene content of 50% was used, also dissolved in the plasticizer DEG-1. And for another day long, rods were produced with the addition of graphene in an amount of 0.02% of the mass of the epoxy compound.
Graphene powder dissolves better in DEG-1, powder particles do not settle on the bottom of the bath, which contributes to a more uniform distribution of particles in the rod. After conducting preliminary tests, an increase in the physical and mechanical properties of the rods (resistance to bending failure) was recorded. Previously, it was necessary to carry out additional heat treatment of the rods in order to obtain the necessary indicators.
To achieve more accurate and stable results, it is necessary to continue experiments – to produce samples with different concentrations of graphene