Scientists from Volgograd State Technical University, as part of a research group, have developed a method to improve the mechanical properties of carbon fiber reinforced plastic. The new material has become significantly stiffer in bending, and the adhesion between its layers has increased. The results of the work were published in the journal Polymer Composites.
Carbon fiber reinforced plastic consists of carbon fabric and a polymer binder. Carbon fibers can withstand heavy loads with low weight, so these composites are used in sports equipment, prostheses, building structures for seismically active areas, and components of spacecraft.
One of the authors of the work, Associate Professor of VolgGTU Sergey Borisov, said that carbon fiber reinforced plastic is usually made stronger by bonding its fibers with special polymers obtained from resins.
The threads used are very thin and brittle, meaning they are easy to break but difficult to tear.
But where the boundary between carbon fibers and the binding resin passes, fractures often occur, he explained.
To strengthen the bond, the researchers treated the surface of the carbon threads with zinc, and changed the composition of the binder by adding components capable of interacting with the metal. The new matrix used triethylene glycol dimethacrylate, methacrylic acid, polyvinyl butyral, and 2-hydroxypropyl methacrylate.
After such treatment, the flexural modulus of elasticity of the material increased by 77%. At the same time, the sample required 28% more force to break.
In addition, the fabric layers began to adhere better: the interlaminar shear stress increased by 62%.
The authors note that the chosen treatment method allows for the preservation of more of the original structure of the carbon fabric compared to more aggressive methods of exposure. This is important for the material itself: strengthening the boundary between the fibers and the binder should not be accompanied by damage to the threads themselves.
The next step will be to test other properties of the new carbon fiber reinforced plastic. The researchers plan to check its behavior under moisture exposure and cyclic loads, as well as evaluate the economic efficiency of the proposed technology.