Numerical and experimental approach to testing the adhesive properties of modified polymer blend based on EVA/PMMA as coatings for optical fibers

The adhesive properties of polymer blends based on poly(ethylene-co-vinyl acetate) (EVA) and poly(methyl methacrylate) (PMMA) were studied. Two samples were prepared, whereby one kind was a physically mixed blend of commercial polymers in a solution of toluene and the other was a blend with EVA-g-PMMA polymer in a toluene solution, produced via in situ free radical polymerization using redox system initiators. A scanning electron microscopy (SEM) revealed the improved microstructure that was achieved blending with graft polymer that could also be seen by FTIR spectral analysis. Optical fibers were glued together using both of the solutions and subjected to a micro mechanical testing machine. The adhesion test showed that the graft copolymer had enhanced mechanical properties as an adhesive than the physical polymer blend. Optical microscopy of the samples after the adhesion test enabled the determination of the type of adhesive failure. Image analysis of the SEM micrographs was used to determine an area of the contact surface, and characterization microstructure. These results were then implemented in a numerical simulation that demonstrated the influence of microstructure on the adhesive properties showing the stress distribution for both samples. The main aim of obtaining an adhesive with uniform structure, great miscibility of the polymers, and good mechanical and adhesive properties was achieved and a numerical model was established that can be used in selecting the adhesive.