Co-authors​ :

 Kristina ZUKIENE (LITHUANIA), Rochele PINTO (LITHUANIA), Gediminas MONASTYRECKIS (LITHUANIA), Marie NOVAKOVA , Vladimir SPACEK , Tatjana GLASKOVA-KUZMINA (LATVIA), Daiva ZELENIAKIENE (LITHUANIA) 

The interfacial adhesion between the fibres and the polymer matrix is crucial in determining the mechanical properties of fibre-reinforced composites. However, basalt fibres struggle to interact with the polymer matrix due to the lack of surface functional groups. This leads to a reduced load-carrying capacity of the composite. It is possible to improve the surface properties and surface interactions of basalt fibre/epoxy composites by incorporating nanomaterials into the matrix or surface treatment of the reinforced fibre. These traditional surface modification methods have drawbacks, including the requirement of additional processing steps and challenges in dispersing nanomaterials evenly. An alternative surface modification method involves the surface segregation of a component with superior adhesive properties on the surface in blends of epoxy and thermoplastics. Studies indicate that highly branched polymer additives, such as star-shaped acrylic polymers, can segregate effectively at the surface or fibre/polymer matrix interface [1].
The aim of the study was to evaluate the effect of the addition of the star-like poly(butyl methacrylate)-poly(glycidyl methacrylate) (PBMA-PGMA) block copolymer to biobased epoxy on the wettability and adhesion to basalt fibres. Group transfer polymerization was used to prepare the star-like PBMA-PGMA block copolymer. It was found that the obtained PBMA-PGMA block copolymer exhibits excellent wetting properties with basalt fibres because of the presence of PGMA, which contains an epoxy group that forms a strong interaction with basalt fibres.
Fourier transform infrared spectrometry and scanning electron microscopy (SEM) were used to study the PBMA-PGMA-modified epoxy resin. SEM analysis indicated that the resulting materials, owing to the amphiphilic character of the star-like copolymer, displayed phase-separated morphologies. The surface properties of the basalt fibre/epoxy composite components and the work of adhesion of the modified epoxy resin to the basalt fibres were determined according to the Owens and Wendt method and from the Dupre equation, respectively. It was revealed that the incorporation of a different PBMA-PGMA block copolymer content increases the viscosity of the epoxy resin. Nevertheless, the wettability between the epoxy resin and the basalt fibres improved with increasing concentration of the star-like copolymer. This improvement is crucial for basalt fibre-reinforced composites, as it helps to eliminate porosity and air voids.
Acknowledgements. This project has received funding from the Research Council of Lithuania (LMTLT), agreement No. S-MIP-23-134.