Study of the influence of surface treatments in kraft paper for the compatibilization with thermoplastic polymers

Abstract

The transports industry has been presenting a set of solutions that integrates natural fibers and their compatibility with structural materials, like polymers. However, it is fundamental to ensure the fulfillment of mechanical requirements. One of the main reasons that is driving the use of this type of fibers, instead of synthetic fibers, is related with the some actual trends, such as weight reduction, which is linked with its lower density. Moreover, weight reduction also contributes, indirectly, to the sustainability and decrease of greenhouse gases emissions, since it makes possible to reduce the fuel consumption of transports.However, due to the different polarities verified between apolar thermoplastic polymers, such as polypropylene (PP), and natural fiber reinforcements, such as kraft paper, a study of the effect of physical and chemical surface treatments was carried out in order to verify their influence on the fiber-matrix interface properties. The physical process, corona treatment, was applied in the kraft paper with different discharge dosages, while the chemical treatment was performed through the use of several alkali solutions with different concentrations of NaOH. The obtained results from the performed tests shows that the alkali solution treatments improved, up to 57%, the mechanical properties of tensile strength and Young Modulus of the composite material, comparatively with the effect of corona treatment on its surface. These results induce an increase of interface compatibility between the matrix and kraft paper