 Polypropylene, PP, based composites are commonly reinforced with glass fibers, GF, but the polymer fiber interface is often weak and susceptible to damage under certain environmental conditions. To address this issue, researchers have attempted to improve the adhesion between the two materials through various techniques, including modifying the glass surface or polymer matrix. Unfortunately, these approaches have not yielded significant cost performance improvements. In this study, researchers proposed a novel approach involving the polymerization of polypropylene, PP, directly onto the glass fibers. This technique was found to significantly increase the strength and toughness of the resulting composite, while also doubling the interfacial strength. This article was authored by Mariana Etcheverry and Sylvia E. Barbosa.