Abstract

Composites based on epoxy resin are a class of high performance structural materials with great potential in a wide variety of industrial sectors. However, being thermoset resins, despite their great benefits in lightness and mechanical performance, they present the great disadvantage that once cured they can not be reprocessed, repaired or recycled. This is hindering the rapid growth of composite materials in applications such as automotive.

In order to overcome the disadvantages of thermosetting resins, this paper presents the development of a new generation of dynamic thermoset epoxy resins able to be reprocessed,  repaired and recycled thanks to the incorporation of reversible bonds within its reticulated structure. As resins containing dynamic bonds, the cured material presents new properties previously unthinkable for thermosetting materials. These new resins have been developed for the manufacture of composite materials reinforced with both glass fiber and carbon fiber. It has been shown that these new composites have mechanical properties equivalent to those of conventional thermosetting composites, but unlike the latter, they are recyclable, repairable and reprocessable, which is a step forward and the creation of new opportunities for sectors such as automotive .

Abstract

Composites based on epoxy resin are a class of high performance structural materials with great potential in a wide variety of industrial sectors. However, being thermoset resins, despite their great benefits in lightness and mechanical performance, they present the great disadvantage that once cured they can not be reprocessed, repaired or recycled. This is hindering the rapid growth of composite materials in applications such as automotive. In order to overcome the disadvantages of thermosetting resins, this paper presents the development of a new generation of dynamic thermoset epoxy resins able to be reprocessed,  repaired and recycled thanks to the incorporation of reversible bonds within its reticulated structure. As resins containing dynamic bonds, the cured material presents new properties previously unthinkable for thermosetting materials. These new resins have been developed for the manufacture of composite materials reinforced with both glass fiber and carbon fiber. It has been shown that these new composites have mechanical properties equivalent to those of conventional thermosetting composites, but unlike the latter, they are recyclable, repairable and reprocessable, which is a step forward and the creation of new opportunities for sectors such as automotive .

Abstract

This work is focus on the development of photocurable resins doped with nanoparticles of very diverse nature, diamond, barium oxide, hydroxyapatite and silver. These nanoreinforcements are being investigated, and even applied industrially, as nanofillers of thermosetting resins, due to the different enhancements and new properties, including increased mechanical, thermal and chemical properties, high electrical and thermal conductivity, improved biocompatibility and antimicrobial properties, among others. The reinforcement of photocurable thermosetting resins can be complex since the added charge can exert shielding to the radiation, limiting to reach high curing degree. For it, it is necessary to use catalysts and sensitizers of UV radiation. In addition, in order to limit this negative effect, a high degree of dispersion of the nanofillers is required, avoiding the presence of micrometric agglomerates. An epoxy system has been selected, whose is commly used for dental applications, and differente contents of nanofillers have been added. Once the dispersion process has been optimized, the effect of the different fillers on the degree of curing of the photocurable resin, measured through its glass transition temperature, has been studied. The degree of curing achieved has been explained through transperance measurements to the visible light of the samples, as well as the morphology of the cured and doped resins.