Abstract

This work is focused on two current and important issues. On one hand, 12 millions of tons of PET are thrown into the sea each year. In fact, in spite of being a recyclable polymer, less than 50 % of processed PET is recycled in Europe. On the other hand, thermoset matrix composites are widely used in the industry and the end-of-life products and scraps need to be recycled. Compared to thermoplastics, thermosets present a problem for being recycled or remolded due to their irreversible curing.

Many researches are focused on the recycling of carbon fiber reinforced epoxy, presenting three different paths: mechanical, thermal and chemical recycling. Thermal recycling is the most promising because it allows to recover clean fiber. However, it is an energetically expensive and non-environmentally friendly process. Chemical recycling, for its part, needs hazardous products, such as nitric acid, to dissolve the matrix. Finally, both, fibers and matrix, are recovered with mechanical recycling which consists on milling the composite to obtain finer parts.

In this work, unidirectional carbon fiber reinforced epoxy is blade-milled and it is used as reinforcement of a new composite. As matrix, PET coming from recycled bottles is used. First of all, pellets of PET are produced from the bottles with a blade mill. Recycled composite and PET are mixed and a sheet is manufactured with a hot plates press. The resulting material is chemically and mechanically tested.

Abstract

This work is focused on two current and important issues. On one hand, 12 millions of tons of PET are thrown into the sea each year. In fact, in spite of being a recyclable polymer, less than 50 % of processed PET is recycled in Europe. On the other hand, thermoset matrix composites are widely used in the industry and the end-of-life products and scraps need to be recycled. Compared to thermoplastics, thermosets present a problem for being recycled or remolded due to their irreversible curing.

Many researches are focused on the recycling of carbon fiber reinforced epoxy, presenting three different paths: mechanical, thermal and chemical recycling. Thermal recycling is the most promising because it allows to recover clean fiber. However, it is an energetically expensive and non-environmentally friendly process. Chemical recycling, for its part, needs hazardous products, such as nitric acid, to dissolve the matrix. Finally, both, fibers and matrix, are recovered with mechanical recycling which consists on milling the composite to obtain finer parts.

In this work, unidirectional carbon fiber reinforced epoxy is blade-milled and it is used as reinforcement of a new composite. As matrix, PET coming from recycled bottles is used. First of all, pellets of PET are produced from the bottles with a blade mill. Recycled composite and PET are mixed and a sheet is manufactured with a hot plates press. The resulting material is chemically and mechanically tested.

Abstract

The investigation into recycling methodologies for composite materials has emerged as a prominent area of study, encompassing both theoretical research and practical implementation. Within this context, the present study focuses on the mechanical recycling of obsolete epoxy resin pieces reinforced with fiberglass, which are subsequently repurposed as fillers in the production of new profiles through pultrusion technology.

A comprehensive examination of the grinding process, granulometric distribution, and rheological properties of the final system was conducted, with the objective of maximizing the filler content within the resin while optimizing the properties of the manufactured profile. Consequently, a flat profile measuring 10 cm in width was successfully fabricated, which incorporates the recycled filler comprising up to 30 % of the resin’s total weight. This achievement was realized by employing a pultrusion system measuring 25 meters in length, coupled with a heated flat plate mold spanning 80 cm.

Following the fabrication of the profile, an extensive characterization of both its physicochemical properties and mechanical behavior was conducted to investigate the influence of filler on the ultimate product. The outcomes obtained demonstrate compelling evidence that the incorporation of the recovered filler effectively enhances the interlaminar properties of the pultruded composite materials, thereby underscoring the inherent potential of the charge as a reinforcing agent.