# Circular Approach to Composite Materials: Synthesis of Carbon Nanomaterials from Polymer Recycling Liquid By-Products

## TL;DR

This paper presents a method to convert waste from polymer recycling into valuable carbon nanomaterials using a sustainable process.

## Contribution

The study introduces a novel upcycling approach using recycling by-products as carbon precursors for nanomaterial synthesis.

## Key findings

- Carbon nanotubes/nanofibers with diameters below 100 nm were successfully produced from recycling by-products.
- The nanomaterials showed high graphitization (ID/IG ratios 0.25–0.58) and thermal stability with up to 90.3% carbon purity.

## Abstract

The growing volume of fiber-reinforced polymer composite waste creates an urgent need for efficient recycling technologies. While solvolysis effectively breaks down thermoset matrices for fiber reinforcement recovery, the process generates hydrocarbon-rich liquid by-products that require further management. This study validates the use of these liquid recycling streams—derived from the solvolysis of unsaturated polyester and epoxy resins—as sustainable carbon precursors for the growth of carbon nanomaterials. Synthesis was performed via catalytic chemical vapor deposition (CVD) at 850 °C using iron nanoparticles impregnated on a zeolite substrate. Morphological analysis confirmed the production of one-dimensional nanostructures (carbon nanotubes/nanofibers), with average diameters below 100 nm. Raman spectroscopy revealed a high degree of graphitization, with ID/IG ratios ranging from 0.25 to 0.58, which is comparable to structures synthesized from conventional precursors. Thermogravimetric analysis (TGA) demonstrated high thermal stability and carbon purity reaching up to 90.3%. These findings demonstrate a viable upcycling pathway that enhances the economic attractiveness of composite recycling by transforming waste into advanced nanomaterials.