Design and research of a construction-grade engineering plastic based on recycled polyamides and polyphthalamides

Abstract The purpose of this article is to design and research a thermoplastic composition based on secondary polyamides and polyphthalamides suitable for construction applications. The scientific novelty of this research lies in the development of a new recycling approach for PPA, where PPA waste is incorporated into a polymer composite as a reinforcing component without complete melting. Unlike conventional methods that require full melting at high temperatures, this approach utilizes finely pulverized PPA particles dispersed within a polyamide 6,6 matrix, allowing low-temperature processing while preserving the reinforcing effect of PPA. A comprehensive literature and patent review did not identify any prior studies investigating this recycling method, confirming its novelty and contribution to sustainable high-performance polyamide recycling. The pulverization stage plays a critical role in ensuring the high quality of the granulated composition by allowing processing at 290°C while minimizing thermal degradation. At these temperatures, polyamide 66 effectively melts, while the polyphthalamide component is presumed to remain in a dispersed phase, enabling granulation without full melting. This approach eliminates the need for high-temperature processing, broadening the applicability of the developed composition. Based on the obtained physical and mechanical properties, the results suggest that the developed compositions have the potential to replace conventional polyamide-6, polyamide-6,6, and glass-reinforced polyamide formulations in engineering and technical applications. Key benefits of the construction-grade composition based on secondary polyamides and polyphthalamides include: low-temperature processability, full compatibility with existing industrial processing equipment at temperatures not exceeding 290°C: reducing energy consumption, broadening industrial applicability, utilization of recycled materials that lower waste and environmental impact and maintenance or improvement of mechanical, thermal, and electrical properties. However, further research is required to validate their performance in specific applications.