Behavior of Injection‐Molded Nylon 6 Composites With Virgin and Field‐Exposed Waste‐Recycled Blends

ABSTRACT Every year, more than 18,600 metric tonnes of glass fiber‐reinforced Nylon 6 composite waste from sucker rod guides used in downhole oil and gas applications are landfilled due to uncertainty about retained performance after prolonged service exposure. This study addresses this issue by evaluating the physical, mechanical, thermal, chemical, and microstructural properties of injection‐molded composites produced by blending virgin and field‐exposed Nylon 6 at different weight ratios (0%–100% recycled content). Results showed maximum reductions of only 30%, 21%, and 25% in tensile, flexural, and impact strength, respectively, due to fiber shortening below the critical fiber length ( L c ). No significant changes were observed in decomposition behavior, chemical structure, elemental composition, or physical properties, even for 100% recycled Nylon 6, apart from a reduction in glass transition temperature. These results show that mechanically recycled Nylon 6 composites recovered from downhole service can be reprocessed and blended with virgin material while maintaining sufficient mechanical and thermal performance, supporting their potential use in secondary polymer composite applications.