Short carbon fiber reinforced poly(lactic acid) and its thermoplastic polyurethane blends: The effect of carbon fiber, polyurethane, and compatibilizer amounts

Abstract Lightweight and multifunctional carbon fiber‐reinforced composites with low production costs are crucial for aerospace and logistics applications. In this study, the integration of compatibilizer to polylactic acid (PLA)/thermoplastic polyurethane (TPU) blends filled with carbon fiber (CF) is performed due to cost‐lowering, besides enhanced mechanical performance and processability. Composite sample loaded with 30% CF is selected and optimized by the varied amount of polymeric MDI (pM) inclusions. As the tensile resistance of PLA/TPU/30CF and PLA/TPU/30CF/pM is compared, it is found that pM additions led to enhancements in tensile strength and tensile modulus. A total of 5% of pM inclusion results in 43% increament in tensile strength of the tensile strength of PLA/TPU/30CF. Similarly, the flexural modulus and flexural strength of composites are improved by a high amount of pM. The impact resistance of PLA significantly increases after CF inclusion. The incorporation of TPU and compatibilizer shifts impact strength to higher levels. 204% improvement is achieved for PLA/TPU blend involving 5 wt% of pM concerning unfilled PLA. According to the thermo‐mechanical analysis of composites, the presence of pM yields a higher elastic modulus for PLA/TPU/CF composites. Additionally, reductions in the glass transition temperature of PLA and composites are observed since the polymer gains ductility by elastomer and compatibilizer inclusions. Scanning electron microscopy (SEM) investigations of composites visualize these findings. Results postulated that pM integration can be utilized in large‐scale production of CF‐reinforced PLA‐TPU blend systems for cost reduction and performance improvement of composite parts in logistics and aerospace applications. Highlights The compatibilizing effect of pMDI on the PLA/TPU/CF blend system is investigated. pMDI inclusions yield improvement in the mechanical resistance of composites. CF‐reinforced PLA/TPU composites gain ductile behavior by the addition of TPU. The increase in elastic modulus ensures an efficient enhancement of compatibility.