Optimization of open-casting process parameters for fabrication of high-performance TPU/CNT/Fe multi-functional polymer composites: a Taguchi with TOPSIS approach

In the present study, conductive carbon nanotubes (CNTs) and iron (Fe) powder were incorporated into a thermoplastic polyurethane (TPU) polymer matrix in different percentage proportions, and the resulting composite was produced using an open-casting process. The optimized performances of the TPU/CNT/Fe multi-functional polymer composite (MFPC) were measured against the pre-set criteria, i.e., thermal conductivity, electrical conductivity, shore hardness, tensile strength, water absorption, mass degradation due to heating, and other morphological properties. A TOPSIS-based MCDM approach was adopted in combination with Taguchi’s robust design philosophy to optimize multi-response parameters of TPU/CNT/Fe functionalized composites. TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) was used to convert multiple responses to a relative closeness coefficient value, which was treated as a Multi-Performance Characteristic Index (MPCI). Finally, the MPCI results were optimized using the Taguchi method to study experimental variations. TPU/CNT sample 9 (with 92% TPU and 8% CNT composition) exhibited the highest overall performance, while sample 4 (with 98% TPU and 2% CNT composition) was the lowest-performing TPU/CNT composite. Similarly, the highest- and the lowest-performing TPU/Fe composites were sample 6 (with 92% TPU and 8% Fe composition) and sample 4 (consisting of 98% TPU and 2% Fe), respectively. Lastly, in the case of the TPU/CNT/Fe composite, the highest and lowest performing was sample 9 (consisting of 88% TPU, 8% CNT, and 4% Fe) and sample 4 (with 94% TPU, 2% CNT, and 4% Fe composition), respectively. The novelty of this study is its contribution to the body of knowledge for suitable matrix-phase and filler material selection for the development of optimum high-performance TPU/CNT/Fe composites suitable for application in aerospace and defense applications, automobile applications electronics and electrical engineering, healthcare and biomedical engineering energy storage and conversion, construction and infrastructure, marine applications for underwater structures, and sports and recreation.