Despite being inexpensive and robust, steel cord reinforcements are often prone to pose risks to user health and safety in some industrial applications such as escalator handrails and rubber conveyor belts. Steel cords can reduce the overall stability and performance of the application over time due to their inherent creep accompanied by cyclic thermal expansion and contraction. In this context, this research focuses on replacing steel cords in some critical thermoplastic polyurethane (TPU) composite applications with continuous sustainable alternate synthetic fibers that possess high specific strength (e.g. carbon, glass, and Kevlar fibers). The first part of this research characterizes the effect of epoxy coating on synthetic fibers alone by studying their mechanical properties before and after modification, whereas the second half of the research involves reinforcing a TPU matrix with raw and epoxy-coated synthetic fibers to fabricate fiber-reinforced composites by compression molding. The effect of the curing temperature of epoxy on the end performance of the manufactured specimen was also tested. An in-depth analysis of mechanical and morphological studies showed that, at almost the same volume fraction of fibers, the TPU reinforced composites with modified carbon fibers showed higher load-bearing capacities than steel cord-based analogs. Conversely, a wide variety of other relevant industrial and commercial applications can potentially draw significant benefits by implementing these modified carbon/TPU composites instead of steel cords.
The initial outbreak of the coronavirus was met with lockdowns being enforced all over the world in March 2020. A prominent change in human lifestyle is the shift of professional and academic work to online platforms, as opposed to previously attending to them in person. As with any major change, the implementation of complete remote work and study is expected to affect different people differently. Through the results of a questionnaire designed as per the implications of the self-efficacy theory shared with people who were either students, working professionals, entrepreneurs, or homemakers aged between 12 and 60 years, the authors perform statistical analysis and subsequently hypothesize how different aspects of remote work affect the population from a mental standpoint using t-test, with respect to their professional or academic work. This is followed by predictive modelling through machine learning algorithms to classify working preference as ‘remote' or ‘in-person'.
In this study, the continuous fiber rowing of 12K carbon was electrolytically oxidized by incorporating three different types of electrolytes: Ammonium bicarbonate, Sulfuric acid, and Sodium hydroxide at various concentrations. Upon chemical treatment, the fibers were grafted with 3-Aminopropyl-triethoxysilane (APTS), a silane coupling agent, to achieve better interlocking and compatibility with the thermoplastic polyurethane (TPU) matrix. Mechanical properties were analyzed by tensile tests, morphological analysis was carried out through Scanning Electron Microscopy, and spectral analysis was studied through X-ray photoelectron spectroscopy (XPS) characterizations. The results show that 10% sulfuric acid treatment plus APTS grafted carbon fiber/TPU composites showed an average tensile load capacity of 2528 N, about 39% higher than raw carbon/TPU. The morphological analysis provided compelling evidence for the increase in mechanical properties of modified fiber composites as the interfacial bonding between the electrolytically modified and silane coated fiber/TPU composites was much better than the raw fiber/TPU composites. Further, XPS results confirm that the atomic percentages of Carbon have been reduced, whereas the percentage of oxygen and nitrogen have increased. These compositional changes indicate that the overall interaction between the fiber and the matrix has been enhanced, accounting for improved compatibility between the two interacting phases.
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