In the past two decades’ significant studies have been reported on electrically conducting thermoplastic composites of acrylonitrile butadiene styrene (ABS), polyvinylidene fluoride (PVDF), etc. for the fabrication of novel energy storage devices (ESD) by 3D printing. But hitherto little has been reported on onlinecondition monitoring of ESD prepared by secondary (2°) recycling of ABS. This study reports the investigations on mechanical and electrical properties of NH₄Cl–ZnCl₂ (electrolyte) reinforced ABS composite (as 3D printed sensor) for online condition monitoring of ESD. In a typical dry cell, the electrolyte is one of the integral parts, and the change in its dielectric properties with the time/ applied electric load has been used to ascertain the health of ESD (online) as the internet of things (IoT) based solution (Bluetooth application) in industry sportsand medicine (ISM) band (2.4 GHz). Based on melt flow index (MFI), 10% NH₄Cl and 10% ZnCl₂ (by weight%) were reinforced in ABS for preparing 3D printed rectangular substrates as ring resonators for calculating dielectric constant (εr) and loss tangent/dissipation factor (tanδ) for the resonant frequency. Transmission line parameters (S₂₁) were observed using a vector network analyzer (VNA), and a high-frequency structure simulation (HFSS) software package. The results are supported by morphological analysis of ABScomposite based on scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), 3D rendering, surface roughness (R_a), area mapping, current (I)–voltage (V), and Fourier transformed infrared (FTIR) characterization.

Polyethylene terephthalate (PET) thermoplastic polyester is durable, formable material that is widely used to manufacture consumer products like sailcloth, sailing spinnakers, food-grade containers, etc. for commercial and engineering applications. The recycling of PET is still a challenge because of its abundance,especially in low-income/developing countries. The present study reports the recycling of PET by utilizing the primary (1°) recycled PET (R-PET) for 3D printing-based sensor applications with the idea of converting waste to wealth. The investigations were performed on PET-based waste collected from institute campus canteens (in form of used food containers/soft drink bottles) after ascertaining their rheological, mechanical, morphological, bonding, and sensing capabilities. The sensing capabilities of R-PET were explored by performing a ring resonator test of a 3D-printed substrate using a vector network analyzer (VNA). The result of the study outlined that R-PET-based sensors may be used in sailcloth, and sailing spinnakers to monitor the location of boats in ashipyard/dock.