Additive manufacturing of polyacrylic rubber and investigation of its sensor applications

Additive manufacturing is a production method that is increasingly used due to the advantages it provides. With different techniques, metals, ceramics, foods and thermoplastics can be produced by this method. However, the production of rubbers by this method is limited to liquid silicone rubber. In this thesis, additive production of temperature-cured rubbers was carried out for the first time. The prepared polyacrylic pastes were 3D printed with the additive production method based on material extrusion, and samples in different filling patterns were produced. For this, the solutions of the doughs prepared on the open shaft were prepared in a volatile organic solvent and fed into the 3D printer nozzle by applying pressure with a pump and printed on the model designed on a table. Afterwards, cross-linking of the samples cured at a certain temperature for a certain period of time was carried out, and cross-linked rubber samples printed with a 3D printer were prepared. Paste containing three different ratios of crosslinker system was used. Samples were produced using 4 different filling models with different strand angles from each dough type. In addition, samples were produced from each paste by pouring solution method in order to compare with traditional production methods. The cross-linking density of the samples was determined by the Flory-Rehner equation, their electrical resistance was measured and their mechanical properties were examined by tensile tests. Finally, the piezoresistive performances were determined by measuring the electrical resistance change (ΔR/R0) values at different strain rates and strain rates with the load-discharge cycles, and their usability as strain sensors was investigated by calculating the Gauge factor (GF) values. From the results obtained, it was understood that the filling type did not have an effect on the crosslinking density, but it varied depending on the dough type. It was observed that the crosslinking density increased as the crosslinker ratio increased. It has been determined that the electrical resistance values vary according to the crosslinking density and filler type. It was determined that the resistance values decreased as the crosslinking density increased, and the filling pattern with a 45°/45° strand angle had the highest resistance value. As the crosslinking density increased, the tensile strength and elastic modulus values increased, while the elongation at break decreased. It was observed that the filling pattern with a 45°/45° strand angle showed the lowest tensile strength and elongation at break. From the mechanical results obtained from the loading-unloading cycle tests, it was determined that the hysteresis values increased as the crosslink density increased, while the filling patterns and strain rates also had an effect on the hysteresis. From the loading-unloading tests, it was observed that the filler type, strain rate and strain rate had an effect on the GF values. The highest GF value was calculated as 26558 with ε=0.2 and έ=500 mm/min parameters in the sample produced with the lowest crosslinking density and 45°/45° strand angle. It has been understood that the strain resistance changes of this sample have high sensitivity and repeatability, and it has been concluded that it can be used as a strain sensor in many technological applications.