Comparing the effects of halloysite nanotubes and precipitated calcium carbonate nanoparticles on the environmental stress cracking resistance and mechanical properties of polycarbonate

Polycarbonate (PC) is a versatile and amorphous engineering thermoplastic used in various areas due to its exceptional me-chanical and thermal properties. However, its susceptibility to environmental stress cracking limits its industrial application inchemically aggressive environments. This study investigates the effects of incorporating surface-modified halloysite nanotubes(HNTs) and precipitated calcium carbonate (PCC) as nanofillers on the mechanical properties and environmental stress cracking(ESC) resistance of PC. PC nanocomposites were prepared with varying filler concentrations (1%, 3%, and 5% by weight) usingtwin-screw extruder and injection molding devices. Comprehensive mechanical characterization, including three-point bending,Charpy impact toughness, and Shore D hardness tests, revealed that introducing 1 wt% of HNT optimally balances stiffness,toughness, and ESC resistance. PCC, on the other hand, significantly improved processability but demonstrated poor ESC perfor-mance, with samples failing within an hour in methanol immersion tests. ESC resistance testing in methanol and sodium laurylether sulfate (SLES) solutions confirmed the superior performance of HNT-reinforced PC nanocomposites. Scanning electronmicroscopy (SEM) analyses provided insights into filler-matrix interactions and crack propagation mechanisms. These findingsoffer valuable guidance for the development of PC nanocomposites tailored for automotive, electronics, and chemical processingindustries.