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 mechanical and thermal properties. However, its susceptibility to environmental stress cracking limits its industrial application in chemically 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) using twin-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 performance, with samples failing within an hour in methanol immersion tests. ESC resistance testing in methanol and sodium lauryl ether sulfate (SLES) solutions confirmed the superior performance of HNT-reinforced PC nanocomposites. Scanning electron microscopy (SEM) analyses provided insights into filler-matrix interactions and crack propagation mechanisms. These findings offer valuable guidance for the development of PC nanocomposites tailored for automotive, electronics, and chemical processing industries.