A study on environmental stress cracking in nano-SiO2-filled polycarbonate

Abstract

In this study, the environmental stress cracking (ESC) resistance of nano-SiO 2 particle-filled polycarbonate (PC) was investigated at room temperature by using a fracture mechanical test method. Two PC-based nanocomposites with nano-SiO 2 content of 1 and 4 vol% were compounded using a twin-screw extruder. The incorporation of nanoparticles into PC leads to an improvement in ESC resistance, which increases with increased filler loading up to 4 vol%. Fractography analyses suggest that the formation of cavities/debonding and localized microdeformation of matrix induced by nanoparticles as a result of energy dissipation are responsible for the improvement of ESC resistance.

Environmental stress cracking (ESC) resistance of polycarbonate/SiO2 nanocomposites in different media

“…In isopropanol, the deformation area develops in two directions, displaying a similar “candle flame” pattern. The appearance of this shape can be explained by the crack‐layer theory . A smaller crazing area with three major directions of deformation spreading surround the crack‐tip is observed in methanol, indicating a different fracture mechanism in this environment .…”

“…reported that the incorporation of organically modified montmorillonite into rubber‐toughened polyester produced a product with improved ESC resistance in sodium hydroxide and hydrochloride acid solutions. Our previous research also established that the incorporation of nanofillers improves the ESC resistance in isopropanol and significantly increases the service lifetime of PC nanocomponents …”

“…All the ESC testings were performed at constant load and ambient temperature (23 ± 1 °C). The development of the macro‐crack length and the crack damage area were monitored and documented using a CCD‐camera (EOS 1200 D, Canon) . All the captured surface images were saved in a computer for further analysis.…”

“…The development of the macro-crack length and the crack damage area were monitored and documented using a CCD-camera (EOS 1200 D, Canon). 17 All the captured surface images were saved in a computer for further analysis. Each ESC experiment was repeated at least three times to verify the reproducibility of the experiment.…”

“…Our previous research also established that the incorporation of nanofillers improves the ESC resistance in isopropanol and significantly increases the service lifetime of PC nanocomponents. 17 The aim of this work was to evaluate the ESC behavior of SiO 2filled PC in different fluids [isopropanol, methanol, aqueous urea solution, and deionized (DI) water] using an optical crack detection method and finally discover and describe the relation between the type of the fluid, the filler content, and the stresscracking resistance. Our findings show that the addition of nanoscale SiO 2 improves the stress-cracking resistance in all investigated fluids, especially if the type/shape of the deformation area in front of the crack changes completely as in mild agents.…”