Monodispersed calcium oxalate as highly effective support filler in PMMA-based nanocomposite

Abstract

This study focuses on the synthesis of monodispersed CaC₂O₄ particles of cubic and donut-shaped novel morphologies and the ultrasonic-assisted in-situ polymerization of PMMA/CaC₂O₄ in the presence of native CaC₂O₄ and commercial CaC₂O₄ particles (0.2–0.8 wt%). The current study explored that particle loading played its role in defining the optimal conditions, whereas the particle morphology, uniformity, concentration, and reaction parameters of the fillers greatly influenced the properties of the resin-based nanocomposites. These observations confirmed that the calcium oxalate filler nanoparticles had an obvious effect on the tribological and mechanical properties of the as-fabricated composite. The optimum concentrations of fillers for enhanced properties of the composite were 0.4, 0.6, and 0.8 wt%, respectively for donut-shaped, cubic-shaped, and commercial calcium oxalate. The incorporation of donut-shaped particles showed enhanced properties as compared to nanocomposites consisting of commercial and cubic-shaped CaC₂O₄ particles. Enhancements in the properties of nanocomposites for different loadings of donut-shaped CaC₂O₄ as compared to blank PMMA are anti-wear = 51.02 ± 0.15%, COF = 66.60 ± 0.4%, and microhardness = 10.50x ± 0.06. These improved properties compared to the previous literature are essentially attributed to the particle morphology, size, uniformity, and uniform dispersion of CaC₂O₄ in the polymer matrix due to intense micro-convection generated by sonication.

GRAPHICAL ABSTRACT

Keywords:

• Calcium oxalate
• nanocomposite
• antiwear/friction
• Vickers hardness

Acknowledgments

The authors are grateful to the National Centre of Excellence in Physical Chemistry, University of Peshawar, Khyber Pakhtunkhwa, and the Higher Education Commission of Pakistan, for facilitating this research work.