Graphene oxide increases PMMA's resistance to fatigue and strength degradation

Cahyanto A 1 , Martins MVS 2 , Bianchi O 3 , Sudhakaran DP 4 , Sililkas N 5 , Echeverrigaray SG 6 Show all authors , Rosa V 7

Affiliations 

  • 1 Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Malaysia; Department of Dental Materials Science and Technology, Faculty of Dentistry, Padjadjaran University, Indonesia. Electronic address: arief.cahyanto@um.edu.my
  • 2 Centre for Advanced 2D Materials, National University of Singapore, Singapore. Electronic address: marcossurmani@gmail.com
  • 3 Departamento de Engenharia de Materiais, Universidade Federal do Rio Grande do Sul, Brazil. Electronic address: otavio.bianchi@gmail.com
  • 4 Centre for Advanced 2D Materials, National University of Singapore, Singapore. Electronic address: deepa@nus.edu.sg
  • 5 Biomaterials Science, Division of Dentistry, School of Medical Sciences, University of Manchester, UK. Electronic address: nick.silikas@manchester.ac.uk
  • 6 Centre for Advanced 2D Materials, National University of Singapore, Singapore. Electronic address: sergio@nus.edu.sg
  • 7 Centre for Advanced 2D Materials, National University of Singapore, Singapore; Faculty of Dentistry, National University of Singapore, 9 Lower Kent Ridge Rd, Singapore 119085, Singapore; ORCHIDS: Oral Care Health Innovations and Designs Singapore, National University of Singapore, 9 Lower Kent Ridge Rd, 119085, Singapore. Electronic address: vini@nus.edu.sg
Dent Mater, 2023 Sep;39(9):763-769.
PMID: 37400298 DOI: 10.1016/j.dental.2023.06.009

Abstract

OBJECTIVES: to characterize the effects of graphene oxide (GO) on polymethyl methacrylate's (PMMA) reliability and lifetime. The hypothesis tested was that GO would increase both Weibull parameters and decreased strength degradation over time.

METHODS: PMMA disks containing GO (0.01, 0.05, 0.1, or 0.5 wt%) were subjected to a biaxial flexural test to determine the Weibull parameters (m: modulus of Weibull; σ0: characteristic strength; n = 30 at 1 MPa/s) and slow crack growth (SCG) parameters (n: subcritical crack growth susceptibility coefficient, σf0: scaling parameter; n = 10 at 10-2, 10-1, 101, 100 and 102 MPa/s). Strength-probability-time (SPT) diagrams were plotted by merging SCG and Weibull parameters.

RESULTS: There was no significant difference in the m value of all materials. However, 0.5 GO presented the lowest σ0, whereas all other groups were similar. The lowest n value obtained for all GO-modified PMMA groups (27.4 for 0.05 GO) was higher than the Control (15.6). The strength degradation predicted after 15 years for Control was 12%, followed by 0.01 GO (7%), 0.05 GO (9%), 0.1 GO (5%), and 0.5 GO (1%).

SIGNIFICANCE: The hypothesis was partially accepted as GO increased PMMA's fatigue resistance and lifetime but did not significantly improve its Weibull parameters. GO added to PMMA did not significantly affect the initial strength and reliability but significantly increased PMMA's predicted lifetime. All the GO-containing groups presented higher resistance to fracture at all times analyzed compared with the Control, with the best overall results observed for 0.1 GO.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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