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Indentation Fracture Mechanics for Toughness Assessment of PMMA/SiO 2 Nanocomposites
Author(s) -
Lach Ralf,
Kim GyeongMan,
Michler Goerg Hannes,
Grellmann Wolfgang,
Albrecht Klaus
Publication year - 2006
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/mame.200500359
Subject(s) - materials science , composite material , fracture toughness , indentation , nanocomposite , brittleness , elastic modulus , fracture mechanics , ceramic , toughness , nanoparticle , polymer , volume fraction , agglomerate , modulus , nanotechnology
Summary: Based on the results from agglomerate‐free PMMA nanocomposites with 10 and 20 wt.‐% spherical SiO 2 nanoparticles, it has been shown that indentation fracture mechanics is a straightforward, powerful, cost‐effective and time‐effective tool for analyzing the fracture resistance of novel polymer materials, such as brittle nanostructured polymer‐ceramic hybrids. In contrast to pure PMMA, the R‐curve effect, i.e., the enhancement in crack resistance as a function of crack size, was not observed in the nanocomposites investigated. Fracture toughness was found to depend on the SiO 2 nanoparticle content, and the maximum value was observed at 10 wt.‐%. A significant reduction in fracture toughness occurred at 20 wt.‐% SiO 2 nanoparticles, which is associated with a percolation of the bound layers (interfacial layers) around the SiO 2 particles. From DSC data, the thickness of the interfacial polymer layer was estimated to be about 9 nm.Hardness, elastic modulus and fracture toughness of PMMA/SiO 2 composites as a function of nanoparticle fraction.