Premium
Free‐volume effects on the thermomechanical performance of epoxy–SiO 2 nanocomposites
Author(s) -
Lizundia Erlantz,
Serna Iñaki,
Axpe Eneko,
Vilas José Luis
Publication year - 2017
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.45216
Subject(s) - nanocomposite , materials science , composite material , epoxy , glass transition , nanoparticle , dynamic mechanical analysis , interphase , volume (thermodynamics) , surface modification , chemical engineering , polymer , nanotechnology , physics , quantum mechanics , biology , engineering , genetics
In this study, free‐volume effects on the thermal and mechanical properties of epoxy–SiO 2 nanocomposites were investigated. SiO 2 particles ranging from 15 nm to 2 µm were used, and the nature of the matrix–filler interphase was modified by surface grafting. Nanoparticles 15 nm in diameter yielded an increase in the glass‐transition temperature ( T g ) of the composites up to 5 °C; at the same time, they increased the storage modulus ( E ′) from 2340 to 2725 MPa. Conversely, large particles markedly decreased both T g and E ′; this suggested the pivotal role of nanoparticle size on the final properties of the nanocomposite. The functionalization of SiO 2 nanoparticles markedly improved their dispersion within the epoxy matrix. The positron annihilation lifetime spectroscopy results indicate that the free volume strongly depended on the interphase. These experimental findings obtained here could be extrapolated to industrially relevant nanocomposites and could provide a rationale for the comprehension of free‐volume effects on the thermal and mechanical properties of nanocomposite materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45216.