Structural characterization, thermal properties, and density functional theory studies of PMMA‐maghemite hybrid material
Author(s) -
Rocha Marcus V.J.,
Carvalho Hudson W.P.,
Sarmento Victor H.V.,
Craievich Aldo F.,
Ramalho Teodorico C.
Publication year - 2016
Publication title -
polymer composites
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.577
H-Index - 82
eISSN - 1548-0569
pISSN - 0272-8397
DOI - 10.1002/pc.23154
Subject(s) - maghemite , materials science , nanocomposite , thermal stability , chemical engineering , methyl methacrylate , nanoparticle , polymerization , poly(methyl methacrylate) , composite material , polymer chemistry , polymer , nanotechnology , engineering
Maghemite (γ‐Fe 2 O 3 )‐poly(methyl methacrylate) (PMMA) nanocomposites were prepared by grafting 3‐(trimethoxy‐silyl) propyl methacrylate on the surface of maghemite nanoparticles, this process being followed by methyl methacrylate radical polymerization. Three different hybrids with 0.1, 0.5, and 2.5 wt% of maghemite nanoparticles were studied. The results indicate that these nanocomposites consist of a homogeneous PMMA matrix in which maghemite nanoparticles with a bimodal size distribution are embedded. The existence of covalent bonding between silane monomers and atoms on the maghemite surface was evidenced. AFM images showed a clear increase in surface roughness for increasing maghemite content. The thermal stability of PMMA‐maghemite nanocomposites is higher than that of pure PMMA and increases for increasing maghemite content. The results of our theoretical studies indicate that the electron density in the maghemite nanoparticle is not homogenous, the low electron density volumes being supposed to be radical trappers during PMMA decomposition, thus acting as a thermal stabilizer. POLYM. COMPOS., 51–60, 2016. © 2014 Society of Plastics Engineers