Thermochemical properties of acrylate-based polymer composites by doping with

Thermochemical properties of acrylate-based polymer composites by doping with
surface-modified ferromagnetic Fe3O4 nanoparticles
Lucie Štruncová, Guido Kickelbick
Saarland University, Inorganic Chemistry, Am Markt Zeile 3, 66125 Saarbrücken
E-mail: [email protected]
Magnetic nanoparticles, which can be heated in an alternating electromagnetic field, show many potential applications in areas such as materials chemistry,
medicine, or smart materials. For these purposes the particles have to be synthesized in specific diameters and functionalized with surface groups to stabilize
them in a defined environment. In the presented study magnetite nano-particles were modified with different phosphonate coupling agents. The degree of
surface coverage was analyzed by TGA and elemental analysis. The thus functionalized nanoparticles were incorporated in a monomer and polymerized to
obtain crosslinked nanocomposites. These materials were compared with systems where the nanoparticles were embedded in a preformed polymer matrix. The
influence of crosslinking degree and the amount of nanoparticles incorporated in the polymers on the Tg was investigated by DSC.
Systematic TGA and elemental analysis studies showed the potential to analyze the degree of coverage on the nanoparticle surface. Both methods correlated
very well with respect to the small amount of functionalization on the nanoparticle surface. DSC revealed that even low amount of particles included in the
polymer matrix can raise the Tg considerably. Both methods, TGA and DSC showed their importance for the characterization of the composite materials from
the molecular to the macroscopic scale. Iron oxide particles can be heat treated due their ferromagnetic properties in electromagnetic field. Nanocomposites
were investigated on their properties in dependency on the various concentration of nanoparticles and power output of the electromagnetic field (AC). In addition
it was observed the model organic compound with inorganic nano-particles can be subject of polymerization in the external electromagnetic field because of the
increase of temperature due the presence of ferromagnetic iron oxide nano-particles.
Thermo-gravimetric investigation of surface-modified Fe3O4nanoparticles
Magnetic nanoparticles: synthesis, functionalisation
and radical polymerisation
O
TG/FT-IR measurement was carried out for all samples. The changes of mass
of the modified particles between 200-800°C was about 30wt% (Fig. 7, Tab 1).
H25 C12
P
-
Fe
3+
2+
OH
+ Fe
H2O
HO
O
(HO) 2P
OH
O
nO
R
Funktionalisierung
"Fe3O 4"
Polymerisation
O
"Fe3O 4"
Nanopartikel
O
P
O
Polymerkomposit
MMA, AIBN
Fig. 7: TGA of the functionalized Fe3O4 nano-particles with various
phosphonic acids (C12-C-18) in comparison with TGA of pristine iron oxidenano-particles
Fig.1: Production of Fe3O4 -Nanoparticles (Size 7- 12 nm)
Phosphonic acid is more
strongly bound to the
surface compared to the
oleic acid. The
functionalisation via
phosphonates is then more
stable.
• agglomerate-free incorporation in the monomer
• Homogeneous distribution of the nano-particles in the nano-composite
Fig. 2: ferro-magnetic particles
of Fe3O4
Fig.3: Inorg.-organic composite
material with increased portion of
Fe3O4, left (5 w/w %) to right
(50 w/w %)
Fe3O4
Fe3O4
Fe3O4
Tabelle 1: TGA - Übersicht
der
Massenverlusten
DDP mod.
Massenverlust
5
10
20
50
Fig.4: Investigation in the electromagnetic field
(100 W, 225 W; 1,95 MHz)
Heating profile
Cooling profile
TGA der reinen EisenoxidNanopartikeln
Abb. 1: TGA der mit
funktionalisierten EisenoxidNAanopartikel im Vergleichen
mit TGA der reinen EisenoxidNanopartikel
Fig.5: IR Determination of the polymer
degree in the nano-composites
Ölsäure
2,29 %
33,21 %
direkt
34,81 %
Fe3O4
DDP mod
ODP mod
26,11 %
30,13 %
Tab
1: Overview
of mass loss and correlation with EA
(200-800
°C)
Fe3O4
Fe3O4
Fe3O4
Fe3O4
virgin
@MPh
@DDP
@Oleic Acid
Mass loss
Fig. 3: Heating of the nanoparticles in the magnetic field;
Device: Hültinger Elektronik GMBH +CO. KG
Typ: IG S/3000 1997
Application:
• „Debonding on Demand“
• „Self –Healing“
Reine
Fe3O4
Fe3O4
@ODP
2,29
26,11
30,13
33,21
34,81
-
18,82/3,46
21,50/3,87
21,01/3,05
25,77/4,70
200-800°C / %
EA
C% / H%
DSC measurement of the PMMA polymer composite and
determination of the glass transition temperature Tg
The DSC measurement of PMMA with various doping amount of modif.
Fe3O4 was carried out. The glass transition temperature Tg of pure PMMA is
indicated at about 105°C. Doping with mod. iron oxide particles increases
the Tg by approx. 15 °C to about 120°C. The increase of Tg does not depend
on the amount of Fe3O4-doping.(Fig. 8).
Fig .8: DSC heating curves of the nanocomposites und increase of Tg
Fig.6: DLS Investigation
Summary: Nanocomposites containing finely dispersed surface-modified iron oxide were prepared via
radical polymerization. TGA and EA were used for characterization of iron nanoparticles while DSC was
used for characterization of nanocomposites. The incorporation of a small amount of Fe3O4-Particles into
the composite increases glass transition temperature Tg of the material by 15°C. Ferromagnetic properties
of iron oxide allow the heat treatment of the composite in electromagnetic field and the monomer doped
with ferromagnetic particles of Fe3O4 was successfully thermally polymerized under assistance of AC.