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Titel: Optical and thermomechanical investigations on thermoplastic nanocomposites with surface modified silica nanoparticles
Verfasser: Becker, Carsten
Müller, Peter
Schmidt, Helmut K.
Sprache: Englisch
Erscheinungsjahr: 1998
Quelle: Organic-inorganic hybrid materials for photonics : 19-20 July 1998, San Diego, California / Liliane G. Hubert-Pfalzgraf ... chairs, eds. - Bellingham, Wash. : SPIE, 1998. - (SPIE proceedings series ; 3469), S. 88-98
SWD-Schlagwörter: Optische Eigenschaft
Thermomechanische Eigenschaft
Thermoplast
Nanokomposit
Werkstoff
Methacrylsäuremethylester
Hydroxyethylmethacrylate
DDC-Sachgruppe: 620 Ingenieurwissenschaften und Maschinenbau
Dokumentart : InProceedings (Aufsatz / Paper einer Konferenz etc.)
Kurzfassung: Dynamic mechanical thermal analysis (DMTA) and UV/VIS spectroscopy were applied ot investigate the thermomechanical and optical properties of thermoplastic nanocomposites. The thermoplastic matrix material used was a copolymer derived from methylmethacrylate (MMA) and 2-hydroxyethlmethacrylate (HEMA). To improve the mechanical properties, especially in the high temperature region above the glass transition temperature (Tg) of the matrix, the copolymer was filled with spherical 10 nm silica particles (filler content 2,5, and 10 vol.% respectively). The particles were introduced in the polymer matrix after appropriate surface coating to control the filler dispersion in the matrix and the filler/matrix adhesion. The coating was perfomed using acetoxypropyltrimethoxysilane (APTS) to achieve higher filler/matrix compatibility compared to unmodified silica particles dispersed in the polymer matrix. Methacryloxypropyltrimethoxysilane (MPTS) was used to improve filler/matrix adhesion by covalent bonding between the filler surface and polymer matrix. The appearance of the poly(MMA-co-HEMA) nanocomposites (denoted: PMH nanocomposites) changes from translucent for the systems containing uncoated silica to more transparent for the compositions containing silane coated silica. This is indicated by a decrease in scattering/absorbance losses from 1.48 dB/cm to 1.06 dB/cm at lampda = 650 nm. Investigations of the morphology of the same nanocomposites using transmission electron microscopy (TEM) showed that by coating the particles with silane an almost perfect dispersion of the fillers in the matrix can be realised. The more homogeneous dispersion of the silane coated particles in the polymer matrix compared to the uncoated silica is responsible for the increase in transparency of the systems. However, the composition dependence of the refractive index is in accordance with the expected behaviour and shows a decrease with increasing amounts of silica (0% silica: ne = 1.5085, 10% silica ne = 1.4965) whereas, the Abbe number remains almost constant at ve = 58 for all compositions. In addition, the fortyfold increase in the value for the storage modulus E' at T = 170°C (derived from dynamic mechanical thermal analysis (DMTA)) for the system with 9.5 vol% MPTS coated particles compared to the unfilled matrix indicates an increased thermomechanical stability of the nanocomposites.
Link zu diesem Datensatz: urn:nbn:de:bsz:291-scidok-28931
hdl:20.500.11880/24641
http://dx.doi.org/10.22028/D291-24585
ISBN der Druckausgabe: 0-8194-2924-4
SciDok-Publikation: 16-Jun-2010
Fakultät: Sonstige Einrichtungen
Fachrichtung: SE - INM Leibniz-Institut für Neue Materialien
Fakultät / Institution:INM
SE - Sonstige Einrichtungen

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