Glass transition temperature behavior of alumina/PMMA nanocomposites.
- Rensselaer Polytechnic Institute, Troy, NY
Alumina/poly(methyl methacrylate) (PMMA) nanocomposites were synthesized by an in situ free-radical polymerization process with 38 and 17 nm diameter {gamma}-alumina nanoparticles. At extremely low filler weight fractions (<1.0 wt % of 38 nm fillers or < 0.5 wt % of 17 nm fillers) the glass-transition temperature (T{sub g}) of the nanocomposites drops by 25 C when compared to the neat polymer. Further additions of filler (up to 10 wt %) do not lead to additional T{sub g} reductions. The thermal behavior is shown to vary with particle size, but this dependence can be normalized with respect to a specific surface area. The nanocomposite T{sub g} phenomenon is hypothesized to be because of nonadhering nanoparticles that serve as templates for a porous system with many internal interfaces that break up the percolating structure of dynamically heterogeneous domains recently suggested by Long, D.; and Lequeux, F. Eur Phys J E 2001, 4, 371 to be responsible for the T{sub g} reductions in polymer ultrathin films. The results also point to a far field effect of the nanoparticle surface on the bulk matrix.
- Research Organization:
- Sandia National Laboratories
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 1002059
- Report Number(s):
- SAND2003-2635J
- Journal Information:
- Proposed for publication in the Journal of Polymer Science Part B: Polymer Physics., Journal Name: Proposed for publication in the Journal of Polymer Science Part B: Polymer Physics. Journal Issue: 23 Vol. 42; ISSN JPBPEM
- Country of Publication:
- United States
- Language:
- English
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