Trans-Interfacial Polymerization and Matter Transport Processes in Epoxy-Alumina Nanocomposites Visualized By Scanning Brillouin MicroscopySanctuary, Roland ; Philipp, Martine ; et alin Journal of Physical Chemistry B (2010), 114(25), 8396-8404 The structural developments in the vicinity of the interface between the reactants of an epoxy are investigated using time- and space-resolved scanning Brillouin microscopy. The hypersonic profile across ... [more ▼] The structural developments in the vicinity of the interface between the reactants of an epoxy are investigated using time- and space-resolved scanning Brillouin microscopy. The hypersonic profile across the phase boundary evolves with strong spatial asymmetry and exhibits erratic behavior within the resin-rich region, which is attributed to a complex interplay between matter transport, dissolution, polymerization, and molecular unravelling process. The presence of alumina nanoparticles in the resin changes the character of these matter transport and reaction processes significantly. On the one hand, the nanoparticles act as transport barriers, hindering the mixing of the reactive components; on the other hand they seem to have a catalytic influence on the epoxy polymerization under certain circumstances. Their transport against gravity is tentatively attributed to gradients in surface tension. [less ▲] Detailed reference viewed: 198 (1 UL) Combination of high performance refractometry and infrared spectroscopy as a probe for chemically induced gelation and vitrification of epoxiesMüller, Ulrich ; Philipp, Martine ; Gervais, P. C. et alin New Journal of Physics (2010), 12 A combination of infrared spectroscopy and high performance refractometry was used to investigate the chemically induced sol-gel and glass transition during the polymerization of epoxies. Representations ... [more ▼] A combination of infrared spectroscopy and high performance refractometry was used to investigate the chemically induced sol-gel and glass transition during the polymerization of epoxies. Representations of the refractive index versus chemical conversion reveal an interesting insight in the optical properties accompanying gelation and vitrification. Whereas the electronic polarizability of the liquid state of small average molecular mass and the glassy state is dominated by the mass density, an unexpected excess polarizability observed during the gelation is attributed to cooperative dipole-dipole interactions. [less ▲] Detailed reference viewed: 214 (1 UL) |
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