References of "Ziehmer, Markus 40000750"
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See detailThe catalytic influence of alumina nanoparticles on epoxy curing
Baller, Jörg UL; Thomassey, Matthieu UL; Ziehmer, Markus UL et al

in Thermochimica Acta (2011), 517

The curing process of diepoxide-triamine systems filled with water and untreated alumina nanoparticles has been investigated. The influence of both types of fillers on the curing process is very similar ... [more ▼]

The curing process of diepoxide-triamine systems filled with water and untreated alumina nanoparticles has been investigated. The influence of both types of fillers on the curing process is very similar. This is reflected by a similar shape of the heat flow (HF) and specific heat capacity curves during curing. A catalytic effect of hydroxyl groups in the water and on the nanoparticles surfaces is made responsible for the observed curing behaviour. It turns out that the strength of the catalytic effect depends on the type of filler. The described influence of alumina nanoparticles on thermoset curing is looked upon as being representative for nanocomposites consisting of epoxy thermosets and metal oxide nanoparticles without surface treatment. [less ▲]

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See detailThermal and chemical glass transition of thermosets in the presence of two types of inorganic nanoparticles
Baller, Jörg UL; Thomassey, Matthieu UL; Ziehmer, Markus UL et al

in Thermoplastic and thermosetting polymers and composites (2011)

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See detailInfluence of Al2O3 nanoparticles on the isothermal cure of an epoxy resin
Sanctuary, Roland UL; Krüger, Jan-Kristian UL; Baller, Jörg UL et al

in Journal of Physics : Condensed Matter (2009), 21

The influence of Al2O3 nanoparticles on the curing of an epoxy thermoset based on diglycidyl ether of bisphenol A was investigated using temperature-modulated differential scanning calorimetry (TMDSC) and ... [more ▼]

The influence of Al2O3 nanoparticles on the curing of an epoxy thermoset based on diglycidyl ether of bisphenol A was investigated using temperature-modulated differential scanning calorimetry (TMDSC) and rheology. Diethylene triamine was used as a hardener. TMDSC not only allows for a systematic study of the kinetics of cure but simultaneously gives access to the evolution of the specific heat capacities of the thermosets. The technique thus provides insight into the glass transition behaviour of the nanocomposites and hence makes it possible to shed some light on the interaction between the nanoparticles and the polymer matrix. The Al2O3 fillers are shown to accelerate the growth of macromolecules upon isothermal curing. Several mechanisms which possibly could be responsible for the acceleration are described. As a result of the faster network growth chemical vitrification occurs at earlier times in the filled thermosets and the specific reaction heat decreases with increasing nanoparticle concentration. Rheologic measurements of the zero-shear viscosity confirm the faster growth of the macromolecules in the presence of the nanoparticles. [less ▲]

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See detailInteractions between silica nanoparticles and an epoxy resin before and during network formation.
Baller, Jörg UL; Becker, Nora UL; Ziehmer, Markus UL et al

in Polymer (2009), 50(14), 3211-3219

In polymer nanocomposites, interactions between filler particles and matrix material play a crucial role for their macroscopic properties. Nanocomposites consisting of varying amounts of silica ... [more ▼]

In polymer nanocomposites, interactions between filler particles and matrix material play a crucial role for their macroscopic properties. Nanocomposites consisting of varying amounts of silica nanoparticles and an epoxy resin based on diglycidyl ether of bisphenol A (DGEBA) have been studied before and during network formation (curing). Rheology and mainly temperature modulated differential scanning calorimetry (TMDSC) have been used to investigate interactions between the silica nanoparticles and molecules of the epoxy oligomer or molecules of the growing epoxy network. Measurements of the complex specific heat capacity before curing showed that interactions between the nanoparticles and DGEBA molecules are very weak. An expression for an effective specific heat capacity of the silica nanoparticles could be deduced. Examination of the isothermal curing process after addition of an amine hardener yielded evidences for a restricted molecular mobility of the reactants in the cause of network formation. These restrictions could be overcome by increasing the curing temperature. No evidences for an incorporation of the silica nanoparticles into the epoxy network, i.e. for a strong chemical bonding to the network, were found. Interactions between the silica nanoparticles and the epoxy resins under study are assumed to be of a physical nature at all stages of network formation. [less ▲]

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