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Frequency dependent dielectric measurements (FDEMS), dynamic mechanical rheometer measurements (DMA) and modulated differential scanning calorimetry (DSC) are applied to observe the formation of a spatial heterogeneity in dimethacrylate/divinylbenzene (D121/DVB) and dimethylacrylate/styrene (D121/St) network systems. The structure evolution information during the reaction, such as T g , the...
The relationship of conductivity and the mobility of the charge carriers to the viscosity have been separately measured during buildup in the network structure of an epoxy–amine as the reaction approaches the gel point and as a function of temperature for the unreacted resin using dielectric and ion-time-of-flight measurements. The mobility, not conductivity, is observed to correlate with the changing...
An in situ and single-step route to creating a uniform dispersion of lanthanum(III) oxide nanoparticles in a polyimide is described. The process of thermally evolving, from the diaquotris(2,4-pentanedionato)lanthanum(III) complex, to a homogeneous dispersion of lanthanum(III) oxide nanoparticles within a 6FDA/1,3(3)-APB polyimide matrix has been characterized. The report also describes the resulting...
Ion mobility time-of-flight (ITOF) measurements can isolate the mobility of the charge carriers during a chemical reaction. The ITOF technique complements conductivity measurements. Together they more accurately monitor changes in the chemical and physical properties such as viscosity of a material as it polymerizes. The use of conductivity due to migration of charges to monitor the advancement of...
An in situ measurement technique that isolates the mobility of charge carriers is described and analyzed. The technique allows significant improvement over conductivity measurements to monitor changes in the physical properties and state of a material as it cures. This is essential in systems where N i , the number of charge carriers, cannot be assumed constant such as during cure of epoxies,...
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