Open structure of the commingled yarns caused higher selleck chemicals llc production stops. As a possible solution, GF/PP commingled yarns with different twisting levels were produced. Effect of twisting on the mechanical properties of commingled yarns

and on their compression molded UD composites are determined. Further tests were executed about yarn/yarn and yarn/metal friction of twisted commingled yarns, which are important properties during textile processing. Theoretical approaches such as a yarn model with linear bar elements and lamina equation with an equivalent angle distortion of over-delivery learn more proved useful to relate the structural parameters and mechanical properties. As a result, twisting did not significantly affect the modulus of elasticity of UD-composites, however, the tensile strength of UD-composites were reduced by further processing even without twisting. Therefore, small twisting levels can be applied on commingled yarns to improve processability of dense preforms without significantly affecting the mechanical performance. (C) 2011 Wiley

Periodicals, Inc. J Appl Polym Sci 123: 246-256, 2012″
“A modeling of organic field-effect transistors’ (OFETs’) electrical characteristics is presented. This model

is based on a one-dimensional (1-D) Poisson’s equation find more solution that solves the potential profile in the organic semiconducting film. Most importantly, it demonstrates that, due to the common open-surface configuration used in organic transistors, the conduction occurs in the film volume below threshold. This is because the potential at the free surface is not fixed to zero but rather rises also with the gate bias. The tail of carrier concentration at the free surface is therefore significantly modulated by the gate bias, which partially explains the gate-voltage dependent contact resistance. At the same time in the so-called subthreshold region, we observe a clear charge trapping from the difference between C-V and I-V measurements; hence a traps study by numerical simulation is also performed. By combining the analytical modeling and the traps analysis, the questions on the C-V and I-V characteristics are answered. Finally, the combined results obtained with traps fit well the experimental data in both pentacene and bis(triisopropylsilylethynyl)-pentacene OFETs. (C) 2011 American Institute of Physics. [doi:10.1063/1.