Dielectric relaxations in amorphous polymers with complex chain architectures

Dielectric relaxations in amorphous polymers with complex chain architectures

By combining thermostimulated current and dynamic dielectric spectroscopies, the dielectric properties characteristic of the molecular mobility can be described over a very broad frequency range. The study of dielectric relaxations of phosphorus-containing dendrimers in the sub-glass transition region, and of poly(n-alkyl methacrylates) at and above the glass transition region allows us to gain...

Molecular-dynamics simulation study of the glass transition in amorphous polymers with controlled chain stiffness.

We report computation results obtained from extensive coarse-grained molecular-dynamics simulations of amorphous ensembles of polymer chains at constant density. In our polymer model, we use bending and torsion potentials acting along the polymer backbone to control the chain stiffness. The static and dynamic properties of the polymer bulk have been analyzed over a large temperature interval in...

Interplay between amorphous and crystalline domains in semicrystalline polymers by simultaneous SAXS, WAXS and Dielectric Spectroscopy

This work presents an experimental study on the interplay between structure and dynamics during isothermal cold crystallization of a copolymer based on poly(ethylene terephthalate) and poly(ethylene isophthalate) of poly(trimethylene terephthalate). Simultaneous X-ray scattering and dielectric spectroscopy measurements revealed that, during cold crystallization, crystalline lamellae tend form l...

Dielectric Spectroscopy of Reactive Polymers

High Frequency Loss Mechanism in Polymers Filled with Dielectric Modifiers

We analyzed the high frequency dielectric relaxation mechanism in high-k composite materials using film substrates made of low loss organic resin filled with ferroelectric ceramics and with single wall carbon nanotubes (SWNT). We performed broadband permittivity measurements of high-k film substrates at frequencies of 100 Hz to about 10 GHz. In order to analyze the effect of the dielectric thic...