Dielectric relaxations in amorphous polymers with complex chain architectures
نویسندگان
چکیده
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 insight into the molecular dynamics of complex architecture systems. From these sets of data wemake an attempt to propose a structural interpretation ofmolecular mobility through the glass transition.
منابع مشابه
Evidence of early stage precursors of polymer crystals by dielectric spectroscopy.
Dielectric spectra of the polyester poly(propylene succinate) were measured upon crystallization. For this model aliphatic polyester the alpha and beta relaxations appear simultaneously and are well resolved in the experimental frequency window. During isothermal crystallization, this fact allows one to use the beta relaxation to characterize the crystalline structural development while the alp...
متن کاملX-ray diffraction, calorimetric, and dielectric relaxation study of the amorphous and smectic states of a main chain liquid crystalline polymer.
Liquid crystalline polymers (LCPs) are complex systems that include features of both orientationally ordered mesophases and amorphous polymers. Frequently, the isotropic amorphous state cannot be studied due to the rapid mesophase formation. Here, a new main chain LCP, poly(triethyleneglycol methyl p,p'-bibenzoate), PTEMeB, has been synthesized. It shows a rather slow mesophase formation making...
متن کاملEffect of morphology and nonbounded interface on dielectric properties of plasma sprayed BaTiO3 Coating
In this research, BaTiO3 thick deposit has been successfully sprayed by air plasma spray. The microstructure and dielectric properties of thick films were investigated by secondary electron microscopy (SEM) and LCR meter respectively. XRD measurement was carried out on plasma sprayed BaTiO3. The results illustrate differences in the crystal structure between plasma sprayed coatings and feed sto...
متن کاملStudy of the Molecular Dynamics of Multiarm Star Polymers with a Poly(ethyleneimine) Core and Poly(lactide) Multiarms
Multiarm star polymers, denoted PEIx-PLAy and containing a hyperbranched poly(ethyleneimine) (PEI) core of different molecular weights x and poly(lactide) (PLA) arms with y ratio of lactide repeat units to N links were used in this work. Samples were preconditioned to remove the moisture content and then characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) ...
متن کاملDIELECTRIC DISPERSION IN SOLUTIONS OF FLEXIBLE POLYMERSt
INTRODUCTION The dielectric properties of polar chain polymers have long1'2 been of great interest to many workers. For solid materials, there is great practical justification for such interest in the sometimes very close relation between mechanical and electrical behaviour, as well as in direct applications to problems of electrical insulation. The study of dielectric constant and loss in dilu...
متن کامل