Viscoelastic Properties and Orientation of Polymers in Solution
نویسندگان
چکیده
Using rheological shear and oscillation measurements, it is possible to determine the viscoelastic properties of a system quantitatively, as a function of the many influential parameters. The aim here was to establish structure-property relationships for a polymer in a solvent system from the viscoelastic material functions correlated with data from polymer analysis These structure-property relationships make it possible to quantitatively predict the viscoelastic properties as a function of the molecular parameters. In addition to these rheo-mechanical measurements, recent years have also seen the parallel determination of rheo-optical material functions, such as flow birefringence and flow dichroism, used in order to investigate macroscopic viscoelastic flow behaviour at a molecular level. Apart from determining these moduli, which are proportional to rheo-mechanical parameters, it was also possible to determine the orientation of polymer segments and aggregated structures. In particular, it became possible to explain aggregation behaviour during the sol-gel transition and during temperature-induced phase separation on a molecular level. The overriding aim of these investigations was to establish new structure-property relationships by correlating the rheomechanical and the rheo-optical material functions.
منابع مشابه
Viscoelastic Properties of Polyacrylamide Nanocomposite Hydrogels Prepared in Electrolyte Media: Effect of Gelant Volume
In this work, nanocomposite (NC) hydrogels based on polyacrylamide/chromium triacetate were prepared at different reaction mixture (gelant) volumes and their crosslinking process and viscoelastic behaviors were studied. The X-ray diffraction (XRD) patterns taken from the NC hydrogels containing laponite nanoparticles did not show any distinct characteristic basal reflection for all of the NC hy...
متن کاملEffect of Polymer Grade and Plasticizer Molecular Weights on Viscoelastic Behavior of Coating Solutions
Film coating solutions containing different grades of HPMC (E5, E15 and E50) with and without polyethylene glycol (with various molecular weights) were examined by an oscillatory method, using Haake CV 100 rheometer. Fundamental rheological parameters (?, G? and G² ) were measured over the frequency range from 0.04 to 2 Hz. The variation with frequency of the loss tangent (a ratio of viscous to...
متن کاملAn Improvement in Fluorocarbon Chain Re-orientation by Reactive Dyes
There is an increasing demand for air-dry performance of fluorocarbon finished materials. Thus, dyeing with different types of reactive, mono, bi, and multi-functional, dyes was evaluated as a novel treatment to create correct surface interface to maintain fluorocarbon performance without ironing or tumble drying. The effects of pre-treatment on fluorocarbon finishing of cotton fabric, a cellul...
متن کاملDynamic response determination of viscoelastic annular plates using FSDT – perturbation approach
In this paper, the transient response of a viscoelastic annular plate which has time-dependent properties is determined mathematically under dynamic transverse load. The axisymmetric conditions are considered in the problem. The viscoelastic properties obey the standard linear solid model in shear and the bulk behavior in elastic. The equations of motion are extracted using Hamilton’s principle...
متن کامل