Polivinil Pirolidon 'un Çözelti Dinamiği ve Dekstran ile Karışabilirliğinin İncelenmesi

Abstract

The investigation of miscibility between immiscible or miscible polymers has become an increasingly important technique for developing commercial polymer materials, which may combine the properties of several single polymers.

Compatibility and miscibility of poly(N-vinylpyrrolidone) (PVP) and Dextran (Dex) blends have been investigated by using and algorithmic approach (HSPiP; Hansen Solubility Parameters in Practice, a computational software) as the theoretical application of the “like dissolves like” principal in two different solvents. The cohesive energy density/solubility parameters, their sub-parameters and sub-parameter combinations of PVP and Dex have been evaluated by using functional group contribution method of HSPiP software pogramme. Then their two-dimensional (2D) and three-dimensional (3D) graphs have been drawn by creating the solubility/affinity profiles of the polymers in different solvents. As a consequence of algorithmic calculations, DMSO was determined to be a better solvents, whereas water poorer solvent for PVP/Dex blend systems.

Initial state of this study, interaction dynamism/chemical affinity of PVP have been investigated in the presences of moisture, by using thermal (DSC, DMA, TGA), spectroscopic (FT-IR, UV-Vis) and viscosimetric methods.

In the light of computational calculations, according to .HSPiP, Fourier Transform Infrared (FT-IR), UV-Vis Spectroscopy (by using OriginPro8.5 software in order to peak analysis/peak-deconvolution), Differential Scanning Calorimethry (DSC), Termogravimetric Analysis (TGA), Dinamic Mechanical Analysis (DMA) and Viscosimetry (Ubbelohde Viscosimetry) were used to characterize the spesific interactions between (mainly hyrogen-bond formations) the polymers (PVP-Dextran) and polymer-solvent systems.

FT-IR has been the method of choice to probe the nature and extent of interactions in polymer blends. H-bond formation, when PVP-Dex mixture is prepared, changes the interaction by dynamics between the two molecules at the molecular level, which can be visualized by FT-IR as the primary method. PVP is capable of forming an H-bond either through nitrogen or mainly the carbonyl group on the lactam ring. This will manifest itself as changes in the frequency bandwidth and band shifts of interacting groups (C=O streching vibrations)

Electronic spectral behavior of PVP and PVP-Dex water solutions and PVP-Dex DMSO solutions have been determined by UV-Vis spectrophotometry, following electronic transitions.

Viscometric behaviors of PVP, Dex and their blend systems in water and DMSO solutions have been studied. The reduced viscosity and intrinsic viscosity have been evaluated for the polymer/water and polymer/DMSO systems by classical Huggins equation.

Thermal behaviours of PVP-Dex systems, have been studied by DSC and TGA methods and the dynamic mechanical properties, glass transition temperatures (Tg) and glass transition temperatures differences of polymers and their blends have been studied using Storage modulus-T and Derivative storage modulus-T scale and main glass transition changes have been observed in polymer blend-water/DMSO systems.

In addition, the influence of moisture on polymer samples and their interaction dynamism has also been analyzed in details.