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Title of Thesis

Mohsan Nawaz
Institute/University/Department Details
Gomal University Dera Ismail Khan/ Department of Chemistry
Number of Pages
Keywords (Extracted from title, table of contents and abstract of thesis)
polymers, intrinsic viscosity, laser light scattering, nylon 6, dielectric constant measurement, solvent system, nonsolvent system

The intrinsic viscosity [ŋ] Huggin constant (KH) Laser Light Scattering. UV and IR measurements of nylon 6 are made in its solvent m-cresol and its mixture with different non-solvents like water, 1,4-dioxane, m-cresol and 0.01N HCI. These measurements are also made at different (20-60 oC) temperatures. It has been noted that the intrinsic viscosity. Rg A2 (2)1/2 (calculated from intrinsic viscosity). RH and UV absorbance firstly increase and then decrease with the increase in the decrease with the intensity in IR spectra shows an opposite trend to that of intrinsic viscosity. The dielectric constant calculated from refractive index of mixture of m-cresol, 1,4-dioxane and polymer solutions in it shows a continuous decrease with the amount of 1,4-dioxane. The activation energy obtained through variation in limiting viscosity number with temperature, first decreases and then increases with the addition of 1,4-dioxane. The variation in intrinsic viscosity, Huggins constant and other characteristics of the polymer solutions with solvent composition and temperature are explained in terms of thermodynamic quality of solvent, its selective adsorption, hydrogen bonding and conformational transitions which have taken place due to it. The linear expansion co-efficient (α3) is also calculated with the help of cross-over concentration. Cx. The results show that α3 first increases and then decreases by increasing the amount of 1,4-dioxane and decreases with the increase in temperature as observed in case of Rg it has been concluded that firstly the addition of 1,4-dioxane enhances the quality of the solvent, encouraging hydrogen bonding and specific adsorption and then deteriorates which results the conformational transitions in polymer molecules. However in case of HCI the viscosity decreased whereas KH increased linearly with the continents showing continuous deterioration of the quality of solvent

In the second phase of the work, investigation are carried out on the compatibility and non-compatibility of various blend systems. The blends studied are nylon-6/PVA/5M H2SO4 PS/PMMA/C6H6, PS/PA/ C6H6, PMMA/PEG/C6H6. These blends are studied with the help of capillary viscometer technique, rotoviscometric technique under different shear rates and dynamic light scattering technique at different temperatures ranging from 20-60 oC. Blends are studied by keeping the concentration of one polymer constant and varying the other. After this study different compositions of the blends are prepared covering a whole range of compositions using the plots of reduced viscosity and poly composition. From all these measurements, it is observed that the various blend systems investigation are not completely compatible and investigations are carried out to check the compatibility and non-compatibility of these blends. The compatibility is determined over the whole range of composition and at temperatures investigated. It is further observed that the result obtained for all these blends through different techniques are consistent with one another. The dynamic light scattering is an advance technique, but still the viscosity is the reliable technique that can be used for the determination of compatibility of the polymers .

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2201.33 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 Contents
77.71 KB
2 1 Introduction 1-20
249.43 KB
3 2 Experimental 21-23
51.91 KB
  2.1 Materials 21
  2.2 Sample Preparation 21
  2.3 Dilute Solution Viscosity Measurements 22
  2.4 Concentrated Solution Viscosity Measurements 22
  2.5 Laser Light Scattering Measurements 22
  2.6 Uv And Ir Measurements 23
  2.7 Refractive Index Increment Measurement 23
  2.8 Dielectric Constant Measurement 23
4 3 Results And Discussion 24-306
1973.87 KB
  3.1 Polymer/Solvent/Solvent System 112-306
  3.2 Polymer/Solvent/Nonsolvent System 36
5 4 Conclusions 307-308
238.17 KB
  4.1 References 309-324
  4.2 List Of Publications 325