“Poli(Metil Vinil Eter-ard-Maleik Anhidrit) ve Poli(Etilen-ard-Maleik Anhidrit) Kopolimerlerinin Çözelti Dinamiği ve Termodinamiği

Abstract

In this study, both theoretical approach and experimental studies have been used to determine chemical affinity profiles of Poly(methyl vinyl ether-ard-maleic anhydride) (Mw = 216,000 g/mol) and Poly(ethylene-ard-maleic anhydride) (Mw = 100,000-500,000 g/mol) in different solvents and to examine solvent dynamic and thermodynamic. In the repeated units of these two selected copolymers, while the maleic anhydride unit was stable, one of the repeated units was selected as methyl vinyl ether and the other was selected as ethylene. As it may be noticed, the repeated unit difference in the copolymers varies only with a methoxy group. In this thesis, it is extensively examined that this group can be different in both theoretical and experimental terms.

In the theoretical phase of thesis, HSPiP program was used to calculate the thermodynamic quantities. By using this program, Chemical Affinity Profiles were calculated with many solvents for both copolymers and these values were followed on 2D and 3D diagrams. In the experiental phase; from large amount of solvents DMSO, MEK and EtAc was chosen for PMVEMA while DMSO, DMA and acetone chosen for PEMA by calculating the solubility parameter differences (l∆δTΙ, ∆δT, RED) for copolymer-solvent systems.

Spectroscopic (FTIR) and Thermal (DSC) studies were carried out by using solid samples obtained by drying/casting the solutions of copolymers experimentally in the specified solvents. Solution Behaviors of copolymers were carried out by using Light Scattering (Static Light Scattering), Viscosimetric and Rheometric methods.

FTIR studies showed significant shifts due to solvent, especially at carbonyl peaks, and these shift values were observed to be numerically larger for ‘good solvents’. In DSC, the Glass Transition Temperature (Tg) behaviors were found to be compatible with the Chemical Affinity Profiles calculated between polymer and solvent.

In the Static Light Scattering method, which is used to observe the behavior of the solutions, Radius of Gyration (Rg) and Second Virial Coefficient (A2) values were calculated for different copolymer-solvent systems. As a result, it was observed that these values are in accordance with the estimations made by calculation.

Lastly, viscosity and rheology study results showing the copolymer-solvent RED reconciliation were obtained. The common result observed in all solution behaviors; Hydrodynamic volumes ([η]), Radius of Gyration and and polymer-solvent interactions (A2) were greater in ‘good solvents’ while in bad solvents these values are smaller