الفهرس | Only 14 pages are availabe for public view |
Abstract It is well known that the thermal stability of polymers has given a great deal of attention for many years. On route to achieve thermally stable polymers is through copolymerization of the primary monomer with traces of a comonomer. The present work involves preparation of (2-acrylamido-4-antipyrinyl) thiazole (PAAT) and poly(4-acrylamidoantipyrine) (PAA) homopolymers and copolymers of 2-acrylamido-4-antipyrinyl thiazole (AAT) and 4-acrylamidoantipyrine (AA) with methyl methacrylate (MMA). The thermal stabilities of the homopolymers and copolymers were investigated. Chapter 1 of this four chapters thesis, includes a literature survey on the mechanisms of stabilization and degradation of polymers. Chapter 2 discuss the preparation of monomers, homopolymers and copolymers under investigated. Analytical techniques and thermal methods of analysis were provided. Four different concentrations of copolymer of MMA-AAT covering the entire composition range were prepared and characterized in chapter 3. The reactivity ratios of copolymerization were determined using 1H-NMR method and found to be r1 (MMA) = 19.14 and r2(AAT) = 0.056. Thermogravimetric analysis shows that the stabilities of the copolymers are intermediate between PAAT and PMMA homopolymers. In Chapter 4, PAA homopolymer and four different compositions of copolymer of MMA-AA were prepared and characterized by using IR , 1H-NMR and 13C- NMR spectroscopic techniques. The reactivity ratios of copolymerization were determined using 1H-NMR method and found to be r1 (MMA) = 3.23 and r2 (AA) = 0.13. Thermogravimetric analysis shows that there is an increase of the thermal stability of PAA homopolymer and AA-MMA copolymers towards PMMA homopolymer. The values of the activation energy for the thermal degradation of the copolymers were determined and found to be increases from 95.61 to 191.22 KJ/mole as the MMA concentration in the copolymer increases. |