Two liquid crystalline aromatic polyesters were studied by isothermal degradation techniques. Both polymers contain a common phenyl side chain group. However, one contains a styryl side chain and the other contains an a-methylstyryl side chain. Isothermal degradations under nitrogen and air were carried on both polymers. From the GC/MS analysis of the cold traps, it showed that both polymers gave off benzene or oxygenated benzene related products. Homopolymers containing only phenyl or a-methylstyryl side chain were prepared by solution polymerization techniques. Then isothermal degradation under air were also carried out on both homopolymers. The GC/MS analysis showed that the a-methylstyryl side chain was responsible for the formation of the oxygenated benzene products. The activation energies determined for the polyesters did not show the relative stability of the polyesters as expected. Solution polymerized polyester 6 was studied initially under both air and nitrogen atmospheres using the Perkin-Elmer TGS-2 TGA. For polyester 6 under nitrogen, the activation energy (Eg) was determined to be 43 kcal/mole. Polyester 6 under air, the Ea determined were 31 kcal/mole for the initial rate and 28 kcal/mole for the final rate. Then using the Seiko thermal instrumentation, all of the polyesters were studied under flowing air. The Eafor polyester 6 was determined to be 22 kcal/mole for the initial rate and 12 kcal/mole for the final rate. Solution polymerized polyester 7 had calculated Eaof 36 kcal/mole. Melt polymerized polyester 7 had calculated Eaof 14 kcal/mole for the initial rate and 11 kcal/mole for the final rate. Solution polymerized polyester 8 had calculated Eaof 16 kcal/mole for the initial rate and 12 kcal/mole for the final rate. Solution polymerized polyester 9 had calculated Eaof 20 kcal/mole for the initial rate and 16 kcal/mole for the final rate.
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Department, Program, or Center
School of Chemistry and Materials Science (COS)
Lee, Scott, "Substituted aromatic polyesters: Degradation studies" (1992). Thesis. Rochester Institute of Technology. Accessed from
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