(Drs. Jianmin Qu and David R. Veazie, co-advisors)
"The Effects of Processing on the Mechanical Properties and Durability of PETI-5 Resins"
In light of the rapid expansion and growth of the global economy, the next generation of long range commercial aircraft will have increased performance requirements to keep pace with new travel demands. The development of advanced lightweight materials or polymer matrix composites for both primary and secondary structures is a key enabling technology. Although polymeric composites are light in weight and possess superior specific mechanical properties, these materials are difficult to process due to the high melt viscosity of the polymeric matrix. As a result, polymers have been altered to reduce the melt viscosity.
The objective of this research was to characterize the mechanical behavior and durability of a candidate polyimide resin, PETI-5 before and after the material was altered to decrease the melt viscosity. Static tests were conducted at room temperature and at an elevated temperature of 177°C to characterize the ultimate tensile strength and stress strain behavior of the materials. Fatigue tests were used to monitor the changes in modulus and cycles to failure. Non-destructive test methods were used to monitor the changes that occurred within the microstructure of the material as a result of cyclic loading. The long-term viscoelastic behavior of the polymeric materials was determined through the use of an accelerated test method, which was accomplished by sequenced creep and recovery tests. The experimental results of the altered material were compared to those of the original material to determine whether the altered materials demonstrate the same mechanical properties as their parent material.