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Influence of molecular weight on the mechanical performance of a thermoplastic glassy polyimide
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Whitley, Karen S. Hinkley, Jeffrey A. Gates, Thomas S. Nicholson, Lee M. |
| Copyright Year | 1999 |
| Description | Mechanical Testing of an advanced thermoplastic polyimide (LaRC-TM-SI) with known variations in molecular weight was performed over a range of temperatures below the glass transition temperature. The physical characterization, elastic properties and notched tensile strength were all determined as a function of molecular weight and test temperature. It was shown that notched tensile strength is a strong function of both temperature and molecular weight, whereas stiffness is only a strong function of temperature. A critical molecular weight (Mc) was observed to occur at a weight-average molecular weight (Mw) of approx. 22000 g/mol below which, the notched tensile strength decreases rapidly. This critical molecular weight transition is temperature-independent. Furthermore, inelastic analysis showed that low molecular weight materials tended to fail in a brittle manner, whereas high molecular weight materials exhibited ductile failure. The microstructural images supported these findings. |
| File Size | 2029915 |
| Page Count | 33 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19990115891 |
| Archival Resource Key | ark:/13960/t2f81960x |
| Language | English |
| Publisher Date | 1999-11-01 |
| Access Restriction | Open |
| Subject Keyword | Nonmetallic Materials Temperature Dependence Polymer Matrix Composites Tensile Tests Notches Mechanical Properties Ductile-brittle Transition Modulus of Elasticity Glass Transition Temperature Molecular Weight Tensile Strength Stress-strain Diagrams Polyimides Elastic Properties Thermoplasticity Microstructure Fractography Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
