Thesis
A study of the thermal oxidative degradation of polyamide 6,6 prediction of the thermal index by a short term analytical method versus long term thermal aging
Washington State University
Master of Science (MS), Washington State University
05/2016
Handle:
https://hdl.handle.net/2376/101588
Abstract
Materials engineers are constantly burdened with the need to balance thermal, electrical, mechanical, chemical compatibility, ease of processing, and flammability properties of polymers to meet design specifications in a rapid, inexpensive, and accurate manner for a multitude of applications. The biggest constraint in performing safety evaluations of plastics is the evaluation of a material's thermal index, the temperature at which the material can safely perform at the heating conditions it will experience as an insulating part in its intended use over a reasonable life time. Traditional long term thermal aging programs extend from 8 to 12 months on average, are labor intensive, and costly. There exist short term analytical methods developed for predicting these thermal indices, however, they are difficult to compare to real world plastics undergoing degradation at relatively low temperatures for many years, where defects and surface degradation could cause a catastrophic failure resulting in risk of electric shock or fire. A study of thermo-oxidative degradation of polyamide6,6 was conducted. The study compared a traditional long term thermal aging approach studying tensile strength degradation, with a short term analytical approach utilizing Thermogravimetric Analysis (TGA) to calculate an Arrhenius activation energy utilizing the Ozawa-Flynn-Wall method, and a hybrid approach combing the activation energy obtained by the TGA method and the mechanical degradation of the traditional method was conducted to intend to shorten the timeline to 2-3 months for determination of the thermal indices without ignoring the physical degradation of the plastic. An unfilled, unpigmented, extruded polyamide 6,6 was the material of study. The traditional long term thermal aging conducted in the range of 130°C to 160°C, yielded a mechanical strength thermal index of 51.0°C. The TGA short term analytical approach, using the Ozawa-Flynn-Wall method, yielded a thermal index of 46.4°C. And finally, the hybrid approach using the analytical activation energy, and a degradation time from 140°C tensile strength aging data yielded a relative thermal endurance index of 81.4°C, very consistent with many entry level, unfilled, non-additive polyamide 6,6s certified for safety by UL.
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Details
- Title
- A study of the thermal oxidative degradation of polyamide 6,6 prediction of the thermal index by a short term analytical method versus long term thermal aging
- Creators
- Karina Marie Wagner
- Contributors
- Dae-Wook Kim (Chair)Yoon Jo Kim (Committee Member)Jong-Hoon Kim (Committee Member) - Washington State University, Engineering and Computer Science (VANC), School of
- Awarding Institution
- Washington State University
- Academic Unit
- Electrical Engineering and Computer Science, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Number of pages
- 136
- Identifiers
- 99900525052601842
- Language
- English
- Resource Type
- Thesis