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1 Journal of Achievements in Materials and Manufacturing Engineering

1 2006

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Mechanical properties and thermogravimetric analysis of PBO thin films

Wu G. M., Hung C. H.

Journal of Achievements in Materials and Manufacturing Engineering

2006

Vol. 17, nr 1-2

27--32

Purpose: In the continued quest for high performance, high temperature, light weight materials, the research and development of poly(1,4-phenylene-cis-benzobisoxazole) or PBO polymer was a significant step. The thermal stability, stiffness, and tensile strength surpass those of many other engineering polymers. In this report, the superior mechanical properties of PBO thin film materials and the thermal characteristics of the isotropic thin films were investigated. Thermogravimetric analysis (TGA) and the Ozawa method were employed to analyze the thermal degradation kinetic parameters. Design/methodology/approach: The quasi-isotropic thin films were processed from 14 wt-% PBO dope with the molecular weight about 130,000. Mini-tensile bar specimens of dog-bone-shape were prepared for MTS testing machine. The ASTM D1708 microtensile testing was carried out at room temperature. The TGA spectra were obtained by employing Thermal Analysis (TA) TA-2050 thermogravimetric analyzer under various heating rates in nitrogen. The Ozawa method has been used for the kinetic data analysis. Findings: The results showed that PBO thin film exhibited outstanding specific tensile properties and thermal resistance. The onset of the decomposition temperature in nitrogen atmosphere was about 670°C. The temperature that corresponded to the maximum decomposition rate was around 750°C. The residual weight was still as high as 73% when heated up to 850°C. The reaction followed a first order mechanism. In addition, the activation energy (Ea ) for PBO thin film material has been estimated to be 445 kJ/mol and the frequency factor (logA) to be 25.2 min-1. Practical implications: The better understanding in PBO thin film processing and characteristics could help to advance the structure design and unique applications. Originality/value: The outstanding specific mechanical properties and excellent thermal resistance should provide great potential applications for this new class of high performance rigid rod polymers.