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Accelerated Zero-stress Hydrothermal Aging of Dry Glass, Basalt, and Carbon Fibers and Service Life Prediction Using Arrhenius Model
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- Author / Creator
- Sunny, John
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The utilization of fiber-reinforced polymer composites (FRPC) has rapidly increased over the past few
decades because of their attractive mechanical properties, comparatively low volumetric mass density, and
excellent corrosion resistance compared to traditional engineering materials like steel and aluminum.
Exposure to moist and humid environments can accelerate the aging process of composite materials and
negatively impact mechanical properties, thus shortening their service life. Environmental aging coupled
with elevated temperature constitutes a severe case of accelerated aging. Notably, different composite
constituents are impacted by environmental aging in different ways. As a result, it is crucial to comprehend
for each constituent the kinetics and mechanisms of environmental aging to ensure the composite’s
environmental durability. Data for service time assessments must currently be obtained via expensive and
time-consuming test procedures.
In recent years, thermoplastic matrix-based composites have been gaining popularity over their
thermoset counterparts due to a practically infinite shelf life of raw materials, the ability to recycle
thermoplastic polymers, and possible reductions in manufacturing cost that can be achieved using rapid and
continuous fabrication processes. While thermosetting matrices typically offer excellent resistance to water,
moisture exposure may significantly affect fibers embedded in thermoplastic polymers. Additionally, some
structural applications use fibers devoid of any matrix (‘dry’ fibers), in which water exposure must be
avoided. In both cases, moisture may significantly impact the reinforcing elements and the degradation rate.
Comprehending the degradation of reinforcements is crucial for service applications involving dry and wet
conditions, especially when prolonged contact with water above room temperature is present. Knowing and
forecasting the extent of the material property deterioration in water is of great interest to designers and
users of FRP structures. Environmental durability becomes a limiting factor in using composites for
structural applications since the uncertainty of the material interaction with the environment compromises
the superior material properties. The present work focused on the effects of hydrothermal aging on the
mechanical durability of long glass, carbon, and basalt fibers by immersion in water at 60°C, 71°C, and
82°C. Unidirectional thermoplastic composite tapes were also exposed to water at elevated temperatures to
extend the study to composites. The main application of interest in the context of this research is
thermoplastic composite piping where dry reinforcements or thermoplastic composite tapes are used as the
load-carrying components. A service life forecast model was created for the fibers utilizing the Arrhenius
technique. Using this modeling approach, it is possible to approximate the time it will take to attain a given
degradation level over a specified range of temperatures. Scanning electron microscopy was used to
evaluate morphology changes of fiber surfaces due to hydrothermal exposure. Fourier transforms infrared
spectroscopy and mass dissolution studies were used to elucidate the mechanism of the strength loss. -
- Graduation date
- Fall 2023
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- Type of Item
- Thesis
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- Degree
- Master of Science
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- License
- This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.