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Water Absorption and Performance Degradation of Natural Fiber Reinforced Thermoplastic Composites Open Access


Other title
Water Absorption and Performance Degradation of Natural Fiber Reinforced Polyethylene Composites
natural fiber
mechanical properties
water absorption
Type of item
Degree grantor
University of Alberta
Author or creator
Robertson, Nicole Lee M.
Supervisor and department
Wolodko, John D. (Agricultural, Food and Nutritional Science)
Nychka, John A. (Chemical and Materials Engineering)
Examining committee member and department
Ulven, Chad (Mechanical Engineering)
Choi, Phillip (Chemical and Materials Engineering)
Eadie, Reg (Chemical and Materials Engineering)
Ayranci, Cagri (Mechanical Engineering)
Department of Chemical and Materials Engineering
Materials Engineering
Date accepted
Graduation date
2017-11:Fall 2017
Doctor of Philosophy
Degree level
Natural fiber reinforced polyethylene biocomposites are an environmentally friendly alternative to non-biodegradable thermoplastic materials. The addition of natural fibers to polyethylene improves mechanical properties such as tensile modulus and tensile strength. Unlike thermoplastics, biocomposites are water absorbant due to the presence of natural fibers. Biocomposites mechanical properties degrade when exposed to water. Immersion in water shortens the product life of biocomposites and limits their use in many applications. However, a shorter product life is advantageous for some applications because early degradation reduces the material's environmental impact. The work herein explores long-term water immersion (6000+ hours) of injection molded hemp and wood pulp fiber reinforced polyethylene. Both low density polyethylene (LDPE) and high density polyethylene(HDPE) were tested, each with three fiber fill fractions. The comprehensive dataset collected for this project allowed for conclusions to be drawn about the effect of fiber type, content and distribution as a function of immersion time to predict water absorption. The extent of mechanical degradation was proven to be dependent on the quantity of water absorbed. A model was developed to predict the percentage of water absorbed over a long time scale that accounts for fiber degradation to enable the prediction of changes to the mechanical properties. The prediction of the rate and magnitude of water absorption by natural fiber thermoplastic composites will allow designers to understand, and account for, the degradation of the material's mechanical properties over time.
This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for the purpose of private, scholarly or scientific research. 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.
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File title: Title Page - Executive Summary - Preface 2017-09-24
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