All ETDs from UAB

Advisory Committee Chair

Selvum Pillay

Advisory Committee Members

Eugenia Kharlampieva

Gregory Thompson

Haibin Ning

Uday K Vaidya

Document Type

Dissertation

Date of Award

2015

Degree Name by School

Doctor of Philosophy (PhD) School of Engineering

Abstract

The abundance of blue - green algae (BGAs) has created a social and industrial problem. The overgrowth of algae blooms in water bodies across the U.S. reduces the quality of water for ecological and recreational purposes. The production of algae biofuels is forecasted to exponentially grow in the coming years, but waste residual algal biomass represents a challenge to biofuel producers. This work explores possible avenues for the utilization of BGAs as an effective reinforcement of natural fiber composites. Natural fiber composites (NFCs) are of great importance for the automotive industry in applications such as interior door panels, headliners, and dashboards. Some advantages of NFCs are their light weight and biodegradability, and reduced emissions and contamination during processing. Currently established natural fibers include sisal, jute, and flax; however some drawbacks such as quality, availability, and price, have created interest in alternative fibers such as pineapple leaf (PALF), coir, banana, and others. Little investigation has been conducted on the extraction of fibers from algal plants such as blue – green algae. Lyngbya algae is a filamentous type of algae which has been sourced and chemically treated to extract fibers by exposing the content of higher crystalline cellulose present in these type of algae. Morphological and mechanical characterization of the single fibers was conducted and fiber properties were found to be density 1.07 g/cm3, tensile strength 215 MPa, tensile modulus of 24 GPa, which are comparable to sisal and jute fiber properties. Processing techniques conventionally applied in synthetic fiber composites (SFCs) need modification to be applied to NFCs. Parameters such as fiber content, fiber form, temperature, and compaction forces have to be considered when processing NFCs. Compression molding has been found to be an acceptable technique to process algae fiber / epoxy composite at higher volume fractions (i.e. > 40 %). In addition, algae fiber / grafted polypropylene composites where processed by extrusion - compression molding. Theoretical modulus corrected by porosity factor was defined. Degradation kinetics is also topic of interest in NFC’s in the automotive industry. Modeling of the solid state kinetics by the Avrami-Erofe’ev model was conducted on algae fiber / grafted polypropylene specimens subjected to accelerated UV light degradation, for an equivalent time of 3 years of aging. The main findings after UV weatherization include activation energy of 28 kJ/mol and kinetic factor of 13. The degradation products of cellulose and polypropylene reported previously were compared to these studies by infrared spectroscopy. The potential of utilized algae blooms as fibers for NFCs has been explored. BGAs growth is a direct result of the population growth and urbanization therefore the future of supply is guaranteed.

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