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PREVENTION OF ENVIRONMENTALLY INDUCED DEGRADATION IN CARBON/EPOXY COMPOSITE MATERIAL VIA IMPLEMENTATION OF A POLYMER BASED COATING SYSTEM

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Date Issued:
2008
Abstract/Description:
As the use of fiber reinforced plastics increases in such industries as aerospace, wind energy, and sporting goods, factors effecting long-term durability, such as environmental exposure, are of increasing interest. The primary objectives of this study were to examine the effects of extensive environmental exposure (specifically UV radiation and moisture) on carbon/epoxy composite laminate structures and to determine the relative effectiveness of polymer-based coatings at mitigating degradation incurred due to such exposure. Carbon/epoxy composite specimens, both coated and uncoated, were subjected to accelerated weathering in which prolonged outdoor exposure was simulated by controlling the radiation wavelength (in the UV region), temperature, and humidity. Mechanical test data obtained for the uncoated specimens indicated a reduction in strength of approximately 6% after an environmental exposure duration of 750 hours. Test data revealed that no further degradation occurred with increased exposure duration. This reduction resulted from the erosion of the epoxy matrix in additional to the formation of matrix microcracks. The protective coatings evaluated were all epoxy based and included two different surfacing films applied during initial cure of the carbon/epoxy composite laminate and a chromate containing epoxy based paint primer applied after the cure was complete. Although the chromate primer performed well initially, degradation of the underlying substrate was detected with extended exposure durations. In contrast, the surfacing films provided superior protection against environmentally induced degradation. Although similar degradation attributes were identified in the surfacing film as observed in the uncoated composite, it is likely that this degradation was either confined within the surfacing film layer or only penetrated the very near surface of the carbon/epoxy substrate, as it did not result in a substantial reduction in mechanical strength.
Title: PREVENTION OF ENVIRONMENTALLY INDUCED DEGRADATION IN CARBON/EPOXY COMPOSITE MATERIAL VIA IMPLEMENTATION OF A POLYMER BASED COATING SYSTEM.
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Name(s): Tipton, Bradford, Author
Sohn, Yongho, Committee Chair
University of Central Florida, Degree Grantor
Type of Resource: text
Date Issued: 2008
Publisher: University of Central Florida
Language(s): English
Abstract/Description: As the use of fiber reinforced plastics increases in such industries as aerospace, wind energy, and sporting goods, factors effecting long-term durability, such as environmental exposure, are of increasing interest. The primary objectives of this study were to examine the effects of extensive environmental exposure (specifically UV radiation and moisture) on carbon/epoxy composite laminate structures and to determine the relative effectiveness of polymer-based coatings at mitigating degradation incurred due to such exposure. Carbon/epoxy composite specimens, both coated and uncoated, were subjected to accelerated weathering in which prolonged outdoor exposure was simulated by controlling the radiation wavelength (in the UV region), temperature, and humidity. Mechanical test data obtained for the uncoated specimens indicated a reduction in strength of approximately 6% after an environmental exposure duration of 750 hours. Test data revealed that no further degradation occurred with increased exposure duration. This reduction resulted from the erosion of the epoxy matrix in additional to the formation of matrix microcracks. The protective coatings evaluated were all epoxy based and included two different surfacing films applied during initial cure of the carbon/epoxy composite laminate and a chromate containing epoxy based paint primer applied after the cure was complete. Although the chromate primer performed well initially, degradation of the underlying substrate was detected with extended exposure durations. In contrast, the surfacing films provided superior protection against environmentally induced degradation. Although similar degradation attributes were identified in the surfacing film as observed in the uncoated composite, it is likely that this degradation was either confined within the surfacing film layer or only penetrated the very near surface of the carbon/epoxy substrate, as it did not result in a substantial reduction in mechanical strength.
Identifier: CFE0002406 (IID), ucf:47731 (fedora)
Note(s): 2008-12-01
M.S.
Engineering and Computer Science, Department of Mechanical Materials and Aerospace Engineering
Masters
This record was generated from author submitted information.
Subject(s): Carbon
epoxy
composite
UV
degradation
Persistent Link to This Record: http://purl.flvc.org/ucf/fd/CFE0002406
Restrictions on Access: public
Host Institution: UCF

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