Electronic Theses and Dissertations

Date of Award

2017

Document Type

Dissertation

Degree Name

M.S. in Engineering Science

Department

Mechanical Engineering

First Advisor

Ellen Lackey

Second Advisor

Prabhakar R. Mantena

Third Advisor

Hunain Alkhateb

Relational Format

dissertation/thesis

Abstract

This paper evaluates the response of experimental mold releases for a pultruded glass fiber reinforced polymer (gfrp). The initial assessment criteria include comparisons between pull forces and surface appearances for each mold release. Composites fabricated using experimental mold releases that exhibited acceptable properties for both were used for further mechanical characterization that included environmental aging for two different exposure lengths (500 hours and 1000 hours) in five different environments: UV, bleach, hydrochloric acid, distilled water at 125â°f, and room temperature salt water. Three-point flexural bending and short beam strength tests were undertaken to determine the effects these environments would have on the composite when compared with the strengths of an unaged sample. This principally will determine how well the matrix is able to distribute the load to the stronger fibers after undergoing environmental degradation. This study found that the bleach environment had the most damaging effects for both flexural and short beam strengths. Notable increases in both flexural and short beam strength were seen for UV, elevated temperature distilled water, and salt water exposures which indicates the poor bonding between the fiber and the matrix material and possible secondary curing of the composite. Additional dma and tga tests were completed on unaged specimens to determine the glass transition temperature and onset temperature values. The mechanical properties for the experimental and commercially available mold releases did not vary significantly and suggests a closeness in chemical composition.

Concentration/Emphasis

Emphasis: Mechanical Engineering

Included in

Engineering Commons

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