Recent studies have shown that the incorporation of carbon nanotubes (CNT) in to carbon fiber composite parts significantly increase mechanical as well as thermal properties. Polymer
nanocomposites are polymer matrix composites that consist of reinforcements that have at least one dimension in the nanometer range. The polymer nanocomposite fabricated parts achieve
greater mechanical, thermal, electrical and other properties with a low CNT reinforcement volume fraction. Nanocomposites achieve improved properties because of the higher properties of
the nano-reinforcement and the high ratio of surface area to volume (aspect ratio) that provides greater interfacial interaction with the matrix. The fabrication of nanocomposites is
primarily by the liquid composite molding (LCM) processes that can be complex process with many challenges. These challenges include poor CNT dispersion, poor bonding between resin and
CNT, and blocking or filtration during the infusion process. The Resin Infusion between Double Flexible Tooling (RIDFT) however offers some advantages over the other LCM processes. The
preservation and extended use of the mold can result in higher productivity and profit. In addition, a significantly lower pressure that translates to lower equipment cost, will be
required to drive the high viscosity CNT-rich resin through the two-dimensional flow in a RIDFT process compared to the three-dimensional flow in the RTM. The RIDFT process may also be
used for out-of-autoclave fabrication of composites from pre-pregs. The RIDFT process however has a number of fabrication issues militating against its wide use. These include long
production cycle time due to the bottle neck associated with the setup time for cleaning the silicone sheet and the high cost of replacement of the flexible silicone membranes of the RIDFT
machine. The introduction of Stretchlon Bagging 800 film may reduce the time that is expended on cleaning the silicone sheets and at the same time reduce the damage that is made to the
silicone membranes. The goal of this thesis is to evaluate the performance of the Stretchlon bagging technique with the RIDFT process with the aim of significantly reducing the production
cycle time as well as the production cost of composites and nanocomposites without adversely affecting the mechanical properties of the fabricated parts. The results show that the use
of the Stretchlon bagging film resulted in reduction in the production cycle time of GFRP and CNT_GFRP parts of 32% and 42% respectively. It also resulted in production set-up (mold
preparation) cost reduction for GFRP and CNT-GFRP parts of 49% and 72% respectively. It resulted in increased durability and service life of the silicon mold thereby helping to reduce
the production cost. In addition, the use of the Stretchlon bagging film did not adversely affect the mechanical properties of the fabricated GFRP and CNT-GFRP parts. It resulted in an
increase of 31.94% and 12.62% in the mean UTS of the GFRP and CNT-GFRP respectively. The Stretchlon film however resulted in reduction in the flexural properties of the fabricated GFRP
and CNT-GFRP parts by 30.12% and 18.69% respectively. The use of the Stretchlon bagging film enhanced the in-plane properties of the fabricated parts by helping to increase the fiber
volume fraction. The lower resin contents in the parts fabricated with the Stretchlon film may have had an adverse effect in the interlaminar properties resulting in lower flexural
strengths. Furthermore, thermal analysis confirmed that there was no change in the glass transition (Tg) temperature of the fabricated parts. Parts fabricated with the Stretchlon bagging
film also exhibited better surface finish than those fabricated without using the Stretchlon bagging film. In addition, a new design for the RIDFT with higher pressure capability for
better quality parts (higher fiber volume fraction and lower void content) fabrication has been made. The new design also incorporates infrared lamp system for expedited curing of the
composite parts in order to reduce the cycle time. Further work is however needed to optimize the RIDFT-Stretchlon film fabrication process for nanocomposites. A more detailed microscopy
study needs to be performed to gain better insights into the reasons for the enhanced fiber volume content and in-plane properties achieved with the use of the Stretchlon film. In
addition, the study needs to be repeated with functionalized CNTs to study the effects of functionalized CNTs on the fabricated parts, the silicon mold and the Stretchlon film. There is
also the need to fabricate the new RIDFT design and optimize its performance for nanocomposite fabrication. / A Thesis submitted to the Department of Industrial & Manufacturing Engineering in partial fulfillment of the Master of Science. / Fall Semester 2015. / October 6, 2015. / Includes bibliographical references. / Okenwa Okoli, Professor Directing Thesis; Zhiyong (Richard) Liang, Committee Member; Tarik Dickens, Committee Member; David Olawale, Committee
Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_291263 |
| Contributors | Bhakta, Divyesh (authoraut), Okoli, Okenwa (professor directing thesis), Liang, Zhiyong (Richard) (committee member), Dickens, Tarik J. (committee member), Olawale, David O. (committee member), Florida State University (degree granting institution), FAMU-FSU College of Engineering (degree granting college), Department of Industrial and Manufacturing Engineering (degree granting department) |
| Publisher | Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text |
| Format | 1 online resource (76 pages), computer, application/pdf |
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