Fabrication and Analysis of Three-Dimensionally Reinforced Cellular Matrix Composites Foamed by Chemical Blowing Agent

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Title: Fabrication and Analysis of Three-Dimensionally Reinforced Cellular Matrix Composites Foamed by Chemical Blowing Agent
Author: Mohamed, Tarek Said
Advisors: Dr. Yiping Qiu, Committee Chair
Abstract: The objective of this research was to investigate the process of three-dimensional textile reinforced cellular matrix composites (3DCMC) and propose it to the industry. The scope of this research involved shortening the production cycle of 3DCMC foamed by a physical blowing agent, investigating the potential of using a chemical blowing agent to foam the structure instead of a physical blowing agent, and finally test the mechanical properties of the structures made by the optimum condition. Using the high pressure foaming apparatus, experiments were conducted by manipulating production parameters, to investigate the possibility of shortening production time. The production time was successfully reduced from twenty hours to six hours. At this point, two problems remained unsolved, the high cost of the equipment and the danger associated with using the equipment. This led to the search for applying a chemical blowing agent to fabricate 3DCMC. A comprehensive review of the literature was done to study the idea behind foaming by chemical blowing agents. Several experiments were conducted by using Thermal Gravitational Analysis (TGA) to study the decomposition behavior of chosen blowing agents. Sodium bicarbonate was chosen as a blowing agent. Composite samples were fabricated using six different concentrations of sodium bicarbonate. An optimum concentration of 5% was chosen to be applied on composite samples and the mechanical properties of those composite samples were tested and compared to 3DRMC. A four point bending test, tensile test, and drop weight impact test were conducted on each sample to evaluate the performance of the fabricated composites. The flexural strength of both 3DCMC and 3DRMC was almost the same, while the tangent modulus of 3DCMC was higher than 3DRMC. There was no significant difference in tensile strength between 3DCMC and 3DRMC. 3DCMC had higher impact energy absorption than 3DRMC at the low impact velocity of 3 m/s, which makes 3DCMC attractive to applications that requires high impact resistance and low density.
Date: 2002-05-28
Degree: MS
Discipline: Textile Engineering
URI: http://www.lib.ncsu.edu/resolver/1840.16/988

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