Glass fiber reinforced poly(ethylene terephthalate), GF/PET has excellent potential for future structural applications of composite materials. PET as a semi-crystalline thermoplastic polyester has high wear resistance, low coefficient of friction, high flexural modulus and superior dimensional stability make it a versatile material for designing mechanical and electromechanical parts.
Glass fibers are currently used as strength giving material in structural composites because of their high strength and high performance capabilities. In order to obtain high interfacial adhesion between glass fiber and polymer, glass fibers are treated with silane coupling agents.
The objective of this study is to produce GF/PET composites with varying glass fiber concentration at constant process parameters in a twin screw extruder. Also, by keeping GF content constant, it is aimed to observe the effects of process parameters such as screw speed and feed rate on structural properties of the composites. Another objective of the study is to investigate the influence of different coupling agents on the morphological, thermal and mechanical properties and on fiber length distributions of the composites.
Tensile strength and tensile moduli of the GF/PET composites increased with increasing GF loading. There was not a direct relation between strain at break values and GF content. The interfacial adhesion between glass fiber received from the manufacturer and PET was good as observed in the SEM photograps. Degree of crystallinity values increased with the addition of GF. Increasing the screw speed did not affect the tensile strength of the material significantly. While increasing the feed rate the tensile strength decreased. The coupling agent, 3-APME which has less effective functional groups than the others showed poor adhesion between glass fiber and PET. Therefore, lower tensile properties were obtained for the composite with 3-APME than those of other silane coupling agents treated composites. Number average fiber length values were reduced to approximately 300& / #61549 / m for almost all composites prepared in this study.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12605216/index.pdf |
| Date | 01 July 2004 |
| Creators | Altan, Cansu |
| Contributors | Bayram, Goknur |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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