The objectives of this study are to synthesize sub-micron sized zinc borate and to use them with other flame retardant additives in poly(ethylene terephthalate) (PET)
based composites.
The study can be divided into two parts. In the first part, it was aimed to synthesize sub-micron sized zinc borate (2ZnO.3B2O3.3.5H2O) with the reaction of zinc oxide and boric acid. For this purpose, low molecular weight additives or surfactants were used in the syntheses to prevent the agglomeration and to decrease particle size. Effect of type of surfactant and its concentration / effect of using nano-sized zinc oxide as reactant on the synthesis, properties and morphology of 2ZnO.3B2O3.3.5H2O were investigated. Synthesized zinc borates were characterized by X-Ray diffraction (XRD), Scanning Electron Microscope (SEM) and Thermogravimetric Analysis (TGA). The results were compared with a commercial zinc borate, Firebrake (FB).
Characterization results showed that at least in one dimension sub-micron size was obtained and synthesized zinc borates did not lose their hydration water until the process temperature of the composites.
In the second part of the study, PET based composites, which mainly included synthesized sub-micron sized zinc borates were prepared by using a co-rotating twin screw extruder and injection molding machine. Synergist materials such as boron phosphate (BP) and triphenyl phosphate (TPP) were also used in the composite preparation. The composites were characterized in terms of flammability and mechanical properties. Flammability of composites was determined by using a Limiting Oxygen Index (LOI) test. Mechanical properties such as tensile strength, elastic modulus, elongation at break and impact strength were also studied.
According to LOI and impact tests, the composites containing 3 wt. % BP and 2 wt. % zinc borate which was modified with poly(styrene-co-maleic anhydride), 2PSMA05/3BP and 2PSMA1/3BP have higher LOI and impact values when compared to neat PET.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12612701/index.pdf |
| Date | 01 December 2010 |
| Creators | Baltaci, Berk |
| 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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