In this thesis there were two main purposes, the first one being to investigate effects
of zinc borate (ZB) on the flammability behavior of ABS when used with and
without a traditional brominated flame retardant (BFR) / antimony trioxide (AO)
system. The second purpose was to investigate contribution of nanoclays (NC) to the
flame retardancy performance of the same traditional BFR compound with various
combinations of AO and ZB again in ABS matrix.
For these purposes, materials were melt compounded by using a laboratory scale
twin-screw extruder, while specimens were produced by injection or compression
molding. Flame retardancy of the specimens were investigated by Mass Loss Cone
Calorimeter (MLC), Limiting Oxygen Index (LOI) measurements and UL-94 vertical
burning tests. Other characterization techniques required in this thesis were / X-ray
diffraction analysis, scanning and transmission electron microscopy,
thermogravimetric analysis and tensile tests.
Studies for the first purpose indicated that almost all flame retardancy parameters
were preserved when antimony trioxide were replaced with zinc borate as much as in
the ratio of 1:3. Residue analyses revealed that predominant flame retardancy
mechanism of traditional system was gas phase action, while zinc borate contributes
especially in the condensed phase action by forming thicker and stronger char layer.
Investigations for the second purpose basically concluded that use of nanoclays
improved all flame retardancy parameters significantly. Residue analyses pointed out
that nanoclays especially contribute to the formation of stronger and carbonaceoussilicate
char acting as a barrier to heat and flammable gases and retarding
volatilization via tortuous pathway.
As an additional third purpose in this thesis, usability of three boron compounds
(zinc borate ZB, boric acid BA, boron oxide BO) with two traditional flame
retardants (organic phosphinate OP and melamine cyanurate MC) in neat PET and
recycled PET were also examined leading to some promising results in MLC
parameters.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12613425/index.pdf |
| Date | 01 July 2011 |
| Creators | Ozkaraca, Ayse Cagil |
| Contributors | Kaynak, Cevdet |
| 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 METU campus |
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