Research Information System
Thesis Type: Postgraduate
Institution Of The Thesis: Gazi University, Fen Bilimleri Enstitüsü, Turkey
Approval Date: 2024
Thesis Language: Turkish
Student: Kerem USLU
Supervisor: Fatih Akkurt
Open Archive Collection: AVESIS Open Access Collection
Abstract:
Today, about 90% of the zinc borate produced is used as a flame retardant and smoke suppressant in polymer matrix composites, as well as being used as a direct fertilizer as a micronutrient element. Today, zinc borate is produced industrially in micron size by the reaction of boric acid and zinc oxide in certain proportions. However, in order for the zinc borate compound to be used in polymer matrix composites, it must be submicron in size. Therefore, within the scope of this thesis, it is aimed to investigate the synthesis, characterization and use of zinc borate in submicron size as flame retardant in epoxy resin composites by using borax decahydrate as a boron source. The study can be evaluated in two sections. The first part is the creation of optimal reaction conditions for the synthesis of zinc borate by the reaction of zinc oxide and borax decahydrate and the production of zinc borate in submicron size (2ZnO.3B2O3.3H2O) include production works. For this purpose, optimum conditions were determined by examining different reaction parameters to produce zinc borate from borax decahydrate. Then, by using sodium dodecyl sulfate as an additive and a commercial modified agent (TMA), grain size reduction studies were carried out at a high mixing speed, and the optimal additive and quantity were determined and zinc borate was produced in sub-micron size. The zinc borate compounds produced were characterized by X-Ray diffraction (XRD), grain size measurement (Mastersizer) and thermogravimetric analysis (TGA) methods. The analysis results show that the zinc borate compounds produced have the same structure as the commercial product and at least 60% of the grain size is produced in sub-micron size. In the second stage of the study, composites were formed by adding the zinc borate compound produced as a flame retardant to epoxy resin in different percentages. Flame retardant and mechanical properties of the prepared composites were determined by limiting oxygen index (LOI), vertical combustion test (UL-94), tensile test and three-point bending tests. When the zinc borate compound synthesized within the scope of the study was added to the epoxy resin at a rate of 5%, the LOI value of the pure epoxy resin composite increased from 19% to 24.5%. It has been found that although zinc borate doping causes brittleness in composites, it does not change the elastic module of composites.
Key Words : Borax, flame retardant, zinc oxide, zinc borate, grain size