The improvement of flame retardancy of glass fiber reinforced polyester composite materials

THE IMPROVEMENT OF FLAME RETARDANCY OF GLASS FIBERREINFORCED POLYESTER COMPOSITE MATERIALS(M.Sc. Thesis)Miyaser DEM RELGAZI UNIVERSITYINSTITUTE OF SCIENCE AND TECHNOLOGYJanuary 2007ABSTRACTNatural and synthetic polymer materials are used in more areas.However fire hazards associate with the use of these polymericmaterials and cause the loss of life and property. The flammability ofpolymer materials is an important issue on their usage. The use offlame retardants to reduce combustibility and smoke production of thepolymer materials becomes an important part of the development andapplication of these materials. The flame retardants are used inelectrical and electronics components, construction and transportationindustries. On the other hand, the development of flame retardantmaterials in household applications is mainly required for the safety ofconsumers.In this study, glass fiber reinforced polyester composite (GRP)materials were produced with flame retardants materials and the effectof flame retardants on the composite materials was examined. For thisobjective, unsaturated polyester resin were used as matrix system,chopped E glass fiber was used as reinforcement system andmagnesium hydroxide, boric acid, zinc borate were used as flameretardants. Composite materials were produced by using moldingtechnique.In order to determine mechanical properties of the composite materialsthree point bending and tensile tests were conducted. Thermalproperties of composite materials were analyzed by using differentialscanning calorimeter (DSC) and thermogravimetric analysis (TGA). Thefracture surface of the composite materials were examined by usingscanning electron microscope (SEM) and the flame retardancy of thecomposite was measured with the Limitting Oxygen Index (LO ) testand smoke density test methods.As a result of Limitting Oxygen Index test boric acid showed a goodflame retardant effect on the GRP. When the boric acid content is usedas 15 wt%, the LOI value of the composite reached up to 25,3. It isobserved that the LOI values of the composites samples increasedwith increasing the boric acid contents. The increase in boric acidcontent from 15 to 30 wt%, the LOI values of composite are enhancedfrom 25,3 to 34,5 by 9.5 units. The results taken from the TGA and DSCthermograms supported these results. The mechanical properties of thecomposites decreased the addition of flame retardants. The tensile andflexural strength and the modulus values of the composite materials,increased with increasing the fiber content. When the glass fibercontent of the composite which include 15 wt% boric acid, increasefrom 5 to 20 wt%, the flexural strength of the composite increased from74,41 MPa to 141,89 MPa and the flexural modulus of the compositeincreased from 41,93 MPa to 74,09 MPa. The SEM micrographs takenfrom fracture surfaces were examined, the glass fiber polyestercomposites showed good wetting of fiber with resin.Science Code : 912.1.092Key Words : Polyester resin, glass fiber, flame retardant, boricacidPage Number : 160Adviser : Prof. Dr. H. Vecihi PAMUKDoç. Dr. Nursel D LS Z