Use of Polishing Alumina as Flame Retardant in Orthophthalic Polyester Resin Matrix Composites

Abstract

The field of Civil Engineering Materials has found a use for a range of industrial waste products as substitutes, that are as effective as standard construction materials but which have the bonus of providing an ecologically sound alternative for materials that would otherwise become an environmental concern. The use of waste materials in polymer composites is a prime example of this practice. These composites display excellent mechanical properties but must be adapted to the combustibility properties. This study aimed to produce polymer concrete composites using waste alumina from metallurgic industrial processing. The composites have an ortophtalic polyester resin as a binder, river sand as aggregates and fly ash as filler. Two kinds of flame retardants were used: a residue, polishing alumina and the other virgin, commercial alumina which were used in four different percentages 15, 30, 45 and 60% in mass in relation to the resin. The samples were subjected to testing of flexural strength, temperature changes of 125, 225 and 325°C and porosity by mercury addition. The results received statistical treatment in order to evaluate the variable significance in relation to the studied properties. In this study the composites displayed flexural strength values around 30 MPa. The statistical analysis showed that the factors temperature changes, addition percentage and the interaction among these factors posed great influence on the studied compositions in relation to the heat resistance testing. In general terms, it can be said that the flame retardant waste, polishing alumina, is an efficient alternative to substitute the trihydrated commercial alumina in the polymer concrete composites with the other components proposed in this study.Key words: polishing alumina, recycling, polymer concrete, fly ash, combustibility