Blast furnace slags as functional fillers on rheological, thermal, and mechanical behavior of thermoplastics

Blast furnace slags (BFS) is a secondary byproduct of iron industry, which has a combination of acidic and basic oxides and show a complex, multiphase structure. If appropriately tailored, BFS could be an effective functional filler, improving the property profile of thermoplastics such as polypropylene (PP) and polystyrene (PS). As a raw material, the proposed filler may introduce both economic and ecological advantages, as it is considered an inexpensive secondary product rather than a natural resource. The current study aims at investigating the effect of incorporating BFS as a micro-sized filler on the rheological, thermal, and mechanical behavior of PP and PS. BFS types in this study are air-cooled, crystalline, and amorphous, grounded types. Both types are ground into 71, 40, and 20 mu m batches and introduced in 10, 20, and 30 weight fractions via melt kneading. Mixtures are then formed into 4-mm and 2-mm thick plates via compression molding. Slight increase in rheological factors is observed with increasing filler loading. BFS hinders the crystallization of PP, resulting in slight increase of crystallization temperatures (T-c) and lowering of crystallization enthalpy (Delta H-c). No significant effect of filler on transition temperatures (T-g) is reported. Mechanically, BFS increases the tensile modulus of PP, but decreases its strength. For PS formulations, a modest toughening effect is observed by slag filler. (c) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43021.