Recent developments in inorganic composites in rotational molding

Rotational molding allows for obtaining hollow parts with good aesthetics and properties, having as main drawbacks the lack of pressure and the long cycle times, which limit the range of materials. Different fillers have been introduced in rotomolding to obtain composite materials assessed. This review has shown that glass fibers or particles are the most common material among them, although carbon fibers or clays have also been studied. In general terms, 10% loadings provide an increase in mechanical properties; higher loadings usually lead to a decrease in processability or final properties. When the filler consists of a micro- or nano-material, such as clay or graphene, lower loadings are proposed, generally not exceeding 3%. The use of fillers of an inorganic nature to obtain composites has not been as explored as the incorporation of lignocellulosic materials and even less if referring to waste materials or side streams from industrial processes. So, there is a broad field for assessing the processing and properties of rotomolded composites containing inorganic waste materials, including the study of the relationship between the ratio of filler/reinforcement and the final properties and also their preprocessing (dry blending vs. melting compounding).