Transforming Marble Waste into High-Performance, Water-Resistant, and Thermally Insulative Hybrid Polymer Composites for Environmental Sustainability

Abstract

Marble waste is generated by marble processing units in large quantities and dumped onto open land areas. This creates environmental problems by contaminating soil, water, and air with adverse health effects on all the living organisms. In this work, we report on understanding the use of calcium-rich marble waste particulates (MPs) as economic reinforcement in recyclable polypropylene (PP) to prepare sustainable composites via the injection molding method. The process was optimized to make lightweight and high-strength thermally insulated sustainable composites. Physicochemical, mineralogical, and microscopic characterization of the processed marble waste particulates were carried out in detail. Composite samples were subsequently prepared via the injection molding technique with different filler concentrations (0%, 20%, 40%, 60%, and 80%) on weight fraction at temperatures of 160, 180, and 200 °C. Detailed analysis of the mechanical and thermal properties of the fabricated composites was carried out. The composites showed a density varying from 0.96 to 1.27 g/cm3, while the water absorption capacity was very low at 0.006%–0.034%. Marble waste particulates were found to considerably increase the tensile, as well as flexural, strength of the sustainable composites, which varied from 22.06 to 30.65 MPa and 43.27 to 58.11MPa, respectively, for the molding temperature of 160 °C. The impact strength of the sustainable composites was found to surge with the increment in filler concentration, and the maximum impact strength was recorded as 1.66 kJ/m2with 20% particulates reinforcement at a molding temperature of 200 °C. The thermal conductivity of the particulates-reinforced sustainable composites was as low as 0.23 Wm−1K−1 at a 200 °C molding temperature with 20% and 40% filler concentrations, and the maximum thermal conductivity was 0.48 Wm−1K−1 at a 160 °C molding temperature with 80% filler concentration. Our findings have shown a technically feasible option for manufacturing a lightweight composite with better mechanical and thermal properties using marble waste particulates as a potential civil infrastructural material.

Eco‐friendly polymer composites: A review of suitable methods for waste management

“…The residue contains aluminum oxide and salts, and the disposal in landfills can release noxious gases in the environment. Marble industry also generates marble waste powder or sludge, around 200 million tons per year worldwide, which has been recently studied as fillers into PP [ 39 ] and epoxy resin composites. [ 40 ] The authors reported a residue rich in dolomite (CaMg(CO 3 ) 2 ) and calcite (CaCO 3 ) or calcium oxides with potential to improve mechanical and thermal properties of materials in order to replace common mineral fillers.…”

Are Natural-Based Composites Sustainable?

“…Cotana states that residual lignin from bioethanol production using Arundo donax as raw material is suitable to be used as filler in composites, as composition and thermal degradation profiles look favorable [ 56 ]. Lignin has been successfully used for the reinforcement of several matrices (PP, PE, PLA or PVA among others) [ 34 , 57 , 58 ], with applications in energy storage devices, adhesives or biosensing [ 32 ]. Moreover, Vaidya [ 59 ] has used lignin from a saccharification process in a biorefinery as a reinforcement of a PHB matrix, obtaining a composite suitable to be 3D-printed, reducing the warpage observed for neat PHB printed parts.…”

“…Waste materials can also be incorporated into polymer matrices to obtain composites with interesting properties. For example, Bakshi and collaborators [ 58 ] have obtained a lightweight material with a low thermal conductivity, which is suitable to be used in civil applications, by adding marble waste particulates into a polypropylene matrix in up to 80% weight. The incorporation of marble particles into the polypropylene matrix led to the increase of tensile and flexural strength.…”

Effect of Filler Particle Size on the Recyclability of Fly Ash Filled HDPE Composites

“…Taking the concept of reinforcing construction materials with fly ash, many researchers have shown that there exists excellent compatibility between fly ash and thermoplastic polymers and developed composites of this kind [ 16 , 17 , 18 , 19 , 20 ]. Other research works have also demonstrated the benefit of using treated fly ash in a wide range of polymer matrices.…”