Thermal and water absorption properties of bio-synthetic hybrid reinforced polypropylene composites I.O. Oladele a,⇑ , J.O. Ajileye a , S.R. Oke a,b , O.O. Daramola a , O.A. Adewumi a a Department of Metallurgical & Materials Engineering, Federal University of Technology Akure, Ondo State, Nigeria b Center for Nanomechanics and Tribocorrosion, School of Mining, Metallurgy and Chemical Engineering, University of Johannesburg, Johannesburg, South Africa article info Article history: Received 19 April 2020 Received in revised form 19 May 2020 Accepted 22 May 2020 Available online xxxx Keywords: Animal waste Environmental protection Polymer composites Water absorption Thermal properties abstract In this study, cattle bone was processed and utilized as complementing reinforcement for the develop- ment of cattle bone/calcium carbonate reinforced polypropylene composites. The processed cattle bone was pulverized, calcined and sieved to obtain 53, 63 and 75 lm sizes that were used for the development of the hybrid composites. The composite consists of hybrid reinforcements amounting to 3, 6, 9, 12, and 15 wt%. Compression moulding machine was used for the production of the composites. The fractured surfaces were examined using scanning electron microscopy. The effect of different reinforcement con- tent and particle sizes on thermal and water absorption capacity of the hybrid composites was investi- gated. The water absorption test revealed that the control sample absorbed less water due to hydrophobic nature of pure polypropylene polymer. The 53 lm hybrid reinforced composite was found to be less porous with good resistance to water intake compared to other particle sizes and hybrid rein- forcements. Similarly, the thermal conductivity of the composite was found to be higher than their cor- responding particle sizes; culminating to reduction in the thermal resistance. The Thermo-gravimetric analysis/Derivative Thermo-gravimetric (TGA/DTG) analysis revealed that 15 wt%, 75 lm hybrid rein- forced composite samples were more thermally stable in comparison with other particle sizes and the control sample. The SEM images revealed good interfacial adhesion in the morphology of 53 lm hybrid reinforced composite sample compared to other particle sizes. Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Sympo- sium on Nanostructured, Nanoengineered and Advanced Materials. 1. Introduction Amongst polymer types, polypropylene (PP) has found exten- sive application due to its light weight. The thermoplastic polymer is the most globally utilized plastic due to its processing simplicity, good corrosion resistance, high chemical stability, low processing cost, and good electrical insulation property [1]. Nevertheless, the use of PP is limited due to low mechanical strength at elevated temperatures, and poor resistance to thermal shock [2]. Attempts to resolve these limitations have attracted the dispersion of sec- ondary phases such as fibres, whiskers, particulates and platelets into PP matrix. The second-phase particles are attractive due to their unusual properties such as high melting point and hardness. The use of PP matrix composite has found wide application due to their high specific strength, high modulus, good fracture and fati- gue as well as corrosion resistance [3,4]. Particulate fillers have been reported to play an important role for the improvement of performance of PP. Various types of synthetic fillers such as alu- mina (Al 2 O 3 ), silicon carbide (SiC), silica (SiO 2 ), titania (TiO 2 ), cal- cium carbonate (CaCO 3 ) have being used as reinforcements in PP based composites [3,5]. Due to high cost of this synthetic fillers, researchers have shifted attention towards the use of agro and animal based waste materials such as natural fibres and ashes processed from animal waste. Fibres like oil palm empty fruit bunch, wood fibre, as well as several fillers such as rice husk have been used as reinforce- ments in different thermoplastic and thermosetting plastic resins [6,7]. The benefits of the agro and animal wastes includes low cost of processing, availability in large quantities, low density, good thermal insulation properties and acceptable specific strength, ease of recycling, and creation of an eco-friendlier environment [8,9]. Despite the advantages of plant and animal based natural fil- lers, they suffer limitations of low mechanical properties, durabil- https://doi.org/10.1016/j.matpr.2020.05.580 2214-7853/Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Symposium on Nanostructured, Nanoengineered and Advanced Materials. ⇑ Corresponding author. E-mail address: iooladele@futa.edu.ng (I.O. Oladele). Materials Today: Proceedings xxx (xxxx) xxx Contents lists available at ScienceDirect Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr Please cite this article as: I. O. Oladele, J. O. Ajileye, S. R. Oke et al., Thermal and water absorption properties of bio-synthetic hybrid reinforced polypropy- lene composites, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.05.580