Arabian Journal for Science and Engineering https://doi.org/10.1007/s13369-018-3073-x RESEARCH ARTICLE - MECHANICAL ENGINEERING Effect of Pistachio Shell Particle Content on the Mechanical Properties of Polymer Composite Mohamad Alsaadi 1 · Ahmet Erkli ˘ g 2 · Khamis Albu-khaleefah 2 Received: 2 May 2017 / Accepted: 31 December 2017 © King Fahd University of Petroleum & Minerals 2018 Abstract The effect of the content of microscale natural pistachio shell particles on the mechanical properties of polyester matrix composites was experimentally investigated. The pistachio shell particle contents were 0, 5, 10, 15, 20, and 25wt%. Tensile, flexural, and Charpy impact tests were carried out on molded composite specimens according to the ISO 179/92 standard. Good dispersion of pistachio shell particles in polymer matrix was observed using SEM micrographs. The highest tensile strength, flexural strength, and impact strength were obtained at a pistachio shell particle content of 10, 5, and 5wt%, respectively. Keywords Pistachio shell · Composite materials · Mechanical properties · Particle filled · Additives 1 Introduction So far, the utilization of solid wastes produced from the industrial and agricultural residues has been limited due to lack as a cost-effective filler in polymer composite fabri- cations. In addition natural materials are environmentally friendly, abundant, and renewable. Peanut shell, palm and coir, jute, rice husk, kenaf fiber, nutshells, olive stone, sug- arcane and bagasse have been usually used as toughened fillers in polymer matrices composites in order to improve the physical and mechanical properties as well as lowering production cost [1–10]. Gharbi et al. [9] prepared olive nuts flour (ONF) as a cost-effective filler from olive oil extraction waste to strengthen unsaturated polyester matrix composites. The ONF/polyester composite specimens were prepared with ONF contents of 10–60 wt%. The tensile, flexural, and impact properties were investigated. The results showed that the flexural strength and modulus were significantly improved. Monteiro et al. [10] tried to use the sugarcane bagasse waste as reinforcement to polymeric resins for fabrication B Mohamad Alsaadi phd.mohamadalsaadi@gmail.com Ahmet Erkli ˘ g erklig@gantep.edu.tr 1 Materials Engineering Department, University of Technology, Baghdad 10066, Iraq 2 Mechanical Engineering Department, Faculty of Engineering, Gaziantep University, 27310 Gaziantep, Turkey of low-cost composites. They reported that composites with homogeneous microstructures could be fabricated and their mechanical properties enable them to have practical appli- cations similar to the ones normally associated with wooden agglomerates. Among the agricultural residues, pistachio shells (PS) are produced in large quantities in Turkey. Tons of pistachio shells are either burned after harvest or left in the field every year. As presented in Table 1, according to statistics of Food and Agricultural Organization of United Nations, Turkey is one of the largest pistachio producers in the world [11]. Due to specific weather conditions and land requirements, culti- vation trees of pistachio are widespread in the southern east region of Turkey, such as Gaziantep, ¸ Sanlıurfa, and Siirt [11– 13]. However, particular attention has not been paid to using agricultural residue as raw materials in polymer composites industries. Therefore, the usage of pistachio shells as filler in polymer composites is very important from an econom- ical and environmental view point. Uses of pistachio shell include medium for orchids, fire starter, animal feed, addi- tive for wood items, etc. [14]. Moreover, Pistachio shell particles have high strength and modulus properties. Fabrication of polymer composites with this filler is suitable for many engineering applications. Gürü [15] investigated the thermal properties and burning characteristics of pistachio shell particle-filled polymer com- posite particleboard using fly ash as a flame retarder. It was concluded that the pistachio shell particles can be securely and economically used in construction applications due to 123