International Journal of Materials Engineering 2017, 7(6): 117-120 DOI: 10.5923/j.ijme.20170706.03 Analysis of Impact and Tensile Properties of Recycled Polypropylene Luiz Gustavo Barbosa * , Matheus Piaia, Gustavo Henrique Ceni Instituto Federal de Educação, Ciência e Tecnologia do Rio Grande do Sul – Campus Erechim, Erechim, Brazil Abstract The present research proposed to evaluate the tensile and impact properties of polypropylene originating from secondary recycling. The polymer chosen for the studies was polypropylene (PP) for its high application and availability. The tensile and impact tests were performed on virgin polypropylene, recycled polypropylene and mixtures of different proportions of both. Thus, for each sample, values of yield strength, elastic modulus, yield elongation and impact strength were obtained. The results of the averages obtained demonstrated that the tensile properties of virgin PP and recycled PP are similar, as well as those of the mixtures between both. Regarding the impact properties, it was observed that the energy absorbed by the recycled polymers is lower than that of the virgin polypropylene. Consequently, recycled polypropylene can replace virgin polypropylene in applications which are subjected to tension stress but not in those subjected it to impact. Keywords Polymers, Recycled Polypropylene, Tensile Properties, Impact Properties 1. Introduction Nowadays, all action related to the disposal of any material should be considered based on the strategy of the four R's: reduction (combating waste generation), reuse (of materials), recycle (use of discarded material in new products) and recover (energy extraction from discarded waste) [1, 2]. Plastic recycling programs have been boosted in the last decade due to growing concern about the environment, the lack of space for the construction of landfills, and even the pressure not only from legislation but also from the society about this disposal [3], since these materials take thousands of years to spontaneously degradate [4]. Beyond keeping the planet clean, recycling offers the potential to reduce fossil fuel consumption, since recycled plastic can compete directly with virgin plastic produced from refined fossil fuels, and the electrical energy needed to process recycled plastics is notably lower than for virgin material [5]. The main application of PP is in the food sector, representing 32% in products such as: packaging, lids, tupperwares, jars, bottles and gallons. In the consumer goods sector PP represents 17% of the market and is applied in packaging and boxes. In civil construction represents 3% of the market and, among others, it replaces asbestos in fibre cement tiles and water tanks, and it serves as a partial substitute of concrete in slabs with the use of BubbleDeck. * Corresponding author: luiz.barbosa@erechim.ifrs.edu.br (Luiz Gustavo Barbosa) Published online at http://journal.sapub.org/ijme Copyright © 2017 Scientific & Academic Publishing. All Rights Reserved Also, it is a raw material for the Pack Less, a plastic pallet. In the automotive sector it represents 9% of the market, being used in dashboards, door panels, bumpers, grilles, for example. [6]. Therefore, all this material when discarded can be recycled and originate new products. In Brazil, about 8.2% of the post-consumer polypropylene is recycled, which is processed into pellets through mechanical recycling and subsequently produces packaging, automobile components and other recycled products [7]. However, few studies have been to verify if the properties of the recycled polymers are similar to those of the virgin polymers. Fernandes and Domingues [8] compared the mechanical properties between virgin high impact polypropylene, injected, and the recycled one. With the purpose of applying the recycled polypropylene in the automotive industry, two mixtures were tested, one composed of 30% recycled PP and 70% virgin PP, and other one of 50% recycled PP and 50% virgin PP. They observed that the mechanical properties under tensile strength (ultimate tensile strength, yield strength and strain) did not vary, however, the impact resistance only for samples with up to 30% recycled PP was acceptable for automotive use. Samples above this percentage (50% and 100% recycled PP) showed a large reduction in impact strength. For comparative purposes the virgin PP had an impact resistance of 78,7 kJ / m² and the PP 100% recycled 19,7 kJ / m². Likewise, Raj et al [9] tested the tensile and impact mixtures of injected virgin and recycled polypropylene in different proportions and have not obtained significant variation in yield strength and elastic modulus. However for the impact resistance, as the percentage of recycled PP