Estudo sobre a viabilidade de substituição de materiais virgens por reciclados em cabides injetados de polipropileno e poliestireno

Abstract

The world economy was and still is supported by a linear model of production, where the entire production chain follows a logic of extracting, transforming, producing and discarding. However, this model will not be sustainable for a long time, so new efforts are being applied in the circular economy, where “discard” in the linear economy is replaced by “recycle”. One of the great challenges of this new economy is, without a doubt, the recycling of plastic, especially polypropylene and polystyrene thermoplastics, which are produced and consumed on a large scale, due to their low cost and great utility. Some of the benefits of recycling are: preservation of natural resources, reduction of environmental pollution, and reduction in the cost of producing items that does not need to work with virgin materials. Therefore, this work sought to analyze the feasibility of replacing virgin materials with recycled ones in injected polypropylene and polystyrene products. The polypropylene materials were prepared and injected in the following mass proportions: 100%V, 50%V/ 50%R1, 100%R1, 75%R1/ 25%R2, 50%R1/ 50%R2, 25%R1/ 75 %R2 and 100%R2, where V represents virgin material, R1 first recycling and R2 second recycling. Those made of crystal polystyrene were prepared as follows: 100%V, 75%V/ 25R, 50%V/ 50%R, 25%V/ 75%R, 100%R, where V represents the virgin material and R the recycled material. A system was created where the samples were then submitted to home tests that simulated a bending test. The injected samples were compared to each other in the visual aspect, in the measure of their displacement in relation to the center of the hanger and, also, in the classification of the presented deformations, elastic, plastic or rupture. In the PP tests, the samples did not have much variation in their visual appearance, unlike the PS tests. In addition, some recycled mixtures of both PP and PS proved to be more resistant than the 100%V material. In the PP samples, the 3 types of deformation occurred (plastic, elastic and rupture), on the other hand, in the PS tests, plastic deformation was not observed, but the PS hangers reacted similarly to the flexion tests, regardless of the composition of recycled material in the mix. Finally, it was possible to conclude that for weights of up to 1 kg (usual clothes), for PP hangers, the sample that presented the best cost-benefit to replace PP 100%V was 100%R2, with an estimated reduction of 55%. As for the PS, replacement was indicated only if another product was created, with an estimated cost reduction of 47%.