From Devulcanization to Revulcanization: Challenges in Getting Recycled Tire Rubber for Technical Applications

Abstract

For a sustainable development, recycling is a very important step, which, beyond saving the use of natural resources, can also be a solution for low-income families, providing them earnings. Recycling is also considered a category of green chemistry and contributes to the reduction of pollution, bringing the improvement to the public health. However, recycling of a material trying to contribute to the environment will not bring positive results if the final properties of the recycled material do not point to an application that is viable. In this sense, the aim of this work is to present a comprehensive study of the revulcanized ground tire rubber samples, previously devulcanized by the action of the microwaves under different exposure times. It is extremely important to know in depth the modifications that occurred in the recycled material during all the stages of the recycling process to which the material was subjected, in order to select the ideal application for the recycled material. The obtained results pointed out to modifications as a result of the revulcanization process, such as in the chemical structure, composition, thermal stability, and morphology.

Elastomeric Composites Containing SBR Industrial Scraps Devulcanized by Microwaves: Raw Material, Not a Trash

“…However, in general, the results showed that an increase in the exposure time of SBR-r to the microwaves resulted in a reduction in this property. These results could be a consequence of the reduction of the viscosity of the devulcanized SBR-r, which improves the interaction and adhesion between the phases, thus, reducing the reinforcing character of the SBR-r. Additionally, as discussed above, these results can also suffer the influence of degradation of the SBR-r during the recycling stages [32,33]. Concerning the elongation at break, no significant variation was observed among the analyzed samples.…”

“…Therefore, the flowability of the recycled rubber, as well as its amount can directly influence these values [31]. Additionally, de Sousa et al [32,33] have shown that, in the case of GTR devulcanized by microwaves and revulcanized, the rubber phases present in GTR, i.e., NR and SBR, are degraded in different levels during the recycling processes, that is, NR phase is preferentially degraded during the microwave devulcanization process, while the SBR phase is preferentially degraded during the revulcanization procedure in heated press, the same recycling methods used in the present work. Thus, the recycled phase in the analyzed composites could have suffered some degradation level, which could have influenced the obtained results.…”

Pros and Cons of Plastic during the COVID-19 Pandemic

“…Besides, it can assist in urban waterproofing, aggravating the problem of floods in cities through the clogging of manholes caused by the accumulation of waste carried by rainwater or winds (Figure 3). Furthermore, clogged manholes and waste disposed of in inappropriate places (Figure 3b) can become ideal environments for the reproduction of disease-transmitting insects, such as Aedes aegypti mosquito, the vector of diseases such as dengue, chikungunya, yellow fever, and zika [71]. 4.…”

Thermomechanical devulcanization of ethylene propylene diene monomer rubber and its application in blends with high‐density polyethylene

“…Devulcanizates may be revulcanised into rubber products with 100% recycled content when mixed with curing agents. 31,32 They can be added to virgin rubber mixtures and thus rubber products with some recycled content can be created. 31,33 Also, they can be blended with thermoplastics, producing thermoplastic elastomers (TPEs).…”

“…According to Forrest and Isayev, 6,30 there are three viable approaches for the utilization of devulcanizates. Devulcanizates may be revulcanised into rubber products with 100% recycled content when mixed with curing agents 31,32 . They can be added to virgin rubber mixtures and thus rubber products with some recycled content can be created 31,33 .…”