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

Abstract

Environmental concerns about waste management systems have stimulated the search for technological and economical alternatives that introduce waste as raw material for production cycles. In this sense, this study aimed to develop and characterize styrene-butadiene rubber (SBR) composites that contain industrial rubber scraps devulcanized by microwaves (SBR-r) as a reinforcing filler. The scraps were ground under ambient conditions. From the obtained powder (SBR-r), composites were prepared, varying the exposure time of the powder to the microwaves (1, 2, and 3 min), as well as the SBR-r content. These composites were compared to a Reference sample (base formulation without SBR-r). The vulcanization parameters were determined by an oscillating disk rheometer. After vulcanization, the composites were characterized by mechanical properties (tensile and tear strength, and compression set). These properties were also evaluated after accelerated aging in an air oven and a UV chamber (ultraviolet light). The results indicated that as a result of increasing the exposure time of the waste to the microwaves, no significant influence in the composite properties was observed. Aged samples presented higher results as compared with the Reference sample (tensile strength up to 175% higher, tear strength up to 107% higher, and compression set up to 91% higher), which indicates the possibility of using these materials in technological applications, such as in the civil and automotive industries.

Real-Time Monitoring of Ground-Tire Rubber Microwave Devulcanization with Thermal and Electrochemical Sensors

“…Therefore, instead of monitoring the MUT temperature, OF sensors may be measuring the temperature of the quartz dish or the MUT-holder effective temperature, which is one potential explanation supported by the results in the following section. Similar threshold temperature values were observed by other authors who employed a conventional microwave oven [38].…”

Microwave Devulcanization of Ground Tire Rubber and Its Improved Utilization in Natural Rubber Compounds

“…The irradiated energy during devulcanization is an important parameter. Zanchet and de Sousa calculated the specific microwave energy ( E ) during microwave devulcanization using the following equation: E = P · t / m , where P is the power of the magnetron (W), t is the exposure time (h), and m is the mass of the sample (kg). They found a correlation between the specific microwave energy and the start of the degradation of styrene–butadiene rubber (SBR).…”

Natural rubber (Hevea brasiliensis Mell.-Arg.) production, processing, and rubber wastes utilization: Challenges and prospects for economic diversification and sustainable development of Nigeria

“…In Nigeria, waste tyres are stockpiled at homes, autoservice centres, roadsides, and often disposed of in unregulated landfills and dumpsites that pave way for the proliferation of disease vectors such as the Aedes aegypti mosquito, Zika (Zanchet and de Sousa, 2020), and breeding sites for rodents (Umeki et al, 2016). In most cases, waste tyres are burnt during protests (e.g., #EndSARS; that is, Police brutality against youths in Nigeria), riots, and other civil disturbances, creating hazardous gases and dirt which result in serious health problems and environmental challenges.…”