Microstructural phenomena in ground tire rubber (GTR) devulcanized via combined thermochemomechanical and microwave processes monitored by FTIR and DTGA assisted by other techniques

Abstract

Analyzing rubber waste is crucial for value-added recycling, but the multitude of ingredients in vulcanized networks makes it challenging to characterize cross-linked rubbers. A combination of analytical techniques is usually required. In this study, two complementary characterization techniques, based on Fourier transform infrared (FTIR) spectroscopy and derivative thermogravimetric analysis (DTGA) were applied to analyze the structural, physical, and thermal behavior of ground tire rubber (GTR) samples devulcanized by two different processes. A set of samples was devulcanized by only microwaves (MW) while another set was treated with a combination of a thermochemomechanical (TM) process, which included the use of a devulcanization aid such as benzoyl peroxide, and microwaves. The combined technique proved to be more efficient in terms of the degree of devulcanization, significantly reducing the cross-linking density. However, the combined thermochemomechanical and microwave (TM/MW) devulcanization process resulted in greater degradation of the main rubber chains in the cross-linked network compared to the process using only microwaves.

Keywords

• devulcanization
• horikx's plot
• recycling of rubbers
• crosslinking agent
• natural rubber