Table 3.

Comparison of different reclamation or devulcanization techniques [74–81]

Techniques	Advantages	Disadvantages
Physical
Thermomechanical	High selectivity for crosslink scission	Potential main chain scission due to high abundancy of carbon–carbon bond
	Easy to scale up for industrial application
Microwave	Homogenous heating environmentally friendly	Restricted to polar rubber molecule which absorbs microwave, otherwise requires suitable additives
Ultrasound	Efficient process that can takes place within a few seconds	High energy input required Costly
Chemical	Wide selection of devulcanizing chemicals and high efficiency	Harmful to environment (secondary pollution)
Biological	High selectivity for crosslink bond by desulfurization enzymes	Microbial degradation is very slow. Devulcanization only happen on rubber surface