Devulcanisation agent

Due to their underlying chemical properties and atomic structures, there is also a difference in the chemical reactivity of the different types of bonds that are present in the rubber matrix and so if chemical agents (sometimes referred to devulcanising agents in the literature) are used that specifically target the sulfur-sulfur and sulfur-carbon bonds, usually aided by other agencies such as heat, this difference in reactivity can be exploited to achieve devulcanisation. 

A lot of relatively recent work, using specially prepared sulfur-cured NR and polyisoprene compounds, has been carried out by a group at Kyoto University led by K. Kojima [10]. In addition to studying the fundamental factors surrounding the use of supercritical CO2 as a reaction medium with polyisoprene-type rubbers, they have used supercritical CO2 in conjunction with a number of devulcanisation agents, for example ... 

Some of the devulcanisation agents that have been used can have disadvantages, for example ... 

The use of CO2 in the supercritical, or liquid state, to facilitate the devulcanisation of rubber has already been mentioned in Sections 4.3 and 4.4. However, because it was used on its own as a non-reactive process aid in those thermal and mechanical processes, it was not regarded as acting as a chemical devulcanisation agent, and so those systems were not included in this section. CO2 has also been used in these types of processes by some workers to swell... 

In addition to the work referred to above, workers at Twente University [55] have also carried out an investigation on the effectiveness of three different devulcanisation agents on the devulcanisation of two different types of EPDM rubber. The three chemical agents were ... 

The use of microwaves in conjunction with a chemical devulcanisation agent is a variation of this technology that assists the process to be more targeted towards the removal of crosslinks. In this variation of the technology, the microwaves are used to generate the heat to enable the devulcanisation reaction to proceed. 

A more recent article that addressed the use of the DeLink process was published in Rubber Journal Asia [13]. It featured the Gujarat Reclaim and Rubber Products Company, which produces reclaimed rubber from both synthetic and NR waste, as well as a light-coloured reclaim from latex scrap using the Rubplast process. The company uses Green Rubber s patented devulcanisation agent, DeLink, at a ratio of two parts DeLink to 100 parts crumbed waste rubber, to produce a product that can be incorporated back into new rubber compounds. The article claims that this is very advantageous to the rubber industry as it enables them to re-use the 5-15% of waste, which they typically throw away. 

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