Thermoplastic elastomers waste rubbers

Mechanical Properties of Thermoplastic Elastomer Composition with Varying Waste-Rubber Loading at Constant Rubber/Plastic Ratio of 70 30 (w/w)... 

Nevada P., Baneqee T.S., Dutta B., Jha A., Naskar A.K., and Bhowmick A.K. Thermoplastic elastomer from reclaimed rubber and waste particles, J. Appl. Polym. Sci., 83, 2035, 2002. 

Another application of the injection system consists of recycling old and waste rubber. The reactive mixing of crumb rubber with a melted polymer represents an innovative way of recycling these waste rubbers [6]. Some thermoplastic elastomer may contain up to 60% recycled rubber derived from used vehicle tires, and thus through the reactive injection system the rubber scrap is revulcanized [7]. 

Rubber matrices have commonly been used as a second phase to improve the toughness of brittle thermoplastic materials, such as polypropylene and polyethylene. These systems, commonly referred to as polyolefin thermoplastic elastomers (TPOs), are a special class of thermoplastic elastomers that combine the processing characteristic of plastics at elevated temperatures with the physical properties of conventional elastomers at service temperature, playing an increasingly important role in the polymer material industry. Polyolefin blends attract additional interest due to the possibility of recycling plastic wastes, avoiding the complex and expensive processes of separation of the different components. 

S. Satapathy, A. Nag, G. B. Nando, Thermoplastic elastomers from waste polyethylene and reclaim rubber blends and their composites with fly ash. ProcessSaf. Environ. Prot. 88 (2), 131-141 (2010). 

Shen and co-workers [29] used a twin-screw extrnder to devnlcanise waste tyre rubber and then blended the resnlting DR into high-density polyethylene (HDPE) to produce thermoplastic elastomers (TPE). They found that the high shear conditions during the extrusion process induced chain scission and oxidative degradation of the GTR. The reduction in crosslink density was apparent in a decrease in the gel content of the rubber/HDPE blends and an increase in the melt flow of the materials. 

A solid-state mechanochemical milling process has been developed that combines both the devulcanisation of tyre waste and its mixing into an HDPE matrix [23]. The resulting product was also dynamically vulcanised within the mill, resulting in a thermoplastic elastomer (TPE) that SEM analysis showed to have good interfacial compatibility between the rubber and thermoplastic phases. 

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