Kinetics of scrap tyre pyrolysis under vacuum conditions

Kinetics of scrap tyre pyrolysis under fast heating conditions

Effect of acid catalysts on scrap tyre pyrolysis under fast heating conditions

The thermal properties ofcis-1,4-polyisoprene and its vulcanizates were investigated by means of thermal analysis and complementary methods. It was found that cross-linking generally increases the thermal stability of this elastomer, though distinct differences between peroxide and sulphur vulcanizates were observed. Polysulphide cross-links cleave readily at elevated temperature, and transform to cross-links of lower sulphidity, mainly disulphide. However, some of them are probably oxidized first to sulphoxides, and further to sulphenic or thiosulphoxylic acids. The products formed involve the ionic decomposition of the peroxides and thereby prevent the autocatalytic thermooxidative destruction ofcis-1,4-polyisoprene.

The effect of the network structure of the thermal properties ofcis-1,4-polyisoprene vulcanizates

CHAPTER 6 – Elastomers

A major objective of this study was to develop a general method by which NR and IR can be differentiated and quantitatively determined in unknown vulcanizates. From the above data, it is apparent that none of the thermal analysis methods—DTG, DSC or DTG-GC—can give an unequivocal answer alone, unless the type and loading of carbon black, the sulfur level and the accelerator system of the unknown compounds are known. The general type of carbon black can be determined using a recently published DTG method, and the loading is readily determined by DTG or an ashing experiment. Determination of the exact accelerator system remains a problem. The limitations of each method can be summarized: (1) The DTG thermogram will differentiate NR and IR provided the sample is vulcanized and contains carbon black. (2) The DSC will differentiate NR and IR on the basis of the observed exothermic heat, provided the sample is vulcanized. (3) In DTG—GC, the appearance of dimethylethylbenzene in the distillate is indica...

N. V. Schwartz

Papers

Differentiation of Natural and Synthetic Polyisoprene by Combined Derivative Thermogravimetry and Gas Chromatography