Abstract
In this work, the evolution of pyrolytic products of nature rubber (NR) and vulcanized NR were studied by performing a series of ReaxFF molecular dynamics simulations. The simulations under different temperatures (2400, 2600, 2800, 3000 K) were performed to investigate the influence of temperature on the distribution and characterization of product. The effect of water on product distribution and sulfur evolution during vulcanized NR pyrolysis were investigated by adding different amount of water molecules (50 and 200) into reaction sys-tems. The mechanism of water molecules promoting the decomposition of vulcanized NR was discussed and proposed. The results show that vulcanized cross-linked structure promotes the decomposition of carbon chains resulting more gas product at low temperature. Water can promote the further decomposition of heavy and light tars into gas product and inhibit the secondary formation of heavy tar. Moreover, water also facilitate the transfer of sulfur atoms to H2S and reduce the content of thiophene compounds at high temperature. Results indicate that water condition can provide a stronger cracking environment by generating OH radicals and reacting with in-termediate products of vulcanized NR pyrolysis forming R-C-OH radicals, which are the main precursors of CO and other oxygen-containing products.