Polymer science be considered polymer science in the modern sense. In the 1840s, Friedrich Ludersdorf and Nathaniel Hayward independently discovered that adding sulfur to raw natural rubber (polyisoprene) helped prevent the material from becoming sticky. In 1844 Charles Goodyear received a U.S. patent for vulcanizing natural rubber with sulfur and heat. Thomas Hancock had received a patent for the same process in the UK the year before. This process strengthened natural rubber and prevented it from melting with heat without losing flexibility. This made practical products such as waterproofed articles possible. It also facilitated practical manufacture of such rubberized materials. Vulcanized rubber
Chemical looping reforming and gasification SMR reaction heat, two CLC-SMR schemes can be configured. In Scheme 1 (Fig 2a), the reaction heat is provided by the reducer (fuel reactor). In Scheme 2 (Fig 2b), the reaction heat is provided by the combustor (air reactor). In either scheme, the combustion of metal oxide by air in the chemical looping system provides the heat source that sustains the endothermic SMR reactions. In the chemical looping system, natural gas and the recycled off-gas from the pressure swing adsorption (PSA) of the SMR process system are used as the feedstock for the CLC fuel reactor operation with CO and