Abstract

Rice straw is a problematic agricultural waste that is currently burnt in tonnes in the Albufera de Valencia after the harvest, with the consequent environmental damage. In this sense, to avoid wasting resources and unnecessary pollution, it is proposed to revalue the product, that is, to use rice straw, as a source of lignin and cellulose, for the development of materials for footwear, such as soles, insoles, or adhesives. The extraction of cellulose fibres from rice straw is done by physical and/or chemical processes, such as: hydrothermal steam treatment (steam explosion); alkaline treatment, peroxides, and bleaching. The extraction method is optimised by combining processes to maximise the yield obtained. To do this, the processing conditions of each of the extraction stages are varied, optimising variables such as: temperature, time, CO2 pressure, among others. Furthermore, through the use of lignin, also present in rice straw, it is possible to produce polyols to synthesise adhesives, achieving a complete revaluation of rice straw. Therefore, this study aims to determine the effect of rice straw processing conditions on the cellulose extraction yield by optimising the hydrothermal process, pre- and post-processing, as well as on the properties of the cellulose fibres, in addition to the extraction of lignin for its future use as a raw material for the production of polyols and synthesis of adhesives.