Influences of binderless briquetting stresses on intrinsic bioconstituents of rice straw based solid biofuel

This is the first article, presenting the use of nonaccelerating nodes of thermal degradation of biomaterials to visualize thermogravimetric-reactivity. The transitions of nonaccelerating nodes, during thermal degradation, due to binderless briquetting stresses on rice straw were studied and critically discussed. Intrinsic biopolymeric transformations of rice straw due to binderless briquetting stresses were analysed using thermogravimetry and Fourier transformed infrared spectroscopy. The non accelerating nodes in briquetted biofuel shifted towards higher temperature in lignin-related region showing that lignin became less reactive in briquetted biofuel. A pattern similar to the sine wave function was noticed in the tail end segment of the acceleration profile of thermal degradation. This function was at a phase-lag of 180 in briquetted biofuel as compared to the raw material. In briquetted biofuel, fluctuations in degradation rate for lignin region subsided revealing consistent and consolidated lignin configuration. The FTIR-node at 1325.06 cm(-1) related to characteristic group vibrations of C-O (lignin) emerged in briquetted biofuel. Reduction in energy, related to OH-stretching, CH-bending, C-O stretching was observed due to briquetting stresses. Due to briquetting stresses, the vibrational energy of CH-stretching, lignin-related C = O vibration, and vibrations of lignin-related benzene ring, increased. The energy-related to Si-O-Si FTIR node drastically reduced due to briquetting. (C) 2018 Elsevier Ltd. All rights reserved.