Thermal Degradation Kinetics and Lifetime Prediction of Cellulose Biomass Cryogels Reinforced by its Pyrolysis Waste

Lídia K Lazzari,Ruth M C Santana,Andrielen B Vanzetto,Roberta M Neves,Ademir J Zattera

doi:10.1590/1980-5373-mr-2021-0455

Abstract

Degradation kinetics is an important tool in order to understand and improve energy conversion and the final application of a material. Cellulose cryogels (CC) are a new class of materials that can be reinforced by several types of particle, including biochar. Apart from it, degradation kinetics and lifetime prediction of biomass cellulose cryogels reinforced by cellulose pyrolysis waste (BC) has been investigated using TG techniques and iso-conversional model free methods. Additionally, the same study was applied to cellulose cryogels reinforced by graphene nanoplatelets (NPG) to compare the behavior of a filler from waste (BC) and a noble filler (NPG). Furthermore, the influence of the addition of the fillers into the cellulose biomass were evaluated in terms of thermal stability and crystallinity. BC and GNP led to higher values of activation energies (Ea) calculated from model-free isoconversional methods and all samples degraded in two-steps. Finally, lifetime prediction was successfully applied and the CC cryogel became more stable over time, maintaining almost 80% of the mass for 1 year exposed at 180 °C. The results of this study shown that only cellulose biomass cryogels are more suitable to produce thermal insulators due to it higher thermal stability.

Highlights

The use of porous materials from biomass presents an alternative to polymers derived from fossil fuels such as polystyrene, polyurethane and, ethylene vinyl-acetate foams
After wood processing for cellulose production, cellulose content increases and lignin decreases[30], for the present sample, there is the presence of lignin in its composition because this material press has not gone through the fiber bleaching process
According to[30] the mechanical and physical properties of the fibers are influenced by their composition, higher levels of crystalline cellulose provide greater thermal stability

Summary

Introduction

The use of porous materials from biomass presents an alternative to polymers derived from fossil fuels such as polystyrene, polyurethane and, ethylene vinyl-acetate foams. Cellulose-based cryogels are a relatively new class of porous materials produced by replacing the liquid phase present in a gel with air (through freeze-drying or freezedrying), without affecting its three-dimensional structure[1]. These materials have characteristics such as high surface area and porosity, and they can be used in different areas. A potential application, according to recent studies, for cryogels is the use as thermal insulators[2-6] for the fact that its thermal conductivity (

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