Despite the current growing interest in rubber composites with natural organic fillers, there is a lack of kinetic analyses that describe the decomposition of these materials during pyrolysis. For this reason, the main objective of this study was the kinetic analysis and determination of formal kinetic parameters for the pyrolytic decomposition of NR–CEL composites with different cellulose content (0, 30, 45, and 55 phr). Thermogravimetric measurements were made at heating rates of 2, 4, 6, 8, 10, and 20 °C min–1 in the temperature range of 20–600 °C. First, Friedman and KAS model-free methods were applied. Therefore, model-based methods and the model-fitting procedure were used to find the optimal multi-step kinetic model. The proposed final model consists of two parallel processes, which are kinetically independent: A → B → C and D → E → F. For each step, a kinetic triplet was calculated: the apparent activation energy, the pre-exponential factor, and the kinetic parameters of the extended empirical Prout–Tompkins model. The master plots method was used to determine the kinetic decomposition mechanism of the individual steps. It was found that step A → B has the shape of an nth-order model, step B → C mainly follows the diffusion model, the mechanism of step D → E transfers from a random scission kinetics model to an nth-order model with an increasing amount of CEL, and step E → F obeys the chain scission mechanism.
2 February 2022 in Continuum Mechanics and Thermodynamics
FTFunGlass – Centre for Functional and Surface Functionalized Glass TnUAD of Trenčín
FunGlass – Centre for Functional and Surface Functionalized Glass TnUAD of Trenčín
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The research and development of new materials that are not only functional, but also ecologically acceptable, is a key aspect in many branches of industry. Such materials include elastomeric composites reinforced with alternative fillers such as cellulose. Cellulose is a renewable and biodegradable alternative to traditional fillers used in elastomeric composites. The main disadvantage of this biopolymer is its poor compatibility with the hydrophobic matrix and low mechanical strength. The free hydroxyl groups on the cellulose surface allow for a wide range of surface modifications. In this work, we focused on the chemical modification of cellulose using two different silanes due to their ability to react with the free hydroxyl groups on the surface of cellulose. This work deals with the characterisation of thermal stability of surface modified cellulose used as filler in polymer composites. Cellulose modified in this way was used in the amount of 45 phr as a filler in the preparation of elastomeric composites with natural rubber (NR) matrix. The NR composite filled with surface modified cellulose was characterized by TG/DSC, IR spectroscopy, XRD and scanning electron microscopy.
26 April 2023 in Materialwissenschaft und Werkstofftechnik
The application of cellulose (CEL) as a filler in elastomeric composites (ECs) was studied, with cellulose examined in its untreated form (RAW), after DCSBD plasma modification, and ozone pre-treatment. Changes in surface fluorescence demonstr...