scholarly journals Effect of Chemical Treatment Sequence on Pineapple Peel Fiber: Chemical Composition, Thermal Stability and Thermal Degradation Kinetics

Author(s):  
Paulo Henrique Fernandes Pereira ◽  
Heitor Luiz Ornaghi ◽  
Daniel Magalhães de Oliveira ◽  
Barbara Pereira ◽  
Valdeir Arantes ◽  
...  

Abstract Millions of tons of fruit wastes are generated globally every year from residual agriculture, which makes essential to find alternative uses to increase their aggregate value and reduce the impact of environmental damage. The present study aimed to explore pineapple peel as an alternative source of cellulose by evaluating its composition and physical properties, which are essential to provide a clue to its application function diverse. Cellulose was extracted by a sequence of chlorine-free treatments to delignify the fresh pineapple peels, followed by characterization using chemical composition, XRD, FTIR, SEM and TGA to determine its crystallinity, structural properties, morphology thermal characteristics, and thermal degradation kinetic study. The result revealed that the pineapple peel amorphous segments containing hemicelluloses and lignin were extensively removed with increasing chemical treatments, leading to increased purity, crystallinity index and thermal stability of the extracted materials. The maximum degradation, and crystallinity index of the 2B isolated from the PPF are 150 °C and 80.91% respectively. The cellulose content increased from 24.05% (pineapple peel) to 80.91% (bleached cellulose). These results indicated that pretreatment via bleaching has suitable potential applications in nanocrystal production and suggests possible uses in the development of cellulose nanocrystal and application for packaging films.

2021 ◽  
pp. 002199832110082
Author(s):  
Azzeddine Gharsallah ◽  
Abdelheq Layachi ◽  
Ali Louaer ◽  
Hamid Satha

This paper reports the effect of lignocellulosic flour and talc powder on the thermal degradation behavior of poly (lactic acid) (PLA) by thermogravimetric analysis (TGA). Lignocellulosic flour was obtained by grinding Opuntia Ficus Indica cladodes. PLA/talc/ Opuntia Ficus Indica flour (OFI-F) biocomposites were prepared by melt processing and characterized using Wide-angle X-ray scattering (WAXS) and Scanning Electron Microscope (SEM). The thermal degradation of neat PLA and its biocomposites can be identified quantitatively by solid-state kinetics models. Thermal degradation results on biocomposites compared to neat PLA show that talc particles at 10 wt % into the PLA matrix have a minor impact on the thermal stability of biocomposites. Loading OFI-F and Talc/OFI-F mixture into the PLA matrix results in a decrease in the maximum degradation temperature, which means that the biocomposites have lower thermal stability. The activation energies (Ea) calculated by the Flynn Wall Ozawa (FWO) and Kissinger Akahira Sunose (KAS) model-free approaches and by model-fitting (Kissinger method and Coats-Redfern method) are in good agreement with one another. In addition, in this work, the degradation mechanism of biocomposites is proposed using Coats-Redfern and Criado methods.


Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1597
Author(s):  
Iman Jafari ◽  
Mohamadreza Shakiba ◽  
Fatemeh Khosravi ◽  
Seeram Ramakrishna ◽  
Ehsan Abasi ◽  
...  

The incorporation of nanofillers such as graphene into polymers has shown significant improvements in mechanical characteristics, thermal stability, and conductivity of resulting polymeric nanocomposites. To this aim, the influence of incorporation of graphene nanosheets into ultra-high molecular weight polyethylene (UHMWPE) on the thermal behavior and degradation kinetics of UHMWPE/graphene nanocomposites was investigated. Scanning electron microscopy (SEM) analysis revealed that graphene nanosheets were uniformly spread throughout the UHMWPE’s molecular chains. X-Ray Diffraction (XRD) data posited that the morphology of dispersed graphene sheets in UHMWPE was exfoliated. Non-isothermal differential scanning calorimetry (DSC) studies identified a more pronounced increase in melting temperatures and latent heat of fusions in nanocomposites compared to UHMWPE at lower concentrations of graphene. Thermogravimetric analysis (TGA) and derivative thermogravimetric (DTG) revealed that UHMWPE’s thermal stability has been improved via incorporating graphene nanosheets. Further, degradation kinetics of neat polymer and nanocomposites have been modeled using equations such as Friedman, Ozawa–Flynn–Wall (OFW), Kissinger, and Augis and Bennett’s. The "Model-Fitting Method” showed that the auto-catalytic nth-order mechanism provided a highly consistent and appropriate fit to describe the degradation mechanism of UHMWPE and its graphene nanocomposites. In addition, the calculated activation energy (Ea) of thermal degradation was enhanced by an increase in graphene concentration up to 2.1 wt.%, followed by a decrease in higher graphene content.


2014 ◽  
Vol 1053 ◽  
pp. 263-267 ◽  
Author(s):  
Xiu Juan Tian

Thermal stability and thermal degradation kinetics of epoxy resins with 2-(Diphenylphosphinyl)-1, 4-benzenediol were investegated by thermogravimetric analysis (TGA) at different heating rates of 5 K/min, 10 K/min, 20 K/min and 40 K/min. The thermal degradation kinetic mechanism and models of the modified epoxy resins were determined by Coast Redfern method.The results showed that epoxy resins modified with the flame retardant had more thermal stability than pure epoxy resin. The solid-state decomposition mechanism of epoxy resin and the modified epoxy resin corresponded to the controlled decelerating ځ˽̈́˰̵̳͂͆ͅ˼˰̴̱̾˰̸̵̈́˰̵̸̳̱̹̽̾̓̽˰̶̳̹̾̈́̿̾̓ͅ˰̶˸ځ˹˰̵̵͇͂˰̃˸́˽ځ˹2/3. The introduction of phosphorus-containing flame retardant reduced thermal degradation rate of epoxy resins in the primary stage, and promote the formation of carbon layer.


2019 ◽  
Vol 39 (2) ◽  
pp. 105-116 ◽  
Author(s):  
Hongyan Li ◽  
Yongqiang Fu ◽  
Hongli Liu ◽  
Cong Sun ◽  
Ruyi Li ◽  
...  

AbstractThe thermo-oxidative and thermal degradation kinetic parameters of polymethyl methacrylate-methacryloxyethyltrimethyl ammonium chloride/silica aerogel composites (PMMA-MTC/SA) were investigated in this paper and were compared with the thermal stability and thermal conductivity of different types of composites. As a composite with electrostatic interaction, the thermo-oxidative and thermal degradation activation energies (E) of PMMA-MTC/SA were 173.97 and 188.05 kJ/mol, respectively. The results indicated that the electrostatic interaction could indeed enhance the thermal stability of silica/polymethyl methacrylate composites on the premise of good mechanical properties and heat insulation performance. It is of great significance for the further development of silica-based thermal insulation composites.


e-Polymers ◽  
2017 ◽  
Vol 17 (5) ◽  
pp. 373-381 ◽  
Author(s):  
Xinxin Cao ◽  
Mengqi Wu ◽  
Aiguo Zhou ◽  
You Wang ◽  
Xiaofang He ◽  
...  

AbstractA novel two-dimensional material MXene was used to synthesize nanocomposites with linear low-density polyethylene (LLDPE). The influence of MXene on crystallization and thermal degradation kinetics of LLDPE was investigated. Non-isothermal crystallization kinetics was investigated by using differential scanning calorimetry (DSC). The experimental data was analyzed by Jeziorny theory and the Mo method. It is found that MXene acted as a nucleating agent during the non-isothermal crystallization process, and 2 wt% MXene incorporated in the nanocomposites could accelerate the crystallization rate. Findings from activation energy calculation for non-isothermal crystallization came to the same conclusion. Thermal gravity (TG) analysis of MXene/LLDPE nanocomposites was conducted at different heating rates, and the TG thermograms suggested the nanocomposites showed an improvement in thermal stability. Apparent activation energy (Ea) of thermal degradation was calculated by the Kissinger method, and Ea values of nanocomposites were higher than that of pure LLDPE. The existence of MXene seems to lead to better thermal stability in composites.


2016 ◽  
Vol 51 (1) ◽  
pp. 125-138 ◽  
Author(s):  
JC Domínguez ◽  
B del Saz-Orozco ◽  
M Oliet ◽  
MV Alonso ◽  
F Rodriguez

In the present work, the thermal stability, changes in chemical structure during thermal degradation, and the kinetics of thermal degradation of a phenolic foam were studied. An 8.5 wt% of Pinus radiata wood flour reinforcement was added to the phenolic foam. A commercial phenolic resol was used as the matrix for the foam. The wood flour-reinforced foam showed a structure similar to the phenolic foam according to the Fourier transform infrared spectroscopy results. The wood flour increased the thermal stability of the phenolic foam in the first stage of thermal degradation ( T 5%), decreased it in the second step ( T 25%), and negligibly influenced the final stage. The activation energies of the degradation processes of the studied materials were obtained by the Kissinger-Akahira-Sunose and Flynn-Wall-Ozawa model-free kinetic methods and a 2-Gaussian distributed activation energy model. The values of the activation energies obtained by the model-free kinetic methods for the first degradation stage of the phenolic foams were in a range between 110 and 170 kJ mol−1, whereas for the wood flour it was 162 kJ mol−1 for almost all of the conversion range of its main degradation stage. The applied models showed good fits for all the materials, and the activation energies calculated were in agreement with the values found in the literature.


2018 ◽  
Vol 39 (1) ◽  
pp. 58-67 ◽  
Author(s):  
Dev K. Mandal ◽  
Haripada Bhunia ◽  
Pramod K. Bajpai

AbstractIn this article, the influence of polylactide and pro-oxidant on the thermal stability, degradation kinetics, and lifetime of polypropylene has been investigated using thermogravimetric analysis under nitrogen atmosphere at four different heating rates (i.e. 5, 10, 15, and 20°C/min). The kinetic parameters of degradation were studied over a temperature range of 30–550°C. The derivative thermogravimetric curves have indicated single stage and two stage degradation processes. The activation energy was evaluated by using the Kissinger, Kim-Park, and Flynn-Wall methods under the nitrogen atmosphere. The activation energy value of polypropylene was much higher than that of polylactide. Addition of polylactide and pro-oxidant in polypropylene decreased the activation energy. The lifetime of polypropylene has also decreased with the addition of polylactide and pro-oxidant.


2012 ◽  
Vol 217-219 ◽  
pp. 780-784
Author(s):  
Yi Heng Lu ◽  
Feng Wei ◽  
Wei Long Liu

The thermal stability and thermal degradation kinetics of proton-exchange membrane were investigated, as the membrane reacted with Fenton reagent at 80°C. Non-isothermal kinetic data of the membrane were analyzed by using the thermo-gravimetry analysis and the Kissinger、Flynn-Wall-Ozawa and Friedman methods under the conditions of flowing gas nitrogen and the heating rate of 5、10 and 20°C/min. The minimum temperature of the thermal degradation is greater than 360.8°C in the conversion rate of 10%. The thermal decomposition process occurred one step. The average value of apparent activation energy is 245.48kJ/mol, pre-exponential factor is 2.52×1018 min-1, the reaction mechanism is controlled by D4.


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