Non‐Isothermal Curing Kinetics of Alkali‐Treated Alfa Fibers/Polybenzoxazine Composites Using Differential Scanning Calorimetry

Bessa, Wissam; Derradji, Mehdi; Tarchoun, Ahmed Fouzi

doi:10.1002/slct.202000596

Cited by 27 publications

(10 citation statements)

References 72 publications

(84 reference statements)

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“…The thermal stability of cellulose and microcrystalline cellulose materials are crucial to estimate their performance and their use in several industries. The thermal properties were investigated using DSC and TGA/ DTG analyses [23,55,66,67]. The thermal parameters of all cellulose samples are reported in Table 2.…”

Section: Thermal Stabilitymentioning

confidence: 99%

Physicochemical Properties and Thermal Stability of Microcrystalline Cellulose Isolated from Esparto Grass Using Different Delignification Approaches

et al. 2020

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Esparto grass, known as alfa, is a renewable biomass widely distributed in southern and western Mediterranean basin. The present work focused on the isolation of pure cellulose from alfa stems, via different approaches, i.e., acidified sodium chlorite (NaClO 2), totally chlorine free (TCF) or their combination, followed by the preparation of microcrystalline cellulose (MCC) using acid hydrolysis method. The obtained samples were characterized using infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry (TGA) and differential scanning calorimeter (DSC). The FTIR spectroscopy exhibited the removal of lignin and hemicellulose after the delignification and alkaline treatments. The XRD data showed that all of the MCCs have higher crystallinity indexes (Alfa-MCC 73-82%) and belong to cellulose I type. From SEM images, it is clear that the different MCC particles presented rough surface and micro-sized particles. The DSC/ TGA analyses revealed that MCC samples present better thermal stability than their respective cellulose ones, with higher temperature of decomposition (more than 350 °C). Moreover, the use of a combined process yields to MCC with higher crystallinity and better thermal stability. Consequently, based on these findings, the delignification with combined method can be considered as a promising approach to extract MCC from alfa fibers with outstanding features.

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Section: Thermal Stabilitymentioning

confidence: 99%

Physicochemical Properties and Thermal Stability of Microcrystalline Cellulose Isolated from Esparto Grass Using Different Delignification Approaches

et al. 2020

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“…The alkaline solutions are known for their ability to eliminate noncellulosic matters responsible for the hydrophilic character of the fibers, which improves the mechanical interlocking to the matrix. [ 13 ] Similarly, silane treatment is a reliable process that shows its potential to ameliorate the fibers–matrix adhesion and enhance the mechanical features of the composite. [ 14 ] A detailed examination was held to demonstrate the effects of the treatment of AD on its structural, morphological, and thermal properties.…”

Section: Introductionmentioning

confidence: 99%

“…[ 15 ] The enhanced thermal, mechanical, and chemical characteristics and the strong three‐dimensional network make thermosets susceptible to be used for high‐performance applications. Composites based on benzoxazine resin and NF as ramie, [ 16 ] hemp, [ 17 ] alfa, [ 13 ] kenaf, [ 18 ] etc. have already been studied.…”

Section: Introductionmentioning

confidence: 99%

Effect of different chemical treatments and loadings of Arundo donax L. fibers on the dynamic mechanical, thermal, and morphological properties of bisphenol A aniline based polybenzoxazine composites

Bessa

Derradji

Ambar³

et al. 2021

Polymer Composites

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In this research paper, bisphenol A aniline based benzoxazine (BA-a) was reinforced with natural, inexpensive, and largely distributed cellulosic plant, namely Arundo donax L. (AD) at various loadings of 5, 15, and 25 wt%. AD fibers were initially subjected to three different chemical surface modifications using alkaline, silane, and combined alkali-silane solutions. The main purpose of this work was to investigate the dynamic mechanical properties, morphological stability, and thermal stability of the as-prepared composites by pointing out the effects of natural reinforcements treated in different ways at different loadings. Dynamic mechanical analysis of the prepared composites revealed an enhancement in storage modulus (E 0 ) and loss modulus (E 00 ) to higher values, especially for composites reinforced by alkali-or combined-treated fibers due to the strong effect of alkaline solution to remove noncellulosic matters. Composite loaded at 25% of alkali-silane treated AD exhibited a glass transition temperature (T g ) of 217 C, while pure polymer had a T g of 188 C. The enhanced properties are a great indicator of the high fiber-matrix adhesion and compatibility. This conclusion is strengthened by scanning electron microscopy images. The thermal stability and degradation of the different biocomposites are also investigated by thermogravimetric analysis, revealing that the nature of the employed chemical treatment affected considerably the thermal behavior and the char yield of the composites.

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“…The kinetic parameters reveal the energy barrier, the rate of reactions, and reaction mechanisms. 28,29 Solid-state kinetics is usually studied by two types of computational methods, model-fitting, and isoconversional methods. It is accepted that model-fitting methods have some weaknesses that lead to erroneous Arrhenius parameters especially for nonisothermal data.…”

Section: Introductionmentioning

confidence: 99%

“…Then, the kinetic parameters are computed. The kinetic parameters reveal the energy barrier, the rate of reactions, and reaction mechanisms 28,29 …”

Section: Introductionmentioning

confidence: 99%

Thermal and kinetic study of hydroxyapatite formation by solid‐state reaction

Javadinejad

Ebrahimi‐Kahrizsangi

2020

Int J of Chemical Kinetics

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Hydroxyapatite (HAP) is one of the most attractive calcium phosphates which is used for different applications. While HAP has been mostly synthesized using wet methods, recently solid-state synthesis methods have attracted more attention. Many efforts have been made to better understand the solid-state synthesis mechanism. In this study, the kinetics of the solid-state reaction between hydroxide calcium (Ca(OH) 2) and phosphorus pentoxide (P 2 O 5) was studied under nonisothermal conditions using isoconversional methods. The phase analysis revealed that HAP is the main product of this process with no impurity. Thermogravimetric (TG) curves were recorded at four heating rates (β = 5, 10, 12 and 15 • C⋅min −1) and analyzed by several well-known isoconversional methods. Activation energy values were determined for each extent of reaction, which varied from ∼139 to 100 kJ/mol at the reaction extent of 0.1-0.9. Comparison between activation energy values obtained by isoconversional methods revealed that Flynn-Ozawa-Wall and Vyazovkin's method are more accurate than other. The preexponential factor and the reaction model were determined through model-free methods. The obtained results indicated that the reaction mechanism was chemically controlled or ordered-based model. Furthermore, the results showed that formation of HAP does not depend on the heating rate; however, it proceeds with increasing temperature.

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Non‐Isothermal Curing Kinetics of Alkali‐Treated Alfa Fibers/Polybenzoxazine Composites Using Differential Scanning Calorimetry

Cited by 27 publications

References 72 publications

Physicochemical Properties and Thermal Stability of Microcrystalline Cellulose Isolated from Esparto Grass Using Different Delignification Approaches

Physicochemical Properties and Thermal Stability of Microcrystalline Cellulose Isolated from Esparto Grass Using Different Delignification Approaches

Effect of different chemical treatments and loadings of Arundo donax L. fibers on the dynamic mechanical, thermal, and morphological properties of bisphenol A aniline based polybenzoxazine composites

Thermal and kinetic study of hydroxyapatite formation by solid‐state reaction

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