The fibrils untwisting limits the rate of cellulose nitration process

Nikolsky, Sergey N.; Zlenko, Dmitry V.; Mel’nikov, V. P.; Стовбун, С. В.

doi:10.1016/j.carbpol.2018.10.019

Cited by 48 publications

(40 citation statements)

References 33 publications

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“…Meanwhile, the surface of nitrated cellulose was observed to be rough instead of clear and smooth ones in the case of ordinary cellulose samples. According to comparable NC microstructure reported in previous studies, the rough surface of conventional NC samples is due to the swelling and untwisting of cellulose fibers during the nitration process, demonstrating the heterogeneous nitration of ordinary cellulose . This finding was in concordance with FTIR and XRD results for the changes in chemical and crystalline structure of cellulose chains after nitration.…”

Section: Resultssupporting

confidence: 90%

“…In comparison with conventional NC, MCCN samples revealed irregular rod‐like structure of microsized fibrils with more rough surface, which is almost similar to their precursors (pure MCC samples), suggesting that the alteration in microstructures is more important in the case of ordinary celluloses than MCC after nitration . This phenomenon can be attributed to the large surface area of MCC precursors with high and strong intermolecular and intramolecular hydrogen bonding, which allow the NO 2 + diffusion into the interior fibers, and decrease significantly the influence of nitration process on the fibrous surface . This conclusion confirms that the use of MCC as precursor conducts to more homogeneous nitration as reported previously by Trache et al Moreover, this statement can be sustained by the results obtained from nitrification degree measurement and XRD analysis, which indicates the high nitrogen content and the elevated crystallinity level of MCCN1 and MCCN2 compared to conventional NC1 and NC2.…”

Section: Resultssupporting

confidence: 57%

“…In contrast, MCCNs present higher density and nitrogen content than conventional NCs. The higher nitration degree is justified by the high crystallinity, great number of easily accessible hydroxyl groups, and short fiber length in the case of MCC precursors, which improve the transfer of the nitronium ion (NO 2 + ) into the interior cellulose fibers and increase the cellulose nitration rate . Moreover, the higher molecular weight of nitrate esters group (ONO 2 ) as compared to the hydroxyl‐function (OH) confirms the increased densities of MCCNs.…”

Section: Resultsmentioning

confidence: 99%

“…NC has a polysaccharide structure constituted by linked β‐glucopyranose units substituted on carbons C2, C3, and C6, by nitrate ester groups (ONO 2 ) . The nitration rate is distinct for each carbon, and the substitution is more advantageous in the C6 carbon followed by C2 and C3 carbons, which have comparable reactivity . The number of ONO 2 present in each glucopyranose unit depends on the nitration conditions and affects the nitrogen content of NC .…”

Section: Introductionmentioning

confidence: 99%

“…Besides that, it has been reported that the origin of cellulose and its preliminary treatment influence the physicochemical, thermal, and energetic features of the produced NC and affect its microstructure . On the other hand, the low combustion temperature, the high impact sensitivity, the high friability, and the low density have restricted the NC applications .…”

Section: Introductionmentioning

confidence: 99%

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A Promising Energetic Polymer from Posidonia oceanica Brown Algae: Synthesis, Characterization, and Kinetic Modeling

Tarchoun

Trache

Klapötke

et al. 2019

Macro Chemistry & Physics

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In this study, microcrystalline cellulose nitrate (MCCN) as energetic polymer is successfully obtained from Posidonia oceanica brown algae (POBA). Fourier transform infrared spectroscopy (FTIR) results show alterations in the intensities of some absorption bands, suggesting a significant difference in the chemical structure between microcrystalline cellulose and the emergent MCCN samples. X‐ray diffraction (XRD) measurements indicate that MCCNs are more crystalline than conventional nitrocellulose (NC). According to scanning electron microscopy (SEM), both NC and MCCN reveal a compact structure and a rough surface. Differential scanning calorimetry (DSC) displays that the thermal degradation of MCCNs shifts to lower temperatures compared to the respective NCs. Furthermore, in comparison with NC samples, MCCN samples exhibit high density, high nitrogen content, low viscosity‐average molecular weight, and good thermal stability. On the other hand, kinetic modeling based on DSC data is carried out by isoconversional integral methods to determine Arrhenius parameters and the decomposition mechanisms. It is found that MCCNs present lower activation energies than conventional NCs with a decrease of ≈6%. Finally, this work opens a new pathway to prepare MCCN from POBA, and it is expected to have applications in several areas such as propellants, energetic binders, and gas generators.

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Section: Resultssupporting

confidence: 90%

Section: Resultssupporting

confidence: 57%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A Promising Energetic Polymer from Posidonia oceanica Brown Algae: Synthesis, Characterization, and Kinetic Modeling

Tarchoun

Trache

Klapötke

et al. 2019

Macro Chemistry & Physics

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Hygroscopicity of nitrocellulose with different nitrogen content

Cao,

Nan,

Zheng

et al. 2024

Propellants Explo Pyrotec

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Research on the hygroscopic behavior of NC is essential because it affects the mechanical properties, combustion properties, and safe storage of NC‐based products. In this study, Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), and scanning electron microscopy (SEM) are used to characterize the chemical structure, crystal structure, and microscopic morphology of NC, respectively. The moisture adsorption isotherms of NC fibers with different nitrogen content are determined by dynamic vapor sorption (DVS) and fitted with Hailwood‐Horrobin (H−H) and Guggenheim‐Anderson‐de Boer (GAB) models. The specific surface area and surface energy of NC are also measured by inverse gas chromatography (IGC). The results show that as the nitrogen content of NC increases, the intensity of the −OH characteristic absorption peak is weakened, the crystallinity does not change much, the number of cracks and pores on the NC fiber surface increases, and the equilibrium moisture content (EMC) of the NC decreases in general. In addition, the fitting results based on the H−H and GAB models show that, under low humidity conditions, the EMC value of NC is determined by the adsorbed water content of the monolayer, which is mainly related to the −OH content in NC. However, with the increase of humidity, the EMC value of NC is gradually determined by the multilayer adsorbed water content, which is influenced by both the nitrogen content and the fiber cleavage structure. Meanwhile, the IGC results show that the surface energy of the NC consists mainly of the dispersive surface energy (values >46 mJ m−2), with the specific surface energy contributing approximately 25 mJ m−2. The total surface energy of NC and the bonding strength between NC molecules and water molecules decrease with increasing nitrogen content.

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