Evolution of the polydispersity of ammonium polyphosphate in a reactive extrusion process: Polycondensation mechanism and kinetics

Yang, Jingxu; Kong, Xingjian; Xu, Dehua; Xie, Wenji; Wang, Xinlong

doi:10.1016/j.cej.2018.11.031

Cited by 24 publications

(24 citation statements)

References 28 publications

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“…This is because the APP in UP-3 begins to decompose at relative low temperatures, generating some small molecules such as phosphoric acid, water, ammonia, etc. [ 33 ]. With the increase in temperature, it is observed that APP can increase the number of residues remarkably, which means that APP promotes charring to form carbonaceous materials.…”

Section: Resultsmentioning

confidence: 99%

Flame Retardancy and Thermal Behavior of an Unsaturated Polyester Modified with Kaolinite–Urea Intercalation Complexes

Yue

Zhou

et al. 2020

Molecules

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Organic modified kaolinite-urea intercalation complex (KUIC) was prepared using dimethyl sulfoxide (DMSO) as the precursor of kaolinite intercalation. Its structure was characterized by Fourier transform infrared (FTIR) and X-ray diffraction (XRD). Subsequently, as a synergistic agent, KUIC was combined with flame retardant ammonium polyphosphate (APP) to improve the flame retardant and smoke suppression performance of unsaturated polyester (UP) resin. A cone calorimeter (CONE) was used to study its flame retardancy and smoke suppression, and a scanning electron microscope (SEM) and thermogravimetry (TG) were used to study the micro morphology of the char and flame retardant mechanism. The results show that 12 phr of APP and 3 phr of KUIC were doped into UP to obtain a 28.0% limiting oxygen index (LOI) value. Compared with UP, the heat release rate and smoke production of UP/APP/KUIC composites were greatly decreased. Meanwhile, KUIC indeed enhanced the mechanical properties of UP.

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Section: Resultsmentioning

confidence: 99%

Flame Retardancy and Thermal Behavior of an Unsaturated Polyester Modified with Kaolinite–Urea Intercalation Complexes

Yue

Zhou

et al. 2020

Molecules

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“…Therefore, different reaction parameters, such as the molar ratio of raw materials, temperature, reaction time, and pressure, exerted significant influences on the features of APP samples (polymerization degree, polymerization rate, solubility, and N and P recovery rates). On the other side, inappropriate manufactory parameters will lead to a serious dissolution recrystallization and excess of water-insoluble substance problems. , …”

Section: Discussionmentioning

confidence: 99%

“…On the other hand, the polymerization rate, as an important parameter of poly-P fertilizers, significantly influenced soil P bioavailability and P fixation . These two parameters are mainly affected by different manufacturing processes and the corresponding fabricating reaction parameters. , …”

Section: Introductionmentioning

confidence: 99%

“…Up until now, PA–urea and MAP–urea are two mainstream manufacturing processes used for producing poly-P fertilizers. , In general, the features of APP fertilizers, including polymerization degree, polymerization rate, solubility, biuret content, pH, and salt index, are vital important parameters used to evaluate the quality of the APP fertilizers . APP manufacturing conditions not only affect the features of APP but also affect the appearance of the product. , Moreover, N and P recovery rates are regarded as important parameters to assess the performance of APP manufacturing processes. All these are directly influenced by different manufacturing processes and reaction conditions (molar ratio of raw materials, reaction time, temperature, and pressure).…”

Section: Introductionmentioning

confidence: 99%

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Optimization and Characterization of Polyphosphate Fertilizers by Two Different Manufacturing Processes

2021

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To explore how different reaction parameters affect the major features of short-chain ammonium polyphosphate (APP) fertilizers, a batch of manufacturing experiments were conducted under two different manufacturing processes [phosphoric acid (PA)–urea and monoammonium phosphate (MAP)–urea]. The APP features including polymerization degree, polymerization rate, solubility, and N and P recovery rates were significantly varied and influenced by the molar ratio of raw materials (P:N), reaction temperature, time, and pressure under different manufacturing conditions. In the MAP–urea process, the optimized APP products were gained under the combination condition of molar ratio = 1.6:1, T = 130 °C, and t = 45 min, while this happened in molar ratio = 1:1.7, T = 180 °C, and t = 60 min in the PA–urea process. Comprehensively, the features of APP fertilizers produced by the MAP–urea process were better than those produced by the PA–urea process. Our results provide valuable references for manufacturing high-quality short-chain APP fertilizers.

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“…In this context, slow-release fertilizers (SRFs) have been shown as a promising approach to manage losses and improve nutrient utilization e ciency 2 . Urea-formaldehyde (UF) is one of the most common and the rst group of products developed for SRFs fertilizer [7][8][9][10][11] . UF fertilizers are based on condensation products, mainly comprised of urea-formaldehyde polymers with different polymerization degrees 12 .…”

Section: Introductionmentioning

confidence: 99%

Different Zn Loading in Urea-Formaldehyde Influences the N Controlled Release by Structure Modification

Giroto

Valle

Guimarães

et al. 2021

Preprint

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Nitrogen fertilization has been a critical factor for high crop productivity, where urea is currently the most used N source due to its high concentration and affordability. Nevertheless, urea fast solubilization leads to frequent losses and lower agronomic efficiency. The modification of urea structure by condensation with formaldehyde has been proposed to improve nutrient uptake by plants and to reduce environmental losses. Herein we show that the co-formulation with Zn strongly modifies the N release (in lab conditions) and, more important, the Zn source – ZnSO4 or ZnO – has a critical role. Urea-formaldehyde (UF) served as a matrix for the zinc sources, whose chemical characterizations revealed that Zn particles influenced the length of the polymeric chains' formation. Release tests in an aqueous medium showed that the UF matrix favors ZnO release and, on the other hand, delays ZnSO4 delivery. Soil incubation with the fertilizer composites proved the slow-release of N from UF, ideal for optimizing nutritional efficiency. Our results indicated that ZnO: UF system has beneficial effects for both nutrients, i.e., reduces N volatilization and increases Zn release.

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Evolution of the polydispersity of ammonium polyphosphate in a reactive extrusion process: Polycondensation mechanism and kinetics

Cited by 24 publications

References 28 publications

Flame Retardancy and Thermal Behavior of an Unsaturated Polyester Modified with Kaolinite–Urea Intercalation Complexes

Flame Retardancy and Thermal Behavior of an Unsaturated Polyester Modified with Kaolinite–Urea Intercalation Complexes

Optimization and Characterization of Polyphosphate Fertilizers by Two Different Manufacturing Processes

Different Zn Loading in Urea-Formaldehyde Influences the N Controlled Release by Structure Modification

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