Hydrophobically modified phosphogypsum and its application in polypropylene composites

Líu, Hao; Nie, Chenchen; Li, Hongping; Xie, Guiming; Cao, Jian

doi:10.1016/j.conbuildmat.2022.128500

Cited by 18 publications

(7 citation statements)

References 41 publications

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“…On the other hand, the incorporation of 1 wt% FA into the matrix slightly increased these values compared to PP_IFR0. It is thought that the presence of silanated FA partially enhanced the compatibility between the additives and PP, as noted in previous studies 38,90–92 . For PP_IFR1, the tensile strength and modulus values were determined to be 27.8 and 696 MPa, respectively.…”

Section: Resultssupporting

confidence: 55%

Synergistic effects of fly ash on thermal, combustion, and mechanical properties of polypropylene including intumescent flame retardant

Demiryuğuran,

Usta

2023

J of Applied Polymer Sci

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In this study, a fly ash (FA), primarily composed of SiO2, Al2O3, Fe2O3, MgO, and CaO, as a synergistic additive (1–5 wt%) was added to enhance the effectiveness of an intumescent flame retardant (IFR) system (25 wt%) in polypropylene (PP). The composites were characterized by various tests to study thermal, combustion, and mechanical properties. Experimental results revealed that both IFR and IFR/FA additions led to early degradation at lower rates, with increased residual mass values. The thermal conductivity coefficient increased up to 16.9% with IFR/FA additions. While the sample containing only IFR met the UL 94 V‐0 requirements with a limiting oxygen index (LOI) value of 30.0%, the addition of 1% and 2% FA satisfied the UL 94 V‐0 criteria with the LOI values of 32.8% and 34.9%, respectively. Cone calorimeter results indicated that IFR had significant positive impacts on the burning characteristics of PP. Furthermore, the incorporation of FA reinforced the char layer formed by IFR, thereby enhancing the fire resistances of the composites. Although the tensile strength and tensile modulus decreased with IFR addition, the Izod impact strength increased. Additionally, FA additions slightly improved the mechanical properties of PP/IFR composites.

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Section: Resultssupporting

confidence: 55%

Synergistic effects of fly ash on thermal, combustion, and mechanical properties of polypropylene including intumescent flame retardant

Demiryuğuran,

Usta

2023

J of Applied Polymer Sci

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“…To prepare water-resistant blocks or gypsum boards, phosphogypsum is typically modified with superplasticizers, [3] silicate clinker, [4] silane-modified styrene-acrylic emulsion, [5] peat soil, [6] saturated fatty acids, [7] stearic acid (SA), [8] calcium stearate, silane coupling agents, or titanate coupling agents. [4] Additionally, phosphogypsum is utilized as a filler to improve the mechanical properties and reduce production costs of composite materials made with polypropylene, [9] polyvinyl chloride, polycarbonate/acrylonitrile butadiene styrene, and unsaturated polyester resin. The primary component of phosphogypsum is CaSO 4 ⋅ nH 2 O, which exists in dihydrate, hemihydrate, or anhydrous form.…”

Section: Introductionmentioning

confidence: 99%

Hydrophobic Modification of the α‐Hemihydrate Phosphogypsum (α‐HH) Surface by Myristic Acid

et al. 2023

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Phosphogypsum is widely used as a filler. However, gypsum fillers exhibit poor water resistance, compromising the performance of subsequent products. To address this issue, we modified α‐hemihydrate phosphogypsum (α‐HH) with myristic acid (ΜΑ), a low surface energy material used to prepare super hydrophobic (SHP) surfaces. The MA concentration, temperature, and modification time were optimized using a Box‐Behnken experimental design method. The surface properties, microstructure, and thermal stability of the modified powders were characterized using contact angle measurements, X‐ray diffraction (XRD), Fourier transform infrared (FT‐IR) spectroscopy, Raman spectrum, X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy coupled with energy‐dispersive X‐ray spectroscopy (SEM‐EDS), and thermal gravimetry‐differential scanning calorimetry (TG‐DSC). Additionally, we discussed the hydrophobic modification mechanism of the modified α‐HH. The modified α‐HH/MA prepared with 11.0×10−4 mol L−1 MA at 60 °C for 60 min exhibited high hydrophobicity. During modification, MA bound to the calcium ions on the surface of α‐HH to form calcium myristate, thereby forming a hydrophobic film. The thermal stability of α‐HH was improved by MA modification. The modified powder maintained high hydrophobicity even at 250 °C.

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“…After being calcined at 600 °C for 2h, β-hemihydrate gypsum was almost completely dehydrated into type-II anhydrite. Liu et al researched that milled PG followed by calcination at 600 °C for 4h obtained type-II anhydrite. After hydroxylation and hydrophobic modification of the anhydrite surface by NaOH and Na 2 SO 4 , the modified anhydrite was used as the filler of the polymer materials.…”

Section: Introductionmentioning

confidence: 99%

Dissolution–Recrystallization Approach to Synthesize Type-II Anhydrite from Phosphogypsum in the H₃PO₄–H₂SO₄–H₂O System

Zhang,

Yang,

Cao

et al. 2023

Ind. Eng. Chem. Res.

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Type-II anhydrite was successfully fabricated in this work using phosphoric acid and sulfuric acid through a dissolution–recrystallization process using phosphogypsum (PG) as the raw material. The effects of different experimental influencing factors on the molar fraction of anhydrite were discussed. Controlling the optimal conversion conditions such as the initial phosphoric acid concentration of 32% P2O5, the H2SO4/H3PO4 (mass ratio) of 20%, the reaction temperature of 90 °C, and the H3PO4/PG (mass ratio) of 5, the molar fraction of the anhydrite reached above 99%, and the morphologies of the anhydrite product were rectangular flakes with the average particle size of 13.45 μm. The purity and whiteness of the anhydrite were 98.45 and 81.8%. The 28-day compressive strength of the anhydrite was 37.2 MPa. The dehydration conversion of PG into anhydrite in the mixture of phosphoric-sulfuric acid follows the dispersive kinetic model. After impurities (Fe3+, Al3+, Mg2+, and SiF6 2– ions) were introduced into the system, the activation enthalpy increased, and the activation entropy decreased causing the nucleation barrier of anhydrite crystals to increase, thus inhibiting the dehydration conversion of PG into anhydrite. As the concentration of impurities increases in the mixture of phosphoric-sulfuric acid, the chemical shifts of Ca, S, and O elements in anhydrite are to the left, resulting in a weaker binding energy between Ca2+ and SO4 2– ions, thereby causing energy of dehydration conversion of PG into anhydrite to increase. The suggested type-II anhydrite synthesized from PG in the H3PO4–H2SO4–H2O system shows promising prospects for applications.

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Hydrophobically modified phosphogypsum and its application in polypropylene composites

Cited by 18 publications

References 41 publications

Synergistic effects of fly ash on thermal, combustion, and mechanical properties of polypropylene including intumescent flame retardant

Synergistic effects of fly ash on thermal, combustion, and mechanical properties of polypropylene including intumescent flame retardant

Hydrophobic Modification of the α‐Hemihydrate Phosphogypsum (α‐HH) Surface by Myristic Acid

Dissolution–Recrystallization Approach to Synthesize Type-II Anhydrite from Phosphogypsum in the H₃PO₄–H₂SO₄–H₂O System

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Hydrophobically modified phosphogypsum and its application in polypropylene composites

Cited by 18 publications

References 41 publications

Synergistic effects of fly ash on thermal, combustion, and mechanical properties of polypropylene including intumescent flame retardant

Synergistic effects of fly ash on thermal, combustion, and mechanical properties of polypropylene including intumescent flame retardant

Hydrophobic Modification of the α‐Hemihydrate Phosphogypsum (α‐HH) Surface by Myristic Acid

Dissolution–Recrystallization Approach to Synthesize Type-II Anhydrite from Phosphogypsum in the H3PO4–H2SO4–H2O System

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Product

Resources

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Dissolution–Recrystallization Approach to Synthesize Type-II Anhydrite from Phosphogypsum in the H₃PO₄–H₂SO₄–H₂O System