Neutral polyethylene oxide with a cofactor recommended for particle flocculation

Abdallah/Qasaimeh, M. R; Hani, Falah Bani; Dawagreh, Abdal-Kareem M. A.

doi:10.1590/s0104-66322011000300012

Cited by 3 publications

(2 citation statements)

References 10 publications

(5 reference statements)

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“…Water-soluble polymers can be used for a wide range of commercial applications, including as flocculants in brewing, 1 for dewatering in paper manufacture 2 − 4 or for municipal water purification. 5 − 7 High molecular weight (>10 5 g mol –1 ) polymers are particularly efficient and include nonionic, anionic, or cationic polyacrylamides, 7 − 9 poly(ethylene oxide) (PEO), 10 and poly(diallyldimethylammonium) chloride (PDADMAC). 11 Such polymers induce aggregation via a bridging flocculation mechanism.…”

Section: Introductionmentioning

confidence: 99%

“…Water-soluble polymers can be used for a wide range of commercial applications, including as flocculants in brewing, for dewatering in paper manufacture − or for municipal water purification. − High molecular weight (>10 5 g mol –1 ) polymers are particularly efficient and include nonionic, anionic, or cationic polyacrylamides, − poly(ethylene oxide) (PEO), and poly(diallyldimethylammonium) chloride (PDADMAC) . Such polymers induce aggregation via a bridging flocculation mechanism. − Water-soluble polymers are also widely employed as viscosity modifiers. − For example, PEO and poly(acrylic acid) (PAA) are commonly used as thickening agents in cosmetics, while polyurethanes (PU) and poly(vinyl alcohol) (PVA) are utilized in paint formulations .…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of High Molecular Weight Poly(glycerol monomethacrylate) via RAFT Emulsion Polymerization of Isopropylideneglycerol Methacrylate

Jesson

Cunningham

Smallridge³

et al. 2018

Macromolecules

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High molecular weight water-soluble polymers are widely used as flocculants or thickeners. However, synthesis of such polymers via solution polymerization invariably results in highly viscous fluids, which makes subsequent processing somewhat problematic. Alternatively, such polymers can be prepared as colloidal dispersions; in principle, this is advantageous because the particulate nature of the polymer chains ensures a much lower fluid viscosity. Herein we exemplify the latter approach by reporting the convenient one-pot synthesis of high molecular weight poly(glycerol monomethacrylate) (PGMA) via the reversible addition–fragmentation chain transfer (RAFT) aqueous emulsion polymerization of a water-immiscible protected monomer precursor, isopropylideneglycerol methacrylate (IPGMA) at 70 °C, using a water-soluble poly(glycerol monomethacrylate) (PGMA) chain transfer agent as a steric stabilizer. This formulation produces a low-viscosity aqueous dispersion of PGMA–PIPGMA diblock copolymer nanoparticles at 20% solids. Subsequent acid deprotection of the hydrophobic core-forming PIPGMA block leads to particle dissolution and affords a viscous aqueous solution comprising high molecular weight PGMA homopolymer chains with a relatively narrow molecular weight distribution. Moreover, it is shown that this latex precursor route offers an important advantage compared to the RAFT aqueous solution polymerization of glycerol monomethacrylate since it provides a significantly faster rate of polymerization (and hence higher monomer conversion) under comparable conditions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis of High Molecular Weight Poly(glycerol monomethacrylate) via RAFT Emulsion Polymerization of Isopropylideneglycerol Methacrylate

Jesson

Cunningham

Smallridge³

et al. 2018

Macromolecules

View full text Add to dashboard Cite

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Deflocculation of Cellulosic Suspensions with Anionic High Molecular Weight Polyelectrolytes

Korhonen¹,

Sorvari²,

Saarinen³

et al. 2014

BioResources

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Pulp fibers have a strong tendency to form flocs in water suspensions, which may cause their undesirable distribution in the paper sheets. This flocculation can be controlled by adding, e.g., an anionic high molecular weight polyelectrolyte in the fiber suspension. The objective of this study was to investigate the effect of anionic polyelectrolytes on deflocculation kinetics, dewatering, and rheology of cellulosic suspensions. The results showed that both microfibrillated cellulose (MFC) and macroscopic pulp fibers can be dispersed using anionic polyacrylamides (APAM). The higher the molecular weight of APAM, the higher is its effect. Adsorption experiments illustrate that anionic polyelectrolytes do not strongly attach to cellulose surfaces but they can be partly entrapped or can disperse nanocellulose fibrils (increase the swelling). Based on rheological experiments, the MFC network became weaker with APAM addition. Similar to the flocculation mechanism of cellulosic materials with polymers, deflocculation is also time dependent. Deflocculation occurs very rapidly, and the maximum deflocculation level is achieved within a few seconds. When mixing is continued, the floc size starts to increase again. Also dewatering was found to be strongly dependent on the contact time with the APAMs. These results indicate that the positive effects of anionic deflocculants are quickly diminished due to shear forces, and therefore, the best deflocculating effect is achieved using as short a contact time as possible.

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Factors Affecting Fines Flocculation Performance with Cofactor-Polyethylene Oxide

Qasaimeh¹,

Qasaimeh²,

Hani³

2014

ACES

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In literature, neutral polyethylene oxide (PEO) flocculated fines at low shear rates, while with cofactor (CF) addition, the formed CF-PEO complex showed larger ability to bridge fines, producing flocs. In this work, some process factors were found having significant effects on fines flocculation. Increases in CF to PEO ratio at constant PEO enhanced the bridging bonds, causing increases in flocculation initial rate (efficiency), amplitude (floc size), and fastness (a decrease in characteristic time). On the other hand, an increase in stirring rate (shear rate) in flocculation vessel caused decreases in initial rate and amplitude, and an increase in the fastness. All runs showed transient flocculation; the amplitude increased with time, reached maximum at equilibrium, and then started to decrease showing deflocculation. In brief, the CF to PEO ratio and the shear rate were found important parameters in mill operation, having significant effects on flocculation efficiency, fastness, and floc size.

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Neutral polyethylene oxide with a cofactor recommended for particle flocculation

Cited by 3 publications

References 10 publications

Synthesis of High Molecular Weight Poly(glycerol monomethacrylate) via RAFT Emulsion Polymerization of Isopropylideneglycerol Methacrylate

Synthesis of High Molecular Weight Poly(glycerol monomethacrylate) via RAFT Emulsion Polymerization of Isopropylideneglycerol Methacrylate

Deflocculation of Cellulosic Suspensions with Anionic High Molecular Weight Polyelectrolytes

Factors Affecting Fines Flocculation Performance with Cofactor-Polyethylene Oxide

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