Novel cofactors/PEO flocculation systems for colloidal suspensions

Goto, Shisei; Miyanishi, Takanori; Pelton, Robert

doi:10.3183/npprj-2000-15-05-p395-399

Cited by 7 publications

(2 citation statements)

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“…Goto et al 12 studied the flocculation of four colloidal suspensions, precipitated calcium carbonate (PCC), clay, TiO 2 , and polystyrene latex, using a combination of polymeric flocculants, PEO, and poly(acrylamide-co-PEG) comb copolymer, and cofactors of various structures and charges. They speculated that the surface charge and the density of the phenolic hydroxyl groups in the cofactor are important for flocculating colloids.…”

Section: Introductionmentioning

confidence: 99%

Molecular Orbital Studies of Gas-Phase Interactions between Complex Molecules

Gaudreault¹,

Whitehead²,

Ven³

2006

J. Phys. Chem. A

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Describing interactions among large molecules theoretically is a challenging task. As an example, we investigated gas-phase interactions between a linear nonionic oligomer and various model compounds (cofactors), which have been reported to associate experimentally, using PM3 semiempirical molecular orbital theory. As oligomer, we studied the hexamer of poly(ethylene oxide) (PEO), and as cofactors, we studied corilagin and related compounds containing phenolic groups (R-OH). These systems are of interest because they are models for PEO/cofactor flocculation systems, used in industrial applications. The PM3 delocalized molecular orbitals (DLMO) describe the bonding between (PEO)6 and cofactors, and some of them cover the complete complex. The DLMOs which cover the traditionally considered hydrogen bonds R-OH...O or R-CH...O show a distinct "pinch", a decrease of the electron density, between the H...O atoms. Calculations of Gibbs free energy, entropy, and enthalpy show that the PEO/cofactor complexes do not form at room temperature, because the loss of entropy exceeds the increase in enthalpy. The change in enthalpy is linearly related to the change in entropy for the different complexes. Even though bond lengths, bond angles, DLMOs, and electron densities for the PEO/cofactor complexes are consistent with the definition of hydrogen bonds, the number of intermolecular R-OH...O and R-CH...O bonds does not correlate with the enthalpy of association, indicating that the bonding mechanism for these systems is the sum of many small contributions of many delocalized orbitals.

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Section: Introductionmentioning

confidence: 99%

Molecular Orbital Studies of Gas-Phase Interactions between Complex Molecules

Gaudreault¹,

Whitehead²,

Ven³

2006

J. Phys. Chem. A

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“…It is common to use co‐factors to improve affinity of PEO into fibers in pulp and paper processes. Typically, co‐factors contain aromatic rings8 and the water solubility of the co‐factor is increased with acid, hydroxyl groups or cationic groups 9. It is assumed that PEO acts as a dispersing agent.…”

Section: Introductionmentioning

confidence: 99%

Poly(ethylene oxide)‐block‐poly[2‐(dimethylamino)ethyl methacrylate] as Strengthening Agent in Paper: Dynamic Mechanical Characterization

Vesterinen¹,

Rich²,

Myllytie³

et al. 2010

Macro Materials & Eng

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To enhance adhesion properties of PEO on wood fibers, block polymers of PEO and 2‐(dimethylamino)ethyl methacrylate were synthesized. The polymers were further modified to obtain strongly cationic species. The resulting polymers were used as additives in paper sheets. Papers were studied by DMA in a controlled‐humidity chamber. Addition of the PEO block co‐polymers enhanced paper strength. The strength of the paper sheets was highest when polymer with molecular weight of 400 kg · mol−1 was used as an additive. Highly cationic block co‐polymers increased moduli of paper sheets more than their weakly cationic analogs, which indicated strong interaction with fiber surfaces. Strength of the paper sheets decreased both with increased temperature and humidity.magnified image

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