Hydrophobic copolymers added with starch at the size press of a paper machine: A review of findings and likely mechanisms

This article reviews publications with the goal of understanding the role of hydrophobic copolymers added to size-press starch as a means to make paper products more resistant to penetration by aqueous fluids. The underlying technology is considered, including background related to starch, size-press equipment, and various hydrophobic copolymers and latex products that have been evaluated. The resulting hydrophobization of the paper has been reported to depend not only on the dosage of the hydrophobic additive, but also on its molecular mass and ionic form. The mechanism appears to rely on an ability of starch to serve as a temporary host for hydrophobic compounds in aqueous solution. It has been proposed that hydrophobic copolymers added with size press starch tend to migrate to the air interface during drying of the starch film, thus allowing the low-energy functional groups, such as styrene or alkyl chains, to face outwards. Further research is needed to address various mechanistic questions. There may be opportunities to further raise the performance of this type of technology as practiced within paper production factories.

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Optical analysis of ink and other contaminants in process waters

TAPPI Journal ◽

10.32964/tj11.8.51 ◽

2012 ◽

Vol 11 (8) ◽

pp. 51-58

Author(s):

ANTTI HAAPALA ◽

MIKA KÖRKKÖ ◽

ELISA KOIVURANTA ◽

JOUKO NIINIMÄKI

Keyword(s):

Optically Active ◽

Process Water ◽

Paper Machine ◽

Optical Analysis ◽

Direct Process ◽

Active Components ◽

Water Contaminants ◽

Dependent Measurement ◽

Measurement Methodology

Analysis methods developed specifically to determine the presence of ink and other optically active components in paper machine white waters or other process effluents are not available. It is generally more interest¬ing to quantify the effect of circulation water contaminants on end products. This study compares optical techniques to quantify the dirt in process water by two methods for test media preparation and measurement: direct process water filtration on a membrane foil and low-grammage sheet formation. The results show that ink content values obtained from various analyses cannot be directly compared because of fundamental issues involving test media preparation and the varied methodologies used to formulate the results, which may be based on different sets of assumptions. The use of brightness, luminosity, and reflectance and the role of scattering measurements as a part of ink content analysis are discussed, along with fine materials retention and measurement media selection. The study concludes with practical tips for case-dependent measurement methodology selection.

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Influence of TOPO and TOPO-CdSe/ZnS Quantum Dots on Luminescence Photodynamics of InP/InAsP/InPHeterostructure Nanowires

Nanomaterials ◽

10.3390/nano11030640 ◽

2021 ◽

Vol 11 (3) ◽

pp. 640

Author(s):

Artem I. Khrebtov ◽

Vladimir V. Danilov ◽

Anastasia S. Kulagina ◽

Rodion R. Reznik ◽

Ivan D. Skurlov ◽

...

Keyword(s):

Quantum Dots ◽

Excited States ◽

Molecular Beam ◽

Surface Passivation ◽

Low Energy ◽

Trioctylphosphine Oxide ◽

Reverse Transfer ◽

Semiconductor Heterostructure ◽

Ligand Type

The passivation influence by ligands coverage with trioctylphosphine oxide (TOPO) and TOPO including colloidal CdSe/ZnS quantum dots (QDs) on optical properties of the semiconductor heterostructure, namely an array of InP nanowires (NWs) with InAsP nanoinsertion grown by Au-assisted molecular beam epitaxy on Si (111) substrates, was investigated. A significant dependence of the photoluminescence (PL) dynamics of the InAsP insertions on the ligand type was shown, which was associated with the changes in the excitation translation channels in the heterostructure. This change was caused by a different interaction of the ligand shells with the surface of InP NWs, which led to the formation of different interfacial low-energy states at the NW-ligand boundary, such as surface-localized antibonding orbitals and hybridized states that were energetically close to the radiating state and participate in the transfer of excitation. It was shown that the quenching of excited states associated with the capture of excitation to interfacial low-energy traps was compensated by the increasing role of the “reverse transfer” mechanism. As a result, the effectiveness of TOPO-CdSe/ZnS QDs as a novel surface passivation coating was demonstrated.

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Rapid removal of rhodamine dye from aqueous solution using casein-surfactant complexes: role of casein-surfactant interaction

Journal of Dispersion Science and Technology ◽

10.1080/01932691.2020.1845963 ◽

2020 ◽

pp. 1-16

Author(s):

M. Vadivel ◽

Sangeetha Jayakumar ◽

John Philip

Keyword(s):

Aqueous Solution ◽

Rapid Removal ◽

Rhodamine Dye

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The role of an energy-dependent inner potential in quantitative low-energy electron diffraction

Surface Science ◽

10.1016/s0039-6028(00)00433-7 ◽

2000 ◽

Vol 458 (1-3) ◽

pp. 155-161 ◽

Cited By ~ 35

Author(s):

S Walter ◽

V Blum ◽

L Hammer ◽

S Müller ◽

K Heinz ◽

...

Keyword(s):

Electron Diffraction ◽

Low Energy ◽

Energy Electron ◽

Low Energy Electron Diffraction ◽

Low Energy Electron ◽

Energy Dependent

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Directing the Growth of Semiconductor Nanocrystals in Aqueous Solution: Role of Electrostatics

ChemPhysChem ◽

10.1002/cphc.200800137 ◽

2008 ◽

Vol 9 (9) ◽

pp. 1309-1316 ◽

Cited By ~ 56

Author(s):

Hao Zhang ◽

Yi Liu ◽

Chunlei Wang ◽

Junhu Zhang ◽

Haizhu Sun ◽

...

Keyword(s):

Aqueous Solution ◽

Semiconductor Nanocrystals

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Role of band structure and local-field effects in the low-energy collective electronic excitation spectra of 2H-NbSe2

Physical Review B ◽

10.1103/physrevb.86.035115 ◽

2012 ◽

Vol 86 (3) ◽

Cited By ~ 24

Author(s):

M. N. Faraggi ◽

A. Arnau ◽

V. M. Silkin

Keyword(s):

Band Structure ◽

Local Field ◽

Electronic Excitation ◽

Low Energy ◽

Excitation Spectra ◽

Field Effects

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Electrochemiluminescence Study of Europium (III) Complex with Coumarin3-Carboxylic Acid

International Journal of Photoenergy ◽

10.1155/2008/131702 ◽

2008 ◽

Vol 2008 ◽

pp. 1-6 ◽

Cited By ~ 9

Author(s):

Stefan Lis ◽

Krzysztof Staninski ◽

Tomasz Grzyb

Keyword(s):

Aqueous Solution ◽

Spectral Analysis ◽

Energy Transfer ◽

Solid State ◽

Carboxylic Acid ◽

Elemental Analysis ◽

Aluminium Electrode ◽

The Eu

The europium (III) complex of coumarin-3-carboxylic acid (C3CA) has been prepared and characterized on the basis of elemental analysis, IR, and emission (photoluminescence and electrochemiluminescence) spectroscopy. The synthesised complex having a formula Eu was photophysically characterized in solution and in the solid state. Electrochemiluminescence, ECL, of the system containing the Eu(III)/C3CA complex was studied using an oxide-covered aluminium electrode. The goal of these studies was to show the possibility of the use of electrochemical excitation of the Eu(III) ion in aqueous solution for emission generation. The generated ECL emission was very weak, and therefore its measurements and spectral analysis were carried out with the use of cut-off filters method. The studies proved a predominate role of the ligand-to-metal energy transfer (LMET) in the generated ECL.

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