The effect of charge density and hydrophobic modification on dextran-based paper strength enhancing polymers

Zhang, Jin; Pelton, Robert; Wågberg, Lars; Rundlöf, Mats

doi:10.3183/npprj-2000-15-05-p440-445

Cited by 21 publications

(19 citation statements)

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“…As seen, by increasing the charge density of CPS, the amount of CPS adsorbed on fibers at the saturation level of adsorption was decreased. Similar behaviors were reported upon applying various cationic polymers on cellulose fibers (Fatehi et al 2011;Zhang and Pelton 2000). On the one hand, polymers with different charge densities developed different configurations on fibers (Wågberg and Hägglund 2001).…”

Section: Adsorption Of Cps On Cellulose Fiberssupporting

confidence: 76%

Preparation and characterization of polypyrrole/cellulose fiber conductive composites doped with cationic polyacrylate of different charge density

Wang

Fei

et al. 2015

Cellulose

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Polypyrrole/cellulose fiber-conductive composites were chemically synthesized in situ by using, for the first time, cationic polyacrylate copolymer as dopant and FeCl 3 as oxidant. The impacts of dopant charge density on the adsorption of the dopant on cellulose fiber, microstructure, tensile strength, conductivity and stability were investigated. In addition, the elemental composition, distribution and doping state of the polypyrrole in conductive fiber were determined by elemental analysis and X-ray photoelectron spectroscopy. Compared with anthraquinone-2-sulfonic acid sodium salt, cationic polyacrylate copolymer was a more effective dopant in increasing the conductivity and conductivity stability of conductive paper. The decay of mechanical properties was also weakened. The surface resistivity decreased from 4.6 to 0.3 KX square -1 with increasing dopant charge density from 0.525 to 0.820 lmol g -1 and then increased with a further increase in the dopant charge density. It was also found that the polypyrrole retention in conductive fiber reached the maximum when the charge density of the dopant was 0.820 lmol g -1 . When the conductive fiber was doped with high-charged dopant, polypyrrole was easier to enter into the fiber lumen, and bipoloran charge carriers were more easily formed. With respect to the conductive fibers prepared with dopant of 0.820 and 0.525 lmol g -1 charge density, the total content of polaron and bipolaron in the former conductive fiber was higher than the content of polaron in the latter conductive fiber. In addition, uniform and denser nanofibrous PPy can be formed by controlling the dopant charge density.

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Section: Adsorption Of Cps On Cellulose Fiberssupporting

confidence: 76%

Preparation and characterization of polypyrrole/cellulose fiber conductive composites doped with cationic polyacrylate of different charge density

Wang

Fei

et al. 2015

Cellulose

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“…In terms of the size of charged polymers, if the polymers are small, they cannot bridge the fibers efficiently (Fatehi and Xiao 2008a;Pelton et al 2003;Zhang and Pelton 2000;Zhang et al 2001). To reach an efficient bonding capacity, the polymer should be sufficiently large.…”

Section: Impact Of Cpva Characteristics On Its Performancementioning

confidence: 97%

Interaction of cationic modified poly vinyl alcohol with high yield pulp

Fatehi

Liu

et al. 2010

Cellulose

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The influence of polymer characteristics on paper properties has not been well understood. In this work, we aimed at analyzing the performance of various cationic-modified poly vinyl alcohols (CPVA), as dry strength additives, on the properties of highyield pulp (HYP). Various dosages of CPVA having different molecular weights (MW) and charge densities were applied on HYPs, and the resulting paper properties were evaluated. Also, an atomic force microscope (AFM) was employed to evaluate the attraction/repulsion force developed between modified fibers and AFM probes. Our results showed that the hydrophilicity and contact area of fibers were increased via CPVA application. High MW CPVA with the charge density of 0.7 meq/g was the most effective one in improving the properties of the fiber networks made from HYPs. The changes in the fiber morphology and chemistry played roles in improving the properties of fiber networks. The introduction of similar charges on HYPs via applying various dosages of different CPVAs confirmed that the changes in the fiber chemistry were not the only dominant factor in improving the properties. Additionally, the significance of polymer bridging (polymer characteristics) on the network properties was hindered due to the presence of fines in the HYP.

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“…Some fundamental knowledge has been collected on this issue (Davison 1972(Davison , 1980McKenzie 1984;Stratton and Colson 1993;Pelton et al 2000;Zhang et al 2000;Rundlo¨f 2002) but there are still no methods available to quantify the relative importance of these two important entities. There is, however, no doubt that both parameters are important and furthermore it is also clear that they are interdependent, i.e.…”

Section: Introductionmentioning

confidence: 99%

Determination of Fibre Pore Structure: Influence of Salt, pH and Conventional Wet Strength Resins

2005

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It has been shown, in the present investigation, that the two methods used to investigate the pore size distribution of unbleached chemical pulps, i.e. inverse size exclusion chromatography (ISEC) and nuclear magnetic resonance (NMR), give different average pore radius for the pores inside the fibre wall. This is due to the way in which these experiments are performed and the sensitivity of the methods to different types of pores in the cell wall. It was also shown that the two methods gave different results when changing the pH and the ionic strength of the pulp suspension. The pore radius, as detected with ISEC, decreased with both increasing ionic strength and decreasing pH, indicating a loose structure of the exterior of the fibrillar network. However, the pore radius as detected with NMR, was virtually unaffected when increasing the ionic strength, indicating a very rigid structure of the interior of the fibre wall. Decreasing pH though, lead to a decrease in pore radius indicating that upon protonation of the carboxylic groups in the fibre wall, the electrostatic repulsion is diminished and the average pore radius decreases. The NMR technique was also used to study wet strength aid penetration into the fibre wall. It was shown that wet strength aids with a small molecular weight, penetrated the fibre wall, as detected by a decrease in pore radius. It was also shown that addition of different wet strength aids increased the tensile index of the sheet and decreased the fibre strength, measured as zero span-strength of the sheets.

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The effect of charge density and hydrophobic modification on dextran-based paper strength enhancing polymers

Cited by 21 publications

References 0 publications

Preparation and characterization of polypyrrole/cellulose fiber conductive composites doped with cationic polyacrylate of different charge density

Preparation and characterization of polypyrrole/cellulose fiber conductive composites doped with cationic polyacrylate of different charge density

Interaction of cationic modified poly vinyl alcohol with high yield pulp

Determination of Fibre Pore Structure: Influence of Salt, pH and Conventional Wet Strength Resins

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