Surface characterisation of mechanical pulps by polyelectrolyte adsorption

Krista Koljonen, Annikka Mustranta, Per Stenius

Research output: Contribution to journalArticleScientificpeer-review

29 Citations (Scopus)

Abstract

The charge properties of Norwegian spruce (Picea abies) pressure groundwood (PGW), thermomechanical (TMP) and chemithermomechanical (CTMP) pulps were studied. Surface and total charge were determined by the polyelectrolyte adsorption method, detecting the end point of polyelectrolyte titrations with a dye indicator or a particle charge detector (PCD). PCD generally yielded slightly lower charges than the dye indicator. Conductometric and potentiometric titrations gave additional information on the origin of the charge in CTMP pulp. Surface carboxyl groups in PGW (in calcium form) were also determined by electron spectroscopy for chemical analysis (ESCA). The charge distributions in unbleached PGW and TMP were quite similar. Among the unbleached pulps, sulphonate group-rich CTMP had the highest charge of all. The effect of dithionite bleaching on the charge of PGW was insignificant. Alkaline treatment doubled the amount of free carboxyl groups. Peroxide bleaching introduced some additional carboxyls. About 35% of the charged groups were accessible to a high Mw polyelectrolyte (PDADMAC Mw 1•105-3•105). Ozone treatment modified the surface lignin and increased the surface charge; up to 70% of the acidic groups in PGW pulp were located in the surface layer. Methylglucuronic (MeGluA) and galacturonic acids (GalA) were analysed by high-performance liquid chromatography (HPLC) after acid hydrolysis together with sulphonic acid, and were found to account for 30-90% of the charge of the pulps. Extractives apparently covered some charged groups attached to other wood components, especially at a high extractives content. The results showed that details of the mechanical pulping process, in CTMP manufacture in particular, may have a strong effect on the fibre charge.
Original languageEnglish
Pages (from-to)495 - 505
Number of pages11
JournalNordic Pulp and Paper Research Journal
Volume19
Issue number4
DOIs
Publication statusPublished - 2004
MoE publication typeA1 Journal article-refereed

Fingerprint

mechanical pulp
Mechanical pulp
Polyelectrolytes
adsorption
pulp
Adsorption
Thymidine Monophosphate
Pulp
bleaching
Bleaching
titration
Titration
detectors
dyes
Acids
acid
dye
mechanical pulping
Coloring Agents
Dyes

Keywords

  • Carboxyl group
  • Chemithermomechanical pulp (CTMP)
  • Electron spectroscopy for chemical analysis (ESCA)
  • Polyelectrolyte adsorption
  • Pressure groundwood (PGW)
  • Sulphonic acid
  • Thermomechanical pulp (TMP)
  • Uronic acid

Cite this

Koljonen, Krista ; Mustranta, Annikka ; Stenius, Per. / Surface characterisation of mechanical pulps by polyelectrolyte adsorption. In: Nordic Pulp and Paper Research Journal. 2004 ; Vol. 19, No. 4. pp. 495 - 505.
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abstract = "The charge properties of Norwegian spruce (Picea abies) pressure groundwood (PGW), thermomechanical (TMP) and chemithermomechanical (CTMP) pulps were studied. Surface and total charge were determined by the polyelectrolyte adsorption method, detecting the end point of polyelectrolyte titrations with a dye indicator or a particle charge detector (PCD). PCD generally yielded slightly lower charges than the dye indicator. Conductometric and potentiometric titrations gave additional information on the origin of the charge in CTMP pulp. Surface carboxyl groups in PGW (in calcium form) were also determined by electron spectroscopy for chemical analysis (ESCA). The charge distributions in unbleached PGW and TMP were quite similar. Among the unbleached pulps, sulphonate group-rich CTMP had the highest charge of all. The effect of dithionite bleaching on the charge of PGW was insignificant. Alkaline treatment doubled the amount of free carboxyl groups. Peroxide bleaching introduced some additional carboxyls. About 35{\%} of the charged groups were accessible to a high Mw polyelectrolyte (PDADMAC Mw 1•105-3•105). Ozone treatment modified the surface lignin and increased the surface charge; up to 70{\%} of the acidic groups in PGW pulp were located in the surface layer. Methylglucuronic (MeGluA) and galacturonic acids (GalA) were analysed by high-performance liquid chromatography (HPLC) after acid hydrolysis together with sulphonic acid, and were found to account for 30-90{\%} of the charge of the pulps. Extractives apparently covered some charged groups attached to other wood components, especially at a high extractives content. The results showed that details of the mechanical pulping process, in CTMP manufacture in particular, may have a strong effect on the fibre charge.",
keywords = "Carboxyl group, Chemithermomechanical pulp (CTMP), Electron spectroscopy for chemical analysis (ESCA), Polyelectrolyte adsorption, Pressure groundwood (PGW), Sulphonic acid, Thermomechanical pulp (TMP), Uronic acid",
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Surface characterisation of mechanical pulps by polyelectrolyte adsorption. / Koljonen, Krista; Mustranta, Annikka; Stenius, Per.

In: Nordic Pulp and Paper Research Journal, Vol. 19, No. 4, 2004, p. 495 - 505.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Surface characterisation of mechanical pulps by polyelectrolyte adsorption

AU - Koljonen, Krista

AU - Mustranta, Annikka

AU - Stenius, Per

PY - 2004

Y1 - 2004

N2 - The charge properties of Norwegian spruce (Picea abies) pressure groundwood (PGW), thermomechanical (TMP) and chemithermomechanical (CTMP) pulps were studied. Surface and total charge were determined by the polyelectrolyte adsorption method, detecting the end point of polyelectrolyte titrations with a dye indicator or a particle charge detector (PCD). PCD generally yielded slightly lower charges than the dye indicator. Conductometric and potentiometric titrations gave additional information on the origin of the charge in CTMP pulp. Surface carboxyl groups in PGW (in calcium form) were also determined by electron spectroscopy for chemical analysis (ESCA). The charge distributions in unbleached PGW and TMP were quite similar. Among the unbleached pulps, sulphonate group-rich CTMP had the highest charge of all. The effect of dithionite bleaching on the charge of PGW was insignificant. Alkaline treatment doubled the amount of free carboxyl groups. Peroxide bleaching introduced some additional carboxyls. About 35% of the charged groups were accessible to a high Mw polyelectrolyte (PDADMAC Mw 1•105-3•105). Ozone treatment modified the surface lignin and increased the surface charge; up to 70% of the acidic groups in PGW pulp were located in the surface layer. Methylglucuronic (MeGluA) and galacturonic acids (GalA) were analysed by high-performance liquid chromatography (HPLC) after acid hydrolysis together with sulphonic acid, and were found to account for 30-90% of the charge of the pulps. Extractives apparently covered some charged groups attached to other wood components, especially at a high extractives content. The results showed that details of the mechanical pulping process, in CTMP manufacture in particular, may have a strong effect on the fibre charge.

AB - The charge properties of Norwegian spruce (Picea abies) pressure groundwood (PGW), thermomechanical (TMP) and chemithermomechanical (CTMP) pulps were studied. Surface and total charge were determined by the polyelectrolyte adsorption method, detecting the end point of polyelectrolyte titrations with a dye indicator or a particle charge detector (PCD). PCD generally yielded slightly lower charges than the dye indicator. Conductometric and potentiometric titrations gave additional information on the origin of the charge in CTMP pulp. Surface carboxyl groups in PGW (in calcium form) were also determined by electron spectroscopy for chemical analysis (ESCA). The charge distributions in unbleached PGW and TMP were quite similar. Among the unbleached pulps, sulphonate group-rich CTMP had the highest charge of all. The effect of dithionite bleaching on the charge of PGW was insignificant. Alkaline treatment doubled the amount of free carboxyl groups. Peroxide bleaching introduced some additional carboxyls. About 35% of the charged groups were accessible to a high Mw polyelectrolyte (PDADMAC Mw 1•105-3•105). Ozone treatment modified the surface lignin and increased the surface charge; up to 70% of the acidic groups in PGW pulp were located in the surface layer. Methylglucuronic (MeGluA) and galacturonic acids (GalA) were analysed by high-performance liquid chromatography (HPLC) after acid hydrolysis together with sulphonic acid, and were found to account for 30-90% of the charge of the pulps. Extractives apparently covered some charged groups attached to other wood components, especially at a high extractives content. The results showed that details of the mechanical pulping process, in CTMP manufacture in particular, may have a strong effect on the fibre charge.

KW - Carboxyl group

KW - Chemithermomechanical pulp (CTMP)

KW - Electron spectroscopy for chemical analysis (ESCA)

KW - Polyelectrolyte adsorption

KW - Pressure groundwood (PGW)

KW - Sulphonic acid

KW - Thermomechanical pulp (TMP)

KW - Uronic acid

U2 - 10.3183/NPPRJ-2004-19-04-p495-505

DO - 10.3183/NPPRJ-2004-19-04-p495-505

M3 - Article

VL - 19

SP - 495

EP - 505

JO - Nordic Pulp and Paper Research Journal

JF - Nordic Pulp and Paper Research Journal

SN - 0283-2631

IS - 4

ER -