Interaction forces between talc and pitch probed by atomic force microscopy.
Colloidal wood resin components present in pulp are collectively called "pitch". The presence of pitch may cause severe problems due to deposits in and on the paper machine. There is thus a need for controlling pitch aggregation and adsorption. To be able to develop more efficient pitch control systems, one needs to develop the understanding of pitch-pitch interactions and of the interactions between pitch and other materials. With this general goal in mind, we present methods for preparing geometrically well-defined pitch particles attached to atomic force microscopy tips. This has enabled us to investigate the interactions between pitch and talc, an additive commonly used for pitch control. We have used model pitch particles consisting of one component only (abietic acid), a mixture of components (collophonium), and particles prepared from real pitch deposits. We show that the forces acting between pitch and talc are attractive and, once the initial approach is made, exert this attraction out to large distances of separation. We present evidence that the formation of bridging air bubbles or cavities is responsible for this interaction.
Wallqvist
Viveca
V
YKI, Ytkemiska Institutet AB/Institute for Surface Chemistry, Box 5607, SE-114 86 Stockholm, Sweden. viveca.wallqvist@surfshemkth.se
Claesson
Per M
PM
Swerin
Agne
A
Schoelkopf
Joachim
J
Gane
Patrick A C
PA