EG60411 Bio-Material Science Toshiharu Enomae Professor, PhD, Paper Device and Eco-friendly materials 2G103, 10:10-11:25, Tuesday

Lecture information and contact
› Homepage of “Biomaterial Science (T. Enomae)" ▷ http://www.enomae.com/ → Handouts in lecture(講義資料) › E-mail address → t@enomae.com for any questions and visit to laboratory (Bio-Agr. Bldg.生農C209 or E201) Disintegration in industry (Drum pulper)
Beating (refining)
▷ Post-disintegration process ▷ Process where shear stress is applied to water-containing fibers resulting in fibrillation (formation of small filaments or fibers) on the surface and concentrically loose structure
Beating (refining)
▷ Beating achieves large bonded area between fibers and thus higher paper strength. Q. Why can this breaking process increase paper strength? Difference between disintegration and beating › Disintegration is a process to separate fibers bonded or entangled, keeping fiber characteristics › Beating is a process to treat mechanically individual fibers, changing fiber characteristics Effect of blades on pulp fibers during beating Refining — movie — refiner Beating — change of fibers — external fibrillation Beating — change of fibers — internal fibrillation External fibrillation l Internal fibrillation =Concentric loosening (Lamellar separation) Connection of small pores formed by lignin removal fiber cell wall by beating Beating — change of paper structure Q. How did fibers and sheets change by beating?
Evaluation of fiber properties
▷ Freeness (Drainability) ▷ Specific surface area ▷ Fiber length distribution ▷ Distinguishment by staining ▷ Fiber coarseness ▷ Curl index Evaluation of Freeness Canadian standard freeness (mLCSF) ♪ One L of pulp suspension at 0.3% and 20 ℃ is pored and the volume (mL) of water drained from the side pipe is measured. Q. Does CSF increase or
Evaluation of Freeness
▷ Canadian standard freeness Unbeaten pulp ca. 650 mL CSF . Beaten pulp ca. 400 mL CSF Reasons why freeness by (E) beating are ›  More fines (small pieces of fibers) ▷ Fibrillation make paths between fibers in a pulp mat thin, winding, and long.
Water Retention Value (WRV)
M,,, : Mass of pulp after centrifugation M a : Mass of the pulp after oven drying

Nitrogen adsorption method
▷ Langmuir model ♪ All the adsorption sites are equivalent and the surface is homogenous. ♪ Monolayer coverage ♪ No interactions between adsorbate molecules on adjacent sites
Nitrogen adsorption method
▷ Langmuir model (cont'd) ▸ The fractional coverage of the surface θ changes at the adsorption rate proportional to gas pressure p and the number of empty sites N(1-0). ▸ The desorption rate proportional to Nθ. Nitrogen molecule Adsorption site Material surface
Nitrogen adsorption method

Length and width of fibers
Softwood tracheid Hardwood fiber Hardwood vessel 1 mm Fiber length and width distribution Fiber tester, ABB(L&W), Sweden
Effect of beating on paper properties
(WFF) ♪ Bending strength of single wet fibers was measured for determination of WFF. ↑ SR = Schopper- Riegler method for determination of drain ability
Effect of beating on paper properties
Stock preparation –  additives › Paper quality control › Size (sizing agent) - water repellency › Filler - brightness and opacity › Strength agent – dry or wet strength › Dye – optical brightening agent (OBA) › Paper manufacturing control › Retention aid – ex. aluminum sulfate – fines, fillers, and size retained more 、Aintiseptic (preservative)