Table of contents
Zellstoff
- verkettung von glucoseeinheiten => Zellbiose
- aneinanderreihung von Zellbiosen => Zellstoffmolekuel
- mehrere Kettenmolekuele => Molekuelbuendel (Mizellen)
- mehrere Mizellen => Fibrillen (get stuck)
- grosse Anzahl Fibrillen => (sichtbare) Zellulosefaser (cationic? and hydrophillic => hydrogen bonds)
- kristalline Bereiche (=> Festigkeit, Steifigkeit)
- amorphe Bereiche (=> Flexibilität, Elastizität)
- Lignin (incoorporated by wooden cells, ligningfrei=holzfrei, makes paper get brown)
- alk-gewinnung??
sizing
- Trends in Neutral Sizing (Excerpts from an Interview with Paul Rostek)
- AKD Mini-Encyclopedia of Papermaking Wet-End Chemistry
- Quantitative Determination of AKD
- paper sizing -composition and methods usp
bulk sizing (JAN78)
- resin (colophony) &
- aluminum or iron sulphate
added to the aqueous suspension of paper pulp
- pro
- internally sized paper
- no further working step (time/work)
- no rewetting and thus only one drying procedure (time/energy)
- contra
- Al-salts (large quantities) => pollution &
- affect fluorescent brightening agents and most dyestuffs adversely
- resin (natural product) => certain variations in quality
- acid medium => corrosion &
- alkaline filler (e.g. chalk- whiter and cheaper than kaolin) conjointly unusable
surface sizing (JAN78)
- modified starch
- pvoh
- cationic agents
- more or less fixing on fibres
- only compatible with basic dyestuffs (indifferent fastness to light)
- anionic agents
- compatible with acid and direct dyestuffs & fluorescent brightening agents
- alkaline medium (=> alkaline fillers usable)
=> latex
water absorption
- hydrophillic fibres
- hollows filled up
- fibre swelling (up to 150% own weight)
loss of consistancy
process not really understood => several thesis:
- hydrophillic glue (starch/resin) solutes
- water between fibres => hydrogen bonds
- water between fibres => space to move and release stucking fibrilles
- water between fibrecells makes them brake more easy
- breaking because of weight increase
absorbing hysteresis
- wetting
- fibres swell
- hollows filled up
- motion
- drying
- new position of fibres
- more/bigger hollows
- rewetting
=> preconditioning (RH, T)
=> conditioning (RH, T)
THE machine
- communicating vessels
- hydrostatic pressure
- capilary forces
- surface tension
- disc-machining/stabilizing
- closing impuls => start ringing => equation of motion
- sensor
- ow-valve
- cushion pressure => fibre swelling/compressing specimen
info/references
to the topic