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

*mini encyclopedia of paper making

to the report

*[http://www.fh-muenchen.de/home/fb/fb06/professoren/maier/Praxisseminar/maier_KollBer.html]