The sorption characteristics of different cellulose fibres by tensiometry

Zelo pomembna lastnost tekstilnih vlaken je njihova sposobnost navzemanja tekočin - njihova sorpcijska sposobnost. Za izboljšanje reaktivnosti regeneriranih celuloznih vlaken je običajno potrebna predobdelava, kot sta pranje in beljenje. Preizkušana viskozna in modalna ter liocel vlakna so enake kemične sestave, razlikujejo se v molekulski in nadmolekulski ureditvi. Razlike v sorpcijskih lasnostih neobdelanih in predobdelanih regeneriranih celuloznih vlaken smo zasledovali z alternativno metodo - tenziometrijo ter rezultate primerjali s klasično metodo zasledovanja hidrofilnosti. Tenziometrija je analizna metoda za določevanje površinske napetosti, stičnega kota ter adsorpcije. S pomočjo Powder Contact Angle metode smo določili kapilarno hitrost preskušanih vzorcev, na osnovi tega pa izračunali stični kot med trdno (vlakno) in tekočo (voda/heptan) fazo. S postopki predobdelave se sorpcijske lasnosti regeneriranih celuloznih vlaken bistveno izboljšajo, kar ugodno vpliva na nadaljne faze plemenitenja. Največjo sorpcijsko sposobnost navzemanja vode in s tem najnižji stični kot med neobdelanimi vzorci vlaken imajo viskozna vlakna (▫$varphi 68,3^o$▫), največji stični kot (▫$varphi 77,1^o$▫) pa modalna vlakna. Na izboljšanje sorpcijskih lastnosti ima največji vpliv predobdelava beljenje, kjer prav tako dosežejo najnižji stični kot beljenja viskozna vlakna (▫$varphi 57,8^o$▫).The improvement of wettability and sorptivity is the major task of textle finishing. In order to create the proper sorption character of regenerated cellulose fibres different pretreatment processes are applied, such as washing and bleaching. Classical viscose, modal and a new type of regenerated cellulose fibres called lyocell, have the same chemical structure, but a different molecular and supramolecular structure. The differences in the sorption properties of untreated and pretreated regenerated cellulose fibres were obtained using a new alternative method - tensiometry and compared with various methods for determining water adsorption. Tensiometry is an analytical method for measuring surface tension, contact angles and adsorption. We measured the sorption abilities using the Powder Contact Angle Method, and as a result we get the capillar velocity. From the velocity we can calculate the contact angle between the solid - fibres and the liquid - water/heptane. The pretreatment increases the adsorption abilities and makes the material more accessible to chemicals used in finishing processes. The raw viscose fibres show the highest amount of moisture and have the lowest contact angle (▫$varphi 68,3^o$▫), raw modal fibres have the biggest contact angle (▫$varphi 77,1^o$▫). Using chemical bleaching we improve the the sorption abilities. The bleached viscose fibres have the lowest cintact angle (▫$varphi 57,8^o$▫)