It has been evidenced as previously reported in Part 1 and Part 2 that effects of the thermal treatment on the physical properties of cellulosic fibers depend on the amount of water sorbed/ adsorbed.
Investigations were successively carried out from various aspects to obtain further informations to know how the water molecule exist on/in the fibers.
The results are abstracted as follows :
1) Monomolecular adsorption layers, adsorption areas and values of C (a BET constant) of water adsorbed on the cellulosic fibers all decreased with the thermal treatment confirming that adsorption sites were reduced by the thermal treatment.
2) Proton spin relaxation times T1 and T2 of water in each fiber specimen were determined by using spin pulsed NMR to deduce and compare the state of water molecules sorbed/ adsorbed in unheated and heated fiber specimens. Both T1 and T2 and ratios of free water to bound water also decreased with the thermal treatment as well as programming of temperature, which suggests a reduction of ratio of free water adsorbed on the surface of heated fibers.
3) Melting and evaporating behaviors of water sorbed/adsorbed in/on the fibers and weight loss were observed by the thermal analyses (DSC and TGA) the results of which also evidenced a reduction of amount of water on the thermally treated fiber surface.
