A theory is presented to give the relation between equilibrium amount of dye sorption (M) and fine-structure parameters of polymer (the crystallinity X and long period L), derived under the assumption that dye sorption takes place only on the surfaces of crystallites. Sorption experiments of C. I. Disperse Red 15 in poly (ethylene terephthalate) (PET) films, unoriented and annealed variously, have been carried out in the dye bath at 95°C. The experimental results shows the equilibrium-dye uptake increases with an increase in X of PET samples. This dye-uptake behavior is qualitatively consistent with our theory, yielding a linear relation between ML and L3/2X. However, some deviations were observed especially for the samples annealed at low temperatures.
This paper is intended to elucidate the mechanism involved in charge control of pulp fibers by cationic additives in papermaking wet end systems, and also to provide information on the role of counter-ions in controlling the surface charge. For these purposes, six model systems consisting of pads of cellulose fibers with and without adsorbed layers of a cationic polyelectrolyte (Poly-DMDAAC) in equilibrium with inorganic salts or the polymer solutions were designed. Zeta potential measurements by the streaming current method were performed on these systems. For systems with irreversibly adsorbed polymer layers, the polarity of the zeta potentials of the fibers with the monolayer (SYSTEM 1) was reversed to the positive; while the polarity of those with the multilayer (SYSTEM 2) remained negative with an increase in the amount of polymer adsorbed. For systems with counter-ions with different valencies, the polarity of the negatively (SYSTEM 3) or the positively (SYSTEM 4) charged fibers was reversed by polyvalent counter-ions at increased concentrations of salts. Regarding systems simulating real papermaking wet ends, the negative charge of the fibers remained negative by increased addition of alum (SYSTEM 5); whereas increased dosage of the polymer permitted reversal of the charge to the positive (SYSTEM 6). Electric double layer models (MODEL 1-6) are proposed to account for the electrokinetic behavior of the above systems. Comparative evaluation of the above systems and models was made with respect to the origin of the surface charge, the potential-determining ions or layers, and the specific or non-specific adsorption. Significance of specific adsorption of polyvalent counter-ions for the effective charge control of the fibers is demonstrated.
Thermogravimetric analysis showed that chlorodeoxycellulose is thermally less stable than cellulose. Hydrogen chloride, which is generated from 6-chloro-6-deoxy-D-glucose residues in chlorodeoxycellulose, catalyzed dehydration, condensation and carbonization. The well-known flame resistance of chlorodeoxycellulose was considered to come from these thermal reactions. Pyrolysis products produced by use of a curie-point pyrolyzer were identified. A route of formation of the characteristic products of chlorodeoxycellulose, 5-methyl-2-furaldehyde and 2-furyl methyl ketone, was discussed.
Aminodeoxycelluloses were prepared by treating cellulose ρ-toluenesulfonates, which were prepared from various kinds of cellulose samples under various conditions, with a solution of ammonia in ethanol at 100° in an autoclave. From cellulose ρ-toluenesulfonates made at 0°, from never-dried, solvent-replaced regenerated cellulose, aminodeoxycellulose with a high degree of substitution (up to 0.82) was obtained with minimum side reaction. Acetylation and 2, 4-dinitro-phenylation of aminodeoxycellulose were studied. Some properties of aminodeoxycellulose are also reported.
By 1H-NMR measurement under standard conditions, the methylol -OH signals of MOLC in DMSO-d6 solutions are found at three different fields but each of them appears as a broad resonance possibly as the result of statistical distribution in the strength of hydrogen bonding between the methylol -OH groups and DMSO molecules. As the methylol groups exist as side chains of high molecular weight cellulose, the hydrogen bonding of the methylol -OH with DMSO is highly affected by the conformation of the polymer chain in the solution. Accordingly, the methylol CH2 protons which are coupled with the methylol -OH protons must also appear as unresolved resonances in the methylenedioxy region. With the application of the techniques of D2O exchange, decoupling by double resonance, decoupling by promoting rapid exchange of the hydroxyl protons in the methylol groups of MOLC with the application of high concentration in one case and high temperature in the other, and 13C-NMR with variable temperature, three different methylol CH2 signals can be confirmed. Assignments of the three peaks are made by comparing the appearance of these signals in MOLC or acetylated MOLC with those in methylolated or acetoxymethylated trityl cellulose. Trityl cellulose with DS of 1.3 was used, in which almost all -OH groups at C-6 and part of the groups at C-2 had previously been blocked by trityl groups.