Swelling Of Cellulose Research Articles

Pore swelling in beads made of cellulose fibres and fibre fragments

The swelling of a new pharmaceutical excipient consisting of highly porous cellulose beads has been studied. Different degrees of swelling were produced by absorption of water and cyclohexane, two liquids with different ‘swelling capacity’. The pore size in cellulose beads with different porosities was investigated using the spin echo NMR technique and found to increase due to swelling. The crystallinity of dry and wet cellulose fibres was investigated using 13C CP/MAS NMR. A basic application of the beads is to use them as well-defined drug carrier particles. The beads can be loaded with drugs by a sorption process from water or organic solvents. It was concluded that it is beneficial to load the beads using drug solutions containing a cellulose swelling liquid.

Photochemistry on surfaces: solvent–matrix effect on the swelling of cellulose. An emission and absorption study of adsorbed auramine O

Auramine O exhibits a significant fluorescence emission at room temperature when adsorbed on microcrystalline cellulose. This emission is about two to four orders of magnitude higher than the previously reported emission in different solvents, also at room temperature. The fluorescence quantum yield, ϕF, varies with the residual degree of humidity of the sample, as alterations in the rigidity of the environment greatly affect the non-radiative de-excitation of auramine O. A limiting upper value of ϕF≈ 0.35 was obtained after prolonged evacuation of the samples.A matrix-isolation mechanism was evaluated by using room-temperature fluorescence measurements of powdered samples of auramine O adsorbed on microcrystalline cellulose. Using polar protic and aprotic solvents, different degrees of swelling of the microcrystalline cellulose were obtained, resulting in changes of the ground-state reflectance spectra of auramine O trapped in the natural polymer chains, as shown by remission function data. The amount of dye adsorbed or entrapped is reflected in both the fluorescence quantum yields and lifetimes.When auramine O was adsorbed on porous silica, the fluorescence quantum yield was much lower, indicating a higher mobility of dye molecules on the silica surface. Oxygen does not affect the room-temperature fluorescence emission of auramine O in silica or in cellulose.

Application of calorimetry to the studies on the processes of dyeing of fabric

The possibility of the use of direct thermochemical measurements for the determination of the enthalpic characteristics of the most important processes taking place during the dyeing of textile materials by reactive dyes is shown. It is established that the exothermicity of dyeing decreases with the rise in the degree of association of the dye and the degree of filling of the fibre surface by the dye molecules, and with the decrease in the degree of swelling of cellulose. This testifies to the importance of the entropic factor for the dyeing process of cellulose materials by reactive dyes.

Effect of cellulose fine structure on kinetics of its digestion by mixed ruminal microorganisms in vitro

The digestion kinetics of a variety of pure celluloses were examined by using an in vitro assay employing mixed ruminal microflora and a modified detergent extraction procedure to recover residual cellulose. Digestion of all of the celluloses was described by a discontinuous first-order rate equation to yield digestion rate constants and discrete lag times. These kinetic parameters were compared with the relative crystallinity indices and estimated accessible surface areas of the celluloses. For type I celluloses having similar crystallinities and simple nonaggregating particle morphologies, the fermentation rate constants displayed a strong positive correlation (r2 = 0.978) with gross specific surface area; lag time exhibited a weaker, negative correlation (r2 = 0.930) with gross specific surface area. Crystallinity was shown to have a relatively minor effect on the digestion rate and lag time. Swelling of microcrystalline cellulose with 72 to 77% phosphoric acid yielded substrates which were fermented slightly more rapidly than the original material. However, treatment with higher concentrations of phosphoric acid resulted in a more slowly fermented substrate, despite a decrease in crystallinity and an increase in pore volume. This reduced fermentation rate was apparently due to the partial conversion of the cellulose from the type I to the type II allomorph, since mercerized (type II) cellulose was also fermented more slowly, and only after a much longer lag period. The results are consistent with earlier evidence for the cell-associated nature of cellulolytic enzymes of ruminal bacteria and suggest that ruminal microflora do not rapidly adapt to utilization of celluloses with altered unit cell structures.

紙の液体浸透特性について （第１報） 有機液体及びエタノール水溶液の浸透

The absorption rate of organic liquids and ethanol aqueous solution into wood-free paper and coated paper was measured using Bristow's method.As for organic liquids, liquid transfer rate was found to follow Lucas-Washburn's equation, and all the measured points fell nearly on the same line on the V and √γt/η figure. However, depending on the degree of swelling, a minute difference in gradients seemed to be derived from the swelling of cellulose by organic liquids.When ethanol aqueous solution was absorbed into paper, transferred volume of the solution increases during wetting time, though it is usually recognized that liquid absorption does not proceed during wetting time. In addition, the rate of absorption increases with the increase in the concentration of ethanol.As for absorption of water or ethanol aqueous solution into slack sized wood-free paper, liquid transfer rate was observed as being almost proportional to the contact time. Consequently, Bristow' s equation could not applicable. Swelling and water molecular adsorption from the vapor phase was likely to affect it.In the case of uncoated paper the roughness index Kr expressed as the intercept of ordinate in the Bristow plotting for organic liquids corresponds to Bekk smoothness. However, comparison of Kr between coated and uncoated paper is not reasonable, possibly because of the difference in the chemical properties and compressibility of the paper surface.

An x-ray diffraction study of intracrystalline swelling of cellulose in solutions of N-methylmorpholine-N-oxide

By the method of X-ray diffraction, the formation of an intracrystalline complex of cellulose with N-methylmorpholine-N-oxide generated by prolonged swelling of cellulose in concentrated solutions of N-methylmorpholine-N-oxide in ethanol was demonstrated. An expansion of the cellulose lattice in a direction normal to the 101 planes was determined, sufficient for accommodation of at least two molecules of N-methylmorpholine-N-oxide in the interlayer space. An assumption for a possible stoichiometric composition of the intracrystalline complex is presented.

Kinetics of swelling of cotton fibers in aqueous ethylenediamine solutions using X‐ray diffraction data

AbstractKinetics of swelling of cotton cellulose with 75% (w/w) ethylenediamine (EDA) solution has been studied using X‐ray diffraction. Apparently, the swelling reaction proceeds at three different rates, all obeying the first‐order kinetics. The first rate (k1), which is the fastest one, is hypothetically attributed to the swelling action of EDA–monohydrate in the amorphous region of cellulose; the second rate (k2), which is extremely slow, is responsible for the penetration of swelling species into the crystallites, accompanied by breakage of the hydrogen bonds in these regions; and the third rate (k3), which is faster than k2 but slower than k1, has been assigned to the decrystallization of the crystalline regions. The increase in temperature of swelling (from 10°C to 55°C) brought about increase in all these three rates with shortening of their respective periods. Thus, at temperatures of 35°C and above, k2 and k3 merge, giving a combined rate (k2+3). These results were confirmed from the data on the activation energy values. The changes in crystallinity were comparatively less, when 65% (w/w) EDA solution was used for swelling cotton fibers. The ineffectiveness of 65% (w/w) EDA solution was explained on the basis of the absence of powerful swelling species in the solution. An attempt has also been made to examine the kinetic data on the basis of the model for cotton fiber fine structure consisting of crystalline elementary fibrils and surfaces or regions of varying extents of hydrogen bonding.

Kinetics of swelling of cotton fibers in aqueous ethylenediamine solutions using moisture regain data

AbstractKinetic studies of swelling of cotton cellulose with 75% (w/w) EDA solution have been carried out. Three rates of the reaction were observed in the temperature range 10–35°C: first, the very fast rate (k1) lasting for about 10 s; second, the extremely slow rate (k2) lasting for 30–50 s; and third, once again a fast rate (k3), k1 being faster than k3. k1 was attributed to the swelling action of EDA–monohydrate in amorphous regions of cellulose; k2 was assigned to the penetration of swelling species into crystallities accompanied by breakage of H bonds in these regions; and k3 was assigned to the opening up of the crystallites. Activation energy values confirmed this trend. At higher temperatures (35–55°C), the middle rate k2 merged with k3, giving only two rates, k1 and k2+3, as the higher temperatures brought about simultaneous diffusion of swelling agent into, and decrystallization of, the crystalline portions of cellulose. EDA solution of 65% (w/w) concentration gave only two rates: the initial fast rate assigned to the swelling of the amorphous portion, followed by a slow one, operating in mesomorphous regions of cellulose, without any appreciable decrystallization. This was atributed to the important fact, viz., the absence of EDA–monohydrates in the solution.

The swelling of alkali cellulose in sodium hydroxide solutions

The swelling of alkali cellulose in sodium hydroxide solutions

Reagents for Low-Formaldehyde Finishing of Textiles

The most important reactants for finishing textiles are the N-methylol compounds. They not only crosslink with the cellulose but also split up to form formaldehyde. To decrease the content of formaldehyde on the fabrics finished with N-methylol compounds, a very efficient fog-chamber technique using solutions of special formal dehyde-binding substances was developed, which reduces the liberation of formalde hyde on finished fabrics to levels below 100 ppm, according to the AATCC Sealed Jar Test Method 112—1975. Low-formaldehyde finishing agents can be prepared by etherifying the methylol groups with alcohols. Fabrics finished with N-alkoxymethyl compounds give off less formaldehyde than those finished with the corresponding unetherified methylol compounds. A few examples are demonstrated. Using the basics of statistical experi mental designs, it was possible to optimize a finishing process with a partly etherified dimethylol-4.5-dihydroxyethyleneurea to obtain simultaneously all desired levels of properties, including a low level of formaldehyde release. A new class of crosslinking agents is described with a nonformaldehyde-containing reactive group beside a N-methylol or N-alkoxymethyl group as a second reactive group on the base of 4-hydroxy- and 4-alkoxy-cycloalkyleneureas. The optimum of application conditions to obtain the desired properties was derived from the results of experimental designs. Another class of crosslinking agents for easy-care, antipilling, and hydrophilic finishing of polyester/cotton fabrics, where cotton is equal or less than 50% in the blend, was developed on the base of polyfunctional carbamates. In comparison to the methylol compounds of cyclic ureas, these products show a higher molecular weight. They are ideal for the swelling and crosslinking of cellulose under heat conditions and provide a smooth, pleasing hand to the finished fabric. This class of reactants exhibits lower abrasion loss than glyoxal reactants and shows less development of unpleasant formaldehyde odor on treated fabrics than most of the usual glyoxal-based reactants.

Influence of surface-active agents on the swelling of cellulose in caustic soda solution

Influence of surface-active agents on the swelling of cellulose in caustic soda solution

Liquid Ammonia vs. NaOH Mercerization as Pretreatment for the Cotton- Butadienediepoxide Reaction. Spectral and Microscopical Studies

Native, mercerized, and ammonia-treated cottons were reacted with butadienediepoxide (BDO), and their fine struc tural changes were followed by x-ray diffractograms, infrared absorption spectra, refractive indices, and in micro scopical cross sections. Conventional mercerization and liquid NH3 pretreatment of native cotton generally produced a more isotropic fiber. But the nature and mode of decomposition of cellulose swelling complexes formed with either NaOH or liquid NH3 differed, as evidenced by differences in crystalline lattices and the optical properties of reaction products. Optical density increased only in the direction of the fiber axis with NH3 but also perpendicularly to the fiber axis with NaOH. Subsequent treatment of NH3-cellulose controls with mercerizing strength NaOH converted their crystalline lattices to Cellulose II. BDO reaction and postmercerization affected the refractive index only in the direction of the fiber axis (η||). Generally, BDO reaction reduced η|| of all but the NH3-cellulose I control; and postmercerization further reduced η|| of only BDO-reaction products that retained the cellulose I lattice. Birefringence of postmercerized BDO-reaction products derived from NH3-cellulose I was lower than that of comparable BDO-reaction products from conventionally mercerized cotton. Before and after BDO reaction, cross sections of most fibers in reaction products from native and NH3-treated cottons with the cellulose I lattice were elliptical, while comparable cross sec tions from conventionally mercerized cotton were round. Changing the catalyst from 2% to 15% NaOH generally increased the number of circular fibers in BDO-treated cottons having the cellulose I structure. All control cottons dissolved in cupriethylenediamine, but BDO-reaction products were insoluble and cross sections appeared solid. Gen erally, reaction products from cottons pretreated with liquid NH3 had a softer hand and dyed more uniformly than did comparable products from conventionally mercerized cotton.

Graft copolymerisation of vinyl monomers on modified cottons. VII. Grafting by chain transfer

AbstractGrafting of methyl methacrylate on cellulosic materials by chain transfer under the catalytic influence of azobisisobutyronitrile (AIBN) was extensively studied. The graft yield is influenced by reaction time, temperature, monomer and initiator concentration, reaction medium and nature of the substrate. In general, the grafting reaction shows an induction period after which the polymerisation proceeds rapidly. The graft yield increases and the induction period decreases by rising the reaction temperature from 50 to 70°C. This is also the case when the monomer concentration was increased from 2 to 6%. Increasing the AIBN concentration up to 0.01 M causes a significant enhancement in grafting while further increase brings about a marked fall in the graft yield. Among the reaction media studied, a water/solvent mixture containing 25% of either methanol, ethanol, propanol, butanol or acetone seems to constitute a reaction medium where the monomer and initiator are completely miscible and the swelling of cellulose by water is not hindered by the presence of these solvents. Increasing the solvent ratio in the water/solvent mixture causes a considerable decrease in the graft yield. The polymer content of the cellulosic materials, i. e. the graft yield, follows the order: partially carboxymethylated cotton > cotton treated with 12N sodium hydroxide > cyanoethylated cotton > cotton treated with 0.5 N sodium hydroxide > purified cotton. In addition, proof of grafting was provided by the fractional precipitation method.

The influence of cellulose structure on the swelling of cellulose in organic liquids

AbstractUsing the method of a modified water‐retention value (LRV), the time dependence and final value of swelling of cellulose in various liquids are found to be determined by the cellulose structure as well as by molar volume and the solubility parameter δH of the liquid, especially its hydrogen bonding part δH and the polar part δP. The different kinetics of swelling of native and regenerated cellulose samples in some liquids of high swelling power like DMSO, as well as the strong influence of the state of drying on the final LRV with native samples, and on swelling kinetics with regenerated cellulose are interpreted by means of the concept of a “pore and void” model of cellulose structure.

Electron-Microscope Study of Cotton Treated with Inter- and Intracrystalline Swelling Agents

Electron micrographs are presented of cotton cellulose treated with aqueous solutions of the inter- and intracrystalline swelling agents, morpholine, piperidine, piperazine, ethylenediamine, and zinc chloride. The concentration of each swelling agent was such as to produce maximum recoverable swelling of cotton cellulose. Physical and fine-structure characteristics of these treated cottons, after complete removal of the swelling agent, revealed that morpholine and piperidine are intercrystalline and piperazine, ethylenediamine, and zinc chloride are intracrystalline swelling agents. Thisw as confirmed by electron-microscope determination of microfibrillar morphology and dimensions. The layer-expansion technique was used to examine these treated cottons along with samples that had been treated with sodium hydroxide and phosphoric and sulfuric acids. The electron micrographs revealed marked gradation in swollen and decrystallized cottons, which may serve as a visual scale at the microfibrillar level for cotton decrystallized to varying degrees. To confirm the extent to which the morphology of decrystallized cotton observed by the layer-expansion technique really exists in the swollen state before the removal of the swelling agent, the cottons treated with sodium hydroxide, morpholine, zinc chloride, and sulfuric acid were embedded in glycol methacrylate in the swollen state and the ultrathin cross sections of these were examined.

Synergistic Effect of Mixed Bases in the Conversion of Cotton Cellulose I to Cellulose II

Several aqueous bases were found which swell cotton yarn greatly, but, after their removal from the cotton, leave the x-ray diffraction pattern unchanged from that of native cellulose I. Such bases include 9.5% lithium hydroxide and 35% benzyltrimethylammonium hydroxide. However, the addition of as little as 1.5% lithium hydroxide or 5% sodium hydroxide, to the benzyltrimethylammonium hydroxide causes substantial conversion of cellulose I to cellulose II. This synergistic effect is attributed to the decrystallizing action of the organic base which, by breaking down the cellulose I lattice, facilitates the action of lithium, sodium, and potassium hydroxides in forming alkali cellulose lattices leading to cellulose II. Rubidium and cesium hydroxides failed to produce this effect when added to the organic base. Cellulose swelling, decrystallization, and recrystallization appear to be distinct steps in lattice conversion. These steps may present greatly different requirements as to optimum cation size and coordination, such requirements being more readily met by mixtures of cations than by any one species. In the absence of the quaternary base, but at alkali concentrations giving maximum fiber swelling, no lattice conversion was produced by lithium or cesium hydroxides, a high degree of conversion occurred with sodium hydroxide, and the other alkalies were intermediate in effect. The strength, elongation, energy-to-rupture, and tenacity of treated yarns varied greatly with the cations present in the alkali. In contrast to yarn, fiber bundles underwent slow and partial conversion to cellulose II by the quaternary base.

Influence of Swelling and Mowosubstitution On the Strength of Cross-Linked Cotton

The reduction in the wear resistance of cotton fabrics in wrinkle-resistant, wash-and- wear, and durable press garments is shown to be related to the lowering of fiber, yarn, and fabric toughness resulting from concentrated cross-linking of limited regions of the cellulose polymer network. Various approaches which have been suggested for improv ing over-all toughness in cotton fabrics are reviewed and discussed. A new concept is presented for achieving major improvements in tensile strength, elongation, tear strength, toughness, flexing resistance, and surface abrasion resistance of wrinkle- resistant cotton fabrics. This concept involves the swelling of cotton fibers to increase the sites for chemical reactions, introduction of bulky, plasticizing side groups, and, finally, cross-linking the distended polymer network to achieve more uniformly placed cross links than is possible in existing methods. Preliminary experimental data are presented for several cases which help to support the above concept. Both by sequential swelling, substitution, and cross-linking and also by one-step reaction with fiber-reactive swelling agents, it is demonstrated that substantial improvements may be obtained in all or some of the various fabric mechanical properties. Studies are described on the characterization of the swelling effect of various organic structures and on the synthesis of cellulose-reactive monofunctional and polyfunctional swelling analogs. Aqueous solutions of increasing concentrations of such compounds are shown to produce variously shaped swelling-concentration curves. When cross-linking swellable, substituted cotton fabrics, much less strength and toughness reduction is produced than is normally obtained in unmodified cotton. Some esterifica tion reactions, however, themselves produce some strength loss prior to cross-linking and need to be improved. Others, such as carbamylation, ethoxylation, and grafting have given higher strength retention. In some cases, substantial increases in both flex and surface abrasion resistance have been produced. This work is continuing in attempts to synthesize the most efficient monofunctional and difunctional cellulose swelling and reactive pair of reagents.

Swelling of Cellulose in Salt Solutions and its Relation to the Radii of Ions

(1966). Swelling of Cellulose in Salt Solutions and its Relation to the Radii of Ions. Journal of the Textile Institute Transactions: Vol. 57, No. 8, pp. T374-T376.

GRAFT COPOLYMERIZATION OF ACRYLAMIDE ONTO GEL-CELLOPHANE BY CERIC ION METHOD

The dimensional and volumeric changes of cellulose gel film during the copolymerization were studied to investigate the behavior of branched polymer formation.The dimensional change of gel film against the grafting yield was found to vary by the thickness direction, the machine direction and the transverse direction of the film, the degree of dimensional change decreased in the following order: thickness direction> transverse direction> machine direction.Since the thickness direction of film is the vertical component of (101) planes of cellulose, on the basis of the results obtained here, the branched polymer is presumed to be formed easily at the space between the micelles oriented to the direction of (101) planes and this conclusion is in accord with the results obtained by the X-ray analysis in the 5th and 6th paper of this series.The volume change against the grafting yield was not detected within 40% of grafting yield, but above 40%, the volume increased proportionally to the grafting yield and the slope of curve at 40_??_300% is recognized to be different from that at above 300%, the value was 0.7 and 1.0, respectively.From the results obtained here, the behavior of dimensional change of gel film during the reaction is presumed to be affected by the swelling of cellulose by water absorption and also the branched polymer is presumed to be formed easily at the surface layer of the film at the lower grafting yield, while it is formed uniformly through the whole layer of the film at above 300%.In addition, the relation between the thickness change of dry grafted film and the grafting yield was studied. The thickness was found to increase proportionally to the grafting yield, but the slope of curve within 100% was recognized to be different from that at above 100%, and the slope of latter curve slightly less than that of former curve.From the results that the behavior of dimensional change against the grafting yield in the case of dry film and wet film was given the opposite result, the state of aggregation of cellulose was affected by the branched polymer and then the dimensional change is presumed to be affected by the shrinkage factor during the drying of the film.Further, the densities of grafted film were measured by the density gradient tube method.The experimental data was found to be in accord with the calculated data by the additive mean value of densities of the polymer components, then the structural change of graft polymer has not clearly been elucidated.

Effect of ethylamine treatment on dielectric properties and crystallinity of cellulose. II

AbstractInvestigations have been made on the influence of (1) beating on the dielectric properties of cellulose, (2) beating before and after ethylamine treatment of cellulose, (3) compressive stress and moisture on the crystallinity of cellulose, (4) pelletizing cellulose for measurement of crystallinity, and (5) employing different methods of drying the cellulose on the crystallinity of cellulose. It was found that existing formulas involving the 002 peak intensity for estimating the crystallinity index seem to be inadequate. It is suspected that ethylamine treatment does not “decrystallize” cellulose but causes swelling of cellulose, resulting in an alteration in the lateral order structure of the so‐called “amorphous content” of cellulose. It is suggested that the moisture regain method is more suitable for comparing the dielectric constant and accessibility of cellulose.