Papers by Fardous Mobarak
An extensive background overview on the use of agricultural residues (wastes) for production of p... more An extensive background overview on the use of agricultural residues (wastes) for production of paper, board, binderless board, energy, different types of fuels by pyrolysis (solid, liquid and gaseous fuel), many petrochemicals substitutes, charcoal (activated carbon), dissolving pulps and rayon. It includes both scientific and industrial data, case studies, current status, sustainability of paper and sugar industries, green nanotechnology, and future prospects.
Keywords: Agricultural Residues (Wastes); Paper and Board manufacture; Sustainability of Paper and Sugar Industries; Green Nanotechnology; Future Prospects
Biomass pyrolysis is a promising renewable sustainable source of fuels and petrochemical substitu... more Biomass pyrolysis is a promising renewable sustainable source of fuels and petrochemical substitutes. It may help in compensating the progressive consumption of fossil-fuel reserves. The present article outlines biomass pyrolysis. Various types of biomass used for pyrolysis are encompassed, e.g., wood, agricultural residues, sewage. Categories of pyrolysis are outlined, e.g., flash, fast, and slow. Emphasis is laid on current and future trends in biomass pyrolysis, e.g., microwave pyrolysis, solar pyrolysis, plasma pyrolysis, hydrogen production via biomass pyrolysis, co-pyrolysis of biomass with synthetic polymers and sewage, selective preparation of high-valued chemicals, pyrolysis of exotic biomass (coffee grounds and cotton shells), comparison between algal and terrestrial biomass pyrolysis. Specific future prospects are investigated, e.g., preparation of supercapacitor biochar materials by one-pot one-step pyrolysis of biomass with other ingredients, and fabricating metallic catalysts embedded on biochar for removal of environmental contaminants. The authors predict that combining solar pyrolysis with hydrogen production would be the eco-friendliest and most energetically feasible process in the future. Since hydrogen is an ideal clean fuel, this process may share in limiting climate changes due to CO 2 emissions.
Keywords Sustainable and renewable energy source; Fossil-fuel alternatives; Biomass pyrolysis; Biofuel (bio-oil, biogas, biochar); Charcoal (activated carbon); Hydrogen fuel
The present work leads to sustainability (responsible management of resources consumption) of bot... more The present work leads to sustainability (responsible management of resources consumption) of both paper and sugar industries. It, simultaneously, upgrades recycled waste paper (namely old newsprint) and creates a new use for molasses (an important byproduct of the sugar industry). This study introduces -for the first time world wide- a novel environmentally safe approach to upgrade recycled natural cellulose fibers (waste paper namely old newsprint), for use as specialty paper green nanocomposites suitable for several advanced purposes. The recycled cellulose fibers are upgraded by increasing their alpha cellulose content, and restoring their natural nanoporous structure, which is -normally- collapsed due to the first cycle of papermaking. Molasses is then incorporated into this restored nanoporous structure to obtain paper green nanocomposites filled with kaolin in presence of molasses. In comparison to conventionally recycled waste paper, the green paper nanocomposites -produced in this work- exhibit high dry and wet strength, and a surprisingly tremendous retention of inorganic fillers used in papermaking. This was achieved through a green nanotechnology process, where the solvent used is water (the ideal green solvent). The input and output components are renewable environmentally safe materials i.e. waste paper (cellulose fibers) and molasses (a by product of the sugar industry). The procedures used are simple physical processes conducted at room temperature rather than hazardous chemical reactions. Thus, saving energy, and decreasing the risk of chemical and thermal accidents, pollutive releases, explosions, and fires.
For the first time, it is shown that water medium allows dissolved methylmethacrylate monomer to ... more For the first time, it is shown that water medium allows dissolved methylmethacrylate monomer to penetrate water-swollen natural nanoporous structure of never-dried cotton fibers (biological cellulose fibers). Unique cellulose copolymer nanocomposites are obtained by green nanotechnology process (solvent is water-ideal green solvent-and reaction conducted at 25ºC). It was found that after only 2 h polymerization the conversion of MMA monomer to polymer was 42.97%, compared to zero polymer conversion in absence of never-dried cotton. Higher water uptake i.e. water retention value (WRV) of the cellulose-PMMA-copolymer nanocomposites prepared from never-dried biological cotton fibers, and microscopic investigations confirmed that the polymer was mostly grafted on the cellulose rather than homopolymer filling the fiber pores. Early products of polymerization e.g. dimmers and trimmers act as spacers and widen the porous structure of cell wall, thus increasing water retention value (WRV). We called this phenomenon "intra-polymerization". As the process of polymerization proceeds, polymerization within cell walls leads to cell wall destruction, increasing WRV of fibers, giving superabsorbent end product. The produced unique biological cotton-PMMA green nanocomposite we discovered find their use in several advanced medical and pharmaceutical fields; as nonwoven pads, bandages or board-like transparent nanocomposites of bending strength up to 955 kg/cm 2 .
The present work shows for the first time worldwide that sucrose can be easily placed by simple t... more The present work shows for the first time worldwide that sucrose can be easily placed by simple techniques within the micropores or nanostructure of the mercerized non-dried cotton linter fibers to create a low-cost cellulose substitute. Such sucrose-containing nanocomposites find suitable use as specialty absorbent paper. Relative to the sucrose-free paper, the sucrose-containing counterparts exhibit greater breaking length and remarkably high water uptake (WRV) up to a sucrose content of 8–15% w/w. Mercerization of cotton linters before incorporating them with sucrose greatly enhanced the retention of sucrose in the prepared paper nanocomposites as compared to the case of unmercerized cotton linters. We assume that regions of the cell wall lamellae, on both sides of the sucrose spacers, are stressed during drying because the sucrose spacers hinder them to relax. This leads to a strain, which makes some microfibrils partially released and protrude out of the fiber. Thus, a sort of fiber beating takes place. We called this phenomenon incorporation beating or encapsulation beating to differentiate it from chemical and mechanical beatings, and it explains the great increase in breaking length of the paper nanocomposites prepared from the mercerized non-dried sucrose-loaded linters.
This work introduces, for the first time worldwide, undeinked recycled old newsprint as a new res... more This work introduces, for the first time worldwide, undeinked recycled old newsprint as a new resource of electrical purposes paper. Impregnation of undeinked recycled old newsprint paper with linseed oil enhances the breaking length of paper and remarkably improves its electrical properties, i.e., the dielectric constant increases greatly and the a.c. conductivity decreases significantly due to impregnation. It was found that the electrical properties of the undeinked old newsprint paper and its linseed oil impregnated counterpart are close to the electrical properties of paper made from the more expensive virgin wood pulps and their linseed oil impregnated counterparts. Using the undeinked pulp is more privileged than using the deinked pulp; because eliminating the deinking step saves money, time, and reagents. In addition, eliminating the deinking step improved the breaking length of paper. Electron dispersive X-ray elemental analysis (EDX) was used to investigate the undeinked and deinked pulps for residual elements originating from the printing materials. EDX was correlated to the slight differences in electrical properties of paper made from undeinked and deinked pulps. However, impregnation was able to overcome these slight differences. It was shown that improvement in electrical properties, due to impregnation, is sustained at elevated temperatures.
This work introduces, for the first time worldwide, an advanced nanocomposite involving two addit... more This work introduces, for the first time worldwide, an advanced nanocomposite involving two additives – a nanoadditive and a conventional additive – within a matrix of natural cellulose fibers. The first additive (the nanoadditive) is sucrose, which incorporates the nanoporous structure of the cell walls of cellulose fibers. The second additive (the conventional additive) is kaolin, the famous paper filler. Kaolin is enmeshed between the adjacent cellulose fibers. This advanced paper nanocomposite was prepared by simple techniques.
The present work shows, for the first time, that sucrose can overcome the ultimate fate of deterioration in strength of paper, due to addition of inorganic fillers such as kaolin. This deterioration was counteracted by incorporating cellulose fibers with sucrose, which leads to incorporation beating of the fibers, and thus increases the strength of the produced paper nanocomposites. In addition, sucrose was proven – for the first time – to act as retention aid for inorganic fillers such as kaolin. We called this phenomenon incorporation retention to differentiate it from the conventional types of retention of inorganic fillers.
Recent studies, by the authors and others, have shown that incorporating cellulose fibers, with sucrose, leads to paper nanocomposites of enhanced strength (breaking length). Also, sucrose is privileged by its small size (0.8 nm), substantial hydrogen bonding capacity, low cost, and abundance. Therefore, sucrose was chosen as a nanoadditive in this work. The present study shows that the nanoadditive sucrose may find its use as a new retention aid and strength promoter in papermaking.
Carbohydrate Polymers, 2009
This work introduces, for the first time worldwide, molasses – a byproduct of the sugar industry ... more This work introduces, for the first time worldwide, molasses – a byproduct of the sugar industry – as a master retention aid and strength promoter in papermaking. The paper nanocomposites produced in the present work – involving molasses, natural cellulose fibers, and kaolin – retained larger amounts of kaolin while exhibiting greater strength, as compared to their molasses-free counterparts. Recently, the authors have shown, for the first time, that the nanoadditive sucrose can overcome the ultimate fate of deterioration in strength of paper, due to addition of inorganic fillers such as kaolin. This deterioration was counteracted by incorporating the nanoporous structure of cellulose fibers with sucrose, which leads to incorporation beating of the fibers, and thus increases the strength of the produced paper nanocomposites. In addition, the nanoadditive sucrose was proven – for the first time – to act as retention aid for inorganic fillers such as kaolin. We called this phenomenon incorporation retention to differentiate it from the conventional types of retention of inorganic fillers. On the other hand, it is well established in the literature that using gums (including starch) as additives in papermaking enhances the strength of paper. Molasses contains both the nanoadditive (sucrose), and gums (including starch). Molasses is a byproduct of sugar industry, which is cheaper than sucrose; and a major part of sucrose lost in sugar industry resides in molasses. Moreover, molasses is an environmentally safe additive. Therefore, the nanoadditive (molasses) was chosen, in the present work, to be manipulated as a master strength promoting retention aid for inorganic fillers used in papermaking, such as kaolin.
Self-bonding of air-dried undebarked cotton stalks during hot pressing in a closely fitting mold ... more Self-bonding of air-dried undebarked cotton stalks during hot pressing in a closely fitting mold was studied. Advanced board-like green nanocomposites from ground undebarked cotton stalks were introduced for the first time in the present work. The dry forming process was adopted. Moderate molding pressure and temperature were selected and applied in a tight die, thus saving water and energy and avoiding the use of any binders to achieve an environment-friendly green product. Green nanocomposites having densities in the range of 1.27–1.29 g/cm3 and 1.03–1.06 g/cm3 were prepared. Particle size and cell wall morphological structure were found to play a major role in self-bonding. Properties of composites prepared from the fine fraction of cotton stalks were superior to those prepared from the cotton stalk coarse fraction at the same conditions. This is attributed—among other things—to the dominance of pith (parenchymal cells) in the fine fraction. Such cells possess a high lumen-to-cell wall ratio, which renders them more deformable under pressure, leading to more intercellular or interparticle bonding. Advanced binderless green nanocomposites having bending strength as high as 637 kg/cm2 and water absorption as low as 12.1 % were obtained from the ground undebarked cotton stalks. The results show clearly that the advanced green nanocomposite obtained by the dry forming process, without the addition of any binders, is superior to hardboard obtained from cotton stalks by the conventional wet web formation process. The mechanism of self-bonding is discussed.
The present work introduces mild – room temperature – potassium permanganate treatment of cellulo... more The present work introduces mild – room temperature – potassium permanganate treatment of cellulosic materials, namely already bleached pulps. Such treatment represents a new approach for upgrading pulp and paper quality, which is lacking in the literature. Potassium permanganate was investigated as a purifying and mild oxidizing agent for commercial already bleached softwood and bagasse pulps. It was found that treatment of the bleached beaten pulps, with 0.25–2% KMnO4 (based on pulp weight), led to significant improvement in paper properties. The strength (breaking length) increased greatly and the brightness increased significantly due to treatment. The improvements were related to the degree of polymerization, and to the alphacellulose content of pulps.
Moreover, potassium permanganate serves as a disinfectant and deodorizer. Thus treatment of bleached pulps with KMnO4 is a promising remedy for the side effects which pulps suffer, during transportation and storage, before papermaking.
This work introduces, for the first time worldwide, the means to preserve and protect the natural... more This work introduces, for the first time worldwide, the means to preserve and protect the natural nanoporous structure of the never-dried plant cell wall, against the irreversible collapse, which occurs due to drying. Simultaneously, these means, used for the above-mentioned aim, provide a gateway to novel nanocomposite materials, which retain the super reactive and super absorbent properties of the never-dried biological cellulose fibers. The present work showed, for the first time worldwide, that glucose can be vaccinated into the cell wall micropores or nanostructure of the never-dried biological cellulose fibers, by simple new techniques, to create a reactive novel nanocomposite material possessing surprising super absorbent properties. Inoculation of the never dried biological cellulose fibers, with glucose, prevented the collapse of the cell wall nanostructure, which normally occurs due to drying. The nanocomposite, produced after drying of the glucose inoculated biological cellulose, retained the super absorbent properties of the never dried biological cellulose fibers. It was found that glucose under certain circumstances grafts to the never dried biological cellulose fibers to form a novel natural nanocomposite material. About 3-8% (w/w) glucose remained grafted in the novel nanocomposite.
Finding new uses for recycled paper (a cellulose rich raw material), and increasing the rate of r... more Finding new uses for recycled paper (a cellulose rich raw material), and increasing the rate of recycling is beneficial to the environmental efficiency of the whole paper industry. The present work introduces, for the first time, deinked recycled old newsprint as a new resource of electrical purposes paper. Impregnation of recycled deinked old newsprint paper, by linseed oil, enhances the breaking length of paper and remarkably improves its electrical properties i.e., the dielectric constant increases greatly and the a.c. conductivity decreases significantly due to impregnation. It was found that the electrical properties of deinked recycled old newsprint paper and its linseed oil impregnated counterpart, are close to the electrical properties of paper made from the more expensive virgin wood pulps and their linseed oil impregnated counterparts. In a series of research articles, the authors and others threw light for the first time on the electrical properties of paper made from agricultural residues pulps, and their linseed oil impregnated counterparts. Some, of the investigated agricultural residues papers, showed electrical properties close to wood papers, or even superior to it. This motivated the authors to expand the studies, on electrical properties of paper, to other cheap and abundant raw materials. Recycled old newsprint is an abundant raw material that is cheaper than virgin wood pulps. Therefore, recycled deinked old newsprint paper was chosen as a new raw material to study its electrical properties in this work. The effect of elevated temperatures on the electrical properties of paper is, also, studied. It is shown that improvement in electrical properties, due to impregnation, is sustained at elevated temperatures. Impregnated deinked recycled old newsprint paper produced in this work finds its use as specialty electrical purposes paper.
The reactivity of cellulose fibers depends on the extent of agglomeration and adhesion of the ele... more The reactivity of cellulose fibers depends on the extent of agglomeration and adhesion of the elementary fibrils due to drying and on the capacity of the reagent to dissoc. the agglomerated elementary fibrils. Mercerization of the fibers dissocd. the microfibrils into the original elementary fibrils and exposed the cell wall surfaces. Cotton fibers subjected to reaction while still in the never-dried biol. state, have similar reactivity as rayon.
Figure 1 linked to Article: Fahmy Y, Mobarak F (1971) On fine structure of cellulose fibers. Sven... more Figure 1 linked to Article: Fahmy Y, Mobarak F (1971) On fine structure of cellulose fibers. Svensk Papperstidning 74(1):2-9 ABSTRACT: For the first time, never-dried cotton from unopened green cotton bolls was isolated and characterized (we designated it as biological cellulose fibers). Several methods for determination of the swellability of cellulose fibers are discussed with respect to their reliability in measuring cell-wall water content. The fiber density, as measured by H2O or xylene displacement, was interpreted in terms of fiber fine structure, i.e., the degree of packing of cellulose molecules in the protofibril. The water retention value of never-dried cotton, isolated from green unopened cotton bolls, was close to that of never-dried rayon. The never-dried cotton became cryst. for the first time after air drying. Water treatment of the air-dried fibers failed to return the cell wall to its original biological volume. The reactivity of cellulose fibers depended on the degree of preservation of the biological volume and on the chemical treatments and drying.
It is shown that cellulose in the biological, i.e. never-dried, native state is much more reactiv... more It is shown that cellulose in the biological, i.e. never-dried, native state is much more reactive than air-dried or conventional cellulose. In the biological state, cellulose fibres are as reactive as the never-dried regenerated cellulose. It is indicated that reactivity of cellulose is correlated to the extent of dissociation of microfibrils to elementary fibrils or protofibrils rather than to crystallinity.
Acetylated samples obtained from biological cotton are characterized by enormously higher water uptake than acetate obtained from conventional cotton. Despite acetyl contents of about 16%, such samples possessed higher WRV than unacetylated conventional cotton. This is accounted for and demonstrates that cellulose derivatives of different properties could be obtained from biological cellulose.
A high fibre saturation point (FSP) of about 120% is ascribed to pure cellulose
nature fibre in ... more A high fibre saturation point (FSP) of about 120% is ascribed to pure cellulose
nature fibre in the never-dried state irrespective of plant origin, as well as to
never-dried regenerated cellulose fibres.
Since FSP is a measure of fibre porosity, all never-dried fibrous cellulose may possess the same accessibility to reagents. Reactivity in such a state represents the highest cellulose reactivity in its coherent fibrous state. This was confirmed experimentally. After nature-, air-drying cellulose fibres respectively and after treating them with water, different fibres revert to the original biological cell wall volume or never-dried volume lo different extents. While dry-regenerated fibres possess a high degree of reversion in water into the never-dried state, dry cotton reverts to a much smaller- degree. Acid treatment also failed to affect considerably the reversion of cotton fibres. Treatment with sodium hydroxide solution of about 18% concentration reverts cotton cell wall completely to the original biological volume as far as FSP is concerned. This is termed 100% reversion.
Higher degrees of reversion indicate the weakening or the beginning of the loss of fibrous structure and its transformation into a more or less non fibrous gel structure, usually accompanied by partial cellulose dissolution. Some examples are given in the paper.
For the first time, never-dried cotton from unopened green cotton bolls was isolated and characte... more For the first time, never-dried cotton from unopened green cotton bolls was isolated and characterized (we designated it as biological cellulose fibers). Several methods for determination of the swellability of cellulose fibers are discussed with respect to their reliability in measuring cell-wall water content. The fiber density, as measured by H2O or xylene displacement, was interpreted in terms of fiber fine structure, i.e., the degree of packing of cellulose molecules in the protofibril. The water retention value of never-dried cotton, isolated from green unopened cotton bolls, was close to that of never-dried rayon. The never-dried cotton became cryst. for the first time after air drying. Water treatment of the air-dried fibers failed to return the cell wall to its original biological volume. The reactivity of cellulose fibers depended on the degree of preservation of the biological volume and on the chemical treatments and drying.
For the first time worldwide, it is shown that our novel nanocomposite produced from natural fibe... more For the first time worldwide, it is shown that our novel nanocomposite produced from natural fibers vaccinated with glucose--by fully green nanotechnology--possesses surprising reactivity towards urea. Magic super absorbent carbamated nanocomposite cotton fabrics having remarkable distinguished properties were obtained in few minutes. It is well established that carbamates possess antibacterial effects. The produced magic nanocomposite fabrics, we discovered for the first time worldwide, find their use as woven or nonwoven hygienic pads, bandages or paper nanocomposites.
Tar and charcoal could be produced in high yields from bagasse by applying a rapid continuous pyr... more Tar and charcoal could be produced in high yields from bagasse by applying a rapid continuous pyrolysis process at a relatively low temperature. The ether extractives of the pyrolytic tar and oil amounted to 9.4 % based on bagasse. Phenols represented 79 % of these extractives. Gas chromatographic separation showed that guaiacol and its derivatives constituted 38 % of the identified simple phenols. There were much smaller amounts of syringol and none at high pyrolysis temperatures. Depithing did not reduce the ash content of the charcoal, but it yielded an environmentally clean charcoal containing practically no sulfur or nitrogen. It was necessary to remove the fine particle size fraction of the bagasse after grinding in order to reduce the ash content of the charcoal The carbon content of the charcoal increased rapidly with increasing temperature, and reached 96 % at 720 ~ C. The charcoal had a remarkably high adsorption capacity despite the fact that it had not been subjected to any activation treatment.
Holzforschung, 1983
Charcoal of >80% C content was obtained from cotton stalks by a rapid continuous pyrolysis proces... more Charcoal of >80% C content was obtained from cotton stalks by a rapid continuous pyrolysis process. The yield was 17-37% depending on the pyrolysis temp. When increasing the temp. from 400-700° the C content of the charcoal initially increased, then remained const. while the yield decreased. The optimum pyrolysis temp. was 600°. At this temp. a produce having 86% C content on a moisture and ash free basis was obtained. Considerable amts. of pyrolytic tar and oil are obtained which can be used as fuel or a feedstock of chems. The bulk d. of charcoal went through a min. at a pyrolysis temp. of 600°. The increase obsd. at higher temps. was attributed to the collapse of the cell wall structure. On the other hand, the adsorption activity decreased continually with increasing pyrolysis temp.
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Papers by Fardous Mobarak
Keywords: Agricultural Residues (Wastes); Paper and Board manufacture; Sustainability of Paper and Sugar Industries; Green Nanotechnology; Future Prospects
Keywords Sustainable and renewable energy source; Fossil-fuel alternatives; Biomass pyrolysis; Biofuel (bio-oil, biogas, biochar); Charcoal (activated carbon); Hydrogen fuel
The present work shows, for the first time, that sucrose can overcome the ultimate fate of deterioration in strength of paper, due to addition of inorganic fillers such as kaolin. This deterioration was counteracted by incorporating cellulose fibers with sucrose, which leads to incorporation beating of the fibers, and thus increases the strength of the produced paper nanocomposites. In addition, sucrose was proven – for the first time – to act as retention aid for inorganic fillers such as kaolin. We called this phenomenon incorporation retention to differentiate it from the conventional types of retention of inorganic fillers.
Recent studies, by the authors and others, have shown that incorporating cellulose fibers, with sucrose, leads to paper nanocomposites of enhanced strength (breaking length). Also, sucrose is privileged by its small size (0.8 nm), substantial hydrogen bonding capacity, low cost, and abundance. Therefore, sucrose was chosen as a nanoadditive in this work. The present study shows that the nanoadditive sucrose may find its use as a new retention aid and strength promoter in papermaking.
Moreover, potassium permanganate serves as a disinfectant and deodorizer. Thus treatment of bleached pulps with KMnO4 is a promising remedy for the side effects which pulps suffer, during transportation and storage, before papermaking.
Acetylated samples obtained from biological cotton are characterized by enormously higher water uptake than acetate obtained from conventional cotton. Despite acetyl contents of about 16%, such samples possessed higher WRV than unacetylated conventional cotton. This is accounted for and demonstrates that cellulose derivatives of different properties could be obtained from biological cellulose.
nature fibre in the never-dried state irrespective of plant origin, as well as to
never-dried regenerated cellulose fibres.
Since FSP is a measure of fibre porosity, all never-dried fibrous cellulose may possess the same accessibility to reagents. Reactivity in such a state represents the highest cellulose reactivity in its coherent fibrous state. This was confirmed experimentally. After nature-, air-drying cellulose fibres respectively and after treating them with water, different fibres revert to the original biological cell wall volume or never-dried volume lo different extents. While dry-regenerated fibres possess a high degree of reversion in water into the never-dried state, dry cotton reverts to a much smaller- degree. Acid treatment also failed to affect considerably the reversion of cotton fibres. Treatment with sodium hydroxide solution of about 18% concentration reverts cotton cell wall completely to the original biological volume as far as FSP is concerned. This is termed 100% reversion.
Higher degrees of reversion indicate the weakening or the beginning of the loss of fibrous structure and its transformation into a more or less non fibrous gel structure, usually accompanied by partial cellulose dissolution. Some examples are given in the paper.
Keywords: Agricultural Residues (Wastes); Paper and Board manufacture; Sustainability of Paper and Sugar Industries; Green Nanotechnology; Future Prospects
Keywords Sustainable and renewable energy source; Fossil-fuel alternatives; Biomass pyrolysis; Biofuel (bio-oil, biogas, biochar); Charcoal (activated carbon); Hydrogen fuel
The present work shows, for the first time, that sucrose can overcome the ultimate fate of deterioration in strength of paper, due to addition of inorganic fillers such as kaolin. This deterioration was counteracted by incorporating cellulose fibers with sucrose, which leads to incorporation beating of the fibers, and thus increases the strength of the produced paper nanocomposites. In addition, sucrose was proven – for the first time – to act as retention aid for inorganic fillers such as kaolin. We called this phenomenon incorporation retention to differentiate it from the conventional types of retention of inorganic fillers.
Recent studies, by the authors and others, have shown that incorporating cellulose fibers, with sucrose, leads to paper nanocomposites of enhanced strength (breaking length). Also, sucrose is privileged by its small size (0.8 nm), substantial hydrogen bonding capacity, low cost, and abundance. Therefore, sucrose was chosen as a nanoadditive in this work. The present study shows that the nanoadditive sucrose may find its use as a new retention aid and strength promoter in papermaking.
Moreover, potassium permanganate serves as a disinfectant and deodorizer. Thus treatment of bleached pulps with KMnO4 is a promising remedy for the side effects which pulps suffer, during transportation and storage, before papermaking.
Acetylated samples obtained from biological cotton are characterized by enormously higher water uptake than acetate obtained from conventional cotton. Despite acetyl contents of about 16%, such samples possessed higher WRV than unacetylated conventional cotton. This is accounted for and demonstrates that cellulose derivatives of different properties could be obtained from biological cellulose.
nature fibre in the never-dried state irrespective of plant origin, as well as to
never-dried regenerated cellulose fibres.
Since FSP is a measure of fibre porosity, all never-dried fibrous cellulose may possess the same accessibility to reagents. Reactivity in such a state represents the highest cellulose reactivity in its coherent fibrous state. This was confirmed experimentally. After nature-, air-drying cellulose fibres respectively and after treating them with water, different fibres revert to the original biological cell wall volume or never-dried volume lo different extents. While dry-regenerated fibres possess a high degree of reversion in water into the never-dried state, dry cotton reverts to a much smaller- degree. Acid treatment also failed to affect considerably the reversion of cotton fibres. Treatment with sodium hydroxide solution of about 18% concentration reverts cotton cell wall completely to the original biological volume as far as FSP is concerned. This is termed 100% reversion.
Higher degrees of reversion indicate the weakening or the beginning of the loss of fibrous structure and its transformation into a more or less non fibrous gel structure, usually accompanied by partial cellulose dissolution. Some examples are given in the paper.