Intercrystalline Swelling in Morpholine-Treated Cotton Cellulose

Betrabet, S. M.; Daruwalla, E. H.; Lokhande, H. T.

doi:10.1177/004051756603600715

Cited by 13 publications

(5 citation statements)

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“…Also, the morpholine pre-treatment process did not lead to a marked reduction in crystallinity index and the 13% decrease observed in comparison to the starting pulp can be attributed to the impact of mechanical shearing (Eyholzer et al 2010;Taheri and Samyn 2016;Tian et al 2016). This result is broadly consistent with the surface chemistry analysis reported in previous studies where morpholine was shown not to affect the crystallinity index of cellulose but to only act as an inter-crystalline swelling agent (Betrabet et al 1966;Betrabet and Rollins 1970;Lokhande 1978;Lokhande et al 1984). In contrast, the carboxymethylation pre-treatment process, coupled with mechanical shearing, led to a 35% decrease in the crystallinity index of CMCNF compared with the starting cellulose pulp.…”

Section: Effect Of Chemical Pre-treatments and Mechanical Processing supporting

confidence: 91%

“…Betrabet, Lokhande and co-workers investigated the use of aqueous morpholine and other amines as swelling agents for cotton to increase its dye uptake (Betrabet et al 1966;Betrabet and Rollins 1970;Kulkarni and Lokhande 1975;Lokhande 1978;Lokhande et al 1984). They observed that aqueous morpholine can swell cotton cellulose without changing its density, crystallinity index and tensile strength (Betrabet et al 1966;Betrabet and Rollins 1970).…”

Section: Introductionmentioning

confidence: 99%

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Aqueous morpholine pre-treatment in cellulose nanofibril (CNF) production: comparison with carboxymethylation and TEMPO oxidisation pre-treatment methods

2017

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In this study, pulped cellulose fibres were pre-treated with aqueous morpholine prior to mechanical disruption in the production of cellulose nanofibrils (CNF). The properties of the morpholine pretreated CNF (MCNF) were closely compared with CNF obtained from carboxymethylation (CMCNF) and TEMPO-oxidation (TCNF) pre-treatment methods. An investigation of the swelling behaviours of cellulose in varying concentrations of morpholine revealed that there is a synergistic behaviour between morpholine and water in its ability to swell cellulose. As a result, cellulose pulp dispersed in 1:1 mole ratio of morpholine to water was well swollen and readily fibrillated by mechanical shear. Surface chemistry analyses indicated that the surface of the MCNF remained unmodified, compared to the CMCNF and TCNF which were modified with anionic groups. This resulted in only a slight decrease in crystallinity index and a minimal effect on the thermal stability of MCNF, compared to CMCNF and TCNF which showed marked decreases in crystallinity indices and thermal stabilities. The average widths of MCNF, CMCNF and TCNF, as measured from electron microscopic images, were broadly similar. The higher polydispersity of MCNF widths however led to a differential sedimentation and subsequent lower aspect ratio in comparison with CMCNF and TCNF as estimated using the sedimentation approach. Also, the presence of electrostatic repulsive forces, physical interactions/ entanglements and lower rigidity threshold of the CMCNF and TCNF resulted in higher storage moduli compared to the MCNF, whose elasticity is controlled by physical interactions and entanglements. Aqueous morpholine pre-treatment can potentially be regarded as an ecologically sustainable process for unmodified CNF production, since the chemical reagent is not consumed and can be recovered and reused.

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Section: Effect Of Chemical Pre-treatments and Mechanical Processing supporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Aqueous morpholine pre-treatment in cellulose nanofibril (CNF) production: comparison with carboxymethylation and TEMPO oxidisation pre-treatment methods

2017

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“…The swelling of cotton cellulose in morpholine has been attributed to the solubility parameter of morpholine, which is comparable to that of the cellobiose molecule and also to its ring NH-and 0-groups [ 2 ] . The structures of piperidine and piperazine are similar .…”

Section: Resultsmentioning

confidence: 99%

“…1 Paper presented at the American Chemical Society 158th National Meeting, September 1969. 2 The research was conducted while the author was pursuing an NRC-ARS Postdoctoral Resident Research Associateship, 1968-1970. Density. Measurements were made in a density gradient column at 25°C, with a mixture of carbon tetrachloride and xylene according to the method of Preston and Nimkar [ 21 ] .…”

Section: Preparation Of Swollen Cellulose Samplesmentioning

confidence: 99%

“…The nature of swelling and the extent of decrystallization have been studied mainly by x-ray diffraction and infrared spectral and deuteration techniques [10, 11, 18, 19, 2 7 ] . Betrabet et al [ 2,3 ] have made some electron-microscope observations on cottons swollen with aqueous solutions of morpholine and zinc chlo-, ride. However, critical examination of cotton treated with different inter-and intracrystalline swelling agents does not seem to have been made extensively with the electron microscope.…”

Section: Introductionmentioning

confidence: 99%

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

Betrabet

Rollins

1970

Textile Research Journal

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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.

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Physical Constants of Cellulose

Ganster

Fink

1999

The Wiley Database of Polymer Properties

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Intercrystalline Swelling in Morpholine-Treated Cotton Cellulose

Cited by 13 publications

References 0 publications

Aqueous morpholine pre-treatment in cellulose nanofibril (CNF) production: comparison with carboxymethylation and TEMPO oxidisation pre-treatment methods

Aqueous morpholine pre-treatment in cellulose nanofibril (CNF) production: comparison with carboxymethylation and TEMPO oxidisation pre-treatment methods

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

Physical Constants of Cellulose

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