An Estimation of the Accessibility of Cotton Cellulose to Formaldehyde in the Vapor Phase

Joarder, G. K.; Rowland, Stanley P.

doi:10.1177/004051756703701215

Cited by 5 publications

(5 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Table I for the cross-linking of decrystallized cellulose are 5-10 times those for the corresponding reactions of the crystalline ceIlulose. These results are certainly in qualitative agreement with expectation on the basis of the differences in accessibilities [9] . Since the crystalline and decrystallized ceIluloses differ markedly in DP (3500 and 410) and, since the molecular weight distribution of the decrystallized ceIlulose has not been characterized, it is appropriate to suspect that part of the 5-IO-fold difference may be due to differences in molecular parameters.…”

Section: • Dp =_~verage Degree Of Polymerization Between Crosssupporting

confidence: 91%

“…The crystallinity indices of the original cotton printcloth the cross-linked cotton printcloth, or the cotton , printcloth subjected to periods of heating (similar to those for the cross-linking reaction) were in the range of 88-90% [9]. Samples of decrystallized cellulose yielded diffractograms which were generally symmetric about a diffraction angle (20) of 20°and from which the crystallinity index was calculated to he zero.…”

Section: Resultsmentioning

confidence: 99%

“…The reactions of cellulose with formaldehyde to incorporate bound formaldehyde under the conditions employed in this study occurred over the course of many hours [9]. Catalyzed reactions proceeded substantially more rapidly than the corresponding uncatalyzed reactions [8].…”

Section: Resultsmentioning

confidence: 99%

“…Decrystallized cellulose (2 g) was mixed with the reagents in a 50-ml ampule which was evacuated and sealed. Reactions were conducted at 125 ± 1°C in an oil bath for periods required to introduce the desired amounts of formaldehyde [8,9]. All of the products were washed in boiling 2% sodium hydroxide for 16 min to remove boric acid, hemiformal substituents, rind un reacted formaldehyde.…”

Section: Methodsmentioning

confidence: 99%

“…Cotton cellulose was employed as the substrate of high crystallinity (i.e., low accessibility), and the same cellulose, decrystal_ lized by vibratory ball-milling, was selected for high accessibility [18]. Under the reaction conditions employed in this study, this decrystallized cellulose exhibits an accessibility of 48-75% compared to 28-29% for the original cotton cellulose [9]. Relative to molecular degradation during the cross-linking reactions, the study has been conducted on products cross-linked in the presence of boric acid as catalyst and in the absence of catalyst.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

A Critical Study of Selected Formaldehyde-Cross-linked Cotton Celluloses by Sol-Gel Analysis and by Distention-Index Analysis

Joarder

Rowland

1969

Textile Research Journal

View full text Add to dashboard Cite

Cotton celluloses selected for pronounced differences in crystallinities and accessibilities have been cross-linked by the vapor-phase deposition of formaldehyde under conditions previously shown to cause different degrees of molecular degradation. The products at various levels of bound formaldehyde have been analyzed for sol and gel fractions and for degree of distention of the gel fraction in cupriethylenediamine hydroxide. The results of these analyses provide quantitative information on the gross uniformity of distribution of cross linkages in the fiber structure of the celluloses, the uniformity of the distribution of cross linkages along the molecular chains of the cellulose, and the ratio of chain scission to molecular cross-linking in the cross-linked compositions. These analyses can now be applied with greater confidence to obtain useful information on cross-linked celluloses, despite the heterogeneity of phases in the cross-linking reactions and the crystallinity of the cellulose.

show abstract

Section: • Dp =_~verage Degree Of Polymerization Between Crosssupporting

confidence: 91%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A Critical Study of Selected Formaldehyde-Cross-linked Cotton Celluloses by Sol-Gel Analysis and by Distention-Index Analysis

Joarder

Rowland

1969

Textile Research Journal

View full text Add to dashboard Cite

show abstract

Gasdurchlässigkeit von mit Dimethylolharnstoffen vernetztem Zellglas

Niebergall¹

1971

Angew. Makromol. Chem.

View full text Add to dashboard Cite

ZUSAMMENFASSUNG :Die strukturellen und verfahrenstechnischen Gesichtspunkte, welche bei Vernetzungsreaktionen in Baumwoll-Cellulose auftreten, wurden an Hand von Literaturangaben eingehend beleuchtet. Aus den hierbei erhdtenen Ergebniasen wurden, unter Zugrundelegung einer strukturellen und chemisch-reaktiven &iichkeit zwischen nativer und regenerierter Cellulose, Vernetzungsmittel und -methoden ausgewiihlt, welche fiir das Studium des Einflusses einer Vernetzung von Zellglas auf dessen Gaspermeabilitat optimal erschienen.Es wurde gefunden, da13 die angewandten Vernetzungsmittel bei gleichen molaren Konzentrationen in der Folie die Permeabilitiit (P *) verschieden stark beeinflussen. 195H. NIEBERQALL nen an Vernetzungsmittel mit zunehmender Herabsetzung von P * ab. Wenn die hochkristallinen, semikristallinen und amorphen Bereiche der Cellulose gleichzeitig vernetzt werden konnen, wie es beim FA der Fall ist, dann entsteht (bei geniigend starker Vernetzung) ein sehr starres Gefuge, das infolge seiner Dimensionsstabilitlt bei hderungen der rel. F. nur noch eine geringe Abhangigkeit des P * von der rel. F. zeigt, bei gleichzeitiger Verlagerung der P*-Werte nach solchen, wie sie eine unbehandelte Folie bei mittleren und niedrigen rel. F. aufweist. Wenn uberwiegend amorphe und semikristalline Bereiche geniigend stark vernetzt werden, d a k ist zwar eine Ordnungsanderung in den kristallinen Bereichen mit der rel. F. noch moglich, was einer gro13eren Abhiingigkeit von P * von der rel. F. entspricht, gleichzeitig werden die P*-Werte jedoch schon von 64 yo rel. F. abwSirts unter den P *-Wert einer unvernetzten trockenen Folie verlagert.Vergleicht man die Permeabilitat einer handelsiiblichen Saranfolie (dichteste in der Praxis verwendete einfache Folie) mit einer DMDHAH-vernetzten Zellglasfolie bei einer mittleren rel. F. von 64 yo, d a m erhalt man eine Verbesserung der Gasdichtigkeit vom 340-bis zum 1100-fachen. Die DMDHAH-vernetzte Folie ist sogar doppelt so gasdicht wie eine Metall-Verbundfolie aus Saran-Aluminium-Zellglas, welche die gasdichteste in der Praxis verwendete Mehrfach-Verbundfolie ist. SUMMARY :Aspects of crosslinking cotton-cellulose are given in view of structure and processing by means of informations from literature. From results found there, crosslinking agents and methods were selected (underlying the similarity of the structure and reactivity of native and regenerated cellulose), which seemed to be optimal for studies of the influence of crosslinking cellophane to the resulting gas-permeability.Various fixed crosslinking agents are found to have a quite different influence on the permeability (P*) of foils at equal molare concentrations of this agents. Effectivity for lowering P * depends, within a certain (

show abstract

Accessibility of cellulose

Roberts¹

1996

Paper Chemistry

View full text Add to dashboard Cite

An Estimation of the Accessibility of Cotton Cellulose to Formaldehyde in the Vapor Phase

Cited by 5 publications

References 5 publications

A Critical Study of Selected Formaldehyde-Cross-linked Cotton Celluloses by Sol-Gel Analysis and by Distention-Index Analysis

A Critical Study of Selected Formaldehyde-Cross-linked Cotton Celluloses by Sol-Gel Analysis and by Distention-Index Analysis

Gasdurchlässigkeit von mit Dimethylolharnstoffen vernetztem Zellglas

Accessibility of cellulose

Contact Info

Product

Resources

About