Spontaneous elongation of cellulose acetate plastics

Fridman, O. A.; Naimark, N.I.; Malinin, L. N.; Vladimirov, Yu.I.

doi:10.1016/0032-3950(82)90045-4

Cited by 3 publications

(2 citation statements)

References 2 publications

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“…This is confi rmed, in particular, by the X-ray diffraction data. The diffraction pattern of the initial fi lm (curve 1) is typical of amorphous samples of cellulose acetates [19]. Upon NM sorption (curve 2), the broad peaks in the diffraction pattern of the CTA fi lm are split into several sharp refl ections corresponding to interplanar spacings of 10.39, 8.56, 6.71, 5.12, and 4.22 Å.…”

Section: Mnmentioning

confidence: 99%

Modification of the structure of cellulose triacetate films in the course of solvent vapor sorption

2014

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The production of fi lms used as materials for package, fi lters, water treatment membranes, electrical insulation, photography, and motion pictures is a promising application fi eld of cellulose acetates (CAs) prepared from a renewable raw material. Because of large-scale practical use and availability, cellulose derivatives still attract much researchers' attention, since many problems associated with their complicated structural organization remain to be solved. The physicomechanical and ecological properties of materials based on cellulose esters are largely determined by the initial structure of the polymeric material, by its changes under the infl uence of solvents, and by the nature of solvents used for manufacturing the material. Studies of the behavior of CAs in various solvents are also of particular interest today, because cellulose esters characterized by increased chain rigidity tend to ordering and formation of liquid crystal (LC) state in solutions and melts, and also in the presence of organic solvent vapors [1,2]. Hydrogen bonds and donor-acceptor interactions play a signifi cant role in the formation of the anisotropic state of polymer systems and in structural transformations on the molecular and supramolecular levels [3,4]. One of the most sensitive methods for analysis of the structure of macromolecules and intermolecular interactions caused by hydrogen bonds is Fourier IR spectroscopy.This method was used previously [4] for studying the LC formation in cellulose diacetate fi lms in nitromethane and dimethylsulfoxide vapors.This work was aimed at studying intra-and intermolecular interactions in cellulose triacetate fi lms in the course of sorption of vapors of solvents differing in the chemical nature and at evaluating the structure of the polymeric fi lm material. EXPERIMENTALExperiments were performed with cellulose triacetate (CTA) fi lms prepared from a 1.5% solution of CTA in methylene chloride. Films were prepared from cellulose acetate produced in Russia by heterogeneous acetylation and saponifi cation, viscosity-average molecular mass М η = 7.3 × 10 4 . The content of acetate groups, according to the certifi cate data, was 60.5%. Films were prepared in Petri dishes. The solvent was evaporated at room temperature in an air thermostat for 24 h and then in a vacuum box to constant weight without heating. The fi lm thickness was 50-80 μm.As solvents we used dimethylsulfoxide (DMSO, aprotic strongly donor polar solvent, donor number DN SbCl 5 = 28.9, dipole moment μ = 3.96 D [5]), nitromethane (NM, Abstract-Intermolecular interaction and structure of cellulose triacetate fi lms in the course of sorption of dimethylsulfoxide, nitromethane, and tetrachloroethane vapors were studied by Fourier IR spectroscopy, X-ray diffraction analysis, and polarization microscopy. Quantitative ratio of different types of intra-and intermolecular hydrogen bonds in polymer fi lms was estimated. Changes in the structure of cellulose triacetate fi lms in the course of solvent vapor sorption were discussed from...

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Section: Mnmentioning

confidence: 99%

Modification of the structure of cellulose triacetate films in the course of solvent vapor sorption

2014

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“…The effect of spontaneous elongation of cellulose ether films and fibres in a medium of specific liquids [3][4][5] and fibres and plastics on attaining the glass transition temperature during linear heating of the polymer [6][7][8] was the first direct evidence of formation of a nematic phase by cellulose derivatives.…”

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The liquid-crystalline state of cellulose acetates: From past to present. Experience of the Saratov school

Shipovskaya

Timofeeva

2006

Fibre Chem

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Mesophasogenic solvents in the vapor state actively affect the structure of cellulose acetates of different morphological forms (fibre, film, bulk polymer). On the supramolecular level, this is manifested by initiation of orientation processes and on the conformational level by a change in the optical density, up to a change in the direction of rotation of the cholesteric helix to the opposite direction. The approach found creates conditions for formation of a given structure and three-dimensional organization of the polymer matrix for manufacture of materials with improved properties and new qualities.Of the large number of polysaccharides, cellulose and cellulose derivatives are the most important in the total production volume of polymeric materials for industrial and domestic applications. This class of macromolecular compounds has been actively studied up to now both to obtain fundamental knowledge and for their practical use.Domestic scientists specializing in polymer science have made an enormous contribution to the study of the structure, composition, and properties of cellulose and its ethers. They include the internationally known scientists

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Spontaneous elongation of cellulose acetate fibres

Timofeyeva

Tolkunova

1986

Polymer Science U.S.S.R.

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Spontaneous elongation of cellulose acetate plastics

Cited by 3 publications

References 2 publications

Modification of the structure of cellulose triacetate films in the course of solvent vapor sorption

Modification of the structure of cellulose triacetate films in the course of solvent vapor sorption

The liquid-crystalline state of cellulose acetates: From past to present. Experience of the Saratov school

Spontaneous elongation of cellulose acetate fibres

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