Thermal transformation in cellulose acetates

Buntyakov, A.S.; Aver'yanova, V.M.

doi:10.1016/0032-3950(71)90306-6

Cited by 4 publications

(2 citation statements)

References 8 publications

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“…4b, curve 2). At this temperature, according to [20], the polymer crystallizes, and the same refl ections, characteristic of the CTA crystalline modifi cation II, appear in the diffraction pattern. The refl ections observed in the diffraction pattern of the CTA fi lm upon DMSO sorption (Fig.…”

Section: Mnmentioning

confidence: 94%

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: 94%

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

2014

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“…Selulosa-asetat ini memiliki keistimewaan dalam hal titik lebur (softening point) yang cukup tinggi (230°C). Hal ini mengindikasikan bahwa polimer tersebut memiliki ikatan hidrogen intermolekuler dan intramolekuler yang kuat dan dapat dimanfaatkan sebagai bahan dalam pembuatan plastik film yang bersifat biodegradable (Buntyakov & Aver'yanova, 1969;Hasnedi, 2009). Komposisi kemasan berindikator dengan bahan dasar polimer tersebut di antaranya adalah kitosan-asetat, polivinil alkohol dan indikator warna bromothymol blue (Hasnedi, 2009).…”

Section: Pendahuluanunclassified

Karakteristik Plastik Indikator sebagai Tanda Peringatan Dini Tingkat Kesegaran Ikan dalam Kemasan Plastik

Riyanto

Hermana

Wibowo

2014

JPBKP

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Tujuan penelitian ini adalah untuk mempelajari karakteristik tanda peringatan dini atau early warning indicators (EWI) yang dibuat dari beberapa jenis indikator pH untuk mendeteksi kesegaran ikan dalam kemasan plastik. Tiga jenis indikator pH dan campuran dua indikator pH digunakan dalam penelitian ini, yaitu bromothymol blue (BTB), bromocresol green (BCG), bromocresol purple (BCP), dan campuran BCG dan methyl red (MR). Sensitivitas masing-masing indikator diuji menggunakan NH 4 OH selama 15 menit dan filet ikan kurisi (Nemipterus nematophorus) selama 15 jam penyimpanan pada suhu ruang. Contoh ikan diambil setiap 3 jam untuk analisis kandungan TVB-N dan jumlah bakteri total (TPC). Hasilnya menunjukkan bahwa indikator BTB memberikan respon lemah terhadap NH 4 OH dan perubahan kesegaran filet ikan. Respon yang lebih baik ditunjukkan oleh BCG, BCP, dan campuran BCG dan MR. Perubahan warna pada indikator tersebut terjadi ketika kandungan TVB-N dan TPC pada filet ikan masing-masing mencapai 33,29 ± 4,24 mgN/100 g dan 10 6 cfu/gr. Perubahan warna dapat dengan mudah dikenali dan diidentifikasi secara visual. Untuk merancang EWI, biaya bahan yang diperlukan untuk membuat indikator kurang penting dibandingkan dengan pertimbangan sensitivitas indikator.

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On the glass temperature of cellulose esters

Naimark

1973

Polymer Science U.S.S.R.

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Thermal transformation in cellulose acetates

Cited by 4 publications

References 8 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

Karakteristik Plastik Indikator sebagai Tanda Peringatan Dini Tingkat Kesegaran Ikan dalam Kemasan Plastik

On the glass temperature of cellulose esters

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