ISSN:
0360-6376
Keywords:
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The degree of substitution (DS) and distribution of O-acetyl groups of water-soluble cellulose acetate (CA) were investigated by 13C-NMR. For this purpose, three different series of CA samples with low DS were prepared by respective homogeneous reaction, i.e., (1) deacetylation of cellulose triacetate (CTA) in acetic acid - water solution (D-series), (2) reaction of CTA with hydrazine (H-series), and (3) acetylation of cellulose with acetic anhydride in a 10% LiCl-dimethylacetamide solution (A-series). It was found that (i) water-soluble CA can be obtained only from D-series products, (ii) the DS value of water-soluble CA ranges from 0.5 to 1.1, (iii) the D-series products exhibit little difference between the relative DS values at C-2, C-3 and C-6 hydroxyl groups, and (iv) the relative DS at C-6 hydroxyl groups is very high compared to those at C-2 and C-3 hydroxyl groups in H- and A-series products. Aqueous solution of water-soluble CA (D-series sample) showed no gel - sol transition, even when the temperature was raised to 95°C. X-ray diffraction observations revealed that the water-soluble D-series samples were essentially noncrystalline, but the water-insoluble A-series samples were crystalline. It was also found that the relative ease of acetylation is C-6 〉 C-2 〉 C-3.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1985.170230511
