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Dielectric study of β‐relaxation in some cellulosic substances
Author(s) -
Saad Gamal R.,
Sakamoto Munenori,
Furuhata Kenichi
Publication year - 1996
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.1996.210410311
Subject(s) - microcrystalline cellulose , dielectric , activation energy , relaxation (psychology) , microcrystalline , steric effects , materials science , cellulose , cellulosic ethanol , chemical engineering , range (aeronautics) , dielectric spectroscopy , chemistry , polymer chemistry , analytical chemistry (journal) , organic chemistry , crystallography , composite material , optoelectronics , psychology , engineering , electrode , electrochemistry , social psychology
6‐(2‐Cyanoethylamino)‐6‐deoxycellulose (Cell‐CEA) as a novel cellulose derivative was prepared from 6‐bromo‐6‐deoxycellulose. The influence of the reaction conditions on the degree of substitution was studied in detail. The dielectric characteristics of a Cell‐CEA sample having degree of substitution of 0.86, together with those of microcrystalline and regenerated celluloses, have been investigated in the temperature range from −60 to 120°C, and frequency range 30 Hz to 100kHz. One relaxation process, designated as β, was recognised, which was attributed to side‐group motions, probably −CH 2 X (X = OH or NHCH 2 CH 2 CN). The higher activation energy of this process and the shift to higher temperature in Cell‐CEA, compared with microcrystalline and regenerated celluloses, reflects the enhanced steric constraints involved in the motion of the bulkier, −CH 2 NHCH 2 CH 2 CN, side groups. The results obtained are discussed in terms of the dielectric parameters ϵ″ max ′ β and Δϵ.