TITLE

Effect of acetylation site on orientation birefringence of cellulose triacetate

AUTHOR(S)
Nobukawa, Shogo; Enomoto-Rogers, Yukiko; Shimada, Hikaru; Iwata, Tadahisa; Yamaguchi, Masayuki
PUB. DATE
October 2015
SOURCE
Cellulose;Oct2015, Vol. 22 Issue 5, p3003
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
The effect of a substitution site on orientation birefringence for cellulose triacetate (CTA) was investigated by the addition of xylan ester. Since CTA has three substitution sites (C-2, C-3, and C-6) while xylan ester has two substitution sites (C-2 and C-3), the change of birefringence by xylan acetate (XylAc) is attributed to the contribution of the C-6 acetyl group. Dynamic mechanical analysis and thermal measurements showed a single glass transition peak, indicating that XylAc is miscible with CTA at any compositions. The orientation birefringence (Δ n) of CTA/XylAc films stretched beyond the glass transition temperature increased with increasing the XylAc content. The result for the stretched film suggested that the contribution of acetyl group in the C-2 and C-3 sites to Δ n is positive while that in the C-6 is negative. The negative sign for the C-6 site is in agreement with the result simulated by using the molecular dynamics method. In addition, Δ n of CTA films containing xylan propionate (or butyrate) indicated that the propionyl and butyryl groups in the C-2 and C-3 sites show positive birefringence similar to the acetyl group.
ACCESSION #
109345622

 

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