Effect of acetylation site on orientation birefringence of cellulose triacetate

Nobukawa, Shogo; Enomoto-Rogers, Yukiko; Shimada, Hikaru; Iwata, Tadahisa; Yamaguchi, Masayuki
October 2015
Cellulose;Oct2015, Vol. 22 Issue 5, p3003
Academic Journal
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.


Related Articles

  • Conformational transition behavior around glass transition temperature. Liang, Taining; Yang, Yong; Guo, Dawei; Yang, Xiaozhen // Journal of Chemical Physics;1/22/2000, Vol. 112 Issue 4 

    The conformational transition behavior around the glass transition temperature has been studied by means of molecular dynamics through a model system, atactic polypropylene in bulk. Various criteria of the conformational transition were examined. A domain at barrier site is defined as the...

  • Length scale of dynamic heterogeneity in supercooled glycerol near T[sub g]. Reinsberg, S. A.; Qiu, X. H.; Wilhelm, M.; Spiess, H. W.; Ediger, M. D. // Journal of Chemical Physics;5/1/2001, Vol. 114 Issue 17 

    This letter presents the first direct measurement of the length scale of dynamic heterogeneity in a low molecular weight glass former without the perturbing effect of probe molecules or confinement. Using a multidimensional [sup 13]C solid-state exchange NMR experiment, 1 nm heterogeneities were...

  • Glass transition and atomic structures in supercooled Ga[sub 0.15]Zn[sub 0.15]Mg[sub 0.7]... Zhao-Hui jin; Ke Lu; Yan-Dong Gong; Zhuang-Qi Hu // Journal of Chemical Physics;6/1/1997, Vol. 106 Issue 21, p8830 

    Simulates glass transition in supercooled gallium, zinc and magnesium metallic liquid by making use of a constant-pressure molecular dynamics technique via the pairwise interatomic potentials. Calculation from a self-consistent nonlocal model pseudopotential theory; Structures of liquids and...

  • Glass formation in simple ionic systems via constant pressure molecular dynamics. Kumta, Prashant N.; Deymier, Pierre A.; Risbud, Subhash H. // Journal of Chemical Physics;6/15/1989, Vol. 90 Issue 12, p7384 

    The utility of constant pressure molecular dynamics (MD) in studies of glass formation is demonstrated by choosing NaCl and ZnCl2 as examples of MX and MX2 salts. Rigid ion pair potentials have been used to model the two salts. Results of these simulations are in good agreement with general...

  • Molecular dynamics simulations of a pressure-induced glass transition. Shumway, Shelly L.; Clarke, Andrew S.; Jónsson, Hannes // Journal of Chemical Physics;1/22/1995, Vol. 102 Issue 4, p1796 

    We simulate the compression of a two-component Lennard-Jones liquid at a variety of constant temperatures using a molecular dynamics algorithm in an isobaric–isothermal ensemble. The viscosity of the liquid increases with pressure, undergoing a broadened transition into a structurally...

  • On the reproducibility of glasses. Speedy, Robin J. // Journal of Chemical Physics;5/1/1994, Vol. 100 Issue 9, p6684 

    The reproducibility of glasses of 500 hard spheres is examined. Most amorphous packings are shown to tend to the limiting density z=0.870±0.008 (relative to the close packed crystal). When the fluid is compressed through the glass transition, in a molecular dynamics experiment, fast enough to...

  • Normal mode analysis of liquid CS2: Velocity correlation functions and self-diffusion constants. Moore, P.; Keyes, T. // Journal of Chemical Physics;5/1/1994, Vol. 100 Issue 9, p6709 

    Normal mode analysis (NMA) is applied in a molecular-dynamics simulation of liquid CS2, modeled with a potential including internal degrees of freedom. The entire supercooled liquid range, from the glass transition at 100 K to melting at 165 K, and the normal liquid from 165 to 293 K, are...

  • How do the properties of a glass depend on the cooling rate? A computer simulation study of a Lennard-Jones system. Vollmayr, Katharina; Kob, Walter; Binder, Kurt // Journal of Chemical Physics;9/15/1996, Vol. 105 Issue 11, p4714 

    Using molecular dynamics computer simulations we investigate how the glass transition and the properties of the resulting glass depend on the cooling rate with which the sample has been quenched. The system we study is a two component Lennard-Jones model which is coupled to a heat bath whose...

  • Dielectric investigation of the molecular dynamics of propanediol in mesoporous silica materials. Huwe, A.; Arndt, M.; Kremer, F.; Haggenmuller, C.; Behrens, P. // Journal of Chemical Physics;12/8/1997, Vol. 107 Issue 22, p9699 

    Discusses the use of broadband dielectric spectroscopy to study the molecular dynamics of the glass-forming hydrogen-bonded liquid propanediol confined to mesoporous M41S silica materials with different topologies. Dynamic glass transition in the mesoporous system; Action of silanization of the...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics