粘弹性
化学工程
成核
流变学
微观结构
形态学(生物学)
醋酸纤维素
化学
三元运算
高分子化学
材料科学
纤维素
色谱法
有机化学
结晶学
复合材料
程序设计语言
工程类
生物
遗传学
计算机科学
作者
John F. Kadla,Reza Korehei
出处
期刊:Biomacromolecules
[American Chemical Society]
日期:2010-12-01
卷期号:12 (1): 43-49
被引量:5
摘要
The effect of dihydric alcohol (nonsolvent) addition on the rheological and microstructural behavior of cellulose acetate (CA) in a ternary CA, N,N-dimethylacetamide (DMA), nonsolvent system was investigated. Increasing the dihydric alcohol concentration led to enhanced steady shear viscosity and dynamic viscoelastic properties that were dependent on CA concentration. Changing the dihydric alcohol from 1,2-ethanediol to 1,4-butanediol and 1,6-hexanediol increased the moduli and decreased the concentration of nonsolvent at which the sol−gel transition occurred. At 10 wt % CA concentration the modulus and gel morphology of the 1,2-ethanediol and 1,4-butanediol systems were quite similar and distinctly different from that of 1,6-hexanediol. In the former, the gel morphologies were more heterogeneous, evident of more extensive coarsening, and likely obtained via nucleation and growth and spinoidal decomposition of off-critical mixtures. The latter exhibited more uniform dense network morphology, indicative of a spinoidal decomposition of near-critical mixtures. The gels were fractal in nature and exhibited different fractal dimensions in-line with the observed differences in microstructure; D ∼ 1.87 ± 0.02 (1,2-ethanediol and 1,4-butanediol) and D ∼ 1.97 ± 0.02 (1,6-hexanediol). However, at 15 wt % CA content, the gels exhibited more similar viscoelastic behavior and gel microstructures; D ∼ 1.97 ± 0.02 for all three dihydric alcohol systems.
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