Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China.
Biomacromolecules. 2010 Jan 11;11(1):126-32. doi: 10.1021/bm900981t.
Some effects of water at levels up to 25% (dry solids basis db) on regenerated cellulose films with a thickness of 100 mum were investigated by dynamic vapor sorption (DVS), X-ray diffraction, tensile testing, and proton-nuclear magnetic resonance (NMR). The sorption isotherm fitted by the D'Arcy and Watt model and the increase in NMR T(2) with water content suggest that a mobile water fraction appears at water contents above 10%db. Water absorption increased the crystallinity of cellulose films from 31% (dry) to 38% (25%db) and altered the dimensions of crystallites. Mechanical measurements on planar and notched samples at all the water contents used here showed ductile fracture behavior. Although the properties of water in these cellulose films are comparable to previously reported data on starch, cellulose films at low water content are much less brittle than starch. The reasons for this difference are explored.
采用动态蒸汽吸附（DVS）、X 射线衍射、拉伸试验和质子核磁共振（NMR）研究了厚度为 100μm 的再生纤维素薄膜在高达 25%（干固物基准，db）水平下的水的一些影响。D'Arcy 和 Watt 模型拟合的吸附等温线以及 NMR T(2)随含水量的增加表明，在含水量高于 10%db 时出现了可动水部分。水分吸收使纤维素薄膜的结晶度从 31%（干燥）增加到 38%（25%db），并改变了微晶的尺寸。在所有使用的含水量下对平面和有缺口的样品进行机械测量表明，表现出韧性断裂行为。尽管这些纤维素薄膜中水的性质与以前关于淀粉的报告数据相当，但在低含水量下的纤维素薄膜比淀粉的脆性小得多。探讨了造成这种差异的原因。
