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【答案】应助回帖
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自由的小鸟: 金币+300, 翻译EPI+1, ★★★★★最佳答案 2015-06-12 20:12:16
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NMMO reagents with different water contents were prepared and studied for the optimum water content to dissolve cotton cellulose; The rheological properties of the solution was determined; Various parameters for the preparation of cellulose membrane by coagulation method, such as bath temperature and cellulose concentration were studied. In addition, the influence of the addition of glycerin as a plasticizer on cellulose membrane mechanical properties, crystallization properties, the composition of functional groups were studied. Through experiments we found that NMMO with a water content at around 13.3%, the temperature at about 90 DEG C had the fastest dissolution rate for cotton cellulose. Rheological studies indicated that the cellulose solution obtained was a shear thinning fluid. Mechanical properties tests on the cellulose membrane showed that cellulose membranes obtained under a coagulation bath temperature at 28 DEG C had the maximal fracture strength and elongation at break. The elongation at break decreased with increasing cellulose concentrations, while the fracture strength increased with increasing cellulose concentrations. Glycerol played a plasticizer role during membrane preparation, cellulose membrane with glycerol had a smooth surface, the tests found that the cellulose membrane prepared with glycerol had tenacity. Using X - ray diffraction method we found that cellulose in membranes had reduced crystallinity; infrared spectrometry analysis revealed that there was no change for the functional groups in cellulose before and after membrane preparation. |
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