Cellulose fibers were obtained from corncob by using microwave-assisted chemical treatments (microwave-assisted alkaline pretreatment and microwave-assisted bleaching). These treatments efficiently removed the hemicellulose and lignin from the original corncob and increased the cellulose fiber content. The morphology, chemical structure, degree of crystallinity and thermal degradation characteristics of the resultant cellulose fibers were studied by using field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and thermogravimetric analysis. These microwave-assisted chemical treatments decreased the diameter of the cellulose fibers from 25–125 µm to 10–20 µm. The crystallinity of the corncob cellulose fibers increased from 32.7% to 73% due to the chemical treatments. The degradation temperature of the cellulose fibers was >260°C. The cellulose fibers obtained from these treatments can be used as biocomposites in reinforced polymer manufacturing.
Gelatinized starch paste was prepared by gelatinizing rice starch at 95 °C in a water bath. Then, the rice starch (both normal rice starch and waxy rice starch) paste was subjected to high-pressure homogenization at homogenizing pressure of 20, 40, 60, 80 MPa. The rheological properties (including shear stress versus shear rate, apparent viscosity versus shear rate and thixotropy) of starch paste were studied. The high-pressure homogenization was able to improve the flow properties of starch paste. The shear stress increased with the increasing shear rate, and the Power law equation was capable of fitting the shear stress versus shear rate quite precisely. High-pressure homogenization treatment sharply decreased the thixotropy of starch paste, and the thixotropy of rice starch (both NRS and WRS) paste decreased with the increasing homogenous pressure.
25 June 2015 in The Open Petroleum Engineering Journal