Effect of concentration on rheological properties of media-milled cellulose

• Main Authors: Ta-Yuan Yu, 于達元
• Other Authors: An-I Yeh
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/82778232674466881666

碩士 === 臺灣大學 === 食品科技研究所 === 96 === In this research, the rheological properties of media-milled cellulose suspension at different cellulose concentration had investigated. The raw cotton cellulose with volume mean diameter 33.19 micrometer was the experiment material. The diameter of cellulose was reduce to nano/submicron scale by wet media milling technology. To characterize the rheological properties influenced by cellulose concentration the particle size distribution(PSD), flow test, oscillation test and morphology were performed. Raw cellulose suspension 400 mL was prepared at content atom of 1, 3, 5, 7, 9, 11 % to 400 mL deionized water. Those suspensions were milled by media, YTZ(yttria-stabilized tetragonal zirconia) bead with average diameter 0.8 mm. After 180 min milling, there are significant reduction on volume mean diameter, which are 0.896, 0.87, 0.804, 0.774, 0.773, 0.769 micrometer respectively. And all the volume percentage of nano/submicron particle are more than 68 %. Media-milled suspension with different cellulose concentration were measured by dynamic rheometer by flow test and oscillation test. The viscosity of suspension increased with the concentration, but decreased with increasing shear rate. The suspensions appeared to be shear-thinning fluid and be described by Williamson model. Media-milled cellulose suspension are viscoelastic material and the loss tangent of 5, 7, 9, 11 % suspension were independent on frequency, but 1, 3 % tend to be viscoelastic fluid on 1, 100 rad/s. TEM photo showed the presence of nano and submicron cellulose particle in media-milled cellulose suspension.