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Scientia Silvae Sinicae ›› 2015, Vol. 51 ›› Issue (11): 97-102.doi: 10.11707/j.1001-7488.20151113

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Performance Improvement of Titania Electrorheological Fluid

Kang Yuning, Chen Wenshuai, Yu Haipeng   

  1. Key Laboratory of Bio-Based Material Science and Technology of Ministry of Education Northeast Forestry University Harbin 150040
  • Received:2014-12-15 Revised:2015-04-30 Online:2015-11-25 Published:2015-12-08

Abstract: [Objective]Electrorheological fluid (ERF), having flow properties that can be modified with electric field, is a suspension liquid composite with micron to nanometer particles dispersed in the oil phase. The ERF is thus expected to be used for semi-automated damping system, clutch brakes, and fluid valves. High dielectric Ti-O system is a common ERF material, but it has some problems such as easy sediment, unstable performance, etc. The cellulose nanowhisker (CNW) which can be disintegrated from forest residues, has the advantages of nanoscale morphology, high aspect ratio, large specific surface area, and high surface energy. The combination of CNW and Ti-O system can be expected to improve the performance and stability of ERF, in terms that the hydroxyl groups at the side chains of CNW can effectively adsorb polar molecules, leading to the chain polymerization easily in the electric field.[Method]In this paper, we prepared the CNWs through the hydrolysis with concentrated sulfuric acid, and the composites comprised TiO2 and CNWs via a sol-gel method. The proportion of CNW in the composite was tailored to 10%, 20% and 30% by adjusting the addition ratio of raw materials. When the CNW-TiO2 composites were added into dimethyl silicone, some properties including the effects of urea addition, electric field intensity, shear rate and temperature on the shear strength of ERF were analyzed. The anti-sedimentation and recycling uses of the ERF were also investigated. [Result]The results showed that the CNW surfaces were covered by amorphous TiO2, exhibiting a 10-15 nm diameter fibrous structure. With the addition of CNW, the sedimentation rate of TiO2 reduced from 46% to less than 20%. With the CNW content increased, lower sedimentation rate of the complex and a more stable performance at high temperature were observed. A certain amount of CNW addition can enhance the performance of ERF shear strength by 1-2 times. Repeatability tests displayed that the electrorheological properties of ERF remained stable, which could effectively avoid the electrical breakdown. [Conclusion]The results confirmed that the addition of CNW making the Ti-O system ERF reduce loss of polar molecules. A significant improvement on the electrorheological performance and service life was achieved.

Key words: cellulose nanowhisker, composite, electrorheological fluid, titania, stability

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