Fabrication of phosphate microcrystalline rice husk based cellulose particles and their electrorheological response.

As a dry-based electrorheological (ER) material, phosphate microcrystalline cellulose (MCC), which exhibits ER properties under anhydrous conditions, was fabricated by the phosphorylation of MCC particles. The MCC particles were initially synthesized by the three step preparation of an alkali treatment, bleaching, and hydrolysis of cellulose particles from rice husk. The phosphate MCC was then synthesized via the phosphoric ester reaction of urea with phosphoric acid and MCC, and its chemical characteristics were examined by energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. The phosphate MCC particles were dispersed in silicone oil to produce an ER fluid (10vol%), and its chain structure was observed directly by optical microscopy. The rheological behavior of the ER fluid was tested using a rotational rheometer under a range of electric fields, showing a polarization mechanism with a slope of 2.0 for the yield stress as a function of the applied electric field strengths.