silicon dioxide is about 0 6 by mass 1 rinse and dry the sheep wool cloth to be treated and weigh 200 g sheep wool cloth immerse the wool cloth into 2 l toluene solution that contains 50 mm n methyl u03b3 aminopropyl trimethoxysilane and 50 mm n methyl u03b3 aminopropyl triethoxysilane hold for 2 h and then take out the sheep wool cloth and dry for 10 h naturally 2 immerse the sheep wool cloth treated by step 1 in a mixed solution of water and dimethyl sulfoxide mixed at a volume ratio of 5 1 with ph adjusted to 11 by sodium hydroxide at a bath ratio of 1 40 agitate for 30 min at room temperature then add methanol solution of tetramethyl orthosilicate at a concentration of 5 mol l and zinc acetate powder in sequence and control the mass fraction of tetramethyl orthosilicate in the mixed solution of water and dimethyl sulfoxide with ph 11 at 5 and the mass fraction of zinc acetate in the mixed solution of water and dimethyl sulfoxide at 10 and agitate for 300 min at a constant temperature of 60 u00b0 c adjust the ph value of the reacting solution with acetic acid to 3 and then oscillate for 20 min at a constant temperature of.