The invention discloses a hyperbranched polyether modified polysiloxane
defoamer containing nanosilicon dioxide. The hyperbranched polyether modified polysiloxane
defoamer is prepared from, by weight, 25-40 parts of polysiloxane, 13-23 parts of hyperbranched polyether, 16-26 parts of
allyl glycidyl ether, 38-58 parts of epoxypropane, 0.3-0.5 part of double
metal cyanide, 50-70 parts of isopropanol, 0.2-0.5 part of a
chloroplatinic acid catalyst, 2-6 parts of ultra-fine
aluminum silicate, 1-2 parts of
sorbitol, 1-2 parts of tween-60, 2-4 parts of
sodium carboxymethylcellulose, an appropriate amount of deionized water, 4-11 parts of nanosilicon dioxide
powder and 45-60 parts of
dodecyl alcohol. The hyperbranched polyether containing a large number of hydroxyls at the
tail end is adopted as a
raw material, end-allyl hyperbranched polyether is prepared, a modified polyether
end group double-bond structure and polysiloxane are adopted for performing a
hydrosilylation reaction, the hyperbranched polyether modified polysiloxane is synthesized, and the
defoamer prepared through the hyperbranched polyether modified polysiloxane has the excellent anti-shearing performance.