| 摘要 |
PURPOSE:To produce an additive providing high flowability to a cement blend over a long time by allowing a styrene-maleic acid copolymer to react with sulfuric acid anhydride to form a sulfonated styrene-maleic acid copolymer. CONSTITUTION:About 10-90pts.wt. sulfuric acid anhydride is added to 100pts.wt. styrene-maleic acid copolymer dissolved in a solvent such as chloroform and a sulfonation reaction is carried out at about 0-100 deg.C under ordinary pressure-about 10kg/cm<2> for about 0.5-10hr to obtain a sulfonated styrene- maleic acid copolymer having sulfonated styrene units represented by formula I (where X<1> is Na, K, 1/2Ca, NH4 or an org. amino group) and maleate units represented by formula II (where each of X<2> and X<3> is Na, K, 1/2Ca, NH4 or an org. amino group). The number average mol.wt. of the copolymer is about 1,000-9,000. When the copolymer is added to cement by about 0.01-1.00wt.% (expressed in terms of solid matter), the compressive strength of hardened cement is improved.
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