chloride with ethanol which was separated from the funnel and dried in a vacuum oven the dried product was a white to yellowish powder which was totally soluble when it was dissolved in water the dried polyaspartic acid chloride was titrated with sodium thiosulfate and finally the content of the n halamine group per g polyaspartic acid chloride was calculated 10 0 g polyaspartic acid was placed into a 500 ml one necked flask and 80 ml purified water was added to dissolve it to prepare an aqueous polyaspartic acid solution then 188 g of 6 84 wt aqueous sodium hypochlorite solution was added to form a mixture the mixture was continuously stirred for 12 h at room temperature so that polyaspartic acid was reacted with sodium hypochlorite the reacted mixture was placed in a separatory funnel to precipitate the polyaspartic acid chloride with ethanol which was separated from the funnel and dried in a vacuum oven the dried product was a white to yellowish powder which was totally soluble when it was dissolved in water the dried polyaspartic acid chloride was titrated with sodium thiosulfate and finally the content of the n halamine group per g polyaspartic acid chloride was calculated 10 0 g polyaspartic acid was placed into a 500 ml one necked flask and 50 ml purified water was added to dissolve it to prepare an aqueous polyaspartic acid solution then 70 2 g of 9 23 wt aqueous sodium hypochlorite solution was added to form a mixture the mixture was continuously stirred for 3 h at room temperature so that polyaspartic acid was reacted with sodium hypochlorite the reacted mixture was placed in a separatory funnel to.