Rid 10a differential

Example 5

This was carried out using the polymerization apparatus shown in FIG. 1. An aqueous solution containing 10 weight % acrylamide (Wako Pure Chemical Industries, Ltd.) and 0.1 weight % potassium persulfate (Sigma-Aldrich Co. LLC.) was mixed with hot water that had been preheated to 200° C. The recovered reaction solution was evaporated to dryness; the polymerization conversion as measured by gravimetry was 54.1%. The residue was redissolved in water and was analyzed by size exclusion chromatography (instrument: Prominence GPC series, Shimadzu Corporation; detector RID-10A differential refractometer, Shimadzu Corporation; column: TSKgel GMPW_XL, Tosoh Corporation): the obtained molecular weights were a weight-average molecular weight (Mw) of 39,600 and a number-average molecular weight (Mn) of 11,000; the molecular weight distribution (Mw/Mn) was 3.60; and a polymer having a relatively uniform length was thus obtained.

Example 3

This was carried out using the polymerization apparatus shown in FIG. 1. An aqueous solution containing 10 weight % acrylic acid (Sigma-Aldrich Co. LLC.) and 0.5 weight % potassium persulfate (Sigma-Aldrich Co. LLC.) was mixed with hot water that had been preheated to 200° C. The recovered reaction solution was evaporated to dryness; the polymerization conversion as measured by gravimetry was 85.8%. The residue was redissolved in water and was analyzed by size exclusion chromatography (instrument: Prominence GPC series, Shimadzu Corporation; detector RID-10A differential refractometer, Shimadzu Corporation; column: TSKgel GMPW_XL, Tosoh Corporation). The results are given in FIG. 5. The obtained molecular weights were a weight-average molecular weight (Mw) of 27,700 and a number-average molecular weight (Mn) of 7,290; the molecular weight distribution (Mw/Mn) was 3.70; and a polymer having a relatively uniform length was thus obtained.

(* The initiator concentration was increased 5× relative to that in the basic pattern.)