淀粉-丙烯酰胺低质量分数接枝共聚反应及产物的流变特性

Graft copoly-merization of acrylamide and starch at low concentration and rheological properties of the product

对作为调剖剂的淀粉与丙烯酰胺的接枝共聚反应进行了研究,流变性实验结果表明,随着淀粉与丙烯酰胺质量分数的降低,接枝共聚反应产物的储能模量即弹性明显降低,而耗损模量即粘性的降低幅度较小,反映了产物的分子质量在减小。在低质量分数条件下,由于淀粉易沉降,造成其与丙烯酰胺单体共聚时体系的不均匀反应,体系上部呈溶液状态,而下部为冻胶;反应物质量分数越低,产物上部分出液体的体积越大。提高温度,缩短反应时间,分出液体的体积会减小。添加剂AL-3有助于水溶性淀粉的分散,从而使反应后体系的分水体积减小。在所研究的范围内,溶解时间越长、搅拌越充分,淀粉溶解越好,则反应后体系的分水体积越小。

The research of the graft copolymerization of acrylamide and starch (profile control agent) shows that the strength of the syn-thetic graft copolymer decreases with the decrease of mass con-centration of the acrylamide and starch. A further rheological ex-periment indicates that a lower concentration of the acrylamide and starch leads to lower graft elasticity and molecular weight of the product. Phase separation will happen during the uneven graft copolymerization between acrylamide and starch caused by the precipitation of starch granule in water under low mass fraction. The reaction products have different states,the upper location re-tains the solution state and gel being forms in lower part. The lower mass-fraction of the product becomes,the bigger liquid vol-ume of the upper separates. The separated volume of the solution will decrease with the increases of temperature and the decrease of reaction time. Additive AL-3 is favorable to disperse the water-soluble starch,which makes the volume of the separated solution decrease after the reaction. The long dissolve time,the more effi-cient stirring and the better solvability,and the less separated volume of the solution after the reaction in the scope of this re-search.