The number of amine end groups in the first (G1), second (G2), third (G3), and fourth (G4) generations of magnetic-cored dendrimers (MCD) was determined experimentally and effect on Pb (II) adsorption was investigated. Calculated end groups in different generation MCDs obtained by thermogravimetric analysis appeared an increase with successive generations, but not doubled. Decrease in end groups was due to the blocking of branches during synthesis and narrow space between end groups. Active amine end groups were also quantified via acid-base titration experiment. The active amines were increased with the generations, except for G3-MCD because of the reduced distance between end groups. However, the active amines were drastically increased in the G4-MCD because the hydrophilic amine groups were stretched in the outer space by the repulsive hydrophobic inner structure of MCD chains. Maximum Pb (II) adsorption was 44.49 mg/g (G1-MCD), 79.57 mg/g (G2-MCD), 44.35 mg/g (G3-MCD), and 116.19 mg/g (G4-MCD), respectively. They are very well correlated with the titration results, confirming the adsorption was directly affected by active amines in MCDs.

中文翻译：

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不同代磁芯树枝状聚合物中 Pb (II) 吸附的比较评估：胺端基活性的意义

实验测定了第一代（G1）、第二代（G2）、第三代（G3）和第四代（G4）磁芯树枝状聚合物（MCD）中胺端基的数量，并研究了对 Pb（II）吸附的影响。通过热重分析获得的不同代MCD中的计算端基随着连续代的增加而增加，但没有增加一倍。端基的减少是由于合成过程中支链的阻断以及端基之间的空间狭窄所致。活性胺端基也通过酸碱滴定实验进行定量。除G3-MCD 外，由于端基之间的距离减小，活性胺随着世代的增加而增加。然而，G4-MCD 中的活性胺急剧增加，因为 MCD 链的排斥性疏水内部结构使亲水胺基在外部空间延伸。 Pb (II) 的最大吸附量分别为 44.49 mg/g (G1-MCD)、79.57 mg/g (G2-MCD)、44.35 mg/g (G3-MCD) 和 116.19 mg/g (G4-MCD)。它们与滴定结果有很好的相关性，证实了吸附直接受到 MCD 中活性胺的影响。