Department of Chemistry, Southern Methodist University, 3215 Daniel Avenue, Dallas, TX 75275, USA.
Macromol Rapid Commun. 2012 May 14;33(9):869-75. doi: 10.1002/marc.201200065. Epub 2012 Apr 18.
Hyperbranched polymers with multiple alkyl bromide peripheral groups were synthesized by the copolymerization of styrene with ethylene glycol dimethacrylate (2.5, 5.0, 7.5, or 10.0 mol% relative to styrene) in the presence of CBr(4) (10-20-fold excess vs. the radical initiator). The latter compound markedly delayed the gelation and served as the source of terminal bromine atoms via transfer to the propagating radicals. The degree of branching increased with the amount of crosslinker. The alkyl bromide groups were used in further chemical modifications (ATRP at low catalyst concentration or azidation with NaN(3) followed by CuBr-catalyzed click coupling of an alkyne-terminated polymer) that yielded star copolymers with hyperbranched cores.
具有多个烷基溴侧基的超支化聚合物是通过苯乙烯与乙二醇二甲基丙烯酸酯（相对于苯乙烯的 2.5、5.0、7.5 或 10.0mol%）共聚，在 CBr4（自由基引发剂的 10-20 倍过量）存在下合成的。后一种化合物显著延迟了凝胶化，并通过转移到增长自由基而成为末端溴原子的来源。支化度随交联剂用量的增加而增加。烷基溴基团用于进一步的化学修饰（低催化剂浓度下的原子转移自由基聚合或与NaN3 进行叠氮化反应，然后用炔烃封端聚合物的 CuBr 催化点击偶联反应），得到具有超支化核的星型共聚物。
