Synthesis of Thermoresponsive Mixed Arm Star Polymers by Combination of RAFT and ATRP from a Multifunctional Core and Its Self-Assembly in Water
Synthesis of Thermoresponsive Mixed Arm Star Polymers by Combination of RAFT and ATRP from a Multifunctional Core and Its Self-Assembly in Water
复制标题
DOI：
10.1021/ma800094d
复制
发表时间：
2008-05
期刊：
影响因子：
5.5
通讯作者：
Krishnan Ranganathan;Rui Deng;R. Kainthan;Chi Wu;D. Brooks;J. Kizhakkedathu
中科院分区：
文献类型：
--
作者：
Krishnan Ranganathan;Rui Deng;R. Kainthan;Chi Wu;D. Brooks;J. Kizhakkedathu
以多引发剂功能化超支化聚甘油（MI-HPG）为核，通过可逆加成-断裂链转移（RAFT）和原子转移自由基聚合（ATRP）合成了聚（N，N-二甲基丙烯酰胺）（PDMA）和聚（N-异丙基丙烯酰胺）（PNIPAm）的混合臂星星共聚物. MI-HPG核由胺官能化的聚甘油合成，依次用2-氯丙酰胺基团（ATRP引发剂）和4，4 ′-偶氮双（4-氰基戊酸）（偶氮引发剂）修饰。以S，S′-双（α，α′-二甲基-α′′-乙酸）三硫代碳酸酯为链转移剂，在乙酸/乙酸钠缓冲溶液中，采用RAFT法，以MI-HPG为核，聚合N，N-二甲基丙烯酰胺。[CTA]/[偶氮引发剂]的比例是控制从MI-HPG核（HPG-g-PDMA）接枝PDMA的分子量的关键。采用原子转移自由基聚合法（ATRP）将PNIPAm接枝到HPG-g-PDMA大分子引发剂上，实现了混合臂星星共聚物的可控合成。临时工
Mixed arm star copolymers of poly(N,N-dimethylacrylamide) (PDMA) and poly(N-isopropylacrylamide) (PNIPAm) were synthesized by a sequential reversible addition−fragmentation chain transfer (RAFT) and atom transfer radical polymerization (ATRP) from a multi-initiator-functionalized hyperbranched polyglycerol (MI-HPG) core. The MI-HPG core was synthesized from an amine-functionalized polyglycerol, modified successively with 2-chloropropionamide groups (ATRP initiator) and 4,4′-azobis(4-cyanovaleric acid) (azo initiator). N,N-Dimethylacrylamide was polymerized from MI-HPG core by the RAFT method using S,S′-bis(α,α′-dimethyl-α′′-acetic acid)trithiocarbonate as a chain transfer agent (CTA) in acetic acid/sodium acetate aqueous buffer solutions. The ratio of [CTA]/[azo initiator] was critical in controlling the molecular weight of the PDMA grafts from MI-HPG core (HPG-g-PDMA). Controlled synthesis of mixed arm star copolymers was achieved by cografting PNIPAm on to the HPG-g-PDMA macroinitiator by ATRP. The temp...