Lorandi Francesca, Fantin Marco, Wang Yi, Isse Abdirisak A, Gennaro Armando, Matyjaszewski Krzysztof
Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States.
Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131, Padova, Italy.
ACS Macro Lett. 2020 May 19;9(5):693-699. doi: 10.1021/acsmacrolett.0c00246. Epub 2020 Apr 27.
The preparation of poly(acrylic acid) (PAA) with tailored architecture and morphology is important for the design of advanced polymer materials. Cu-catalyzed atom transfer radical polymerization (ATRP) of AA is challenging due to the tendency of dormant chains to undergo an intramolecular lactonization reaction with consequent loss of chain-end functionalities, as previously reported for ATRP of methacrylic acid (MAA). In addition, AA can coordinate to the Cu catalyst. Moreover, the lower ATRP reactivity of AA relative to MAA enhances side reactions during polymerizations. These issues were overcome by adjusting the composition of the catalytic system, the polymerization setup, and the initiator nature. AA conversion >70-80% was obtained in 5 h, producing PAA with ≈1.4. Multifunctional water-soluble initiators provided PAA and PMAA with telechelic and star-shaped architectures. Block copolymers of MAA and AA confirmed the retention of chain-end functionalities during ATRPs.
制备具有定制结构和形态的聚丙烯酸（PAA）对于先进聚合物材料的设计至关重要。由于休眠链倾向于发生分子内内酯化反应，导致链端官能团丧失，因此丙烯酸（AA）的铜催化原子转移自由基聚合（ATRP）具有挑战性，正如先前报道的甲基丙烯酸（MAA）的ATRP情况一样。此外，AA可以与铜催化剂配位。而且，AA相对于MAA较低的ATRP反应活性会增强聚合过程中的副反应。通过调整催化体系的组成、聚合装置和引发剂性质，这些问题得以克服。在5小时内获得了>70 - 80%的AA转化率，制备出了具有≈1.4的PAA。多功能水溶性引发剂提供了具有遥爪型和星形结构的PAA和聚甲基丙烯酸（PMAA）。MAA和AA的嵌段共聚物证实了在ATRP过程中链端官能团得以保留。
