Chen Xin, Zhang Chi, Li Weidong, Chen Lei, Wang Wusheng
School of Chemistry and Chemical Engineering, Anhui University, 111 Jiu long Road, Hefei 230601, China.
Polymers (Basel). 2018 Feb 23;10(2):219. doi: 10.3390/polym10020219.
A key for the preparation of polyacrylate-based polyurethane is the synthesis of hydroxyl-terminated polyacrylate. To our knowledge, exactly one hydroxyl group of every polyacrylate chain has not been reported. The hydroxyl-terminated poly(butyl acrylate) (PBA) has been successfully synthesized by degenerative iodine transfer polymerization (DITP) of the -butyl acrylate (-BA) using 4,4'-azobis(4-cyano-1-pentanol) (ACPO) and diiodoxylene (DIX) as initiator and chain transfer agent, respectively, and subsequently substituted reaction of the iodine-terminated PBA with β-mercaptoethanol in alkaline condition. The latter reaction was highly efficient, and the terminal iodine at the end of polymer chains were almost quantitatively transformed to a hydroxyl group. 2,2'-Azobis(isobutyronitrile) (AIBN) and ACPO were used as initiators in the DITPs of -BA. The results demonstrated that they had a significant influence on the terminal groups of the formed polymer chains. The structure, molecular weight, and molecular weight distribution of the hydroxyl-terminated PBA have been studied by ¹H, C NMR, and GPC results. The components of hydroxyl-terminated PBA were determined by MALDI-TOF MS spectra, and their formation is discussed. The broad molecular weight distribution of the PBA and the difference in the polymerization behaviors from typical living radical polymerization are explained based on the results of ¹H NMR and MALDI-TOF MS spectra. The hydroxyl-terminated PBA has been successfully used in the preparation of PBA-based polyurethane dispersions (PUDs). The aqueous PUDs were stable, and based on the DSC results it can be said that the miscibility of hard segments with PBA chains was improved.
制备聚丙烯酸酯基聚氨酯的关键在于合成端羟基聚丙烯酸酯。据我们所知，尚未有关于每条聚丙烯酸酯链恰好只有一个羟基的报道。通过使用4,4'-偶氮双(4-氰基-1-戊醇)(ACPO)和二碘代二甲苯(DIX)分别作为引发剂和链转移剂，对丙烯酸丁酯(BA)进行退化碘转移聚合(DITP)，成功合成了端羟基聚(丙烯酸丁酯)(PBA)，随后在碱性条件下使碘端基PBA与β-巯基乙醇发生取代反应。后一反应效率很高，聚合物链末端的碘几乎定量地转化为羟基。在BA的DITP中使用2,2'-偶氮二异丁腈(AIBN)和ACPO作为引发剂。结果表明，它们对所形成聚合物链的端基有显著影响。通过¹H、¹³C NMR和GPC结果研究了端羟基PBA的结构、分子量和分子量分布。通过基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)光谱确定了端羟基PBA的组成，并讨论了它们的形成过程。基于¹H NMR和MALDI-TOF MS光谱的结果，解释了PBA宽分子量分布以及与典型活性自由基聚合在聚合行为上的差异。端羟基PBA已成功用于制备基于PBA的聚氨酯分散体(PUDs)。水性PUDs稳定，基于差示扫描量热法(DSC)结果可以说硬段与PBA链的混溶性得到了改善。
