In recent years, poly(2-oxazoline)s (POx) have become a sought-after biomaterial to replace PEG. However, access to POx based block copolymers is rather limited and their combination with controlled radical polymerization (CRP) techniques is required. Herein, we report the combination of cationic ring opening polymerization (CROP) and nitroxide mediated radical polymerization (NMP) to enable block copolymerization of poly(2-oxazoline)s with styrenics, acrylics, 1,3-dienes, and acrylamides as the second block. A well-defined poly(2-ethyl-2-oxazoline) macroinitiator has been prepared via CROP and in situ termination via the carboxylic acid functional group of BlocBuilder alkoxyamine has been achieved with a functionalization efficiency of 78%. Four different monomers in each class have been copolymerized via NMP and gel permeation chromatography analysis allowed us to identify the suitable set of comonomers to be utilized in block copolymerization with POx in an efficient, facile, metal- and sulfur-free polymerization environment.

中文翻译：

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通过硝基氧介导的聚合扩大聚（2-恶唑啉）嵌段共聚物的可能性


近年来，聚（2-恶唑啉）（POx）已成为替代 PEG 的热门生物材料。然而，基于 POx 的嵌段共聚物的获得相当有限，并且需要将它们与受控自由基聚合 (CRP) 技术相结合。在此，我们报道了阳离子开环聚合（CROP）和硝基氧介导的自由基聚合（NMP）的组合，使聚（2-恶唑啉）与苯乙烯类、丙烯酸类、1,3-二烯和丙烯酰胺进行嵌段共聚作为第二种方法堵塞。通过CROP 制备了结构明确的聚（2-乙基-2-恶唑啉）大分子引发剂，并通过BlocBuilder 烷氧基胺的羧酸官能团实现了原位终止，官能化效率为 78%。每类四种不同的单体均通过NMP 进行共聚，凝胶渗透色谱分析使我们能够确定合适的共聚单体，用于在高效、简便、不含金属和硫的聚合环境中与 POx 进行嵌段共聚。