Abstract The properties of copolymers are affected greatly by the composition as well as the chain structure of the copolymers. Consequently, gradient copolymers, due to the uniqueness of their structures show significantly different properties than those of the conventional statistical and block copolymers. This study reports the synthesis of 4-acetoxystyrene – t-butyl acrylate (AOST-tBA) statistical copolymers by reversible addition-fragmentation chain-transfer (RAFT) and free radical polymerization (FRP) methods, and also the synthesis of block and gradient copolymers of AOST-tBA by the RAFT method. The gradient structure in the AOST-tBA copolymer was produced by continuously adding a second monomer to the polymerization system to taper the copolymer composition. Differential scanning calorimetry (DSC) analysis found a broad transition for the gradient copolymer, in contrast to a single narrow transition for the statistical copolymer and two narrow transitions for the block copolymer. The acetoxy groups from the AOST-tBA copolymers were de-acetylated to convert the AOST to hydroxystyrene (HOST). Fourier transform infra-red (FTIR) studies revealed that the extent of hydrogen bonding in thin films of the HOST-tBA copolymers is greatly influenced by the copolymer composition as well as the chain structure. However, no significant differences were found for the surface compositions and surface free energies of copolymers. The properties of HOST-tBA copolymers synthesized by RAFT and FRP have also been compared in this study.

中文翻译：

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4-乙酰氧基苯乙烯-丙烯酸叔丁酯统计、嵌段和梯度共聚物的合成，以及共聚物结构对其性能的影响

摘要 共聚物的性能受共聚物的组成和链结构的影响很大。因此，梯度共聚物由于其结构的独特性而表现出与常规统计共聚物和嵌段共聚物显着不同的性质。本研究报告了通过可逆加成断裂链转移 (RAFT) 和自由基聚合 (FRP) 方法合成 4-乙酰氧基苯乙烯 - 丙烯酸叔丁酯 (AOST-tBA) 统计共聚物，以及嵌段和梯度共聚物的合成AOST-tBA 通过 RAFT 方法。AOST-tBA 共聚物中的梯度结构是通过向聚合体系中连续添加第二个单体以使共聚物组成逐渐变细而产生的。差示扫描量热法 (DSC) 分析发现梯度共聚物的宽转变与统计共聚物的单一窄转变和嵌段共聚物的两个窄转变形成对比。来自 AOST-tBA 共聚物的乙酰氧基被去乙酰化以将 AOST 转化为羟基苯乙烯 (HOST)。傅里叶变换红外 (FTIR) 研究表明，HOST-tBA 共聚物薄膜中的氢键程度受共聚物组成和链结构的影响很大。然而，共聚物的表面组成和表面自由能没有发现显着差异。本研究还比较了由 RAFT 和 FRP 合成的 HOST-tBA 共聚物的性能。与统计共聚物的单一窄跃迁和嵌段共聚物的两个窄跃迁形成对比。来自 AOST-tBA 共聚物的乙酰氧基被去乙酰化以将 AOST 转化为羟基苯乙烯 (HOST)。傅里叶变换红外 (FTIR) 研究表明，HOST-tBA 共聚物薄膜中的氢键程度受共聚物组成和链结构的影响很大。然而，共聚物的表面组成和表面自由能没有发现显着差异。本研究还比较了由 RAFT 和 FRP 合成的 HOST-tBA 共聚物的性能。与统计共聚物的单一窄跃迁和嵌段共聚物的两个窄跃迁形成对比。来自 AOST-tBA 共聚物的乙酰氧基被去乙酰化以将 AOST 转化为羟基苯乙烯 (HOST)。傅里叶变换红外 (FTIR) 研究表明，HOST-tBA 共聚物薄膜中的氢键程度受共聚物组成和链结构的影响很大。然而，共聚物的表面组成和表面自由能没有发现显着差异。本研究还比较了由 RAFT 和 FRP 合成的 HOST-tBA 共聚物的性能。傅里叶变换红外 (FTIR) 研究表明，HOST-tBA 共聚物薄膜中的氢键程度受共聚物组成和链结构的影响很大。然而，共聚物的表面组成和表面自由能没有发现显着差异。本研究还比较了由 RAFT 和 FRP 合成的 HOST-tBA 共聚物的性能。傅里叶变换红外 (FTIR) 研究表明，HOST-tBA 共聚物薄膜中的氢键程度受共聚物组成和链结构的影响很大。然而，共聚物的表面组成和表面自由能没有发现显着差异。本研究还比较了由 RAFT 和 FRP 合成的 HOST-tBA 共聚物的性能。