Impact of bottlebrush chain architecture on Tg‐confinement and fragility‐confinement effects enabled by thermo‐cleavable bottlebrush polymers synthesized by radical coupling and atom transfer radical polymerization,Journal of Polymer Science

当前位置： X-MOL 学术 › J. Polym. Sci. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Impact of bottlebrush chain architecture on Tg‐confinement and fragility‐confinement effects enabled by thermo‐cleavable bottlebrush polymers synthesized by radical coupling and atom transfer radical polymerization
Journal of Polymer Science ( IF 3.9 ) Pub Date : 2020-09-09 , DOI: 10.1002/pol.20200537
Lingqiao Li ₁ , Zhe Qiang ₁ , Xi Chen ₁ , Kailong Jin ₁ , Muzhou Wang ₁ , John M. Torkelson _{1,

2}

Affiliation

Thermo‐cleavable bottlebrush polymers were synthesized by a facile grafting‐to method via radical coupling and atom transfer radical polymerization (ATRP) without small‐molecule synthesis involved. Bottlebrushes were achieved by coupling backbones of poly(4‐methacryloyloxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyl), which contain nitroxide radicals, and ATRP‐synthesized side chains, which can be halogen‐abstracted to generate carbon‐centered radicals. Bottlebrushes were prepared using homopolymer or block copolymer side chains. Alkoxyamine covalent bonds resulting from radical coupling are thermo‐reversible at high temperature, and grafting density may be tuned by annealing of post‐synthesis bottlebrush, with the bottlebrush regime going from loose bottlebrush to dense comb and loose comb. The effects of confinement on the T_g and fragility of films of polystyrene bottlebrush were studied by ellipsometry; comparisons were made to thermally cleaved linear components obtained directly after annealing. Relative to linear polymer, bottlebrush topology reduces bulk fragility and suppresses T_g‐ and fragility‐confinement effects. The correlation between the strengths of the confinement effects is consistent with other film studies of linear and non‐linear polymers and supports the notion that fragility is a fundamental property underlying perturbations to T_g. Besides providing a platform for advancing fundamental scientific understanding, our synthetic strategy may afford novel applications of bottlebrushes via incorporated dynamic chemistry.

中文翻译：

自由基偶联和原子转移自由基聚合合成的热裂解型瓶刷聚合物对瓶刷链结构的Tg约束和脆性约束作用的影响

通过自由基偶联和原子转移自由基聚合（ATRP）的简便接枝方法合成了可热裂解的牙刷聚合物，而无需进行小分子合成。通过偶联含有硝基自由基的聚（4-甲基丙烯酰氧基-2,2,6,6-四甲基哌啶-1-氧基）骨架和ATRP合成的侧链（可以被卤素抽象生成碳原子）来制成牙刷。集中的部首。使用均聚物或嵌段共聚物侧链制备牙刷。由自由基偶合产生的烷氧基胺共价键在高温下可热逆转，并且可以通过合成后牙刷的退火来调节接枝密度，该牙刷的处理方式从松散的牙刷变为密梳和松散的梳子。限制对T的影响用椭圆偏振光度法研究了聚苯乙烯牙刷的膜的_克和脆性。对退火后直接获得的热裂解线性组分进行了比较。相对于线性聚合物，洗瓶刷拓扑结构降低了整体脆性，并抑制了T _g和脆性限制作用。约束作用强度之间的相关性与其他关于线性和非线性聚合物的薄膜研究一致，并支持以下观点：脆性是对T _g扰动的基本性质。除了提供增进基础科学理解的平台外，我们的合成策略还可以通过结合动态化学方法为牙刷提供新颖的应用。

更新日期：2020-10-17

点击分享查看原文

点击收藏

阅读更多本刊最新论文