A Well-defined Hierarchical Hydrogen Bonding Strategy to Polyureas with Simultaneously Improved Strength and Toughness
A Well-defined Hierarchical Hydrogen Bonding Strategy to Polyureas with Simultaneously Improved Strength and Toughness
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明确的聚脲分层氢键策略，同时提高强度和韧性
DOI：
10.1007/s10118-019-2275-3
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发表时间：
2019-06
影响因子：
4.3
通讯作者：
Guo Baohua
中科院分区：
文献类型：
--
作者：
Li Ting;Zheng Tianze;Guo Zhaoxia;Xu Jun;Guo Baohua
创新性地设计了一种明确的四重氢键策略，涉及 2-脲基-4[1H]-嘧啶酮 (UPy) 单元的二聚，以制备具有高整体机械性能的聚脲。通过用 UPy 衍生的二异氰酸酯替换部分异佛尔酮二异氰酸酯 (IPDI)，合成了三种含有不同量 UPy 单元的聚脲。核磁共振（NMR）和傅里叶变换红外光谱（FTIR）证实了通过UPy二聚体在硬链段中形成四重氢键。通过单轴拉伸试验评价聚脲的机械性能。与不含UPy单元的聚脲相比，掺入UPy单元时杨氏模量、拉伸强度和韧性同时得到显着改善。强强化效应背后的机制源于四重氢键带来的硬链段之间更强的分子间力，其强于脲基之间固有的二齿和单齿氢键，以及软链段的Tg和弛豫时间增加所揭示的较慢的软链段动力学。强增韧效应背后的机制归因于四氢键带来更有效的能量耗散，四氢键在变形时充当更强的牺牲键。这项工作可能为机械性能全面改善的聚脲弹性体的设计提供新的见解。
A well-defined quadruple hydrogen bonding strategy involving dimerization of 2-ureido-4[1H]-pyrimidone (UPy) units is innovatively designed to prepare polyureas with high overall mechanical properties. Three polyureas containing different amounts of UPy units were synthesized by replacing a portion of isophorone diisocyanate (IPDI) with a UPy-derived diisocyanate. The formation of quadruple hydrogen bonds in hard segments via UPy dimers was confirmed by nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). The mechanical properties of the polyureas were evaluated by uniaxial tensile testing. Compared to the polyurea without UPy units, remarkable improvements in Young’s modulus, tensile strength, and toughness were simultaneously achieved when UPy units were incorporated. The mechanism behind the strong strengthening effect rooted in the stronger intermolecular forces among hard segments brought by the quadruple hydrogen bonds, which were stronger than the inherent bidentate and monodentate hydrogen bonds among urea groups, and the slower soft segmental dynamics reaveled by both increased Tg and relaxation time of the soft segments. The mechanism behind the strong toughening effect was ascribed to more effective energy dissipation brought by the quadruple hydrogen bonds that served as stronger sacrificial bonds upon deformation. This work may offer new insight into the design of polyurea elastomers with comprehensively improved mechanical properties.
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影响因子：
5.5
作者：
Gooch, Adam;Nedolisa, Chinemelum;Wilson, Andrew J.
通讯作者：
Wilson, Andrew J.
影响因子：
4.6
作者：
Sami, Selim;Yildirim, Erol;Wilkes, Garth L.
通讯作者：
Wilkes, Garth L.
影响因子：
5.5
作者：
Dankers, Patricia Y. W.;Zhang, Zheng;Meijer, E. W.
通讯作者：
Meijer, E. W.
影响因子：
2.5
作者：
Sanchez-Ferrer, Antoni;Rogez, Daniel;Martinoty, Philippe
通讯作者：
Martinoty, Philippe
DOI：
10.1002/polb.22352
发表时间：
2011-12
期刊：
Journal of Polymer Science Part B
影响因子：
--
作者：
R. G. Rinaldi;M. Boyce;S. Weigand;D. Londono;M. Guise
通讯作者：
R. G. Rinaldi;M. Boyce;S. Weigand;D. Londono;M. Guise