On December 31, 2019, Li, Ting; Zheng, Tian-Ze; Guo, Zhao-Xia; Xu, Jun; Guo, Bao-Hua published an article.Product Details of 517-23-7 The title of the article was A Well-defined Hierarchical Hydrogen Bonding Strategy to Polyureas with Simultaneously Improved Strength and Toughness. And the article contained the following:
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 mech. 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 NMR and fourier transform IR spectroscopy. The mech. 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 intermol. 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 revealed 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 mech. properties. The experimental process involved the reaction of 3-Acetyldihydrofuran-2(3H)-one(cas: 517-23-7).Product Details of 517-23-7
The Article related to polyurea elastomer preparation hierarchical hydrogen bonding mech property, Synthetic Elastomers and Natural Rubber: Elastomer Synthesis and other aspects.Product Details of 517-23-7
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