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Download fileSustainable Thermosetting Polyurea Vitrimers Based on a Catalyst-Free Process with Reprocessability, Permanent Shape Reconfiguration and Self-Healing Performance
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posted on 2019-11-04, 11:29 authored by Liang Jiang, Zhimeng Liu, Yuan Lei, Ye Yuan, Bo Wu, Jingxin LeiTraditional
thermosetting polyureas (TPUs) with eminently comprehensive
performance have been used in a variety of industrial applications.
However, they suffer from a certain intractable difficulty in achieving
multiple functions such as reprocessability, shape reconfiguration,
or self-healing performance due to the extremely stable covalent cross-linking.
Herein, we employ hindered urea bonds (HUBs) as a reversible dynamic
covalent cross-linkage to design catalyst-free hindered thermosetting
polyureas (HTPUs). By incorporating HUBs into TPUs, the synthesized
HTPUs can be reprocessed by using hot press or microinjection technique
without any catalyst. In addition, those obtained materials have achieved
great abilities of permanent shape reconfiguration and self-healing.
Especially, the combination of the conventional elastic shape memory
with the solid-state plastic shape reconfiguration in these HTPUs
will broaden the geometrically complex shapes for shape memory polymer.
Importantly, introducing longer and more bulky substituents into HTPUs
can simultaneously endow the materials with excellent mechanical properties
and the aforementioned multiple functions. Despite what is mentioned
in this article, more potential HTPUs with excellent mechanical properties
and multiple functions could be further designed by introducing longer
and more bulky substituents into the formal polymers.