Lepage ML, Simhadri C, Liu C, Takaffoli M, Bi L, Crawford B, Milani AS, Wulff JE. A broadly applicable cross-linker for aliphatic polymers containing C-H bonds.
Science 2020;
366:875-878. [PMID:
31727835 DOI:
10.1126/science.aay6230]
[Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 10/09/2019] [Indexed: 12/27/2022]
Abstract
Addition of molecular cross-links to polymers increases mechanical strength and improves corrosion resistance. However, it remains challenging to install cross-links in low-functionality macromolecules in a well-controlled manner. Typically, high-energy processes are required to generate highly reactive radicals in situ, allowing only limited control over the degree and type of cross-link. We rationally designed a bis-diazirine molecule whose decomposition into carbenes under mild and controllable conditions enables the cross-linking of essentially any organic polymer through double C-H activation. The utility of this molecule as a cross-linker was demonstrated for several diverse polymer substrates (including polypropylene, a low-functionality polymer of long-standing challenge to the field) and in applications including adhesion of low-surface-energy materials and the strengthening of polyethylene fabric.
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