Controlled Synthesis of a Homopolymer Network Using a Well-Defined Single-Component Diels–Alder Cyclopentadiene Monomer

Cyclopentadiene is known for its
high reactivity and
propensity
to dimerize, making monomer synthesis and polymerization notoriously
challenging. In fact, despite its long history and compelling chemistry,
only two reports have appeared in the literature since the first attempt
to homopolymerize cyclopentadiene by Staudinger in 1926. Herein, we
present a strategy not only to synthesize, isolate, and homopolymerize
a well-defined tetracyclopentadiene monomer but also to de-cross-link
the network homopolymer. Mechanical properties are also investigated,
including creep–recovery, shape memory, and tensile behaviors.
Interestingly, the tensile test reflects a tough and elastic material,
in contrast to prior Cp-based homopolymer networks. This work provides
a versatile platform to access and study new cyclopentadiene-based
and better-defined homopolymer networks with potential applications
ranging from shape memory polymers to degradable thermosets.