Molecularly Designed Additives for Chemically Deconstructable Thermosets without Compromised Thermomechanical Properties

Abstract

Metrics & MoreArticle Recommendations * sı Supporting Information ABSTRACT: "Drop-in" additives that introduce chemically cleavable bonds into thermosets without compromising thermomechanical properties could enable triggered material deconstruction and enhanced sustainability. While the installation of cleavable bonds into the strands of the commercial thermoset polydicyclopentadiene (pDCPD) using comonomers facilitates chemical deconstruction, these additives can lower the material's glass transition temperature (T g ). By contrast, the installation of cleavable crosslinkers into pDCPD can maintain or potentially increase T g but does not facilitate chemical deconstruction. Here, we introduce "strand-cleaving crosslinker" (SCC) additives that provide cleavable pDCPD network junctions. Notably, pDCPD samples featuring 10% v/v of SCCs can be deconstructed under mild conditions to yield soluble products and display a 48 °C higher T g than analogous decontructable pDCPD made using cleavable comonomers and an equivalent T g to virgin pDCPD. The SCC concept could offer a general strategy for the design of chemically deconstructable thermoset materials without compromise on thermomechanical performance.

Fully degradable polymer networks from conventional radical polymerization of vinyl monomers enabled by thionolactone addition

“…24 They demonstrated that crosslinked polydicyclopentadiene synthesized by ringopening metathesis polymerization underwent a complete degradation after addition of only 10 mol% of a silyl ether-based, cleavable comonomer. [24][25][26] In the case of vinyl polymers, degradable bonds can be installed in the backbone by radical ring-opening polymerization (RROP) of cyclic monomers such as cyclic ketene acetals or allyl sulfide lactones. [27][28][29][30][31] Thionolactones, such as dibenzo[c,e]oxepane-5-thione (DOT) have been recently presented as a degradable comonomer which undergo RROP with acrylates, acrylamides, acrylonitrile, [32][33][34][35] as well as vinyl esters, 36 styrene and methacrylates.…”

Orthogonally deconstructable and depolymerizable polysilylethers via entropy-driven ring-opening metathesis polymerization

“…Our group previously reported that 8- and 7-member cyclic bifunctional silyl ether olefins could be efficiently prepared and statistically copolymerized with a variety of ROMP-active norbornene derivatives with potential applications in drug delivery and recyclable thermosets. 12,14,15 At the concentrations at which these copolymerizations were previously conducted (50 mM), however, these monomers were not found to homopolymerize. 12 Stemming from this observation, we sought to identify conditions under which these monomers could be homopolymerized as we anticipated their respective polymers would possess desirable properties including facile deconstructability and thermal properties akin to polydimethylsiloxane (PDMS).…”

Thionolactone as a Resin Additive to Prepare (Bio)degradable 3D Objects via VAT Photopolymerization**

“…The combination of DOT/acrylate polymerization and VAT photopolymerization could be an efficient way to prepare (bio)degradable 3D objects. It has been shown that only few percent (5-10 vol %) of cleavable units are required to impart degradability of thermosets [28,29] and also that DOT has a slightly higher rate of incorporation [33] than acrylate derivatives during their copolymerization, making it possible to use a very low amount of DOT as additive.…”