Vitrimers: Associative dynamic covalent adaptive networks in thermoset polymers

Krishnakumar, Balaji; Prasanna, Sanka Rama V. Siva; Binder, Wolfgang H.; Parthasarthy, Vijay; Rana, Sravendra; Karak, Niranjan

doi:10.1016/j.cej.2019.123820

Cited by 340 publications

(216 citation statements)

References 96 publications

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“…21 The reported epoxy vitrimers execute associative exchanges through trans-esterication reactions, and the role of catalysts in exchange reactions was investigated thoroughly. 22 Since then, many reports have discussed vitrimer materials with different chemistries such as transesterication, [23][24][25][26] transalkylation, 27 transamination, 28 disulde, 29-31 transcarbamoylation 32,33 and transcarbonation. 34 Among these reactions, disulde exchanges were prominently discussed in self-healing studies to realize effective properties.…”

Section: Introductionmentioning

confidence: 99%

Disulfide exchange assisted self-healing epoxy/PDMS/graphene oxide nanocomposites

et al. 2020

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Section: Introductionmentioning

confidence: 99%

Disulfide exchange assisted self-healing epoxy/PDMS/graphene oxide nanocomposites

et al. 2020

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“…Among them, a successful approach describes the viscous response by harnessing the temperature-dependent bond kinetics existing at the molecular scale [166][167][168]. For instance, in polymers with physical bonds and in highly cross-linked thermosets (vitrimers) [169], the viscoelastic behaviour is modelled by means of the chains attachment and detachments mechanisms. In such polymers, viscoelastic effects (creep or stress relaxation) are triggered by temporary chains in the polymer network, which can detach from their stretched state and reattach to the network in a stress-free state upon dissociation and reformation of the dynamic cross-links [168].…”

Section: Discussionmentioning

confidence: 99%

Laser-based additively manufactured polymers: a review on processes and mechanical models

et al. 2020

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Additive manufacturing (AM) is a broad definition of various techniques to produce layer-by-layer objects made of different materials. In this paper, a comprehensive review of laser-based technologies for polymers, including powder bed fusion processes [e.g. selective laser sintering (SLS)] and vat photopolymerisation [e.g. stereolithography (SLA)], is presented, where both the techniques employ a laser source to either melt or cure a raw polymeric material. The aim of the review is twofold: (1) to present the principal theoretical models adopted in the literature to simulate the complex physical phenomena involved in the transformation of the raw material into AM objects and (2) to discuss the influence of process parameters on the physical final properties of the printed objects and in turn on their mechanical performance. The models being presented simulate: the thermal problem along with the thermally activated bonding through sintering of the polymeric powder in SLS; the binding induced by the curing mechanisms of light-induced polymerisation of the liquid material in SLA. Key physical variables in AM objects, such as porosity and degree of cure in SLS and SLA respectively, are discussed in relation to the manufacturing process parameters, as well as to the mechanical resistance and deformability of the objects themselves. Graphic abstract

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“…136 (2) Permanent dynamic networks. 137 (3) Reversible dynamic networks. 125 While the responsive chemistries overlap between the subsections, the distinctions in physical responses (actuation and folding versus responsive phase change) are relevant for different fields and applications therein.…”

Section: Overview and Challengesmentioning

confidence: 99%

“…72 (3) Reversible dynamic networks. 137 One of the limitations of developing high-temperature SMPs is reaching responsive temperatures while maintaining reversibility and mechanical or chemical stability. While these responses are reversible, there is typically a complicated mechanism to reestablish the original stress state.…”

Section: State Of the Artmentioning

confidence: 99%

Stimuli‐responsive mechanical properties in polymer glasses: challenges and opportunities for defense applications

Dennis

Savage

Mrozek

et al. 2020

Polymer International

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The potential utility that responsive glasses provide in the areas of aeronautics, protection and unmanned systems is reviewed in this article. The article focuses on two broad classes of stimuli, photo and thermal, to better illustrate the challenges and convey some of the potential in developing these materials for the often extreme operational environments of defense applications. Three response mechanisms are outlined to provide a range of mechanical behaviors on demand: (i) shape-changing functionalities which locally yield or soften the material to stimulate chain mobility; (ii) bond forming (or breaking) chemistries which increase (or decrease) the stiffness of the material; and (iii) energy absorbing groups which convert the incoming stimuli into a spatially controlled heating and result in a designed softening of the material. Overall, continuing to develop responsive polymer glasses that respond rapidly and efficiently under low energy inputs will be critical for future defense applications.

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Vitrimers: Associative dynamic covalent adaptive networks in thermoset polymers

Cited by 340 publications

References 96 publications

Disulfide exchange assisted self-healing epoxy/PDMS/graphene oxide nanocomposites

Disulfide exchange assisted self-healing epoxy/PDMS/graphene oxide nanocomposites

Laser-based additively manufactured polymers: a review on processes and mechanical models

Stimuli‐responsive mechanical properties in polymer glasses: challenges and opportunities for defense applications

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