Polyethylene vitrimers via silyl ether exchange reaction

Żych, Arkadiusz; Pinalli, Roberta; Soliman, Maria; Vachon, Jérôme; Dalcanale, Enrico

doi:10.1016/j.polymer.2020.122567

Cited by 74 publications

(90 citation statements)

References 28 publications

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“…The Reduction of elongation at break is a well-known characteristic of crosslinked materials. 57 Recent studies have confirmed the increase in brittleness with the crosslinking degree for solid vitrimers (PE-based vitrimers 26,27,39 and polydimethylsiloxane-based vitrimers 17 ). Furthermore, the PBT elongation at break has already been observed to sometimes strongly decrease with temperature in a 50°C temperature interval above The mechanical properties of the pristine PBT as well as those of , figure 10b).…”

Section: Temperature Dependency Of Vitrimers' Mechanical Propertiesmentioning

confidence: 94%

“…Conversely, at processing temperatures a higher rate of exchange reactions means the material remains easy to shape. 23,30 With the exception of shape-memory vitrimer formulations which include a volume fraction of semi-crystalline phase, 9,[33][34][35][36] the semi-crystalline vitrimers that have been reported so far have been based on two types of semicrystalline polymer (SCP) precursors: 1) PBT (Poly(butylene terephthalate)) 13,30,37 , the polymer we used in the present study, and 2) PE (Polyethylene) 26,27,[38][39] . The influence of the dynamic permanent covalent network on the rheological properties of SCP-based vitrimers has mainly been studied in the "molten state", i.e.…”

Section: Introductionmentioning

confidence: 99%

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Solid Rheological Properties of PBT-Based Vitrimers

et al. 2021

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We present an experimental investigation of the mechanical properties of solid vitrimer samples obtained by incorporating a diepoxide into a commercial PBT in the presence of a Zn(II) catalyst using batch compounder and injection molding machines. Tensile experiments were carried out at different temperatures (80°C, 120°C, 160°C) below the melting point (220°C) and with various diepoxide concentrations (0, 1, 2wt%,). We found that vitrimer plastic deformation mechanisms differ drastically from those of the PBT precursor, and more generally from the regular behaviour of other semi-crystalline polymers. In PBT vitrimers, strain localization (necking) is very weak and can even be suppressed. This type of behaviour is due to the increase in strain hardening caused by vitrimer crosslinking. The creep resistance and stiffness of PBT vitrimers are significantly higher than that those of the pristine PBT. We found that vitrimer modification of PBT at moderate levels improves dimensional stability without inducing brittleness. These promising results highlight the need to find processes which enable significant 2 production levels of these new materials. In the perspective section, we briefly present a way to produce PBTbased vitrimers using CRE (Continuous Reactive Extrusion).'' G ) moduli measured by rheometry with temperature or frequency sweeps. 6,13,27,30,37,[40][41] In particular, it is possible to roughly estimate whether a vitrimer has predominantly "rubber" ( ' '' GG  ) or "viscous" behaviour ( '' ' GG  ) for a given temperature and time scale. During vitrimer synthesis, the measurement of the temporal increase of ' G and '' G also makes it possible to monitor how the crosslinking reaction progresses and find the gelation point, which occurs approximately when ' '' GG . 13,[40][41] After the gelation point, the crosslinking reaction ends and the storage and loss moduli reach constant values with ' '' GG  . The molten polymer remains then in the "rubbery" state except when destruction of cross-links takes place by thermal degradation. 27 At service temperatures, i.e. in the solid state or below m T , the published results concern mainly the viscoelastic characteristics of vitrimers, or more specifically the creep properties of these materials. Röttger et al. and Caffy et

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Section: Temperature Dependency Of Vitrimers' Mechanical Propertiesmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Solid Rheological Properties of PBT-Based Vitrimers

et al. 2021

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“…In this case, the transesterification kinetics was controlled with a catalyst. [ 5 ] Other types of exchange reactions can be found in the literature including vinylogous transamination reaction, [ 7,11 ] transcarbonation, [ 12 ] trans alkylation, [ 13 ] imine exchange, [ 14 ] silyl ether exchange, [ 15,16 ] olefin metathesis, [ 17 ] dioxaborolane metathesis, [ 4 ] boronic ester transesterification [ 18 ] and disulfide metathesis. [ 9,19–24 ] Only a few of these exchange reactions have been introduced in commercial plastics.…”

Section: Introductionmentioning

confidence: 99%

Processing and rheological behavior of cross‐linked polyethylene containing disulfide bonds

2021

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Vitrimers are a new class of materials that consist of chemically cross‐linked networks that engage in thermoactivated associative exchange reactions. These exchange reactions can impart malleability, healing, and recyclability properties to thermosets. In this study, a one‐step protocol to prepare linear low‐density polyethylene (LLDPE) vitrimer‐like materials with disulfide exchange bonds via reactive blending is presented. The cross‐linking reaction of maleic anhydride‐grafted‐linear low‐density polyethylene (LLDPE‐MAH) and 4,4′‐dithiodianiline was followed in a torque rheometer. The degree of MAH‐functionalization and its impact on the melt rheology, dynamic mechanical properties, and thermal properties of the vitrimer was studied. The cross‐linked LLDPE possessed a mostly elastic behavior, with storage modulus (G′) higher than loss modulus (G′′) in the entire frequency range. The complex viscosity of cross‐linked LLDPE at high frequencies (>100 rad/s) was comparable to the thermoplastic LLDPE. The MAH‐groups and formation of cross‐links decreased the degree of crystallinity, which led to a decrease in the storage modulus at a temperature of 35°C. The storage modulus and dimensional stability of the materials improved with cross‐linking density, suggesting potential benefits of LLDPE vitrimers in secondary manufacturing processes. Finally, the reprocessing ability was demonstrated via internal mixing and the rheological and mechanical properties were retained.

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“…through the reversible depolymerization or exchange reactions of their dynamic cross-links [ 3 , 9 , 10 , 11 ]. So far, a number of CANs based on Michael addition [ 12 , 13 , 14 ], Diels-Alder reaction [ 15 , 16 ], disulfide exchange [ 17 , 18 , 19 ], imine metathesis [ 20 , 21 , 22 ], transesterification [ 23 , 24 , 25 ], olefin metathesis [ 26 , 27 ], silyl ether transalkoxylation [ 28 , 29 ], diketoenamine exchange [ 30 , 31 ], and dioxaborolane metathesis [ 32 , 33 ] have been proposed in the literature. Besides recyclability, many other adaptive properties of CANs were also investigated, such as reconfigurability [ 34 , 35 ], shape memory [ 36 , 37 ], and network topological transformation [ 18 , 25 , 38 ].…”

Section: Introductionmentioning

confidence: 99%

Reprocessable, Reworkable, and Mechanochromic Polyhexahydrotriazine Thermoset with Multiple Stimulus Responsiveness

et al. 2020

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Developing recyclable, reworkable, and intelligent thermosetting polymers, as a long-standing challenge, is highly desirable for modern manufacturing industries. Herein, we report a polyhexahydrotriazine thermoset (PHT) prepared by a one-pot polycondensation between 4-aminophenyl disulfide and paraformaldehyde. The PHT has a glass transition temperature of 135 °C and good solvent resistance. The incorporation of dual stimuli-responsive groups (disulfide bond and hexahydrotriazine ring) endows the PHT with re-processability, re-workability, and damage monitoring function. The PHT can be repeatedly reprocessed by hot pressing, and a near 100% recovery of flexural strength is achieved. The PHT can also degrade in inorganic acid or organic thiol solutions at room temperature. The thermally reworkable test demonstrates that, after heating the PHT at 200 °C for 1 h, the residuals can be easily wiped off. Finally, the PHT exhibits a reversible mechanochromic behavior when damaged.

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Polyethylene vitrimers via silyl ether exchange reaction

Cited by 74 publications

References 28 publications

Solid Rheological Properties of PBT-Based Vitrimers

Solid Rheological Properties of PBT-Based Vitrimers

Processing and rheological behavior of cross‐linked polyethylene containing disulfide bonds

Reprocessable, Reworkable, and Mechanochromic Polyhexahydrotriazine Thermoset with Multiple Stimulus Responsiveness

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