Recent advances in entropy-driven ring-opening polymerizations

Strandman, Satu; Gautrot, Julien E.; Zhu, Xiaoxia

doi:10.1039/c0py00328j

Cited by 96 publications

(95 citation statements)

References 102 publications

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“…While the ROP of smaller cycles is dictated by the relief of the cyclic monomer ring‐strain, and it is usually an enthalpy‐driven process, for larger cyclic monomers the thermodynamic data suggested a rather small ring‐strain accompanied conversely by an increase in the polymerization entropy, probably due to a relatively high flexibility of the long polymethylene chains . In the case of large lactones, the polymerization will behave as an entropy‐driven polymerization and will be favored by a temperature increase . The thermodynamic parameters for one of the most explored macrolide, the ω‐pentadecalactone (ω‐PDL), are indeed consistent with an entropy‐driven polymerization reaction .…”

Section: Introductionmentioning

confidence: 81%

Tuning the thermal properties of poly(ethylene)‐like poly(esters) by copolymerization of ε‐caprolactone with macrolactones, in the presence of a pyridylamidozinc(II) complex

Naddeo

D’Auria

Viscusi

et al. 2020

Journal of Polymer Science

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Linear aliphatic poly(ester)s, as thermoplastic materials, are more and more envisaged as the potential “green” alternative to traditional plastics. Aliphatic polyesters having long methylene chain behave as “polyethylene‐like” materials and can be prepared by ring‐opening polymerization (ROP) of macrolactones. A pyridylamidozinc(II) complex was used for the ROP of ε‐caprolactone (CL) and of two large ring size lactones, the ω‐6‐hexadecenlactone (6HDL) and the ω‐pentadecalactone (PDL). High turnover frequencies were observed for the CL polymerization, while for the macrolactones, an entropy‐driven behavior was recognized. Random copolymerizations of the PDL with 6HDL and of the macrolactones with CL were successfully achieved, and the copolymer microstructure was ascertained by NMR and MALDI analyses. The copolymer melting temperatures, measured by DSC, and the thermal degradation behavior, studied by TGA in nitrogen and air atmosphere, were dependent on the copolymer's composition. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 528–539

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Section: Introductionmentioning

confidence: 81%

Tuning the thermal properties of poly(ethylene)‐like poly(esters) by copolymerization of ε‐caprolactone with macrolactones, in the presence of a pyridylamidozinc(II) complex

Naddeo

D’Auria

Viscusi

et al. 2020

Journal of Polymer Science

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“…Concentration affects directly the reaction rate and ring‐chain equilibrium shifts towards a higher yield of cyclic products under dilute conditions, unless the macrocyclic structures are removed along the way . Most publications have demonstrated this shift in equilibrium at concentration range of 0.001–0.02 M .…”

Section: Lactonization and Ring‐opening Polymerizationmentioning

confidence: 99%

Recent Developments and Optimization of Lipase-Catalyzed Lactone Formation and Ring-Opening Polymerization

Champagne

Strandman

Zhu

2016

Macromol. Rapid Commun.

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To obtain materials useful for the biomedical field, toxic catalysts should be removed from the synthetic route of polymerization reactions and of their precursors. Lipase-catalyzed ring-opening polymerization and the synthesis of cyclic precursors can be performed with the same catalyst under different conditions. Here, we highlight the use of lipases as catalysts and optimization of their performance for both ring-closing and ring-opening polymerization, via varying parameters such as ring size, concentration, substrate molar ratio, temperature, and solvent. While the conditions for ring-closing reactions and ring-opening polymerizations of small molecules, such as ε-caprolactone, have been extensively explored using Candida antarctica lipase B (CALB), the optimization of macrocyclization, especially for more bulky substrates is surveyed here. Finally, recent methods and polymer architectures are summarized with an emphasis on new procedures for more sustainable chemistry, such as the use of ionic liquids as solvents and recycling of polyesters by enzymatic pathways.

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“…With the huge progress in controlled/living polymerizations (i.e. [21][22][23] Nonetheless, another type of responsive block copolymers has gained attention where a cleavable junction between polymer blocks is introduced, paving the way to interesting features in, among other fields, nanolithography where one block might be selectively removed under mild conditions. [11][12][13] Nevertheless, the second strategy has emerged as an interesting pathway with the introduction in the polymer field of very efficient organic reactions such as amide coupling, urethane ligation [14][15][16] and reactions involved in the Click Chemistry concept.…”

Section: Introductionmentioning

confidence: 99%

Catechol/boronic acid chemistry for the creation of block copolymers with a multi-stimuli responsive junction

et al. 2016

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Two original Chain Transfer Agents (CTAs) integrating either a nitrocatechol or a boronic acid moiety were synthesized allowing the conception of a wide library of end-functionalized well-defined homopolymers via the Reversible Addition-Fragmentation chain Transfer (RAFT) process. Kinetic studies using NMR spectroscopy and Size Exclusion Chromatography (SEC) were carried out, revealing a good control of polymerizations for various monomers. Then, a coupling reaction between the complementary nitrocatechol and boronic acid end-chain polymers was optimized to create a dynamic boronate ester junction between polymer blocks. The effectiveness of the reaction was demonstrated by means of NMR ( 1 H, DOSY), SEC and cyclic voltammetry. The ability of the covalent bond, and thus the block copolymers, to be disrupted on demand was assessed using a competitive molecule (2-naphthylboronic acid) and UV irradiation as stimuli. Figure 3. A) Kinetic plots and B) dependence of the molar mass and polydispersity index on monomer conversion for the RAFT polymerization involving ND-CTA (see Table 1 for experimental conditions).After the obtention of well-defined homopolymers bearing either a nitrocatechol moiety (ND-Polymer) or a boronic acid group (Boro-Polymer) at their extremity, we next turned our attention to whether they can be readily connected through the boronate ester formation to furnish diblock copolymer architectures. This was exemplified by mixing two complementary end-functionalized homopolymers, ND-PDMAc (M n,NMR =1700 g.mol -1 , Ð=1.2) and Boro-PnBuA (M n,NMR =2000 g.mol -1 , Ð=1.1), in acetonitrile under reflux for 24 hours. The block copolymer PDMAc-b-PnBuA was recovered after purification through dialysis (MWCO = 3500 g/mol) in acetonitrile and then characterized by 1 H NMR spectroscopy. First, we tried to perform the coupling reaction from an equimolar amount of each polymer in acetonitrile for 24h. After dialysis, 1 H NMR analysis revealed the presence of the pure block copolymer in the dialysis bag and traces of both starting homopolymers in the filtrate, suggesting that the reaction was not quantitative. Thus, to ensure a complete reaction, 2 equivalents of Boro-PnBuA and 1 equivalent of ND-PDMAc were next reacted in similar reaction conditions. In that case, no trace of unreacted ND-PDMAc was detected in the filtrate after purification. linked block copolymer (1 equivalent). Indeed, it has already been demonstrated that NBA displays a much lower fluorescence intensity in organic medium once bounded to diols. 65 Thus, this trend has been exploited to monitor the disassembly of a block copolymer PDMAcb-PnBuA (Scheme 3). Scheme 3. Reaction between NBA and ND-PDMAc (Pathway 1) and PDMAc-b-PnBuA (Pathway 2).On Figure 8, the typical emission spectrum of NBA is presented while the block copolymer PDMAc-b-PnBuA exhibits no fluorescence. On the other hand, when the homopolymer ND-PDMAc is directly coupled with NBA (pathway 1, Scheme 3), the resulting functionalized NBA-PDMAc is less fluorescent than NBA alone, as d...

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Recent advances in entropy-driven ring-opening polymerizations

Cited by 96 publications

References 102 publications

Tuning the thermal properties of poly(ethylene)‐like poly(esters) by copolymerization of ε‐caprolactone with macrolactones, in the presence of a pyridylamidozinc(II) complex

Tuning the thermal properties of poly(ethylene)‐like poly(esters) by copolymerization of ε‐caprolactone with macrolactones, in the presence of a pyridylamidozinc(II) complex

Recent Developments and Optimization of Lipase-Catalyzed Lactone Formation and Ring-Opening Polymerization

Catechol/boronic acid chemistry for the creation of block copolymers with a multi-stimuli responsive junction

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