alpha,omega-Bis(trialkoxysilyl) difunctionalized polycyclooctenes from ruthenium-catalyzed chain-transfer ring-opening metathesis polymerization

International audienceThe ring-opening metathesis polymerization/cross-metathesis (ROMP/CM) of cyclooctene (COE) using bis(trialkoxysilyl)alkenes as chain-transfer agents (CTAs) and Ru catalysts to afford difunctionalized polyolefins is reported. The formation of alpha,omega-bis(trialkoxysilyl) telechelic polycycloolefins (DF) with controlled molar mass values takes place quite selectively (>90 wt%), along with minor amounts of cyclic non-functionalized polymers (CNF), as evidenced by NMR, MALDI-ToF MS, SEC analyses and fractionation experiments. The nature of the CTA and catalyst influenced much the efficiency and selectivity of the reaction. (MeO)(3)SiCH2CH=CHCH2Si(OMe)(3) (2) and (MeO)(3)Si(CH2)(3)NHC(O)OCH2CH=CHCH2OC(O)NH (CH2)(3)Si(OMe)(3) (5) proved to be the most efficient CTAs in terms of reactivity, catalyst productivity and selectivity towards DF. Diurethane CTA 5 is easily prepared, and can also be conveniently generated in situ during the ROMP/CM. Grubbs' 2nd-generation catalyst (G2) and Hoveyda-Grubbs's catalyst (HG2) afforded the best compromise in terms of selectivity and productivity, with turnover numbers of up to 95 000 mol(COE) mol(Ru)(-1) and 5000 mol(CTA) mol(Ru)(-1)

Ring-opening metathesis polymerization of cyclooctene derivatives with chain transfer agents derived from glycerol carbonate

International audienceThe synthesis of a variety of mono- and di-(glycerol carbonate) telechelic polyolefins has been achieved upon ruthenium-catalyzed ring-opening metathesis polymerization (ROMP) of cyclooctene (COE) derivatives in the presence of a vinyl or acryloyl derivative of glycerol carbonate (GC) acting as a chain-transfer agent (CTA). Reaction monitoring based on SEC and 1H NMR analyses suggested that the ROMP proceeds through the formation of first the α-GC,ω-vinyl-poly(cyclooctene) (PCOE) intermediate, which eventually evolves over time into the α,ω-di(GC)-PCOE. The nature of the solvent was shown to have a significant impact on both the reaction rates and the eventual selectivity for the mono-/di-telechelic PCOE. ROMP of 3-alkyl (methyl, ethyl, n-hexyl)-substituted COEs (3-R-COEs) afforded only the α-GC,ω-vinyl-poly(3-R-COE)s, as a result of the steric hindrance around the active intermediate, while a 5-ethyl substituted COE (5-Et-COE) enabled access to the corresponding α,ω-di(GC)-poly(5-Et-COE). The ROMP of 5,6-epoxy-, 5-hydroxy- and 5-oxo-functionalized COEs in the presence of acryloyl-GC as the CTA has also been achieved, affording from the first two monomers polymers with GC end-groups at both extremities, while a 60 : 40 mixture of mono- and di-GC terminated P(5-O[double bond, length as m-dash]COE) was observed in the latter case

α,ω-Di(glycerol carbonate) telechelic polyesters and polyolefins as precursors to polyhydroxyurethanes: an isocyanate-free approach

International audienceα,ω-Di(glycerol carbonate) telechelic poly(propylene glycol) (PPG), poly(ethylene glycol) (PEG), poly(ester ether) (PEE), and poly(butadiene) (PBD) have been synthesized through chemical modification of the corresponding α,ω-dihydroxy telechelic polymers (PPG-OH2, PEG-OH2, PEE-OH2 and PBD-OH2, respectively). Tosylation of the polymer diols with 4-tosylmethyl-1,3-dioxolan-2-one (GC-OTs) afforded, in high yields, the desired PPG, PEG, PEE and PBD end-capped at both termini with a five-membered ring cyclic glycerol carbonate (4-hydroxymethyl-1,3-dioxolan-2-one, GC). The GC-functionalization of the polymers at both chain-ends has been confirmed by NMR (1H, 13C, 1D and 2D) and FTIR spectroscopies. Using PPG-GC2 to demonstrate the concept, the corresponding polyhydroxyurethanes (PHUs/non-isocyanate polyurethanes (NIPUs)) have been subsequently prepared following a non-isocyanate method upon ring-opening catalyst-free polyaddition of the PPG-GC2 with JEFFAMINEs (Mn = 230-2000 g mol−1). The effect of various additives introduced during the polyaddition reaction has been studied at different temperatures. In particular, addition of LiBr (5 mol%) to the reaction medium was found to slightly promote the cyclocarbonate/amine reaction. The polymerization process was supported by FTIR and SEC analyses

Diels–Alder thermoreversible isocyanate-free polyurethanes

International audienc

Thiophenium Salts as New Oxidant for Redox Polymerization under Mild- and Low-Toxicity Conditions

In mild conditions (under air, room temperature, no monomer purification and without any energy activation), redox free radical polymerization (RFRP) is considered as one of the most effective methods to polymerize (meth)acrylate monomers. In the past several years, there has been a growing interest in research on the development of new redox initiating systems (RISs), thanks mainly to the evolution of toxicity labeling and the stability issue of the current RIS based on peroxide and aromatic amine. In this study, a new, low-toxicity RIS based on thiophenium salt as the oxidant species is presented with various reductive species. The reactivity and the stability of the proposed RISs are investigated and the synthesis of new thiophenium salts reported

Remendable thermosetting polymers for isocyanate-free adhesives: a preliminary study

International audienc

Polyolefin/Polyether Alternated Copolymers: Silyl-Modified Polymers as Promising Monocomponent Precursors to Adhesives

International audienceα,ω-Bis(trialkoxysilyl) telechelic polyether/polyolefin copolymers were synthesized and evaluated as monocomponent adhesive precursors. The Ru-catalyzed tandem ring-opening insertion-metathesis polymerization (ROIMP) and cross-metathesis (CM) reactions in the presence of a bis(trialkoxysilyl)alkene as chain-transfer agent (CTA) were first explored toward the synthesis of such silyl-modified polymers (SMPs). The one-pot, two-step ROIMP/CM of cyclooctene (COE) and poly(propyleneglycol) diacrylate (PPG(*)) with {(EtO)3Si(CH2)3NHC(O)OCH2CH═}2 (CTAEt) catalyzed by Grubb’s second generation catalyst (Method II) successfully enables the preparation of α,ω-[(EtO)3Si]2-PCOE/PPG(*) alternated copolymers, isolated in 10–100 g. The polyether/polyolefin copolymers were thoroughly characterized by SEC, 1D and 2D NMR, and FTIR spectroscopies and mass spectrometry analyses. The good thermal stability and rheofluidifying profile of the PCOE/PPG* copolymers are maintained following their catalyzed moisture-curing, as revealed by TGA, DSC, and rheology. The corresponding siloxane cross-linked copolymers then demonstrate strain-at-break, elongation-at-break, and wood-adhesion properties greater than those of the benchmarked SMP reference from Bostik, namely, Polyvest E100 (strain-at-break on wood up to 4.0 vs 2.6 MPa, respectively). These characteristics can be tuned according to the PCOE/PPG* ratio and also revealed significantly better than the ones of our previously reported alike siloxane cross-linked PCOE/PPG* copolymers similarly prepared, yet from a one-pot, one-step ROIMP/CM approach (Method I). Such polyolefin/polyether monocomponent SMPs are thus promising adhesive precursors

Mono- and di-cyclocarbonate telechelic polyolefins synthesized from ROMP using glycerol carbonate derivatives as chain-transfer agents

International audienceThe ring-opening metathesis polymerization (ROMP) of cyclooctene (COE) has been achieved with Grubbs 2nd generation ruthenium catalyst in the presence of vinyl or acryloyl derivatives of glycerol carbonate. Such asymmetric chain-transfer agents enabled the synthesis in high yields of α-cyclocarbonate,ω-vinyl-poly(cyclooctene) (PCOE) and, more rewardingly, of the highly valuable α,ω-dicyclocarbonate telechelic PCOE

Promising mechanical and adhesive properties of isocyanate-free poly(hydroxyurethane)

International audienc

From Epoxide to Cyclodithiocarbonate Telechelic Polycyclooctene through Chain-Transfer Ring-Opening Metathesis Polymerization (ROMP): Precursors to Non-Isocyanate Polyurethanes (NIPUs)

International audienceTelechelic polycyclooctenes (PCOEs) have been successfully synthesized by ring-opening metathesis polymerization (ROMP)/cross-metathesis (CM) of cyclooctene (COE) using Grubbs' second-generation catalyst (G2) in the presence of epoxide-functionalized chain-transfer agents (CTAs). The monofunctional epoxide oxiran-2-ylmethyl acrylate CTA (1) afforded the isomerized alpha-(glycidyl alkenoate),omega-propenyl functional (IMF) PCOEs. The use of 1,4-benzoquinone (BZQ) as additive completely inhibited the C=C isomerization process, thereby leading selectively to alpha-(glycidyl alkenoate),omega-vinyl telechelic (MF) PCOE. On the other hand, difunctional epoxide CTAs, bis(oxiran-2-ylmethyl) fumarate (3), bis(oxiran-2-ylmethyl) maleate (4), bis(oxiran-2-ylmethyl) (E)-hex-3-enedioate (5), and (Z)-1,4-bis(oxiran-2-ylmethoxy)but-2-ene (6), selectively afforded the corresponding alpha,omega-di(glycidyl alkenoate) telechelic PCOEs (DF) along with minor amounts of cyclic nonfunctional (CNF) PCOE. In the presence of these difunctional symmetric CTAs, the mechanism is proposed to proceed through a tandem one-pot CM/ROMP/ring-closing metathesis (RCM) approach. CM was more effective with Z- than E-configurated CTAs (4 > 6 >> 3 >> 5), regardless of the presence of a methylene group in-between the C=C double bond and the glycidyl moiety. Subsequent dithiocarbonatation of the alpha,omega-diepoxide telechelic PCOEs upon reaction with CS2 in the presence of LiBr quantitatively afforded the first examples of bis(cyclodithiocarbonate) end-functional PCOEs. Ensuing aminolysis of the bis(cyclodithiocarbonate) telechelic PCOEs with the polyether (triethylene glycol) diamine JEFFAMINE EDR-148 quantitatively afforded, at room temperature without any added catalyst, the desired poly(mercaptothiourethane)s NIPUs, as evidenced from FTIR spectroscopy, TGA, and DSC analyses