Frédéric Simon

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

α,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.

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

This study describes the synthesis and polymerization of a dicyclocarbonate Diels–Alder (DA) adduct to give a thermoresponsive non-isocyanate polyurethane (NIPU). Firstly a model adduct was synthesized by DA reaction between N-methylmaleimide and furfuryl cyclocarbonate ether (FCE). This adduct was characterized by 1H-NMR and its thermal behavior was studied by 1H-NMR, and differential scanning calorimetry (DSC). Then a telechelic dicyclocarbonate DA adduct was obtained by DA reaction between a bismaleimide oligomer and FCE in bulk with full conversion. Its thermal behavior was studied by thermogravimetric analysis (TGA) and DSC. The dicyclocarbonate adduct was polymerized by step-growth polymerization with a diamine, Jeffamine EDR148. The polymerization was performed at room temperature (in order to avoid adduct deprotection) with triazabicyclodecene as the catalyst. The obtained polymer was characterized by size exclusion chromatography (SEC) and 1H-NMR. The polymer thermal behavior was fully characterized by three complementary analyses. By DSC, retro-Diels–Alder temperatures could be measured to be 90–120 °C. By a 1H-NMR kinetic study at 100 °C, it could be shown that after 120 min at 100 °C, 85% of the adducts are deprotected. Finally, by SEC, it was demonstrated that the obtained NIPU polymer chains undergo thermal scission by rDA reaction.

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

The 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.

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

The 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-OCOE) was observed in the latter case.

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

The 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 α,ω-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)3SiCH2CHCHCH2Si(OMe)3 (2) and (MeO)3Si(CH2)3NHC(O)OCH2CHCHCH2OC(O)NH(CH2)3Si(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–Grubbss 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.