We report the synthesis of sustainable isocyanate-free polyurethane foams. For the first time, polyhydroxyurethane (PHU) foams were synthesized at room temperature by high conversion step growth polymerization of cyclic carbonates and diamines. Trimethylolpropane tris-carbonate and polypropylene oxide bis-carbonate were copolymerized with EDR148 diamine with thiourea as catalyst. A poly(methylhydrogenosiloxane) was used as blowing agent to foam the NIPU by reaction with diamines. NIPU foams were characterized by scanning electron microscopy and by measurement of their swelling index and apparent density. The mechanical compression and the recovery of these NIPU foams were analyzed by dynamic mechanical analyses at room temperature. The thermal insulating capacities and thermal degradation mechanism were determined. (C) 2016 Elsevier Ltd. All rights reserved.

•We studied reactivity of secondary amines towards cyclic carbonates.•Reaction between secondary amines and cyclic carbonates was performed.•Polyhydroxyurethanes PHUs were synthesized from di- and tri-cyclic carbonates and secondary amines.•Properties of PHUs polymers were characterized.

The role of secondary amine, usually not taken into account in the case of polyhydroxyurethanes (PHUs) synthesis, was inspected. Butanediol bis carbonate BBC, trimethylolpropane tris carbonate TMPTC and resorcinol bis carbonate RBC were synthesized by carbonation of corresponding epoxides. The products, obtained with high yield, were characterized by NMR and mass spectrometry analysis. These carbonates were converted to biobased polyhydroxyurethanes by step growth polymerization with tetraethylene pentamine TEPA. The optimal carbonate–amine ratio was determined from the differential scanning calorimeter results. A maximum Tg value of 16 °C was found for the BBC–TEPA system considering three reactive amine group among five of TEPA hardener. These results were completed by model reactions. Firstly, the reaction between BBC and a secondary diamine (N,N′-dimethyl-1,6-hexanediamine) was hightlighted by differential scanning calorimetry. Moreover, the products of reaction between a monocarbonate (i.e. propylene carbonate) and TEPA or N,N′-dimethyl-1,6-hexanediamine were characterized by FTIR, NMR and mass spectrometry, allowing the demonstration of the formation of hydroxyurethane groups. Contrary to most of the results found in the literature, this work clearly demonstrates that secondary amines can also react with cyclic carbonates. Further details, such as activation energy of 28 kJ mol−1 (BBC–TEPA system), glass transition temperatures (from 16 to 67 °C) and good degradation temperature (Td 5% between 198 and 256 °C) completed this work.

Phenolic extract from the green tea leaves was used for the production of thermoset epoxy resins. The commercial green tea extract (GTE) was functionalized by the reaction with epichlorohydrin in the presence of phase transfer catalyst. The glycidyl ether derivative of the green tea extract (GEGTE) obtained with a good yield was cured in epoxy polymer with isophorone diamine (IPD) and the resulting network was compared to catechin-IPD and diglycidyl ether of bisphenol A (DGEBA-IPD) systems. The thermal and mechanical analyses of this bio-based epoxy polymer showed its high reactivity associated with a high crosslinking density (Tg: 140–190°C), a high thermal resistance and interesting mechanical properties.

Waterborne epoxy dispersions have been employed effectively for many years in response to environmental regulations aimed at reducing solvent levels in coatings. Very few non-toxic bio-based polyamines have been reported in the literature as curing agents for epoxy-functional waterborne dispersions. Currently to our knowledge the only bio-based amino hardener used to cure a waterborne epoxy prepolymer is ϵ-polylysine. Being one of the rare primary amine-containing polymers of natural origin, chitosan is produced commercially by the deacetylation of chitin. In the work reported here, chitosan and oligochitosan were evaluated as curing agents for diepoxy prepolymers. A solvent-free prepolymer (Epotec) and a waterborne prepolymer dispersion (Epirez) were both used. A crosslinked network was obtained when the reaction was performed with the waterborne epoxy dispersion. The influence of the hardener-to-epoxy prepolymer ratio on the crosslinking density was investigated. The thermal properties of networks were measured using differential scanning calorimetry and thermogravimetric analysis. © 2013 Society of Chemical Industry

Tara pods powder was used as a phenolic source in the synthesis of thermosetting epoxy polymer. The tannase-assisted hydrolysis of galloylquinic acids contained in tara powder allowed the determination of the tannins hydroxyl value (13.7 mmol/g powder). Then, galloylquinic acids were reacted with epichlorohydrin and an aqueous solution of sodium hydroxide in the presence of benzyltriethylammonium chloride as phase transfer catalyst (PTC). The 1D and 2D NMR analyses of glycidylated products revealed the galloylquinic esters hydrolysis and the dimerisation of the glycidylated gallic moities. The glycidylated derivatives of tara tannins (GETT) were cured in epoxy polymer with isophorone diamine (IPD). The glass transition temperature (T-g = 129 degrees C) and the thermal resistance (T-d30 = 294 degrees C) of the resulting network were determined. Preliminary results showed that this new epoxy polymer based on GETT displayed interesting properties which are close to those of the epoxy polymer formulated with commercial diglycidyl ether of bisphenol A (DGEBA). (C) 2014 Elsevier Ltd. All rights reserved.

This article focuses on the synthesis and characterization of polyhydroxyurethanes (PHUs) obtained from the reaction between bis[(2-oxo-1,3-dioxolan-4-yl)methyl]benzene-1,4-dicarboxylate (DCter) and various diamines (aliphatic, cycloaliphatic and oligomeric) or polyamines (diethylenetriamine (DETA) and diethylenetetramine (TETA)). The temperature and time conditions associated with each step-growth polyaddition were defined by rheological tests directly performed on the reactive mixture. The chemical structures of DCter-based PHUs containing primary and secondary alcohol groups were characterized using Fourier transform infrared spectroscopy. Differential scanning calorimetry experiments were performed on the various PHUs in order to investigate the influence of the chemical structure of the amines on the thermal properties of the polymers. Two different kinds of PHUs were obtained. On the one hand, the use of diamines led to thermoplastic polymers with a glass transition temperature (Tg) ranging from 4 to 78 °C depending on the flexibility of the diamine involved in the reaction. The hierarchy based on PHU Tg could be verified using the Van Krevelen methodology. On the other hand, PHUs produced from polyamines TETA and DETA were found to be insoluble and infusible due to the creation of polymeric networks. The DCter–DETA polymer had a higher Tg revealing a probable difference in the reactivity of primary and secondary amine groups. Copyright © 2012 Society of Chemical Industry

Polyhydroxyurethanes (PHUs) produced by the reaction between dicyclocarbonate and diamine groups are often presented as possible candidates to substitute for classical polyurethanes based on isocyanate precursors. In the literature, the synthesis of this class of polymers is often performed according to arbitrary conditions of time and temperature without any scientific justification. As such, the real potential of PHUs is probably not fully known. Numerous contradictions in previously published results seem to support this hypothesis. Our paper proposes two methodologies based on dynamic rheometry to determine optimized conditions for the synthesis of PHUs. The case of a PHU formed by the reaction between 1,10-diaminodecane and a dicyclocarbonate bearing a central aromatic group is described more precisely. The first approach consists of conducting various rheological experiments (kinetics, thermomechanical analyses) in situ on the reaction mixture. The second one retains the same technique to qualify the viscoelastic properties of PHUs synthesized according to various conditions. In this latter case, all samples show thermomechanical behaviour of amorphous thermoplastic polymers. But discrepancies are observed with regard to the value of the glass transition temperature and the existence or not of a rubbery zone. Comparison of these data with size exclusion chromatography results shows that these differences are direct consequences of the polymer molecular weight that can be predicted using macromolecular theory. The properties of the PHUs obtained after optimization of the polymerization reaction were compared with literature data in order to complete the evaluation of the efficiency of the rheological methodology. Copyright (C) 2012 Society of Chemical Industry

A new synthesis of 4-[(prop-2-en-1-yloxy)methyl]-1,3-dioxolan-2-one (AGC) was performed by Williamson ether synthesis from 4-(hydroxymethyl)-1,3-dioxolan-2-one. Dicyclocarbonates were synthesized by UV thiol–ene coupling of allyl-cyclocarbonate with a 2,2′-oxydiethanethiol. This photochemical thiol–ene reaction was carried out under air, with neither solvent nor photoinitiator. The products, obtained with high yield, were characterized by 1H NMR and FTIR analysis. The synthesized dicyclocarbonates were used without purification to synthesize polyhydroxyurethanes without isocyanate by step growth polyaddition with 1,10-diaminodecane. The synthesized polyhydroxyurethanes were characterized by 1H NMR, FTIR, ATG and DSC analysis. These polyhydroxyurethanes exhibited glass transition temperatures from −31 °C to −14 °C, molecular weight from 7,000 g mol−1 to 9000 g mol−1 and degradation temperature for 5% of weight loss (Td 5%) between 227 °C and 250 °C.

ABSTRACT Urea-based bis-silylated 2,2′–Bipyridine (bpy) organic–inorganic hybrids incorporating different lanthanide (Ln3+) ions (Eu3+, Gd3+, Tb3+ or Eu3+/Tb3+) were obtained by the sol–gel process. The structure and the emission characteristics of the hybrids were ascertained using X-ray diffraction, nuclear magnetic resonance, Fourier transform infrared spectroscopy, photoluminescence, and quantum yield measurements. The hybrids feature both the emission of the host and the Eu3+ and/or Tb3+ transitions allowing a fine-tuning of the color from the blue to the red, orange, or green spectral regions. Bpy-to-Ln3+ and Tb3+-to-Eu3+ energy transfer mechanisms are demonstrated and the hybrids present slightly distinct Ln3+ coordination spheres due to the different bpy/Ln3+ ratios.

A simple β-diamide ligand was immobilized by the sol–gel process on hybrid silica for Cu-mediated O-arylation reactions. Combined with 5% of CuI, the latter can easily be recovered and reused to generate diarylethers under smooth conditions from cheap aryl bromides in an eco-friendly solvent (MIBK). Besides, negligible metal leaching occurred after reaction in solution from the supported catalyst.

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A new hybrid silica with urea-based bipyridyl bridging units has been synthesized by a sol-gel process. The copper-complexed hybrid silica is an efficient heterogeneous catalyst for the Ullmann coupling of aryl halides with phenols. It is easily withdrawn and recovered from the reaction media by filtration. It is also a versatile catalyst for subsequent reactions with several substrates yielding products with the same efficiency even after ten re-uses and with minimal leaching. This is the first example of the use of a copper-complexed bridged silsesquioxane for the preparation of a recoverable catalyst in modern Ullmann chemistry. This may represent a promising route to the reduction of waste while maintaining economic viability.