Carine Alfos

Synthesis of Biobased Polyurethane from Oleic and Ricinoleic Acids as the Renewable Resources via the AB-Type Self-Condensation Approach

Polyurethane (PU) from methyl oleate (derived from sunflower oil) and ricinoleic acid (derived from castor oil) was synthesized using the AB-type self-polycondensation approach for the first time. In the present work, three novel AB-type monomers, namely, a mixture of 10-hydroxy-9-methoxyoctadecanoyl azide/9-hydroxy-10-methoxyoctadecanoyl azide (HMODAz), 12-hydroxy-9-cis-octadecenoyl azide (HODEAz) and methyl-N-11-hydroxy-9-cis-heptadecen carbamate (MHHDC) were synthesized from methyl oleate and ricinoleic acid using simple reaction steps. Out of these, HMODAz and HODEAz monomers were polymerized by the acyl-azido and hydroxyl AB-type self-condensation approach, while MHHDC monomer was polymerized through AB-type self-condensation via transurethane reaction. The acyl-azido and hydroxyl self-condensations were carried out at various temperatures (50, 60, 80. and 110 degrees C) in bulk with and without catalyst. A FTIR study of the polymerization, using HMODAz at 80 degrees C without catalyst, indicates in situ formation of an intermediate isocyanate group in the first 15-30 min, and further onward, the molar mass increases as observed by SEC analysis. In the case of the MHHDC monomer, a transurethane reaction was used to obtain a similar PU (which was obtained by AB-type acyl-azido and hydroxyl self-condensation of HODEAz) in the presence of titanium tetrabutoxide as a catalyst at 130 degrees C. HMODAz, HODEAz, MHHDC, and corresponding polyurethanes were characterized by FTIR, (1)H NMR, (13)C NMR, and MALDI-TOF mass spectroscopy. Differential scanning calorimetric analysis of polyurethanes derived from HMODAz, HODEAz, and MHHDC showed two different glass transition temperatures for soft segments (at lower temperature) and hard segments (at higher temperature), indicating phase-separated morphology.

Solubility in CO2 and carbonation studies of epoxidized fatty acid diesters: towards novel precursors for polyurethane synthesis

Novel linear polyurethanes were synthesized by bulk polyaddition of diamines with two vegetable-based biscarbonates produced from oleic acid methyl ester. Internal carbonated fatty acid diester (ICFAD) and terminal carbonated fatty acid diester (TCFAD) were obtained by the reaction of their epoxide precursors with CO2. Terminal epoxy fatty acid diester (TEFAD) was found to be more soluble and more reactive in CO2 than internal epoxy fatty acid diester (IEFAD). Polyurethanes obtained by polyaddition of TCFAD and ICFAD with diamines exhibit molecular weights up to 13 500 g mol−1 and glass transitions around −15 °C. Amide linkages were not observed when secondary diamine was used as the comonomer.

Novel green fatty acid-based bis-cyclic carbonates for the synthesis of isocyanate-free poly(hydroxyurethane amide)s

Fatty acid-based bis-cyclic 5-membered carbonates containing amide linkages were prepared from methyl 10-undecenoate. The reaction in bulk of these bio-based carbonates with a series of di-amines led to poly(hydroxyurethane amide)s with molar masses up to 31 000 g mol−1. As expected, the so-formed bio-based thermoplastic poly(hydroxyurethane)s exhibit amorphous to semi-crystalline features with respect to the chemical structure of the monomers used.

Fatty acid-based (bis) 6-membered cyclic carbonates as efficient isocyanate free poly(hydroxyurethane) precursors

(Bis) 6-membered cyclic carbonates were prepared from methyl 10-undecenoate, which is produced from ricinoleic acid, a main constituent of castor oil. Kinetic studies on these new fatty acid-based 6-membered cyclic carbonates revealed that they are much more reactive than their homologs, 5-membered ones (30 times). Poly(hydroxyurethane)s (PHUs) were then synthesized from these bis 6-membered cyclic carbonates at a temperature as low as room temperature and in the solvent or bulk. Unexpectedly, chemical gels were obtained. The latter were the consequence of side reactions of carbonate ring-opening with the hydroxyl groups of the formed poly(hydroxyurethane)s. Quenching with a large excess of hexylamine enabled the breaking-up of the gel with the formation of urea linkages.

Solubility in CO2 and swelling studies by in situ IR spectroscopy of vegetable-based epoxidized oils as polyurethane precursors

The phase behaviour of carbon dioxide/vegetable based epoxidized oil (VBEO) mixtures has been investigated at three different temperatures (40, 70 and 100 degrees C) and pressures ranging between 0.1 and 20 MPa. The measurements have been performed using an efficient in situ FTIR method that allowed us to determine the variation of the concentration of each component in the two phases (CO2 rich phase and VBEO rich phase) as a function of temperature and pressure. Several epoxidized mono-, di- and triglyceride derivatives have been tested. The solubility of these epoxidized oils in the CO2 rich phase and the swelling of the VBEO rich phase resulting from the CO2 sorption have been investigated. From these concentration measurements, we could establish the pressure-composition phase diagrams of these VBEO/CO2 binary mixtures. The three studied monoglyceride derivatives were found to be more soluble in CO2 and more easily swelled by CO2 in comparison to the di- and tri-glyceride derivatives. Nevertheless, it was found that a significant amount of CO2 was incorporated in all these VBEO at relatively moderate pressures. Thus, we expect these VBEO to be good candidates for performing carbonation reaction to generate in good yields vegetable-based cyclic carbonates as polyurethane precursors.

Methyl 10-undecenoate as a raw material for the synthesis of renewable semi-crystalline polyesters and poly(ester-amide)s

Castor oil was efficiently used as a raw material for the synthesis of polyesters and poly(ester-amide)s. Aliphatic diols containing monoester, diester, ester-amide, monoamide and diamide linkages were synthesized from methyl 10-undecenoate through transesterification, amidation and thiol–ene reactions. These diols were then reacted with a bio-based methyl diester in the presence of TBD as a transesterification catalyst, yielding polyesters or poly(ester-amide)s with relatively high molar masses. These polyesters were characterized by FTIR, SEC and 1H-NMR spectroscopy and showed good accordance in terms of chemical structure with the theoretical compositions. Most of the polyesters displayed good thermal stability with temperature at 5% weight loss in the range 330–350 °C. Due to the fully aliphatic nature, the glass transition temperature of these materials was well below room temperature. However the incorporation of amide functions in the polyester backbone resulted in semi-crystalline materials with melting points ranging from 22 °C to 127 °C and complex melting behaviors due to polymorphism and melting–crystallization processes. Tensile properties of these polyesters were also investigated revealing a large increase of Youngs modulus from 83 to 363 MPa with increasing ratios of amide functions.

Fully bio-based poly(L-lactide)-b-poly(ricinoleic acid)-b-poly(L-lactide) triblock copolyesters: investigation of solid-state morphology and thermo-mechanical properties

In this work, a set of ABA triblock poly(L-lactide)-b-poly(ricinoleic acid)-b-poly(L-lactide) aliphatic copolyesters were prepared by consecutive AB type self-condensation and ring-opening polymerization. Condensation of methyl ricinoleate, produced from castor oil, in the presence of a small amount of 1,3-propanediol afforded α,ω-hydroxy-terminated poly(ricinoleic acid) with a molar mass of 11 kg mol−1. Polymerization of L-lactide initiated from the terminal hydroxyl moieties of the α,ω-hydroxy-terminated poly(ricinoleic acid) led to triblock copolymers with a composition ranging from 35 to 83 wt% of PLLA. The block structure was confirmed by several techniques. The copolymers displayed a multi-step thermal degradation with a temperature corresponding to 5 wt% loss in the range 175–225 °C. DSC analyses showed that the PRic block had a moderate effect on PLLA melting behavior. The solid-state morphology of the so-formed copolymers was highly dependent on their chemical composition, as evidenced by SAXS and WAXD analyses. The high degree of separation of hard and soft phases was also confirmed by dynamic mechanical analysis as seen from the distinct α-relaxations. Finally, the tensile properties of these block copolymers ranged from thermoplastic to elastomeric depending on their composition.

Aliphatic polycarbonates and poly(ester carbonate)s from fatty acid derived monomers

Fatty acid derivatives were efficiently used as starting materials for the synthesis of polycarbonates and poly(ester carbonate)s. A novel AB-type self-condensable monomer, ethyl(9-hydroxy-10-methoxyoctadecyl)carbonate (EHMOC) and a dicarbonate monomer, 4-[(ethoxycarbonyl)oxy]butyl-12-[(ethoxycarbonyl)oxy]octadec-9-enoate (EOBEOE) were prepared from oleyl alcohol and ricinoleic acid, respectively. Of these, EHMOC was polymerized by the alcohol–carbonate exchange self-polycondensation approach, while EOBEOE was polycondensed with various biobased diols to give polycarbonates and poly(ester carbonate)s, respectively. The monomers and polymers were well characterized by FTIR and 1H-NMR spectroscopy. The 13C-NMR spectroscopy revealed the formation of randomly distributed sequences in the poly(ester carbonate)s due to the carbonate interchange reaction. An unexpected formation of polyricinoleate was observed and confirmed by NMR and MALDI-TOF spectroscopy. Most of the polymers displayed good thermal stability with the temperature at 10% weight loss in the range 273–325 °C. Due to the presence of aliphatic segments, these materials exhibit very low glass transition temperature.

Branched polyethylene mimicry by metathesis copolymerization of fatty acid-based α,ω-dienes

Castor oil and vernonia oil platforms were used to synthesize two linear and branched α,ω-diene monomers. ADMET copolymerization conducted in bulk yielded a series of copolyesters with various degrees of branching with respect to the feed ratio between the two α,ω-dienes. After hydrogenation, these copolyesters showed thermo-mechanical properties in accordance with the ones of LLDPE and VLDPE with tunable melting points between 50 °C and 90 °C. As expected, and similarly to the “PE-like” polyesters reported in the literature, the presence of ester functions distributed along the polyethylene backbone slightly lowered the crystalline ability of the so-formed polyesters. Nevertheless, these novel bio-based polyesters constitute a good sustainable alternative to olefin-based elastomers (LLDPE and VLDPE), especially for specific applications which require degradability.

Glycolipids as a source of polyols for the design of original linear and cross-linked polyurethanes

Two novel sugar-based fatty ester polyols were synthesized by selective transesterification of epoxidized methyl or ethyl oleate with unprotected methyl α-D-glucopyranoside and sucrose respectively, followed by hydrolysis of the epoxide moiety. The so-formed polyols were then used as polyurethane (PU) precursors in the polyaddition with isophorone diisocyanate (IPDI) in the presence of dibutyl tin dilaurate (DBTDL) as a catalyst. Interestingly, the reactivity of the hydroxyl functions attached to the sugar and to the fatty ester chain moieties respectively could be discriminated with respect to the solvent used, enabling the synthesis of either linear or cross-linked PUs. The linear PUs were studied by means of FTIR, 1H NMR spectroscopy and size exclusion chromatography, SEC. The thermo-mechanical properties of these original PUs bearing pendant or intramolecular sugar units were also analyzed by differential scanning calorimetry, DSC.