Elastomeric copolyesters of omega-pentadecalactone and cyclohexylenedimethylene succinate obtained by enzymatic polymerization

The use of renewable monomers and green polymerization processes for preparing new synthetic polymers is a hot topic today. In this work we have obtained high molecular weight copolyesters derived from ¿-pentadecalactone (PDL), dimethyl succinate (DMS) and 1,4-cyclohexanedimethanol (1,4-CHDM) by a combination of ring opening polymerization (ROP) and two step melt polycondensation processes. The reaction has been carried in bulk under mild conditions (80–120 ¿C) and catalyzed by immobilized Candida artarctica lipase B (N435 biocatalyst). These reactions were followed by 1 H NMR and it was observed that although PDL reacted faster, at the end copolyesters displayed a random microstructure due to transesterification reactions taking place during polymerization. These copolyesters were thermally stable up to around 350 ¿C and semicrystalline for all compositions with melting temperatures decreasing with the increased content of the counterpart comonomer up to a pseudo-eutectic point located at 40 mol-% of PDL composition. The crystalline structure and transitions taken place by heating have been studied by WAXS and SAXS synchrotron X-ray diffraction. Copolyesters with elastomeric properties could be obtained at intermediate compositions.Peer ReviewedObjectius de Desenvolupament Sostenible::13 - Acció per al ClimaObjectius de Desenvolupament Sostenible::3 - Salut i BenestarPostprint (published version

Poly(butylene succinate) ionomers and their use as compatibilizers in nanocomposites

A series of low-molecular-weight poly(butylene succinate-co-glutarate-co-2-trimethylammonium chloride glutarate) terpolyester ionomers containing 35% mol of total glutarate units but varying in the content of charged units were synthesized by polycondensation at mild temperatures using a scandium catalyst. The terpolyester ionomers started to decompose at the temperatures of >175°C and all of them were semicrystalline and have glass transition temperature similar to poly(butylene succinate) (PBS). These terpolyesters were used to compatibilize the nanocomposites made of PBS-cloisite (CL) prepared by melt extrusion. X-ray diffraction revealed that an intercalated structure was present in these nanocomposites. The thermal properties of the three-component mixtures did not differ substantially from those of PBS–CL but the mechanical properties were significantly improved by the addition of the ionomer, in particular tenacity. The beneficial effect afforded by the terpolyester ionomer was attributed to its ability for strengthening the binding between the PBS and the nanoclay.A series of low-molecular-weight poly(butylene succinate-co-glutarate-co-2-trimethylammonium chloride glutarate) terpolyester ionomers containing 35% mol of total glutarate units but varying in the content of charged units were synthesized by polycondensation at mild temperatures using a scandium catalyst. The terpolyester ionomers started to decompose at the temperatures of >175°C and all of them were semicrystalline and have glass transition temperature similar to poly(butylene succinate) (PBS). These terpolyesters were used to compatibilize the nanocomposites made of PBS-cloisite (CL) prepared by melt extrusion. X-ray diffraction revealed that an intercalated structure was present in these nanocomposites. The thermal properties of the three-component mixtures did not differ substantially from those of PBS–CL but the mechanical properties were significantly improved by the addition of the ionomer, in particular tenacity. The beneficial effect afforded by the terpolyester ionomer was attributed to its ability for strengthening the binding between the PBS and the nanoclay.Peer ReviewedPostprint (author's final draft

Poly(butylene succinate) ionomers with enhanced hydrodegradability

A series of poly(butylene succinate) (PBS) ionomers containing up to 14 mol%of sulfonated succinate units have been synthesized by polycondensation in the melt-phase. The copolyesters were obtained with weight average molecular weights oscillating between 33,000 and 72,000 g·mol-1. All copolyesters were semicrystalline with melting temperatures and enthalpies decreasing and glass transition temperatures increasing with the content of ionic units. The thermal stability of PBS was slightly reduced by the incorporation of these units, and it was also found that the copolyesters were stiffer but also more brittle than PBS. The hydrolytic degradability of PBS was enhanced by copolymerization, an effect that was much more pronounced in basic media.Peer ReviewedPostprint (published version

Poly(hexamethylene terephthalate-co-p-dioxanone) copolyesters obtained by ring-opening polymerization

Abstract del poster presentat al congrés.Peer ReviewedPostprint (published version

Poly(hexamethylene terephthalate-co-caprolactone) copolyesters by ring opening polymeriztation: influence of the oligoterephthalate cycle size

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Synthesis and characterization of poly(butylene terephthalate) copolyesters derived from threitol

The synthesis, characterization, and thermal properties of partially renewable poly(butylene terephthalate) copolyesters containing alditol units are described. These copolyesters were obtained by polycondensation in solution from mixtures of 1,4-butanediol and 2,3-di-O-benzyl-L-threitol with terephthaloyl chloride. Copolyesters with weight-average molecular weights oscillating between 4 000 and 12 000 g·mol-1 and dispersities around 1.5 were obtained. All them had a random microstructure and were thermally stable well above 300°C. Copolyesters containing up to 30% of dibenzyl threitol units were found to be crystalline and to adopt the same crystal structure as the parent homopolyester poly(butylene terephthalate). The melting temperature and crystallinity were observed to decrease, and the glass transition temperature to increase, with increasing amounts of alditol units incorporated in the copolyester. Furthermore, the crystallizability was depressed by copolymerization.Peer ReviewedPostprint (author's final draft

Poly(ethylene terephthalate-co-isophthalate) copolyesters obtained from linear oligomeric blends

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Cationic poly(butylene succinate) copolyesters

The synthesis, characterization and comparative evaluation of properties of two series of cationic PBS copolyesters bearing respectively ammonium and tributylphosphonium side groups, are reported. The copolyesters with contents in ionic units up to 50 mole-% as well as the fully ionic homopolyesters were prepared by polycondensation in the melt catalyzed by CALB or TBT. Their Mn ranged between 20,000 and 5000 g mol-1 depending of composition and the type of ionic group that is involved. All the copolyesters were non-water soluble and showed good thermal stability. They were semicrystalline with melting temperatures and enthalpies decreasing with the ionic contents. The interactions interplayed by the ionic groups restricted largely the molecular mobility and caused a significant increase in the melt viscosity and glass transition temperature of PBS and a decrease in crystallization rate. Both ammonium and phosphonium containing PBS copolyesters were able to be coupled with sulfonated PBS to generate ionic polymer blends with modified crystallizability. The presence of both ammoniums and phosphoniums provided PBS with remarkable antimicrobial activity against gram-positive and gram-negative bacteria.Peer ReviewedPostprint (author's final draft

Bio-based PBS copolyesters derived from a bicyclic D-glucitol

2,4:3,5-di-O-methylene-D-glucitol (Glux-diol) was used for the synthesis of poly(butylene succinate) (PBS) copolyesters by melt polycondensation. Glux-diol possess a rigid bicyclic asymmetric structure made of two fused 1,3-dioxane rings and two hydroxyl functions at the end positions. Copolyesters were prepared over the whole range of compositions with molecular weights varying from 26 000 to 46 000 g mol-1 and a random microstructure. The thermal stability of PBS did not significantly alter with the presence of Glux units. The glass transition temperatures (Tg) steadily increased from -28 to 80 ºC along the whole copolyester series with the insertion of Glux. On the contrary, melting temperature (Tm) and crystallinity decreased because of the lack of regularity of the polymer chain although copolyesters with contents of Glux units up to 30 mole% were semicrystalline. The stress–strain behavior changed according to variations produced in thermal transitions. The replacement of 1,4-butanediol by Glux-diol slightly increased both the hydrolytic degradability and the biodegradability of PBS. Compared to other bicyclic sugar-based diols reported in the literature, Glux-diol appeared to be more efficient in both increasing the Tg and enhancing the susceptibility to hydrolysis of PBS.Peer ReviewedPostprint (author's final draft

Nanostructured amphiphilic systems based on hyaluronic acid ionic complexes

In this communication we wish to report on HyA ionic complexes prepared by coupling with a) choline-based surfactants (nACh·HyA complexes), and b) alkylphosphonium surfactants (nATMP·HyA complexes) with n being the number of carbons of the alkanoyl or alkyl side chain. nACh surfactants are synthesized from choline and fatty acids, and distinguished because they are fully biobased and biocompatible. The nATMP surfactants have been scarcely studied as counterions of polyacids in spite of being more stable to heat and less harmful than their alkylammonium analogs.Postprint (published version