Sophie Lingier

The interplay of the relative configuration of diastereomeric vicinal difluoride groups on the conformational properties of polyesters has been investigated and compared to their non-fluorinated and per-fluorinated counterparts. The incorporation of syn and meso vicinal difluoride units in the polymer backbone was expected to influence the rigidity and stacking behaviour of the polymers in a significant way, and therefore to result in different thermal properties, such as melting point and… Show more

The interplay of the relative configuration of diastereomeric vicinal difluoride groups on the conformational properties of polyesters has been investigated and compared to their non-fluorinated and per-fluorinated counterparts. The incorporation of syn and meso vicinal difluoride units in the polymer backbone was expected to influence the rigidity and stacking behaviour of the polymers in a significant way, and therefore to result in different thermal properties, such as melting point and melting enthalpy. Both syn and meso-2,3-difluoro butanediol have been reacted with the diester dimethyl succinate, leading to the formation of polyesters that have been characterized with 1H, 13C and 19F NMR. The polyesters showed molar masses up to 20 kg/mol (SEC). Surprisingly, the syn and meso-polymers displayed identical crystallization and melting behaviour. In contrast, differences were observed in the crystallization kinetics and melting points of syn and meso oligomers. Relying on time-resolved synchrotron SAXS and WAXD experiments, the complex multiple melting behaviour of these oligomers was explained in terms of crystal size and surface effects. The slower crystallization kinetics for the meso oligomers was tentatively associated with a stronger tendency to adopt gauche configurations. Apparently, such effects no longer affect the crystallization kinetics when larger polymers crystallize. It was also found that the syn and meso-polymers have identical equilibrium melting points and melting enthalpies notwithstanding molecular and crystallographic differences. Show less

Synthetic thermoplastic polyacetals have a long history dating back to 1912. While polymers with non-cyclic acetal repeat units are typically well soluble and degrade easily at biologically relevant pH values, polycycloacetals have a rigid polymer backbone, resulting in favorable thermal and mechanical properties but are often insoluble and thus challenging to process. In recent years, the degradation behavior and the availability of many building blocks from renewable resources have sparked… Show more

Synthetic thermoplastic polyacetals have a long history dating back to 1912. While polymers with non-cyclic acetal repeat units are typically well soluble and degrade easily at biologically relevant pH values, polycycloacetals have a rigid polymer backbone, resulting in favorable thermal and mechanical properties but are often insoluble and thus challenging to process. In recent years, the degradation behavior and the availability of many building blocks from renewable resources have sparked renewed interest in poly(cyclo)acetals. This review provides a critical overview over the synthetic routes to polyacetals, highlighting where possible the material properties. Direct polyacetalization and polytransacetalization techniques are discussed first, followed by the polymerization of acetal containing monomers and recent ring opening polymerization approaches. Thermoplastic polyacetals show promise in delivery applications but also as bulk materials, where a combination of excellent material properties, a potential for renewable sourcing and degradation as an end-of-life option are of ever increasing importance. Show less

A library of alpha,omega-dienes has been prepared via Williamson ether synthesis from aromatic diols, which can be extracted from lignin as biosource or exhibit related structural motifs. These dienes were subsequently subjected to acyclic diene metathesis polymerisation (ADMET). The molecular characterisation of monomers and polymers was performed using NMR spectroscopy, GC-MS, and SEC. The influence of the monomer structure on the thermal properties of the phenolic polyether polymers was… Show more

A library of alpha,omega-dienes has been prepared via Williamson ether synthesis from aromatic diols, which can be extracted from lignin as biosource or exhibit related structural motifs. These dienes were subsequently subjected to acyclic diene metathesis polymerisation (ADMET). The molecular characterisation of monomers and polymers was performed using NMR spectroscopy, GC-MS, and SEC. The influence of the monomer structure on the thermal properties of the phenolic polyether polymers was investigated by DSC. Glass transition temperatures (T-g) in the range of -44 to 18 degrees C were detected depending on the monomer structure while TGA analysis showed degradation temperatures between 160 degrees C and 300 degrees C. T-g-values could be further increased up to a value of 110 degrees C by fast and versatile post-modification with 1,2,4-triazolinedione (TAD) click chemistry. In addition, the characteristic double bonds of the ADMET-derived polymer chains allowed for crosslinking by this TAD chemistry. Show less

In this study novel, fully and partially bio-based polyamides containing spiroacetal moieties in the backbone derived from bio-glycerol and bio-ethanol were prepared and characterized. The renewable diamine employed to obtain a series of polyamides was synthesized by means of thiol-ene click chemistry and therefore contains flexible thioether as well as rigid spiroacetal moieties. Two different chemical pathways for the polymerization were investigated and evaluated. The polymerization of… Show more

In this study novel, fully and partially bio-based polyamides containing spiroacetal moieties in the backbone derived from bio-glycerol and bio-ethanol were prepared and characterized. The renewable diamine employed to obtain a series of polyamides was synthesized by means of thiol-ene click chemistry and therefore contains flexible thioether as well as rigid spiroacetal moieties. Two different chemical pathways for the polymerization were investigated and evaluated. The polymerization of polyamide salts proved to be the most promising method and therefore salt polymerization was applied in the synthesis of polyamides with aliphatic and aromatic dicarboxylic acids. Subsequently, the structure of the polymers was confirmed by Maldi-ToF analysis and additionally thermal and mechanical properties were investigated revealing Tg’s between 24 and 80 °C and ductile materials with moduli between 1.0 and 1.5 GPa. Both semicrystalline and amorphous polyamides were thermally stable and therefore suitable for thermal processing. In the end, degradation studies were performed on the acetal containing polyamides which showed that the polymers were stable at pH 3 and higher Show less

Two novel biobased diols containing rigid cyclic ketal functionalities have been synthesized on a relatively large scale from glycerol and two diketones, i.e., 1,4-cyclohexanedione and 4,4′-bicyclohexanone. The diols have been used in several types of step growth reactions, resulting in polycarbonates, polyesters, and polyurethanes. While molecular weights (Mn) of up to 50 kg mol–1 are obtained for the polyurethanes, they also exhibit high glass transition (Tg = 95–150 °C) and degradation… Show more

Two novel biobased diols containing rigid cyclic ketal functionalities have been synthesized on a relatively large scale from glycerol and two diketones, i.e., 1,4-cyclohexanedione and 4,4′-bicyclohexanone. The diols have been used in several types of step growth reactions, resulting in polycarbonates, polyesters, and polyurethanes. While molecular weights (Mn) of up to 50 kg mol–1 are obtained for the polyurethanes, they also exhibit high glass transition (Tg = 95–150 °C) and degradation temperatures (Td = 260–320 °C), are transparent, and show a high mechanical strength (E = 1.10–1.35 GPa) but brittle behavior. For the polycarbonates, Mn values higher than 24 kg mol–1 and Tg’s in the range of 70–100 °C have been obtained. Moreover, the polycarbonates show good mechanical properties like ductility and are transparent. Finally, a new generation of fully renewable polyesters have been synthesized with dimethyl succinate and dimethyl furan dicarboxylate. While moderate molecular weight values are obtained, the polyesters show Tg’s of up to 96 °C as well as high Td’s (±315 °C). Show less

Processable poly(cycloacetal)s with high molar masses (Mn) up to 38 kDa were synthesized in a systematic manner. Di-trimethylolpropane (Di-TMP) was used as tetravalent alcohol and was combined with a series of available dialdehydes, after a model reactivity study. These polymers have a high thermal stability with degradation temperatures (Td) up to 370
C while the glass transition temperatures (Tg) ranged from room temperature to 115
C. Trends in Tg modulation were confirmed by a theoretical… Show more

Processable poly(cycloacetal)s with high molar masses (Mn) up to 38 kDa were synthesized in a systematic manner. Di-trimethylolpropane (Di-TMP) was used as tetravalent alcohol and was combined with a series of available dialdehydes, after a model reactivity study. These polymers have a high thermal stability with degradation temperatures (Td) up to 370
C while the glass transition temperatures (Tg) ranged from room temperature to 115
C. Trends in Tg modulation were confirmed by a theoretical simulation. Moreover, the poly(cycloacetals) showed favourable mechanical and optical properties. Show less