Thermotropic polymers based on 2,5-furandicarboxylic acid

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Nucleating agents for biopolymers

Use of a compound or a combination of compounds for crystallization of polyhydroxy-alkanoate (PHA), poly-lactic acid (PLA) or combinations thereof, characterized in that each of said compounds comprises a core motif with two oxalamide motifs, flanked by two arms, wherein said core motif has the formula: R-NH-C(O)-C(O)-NH-(CH2)n-NH-C(O)-C(O)-NH-R', wherein n is between 1 and 10 and the arms R and R' are each independently of one another chosen from: (i) H; (ii) an alkyl group with a total number of carbon atoms between 1 and 20; (iii) an aromatic ring; or (iv) an ester group as e.g. - X-Ester-Y, or - X-Ester- X-Ester-Y, wherein X is a saturated aliphatic hydrocarbon group comprising 1 to 20 carbon atoms, Y is chosen from H, an alkyl group with a total number of carbon atoms between 1 and 20 or an aromatic ring and Ester is -C(O)-O- or -O-C(O)-

Liquid crystalline furandicarboxylic acid-based aromatic polyesters

The invention pertains to a fully aromatic liquid crystalline furandicarboxylic acid- based aromatic polyester obtainable from a mixture of monomers comprising 2,5- furandicarboxylic acid, p-hydroxybenzoic acid, an aromatic diol, and 5-40 mol% of an aromatic monocarboxylic acid selected from vanillic acid, ferulic acid, salicylic acid, and syringic acid, or mixtures thereof. In a preferred embodiment at least 90% of the 2,5-furandicarboxylic acid and aromatic monocarboxylic acid are bio-based monomers

Small-scale screening of novel biobased monomers:the curious case of 1,3-cyclopentanediol

\u3cp\u3eIn this work, we report on the small scale polycondensation and consecutive analysis of novel polyesters based on the potentially renewable 1,3-cyclopentanediol (CPdiol). To avoid evaporation of monomers during thin-film polymerization reactions, trimer pre-polyesters have been synthesized from the corresponding acid-chlorides with diol monomers. Polymerization of these trimers was explored by thermogravimetric analysis to identify potential side reactions, and to assess the ideal polymerization temperature. In general we observe that trans-1,3-cyclopentanediol exhibits good thermal stability up to 200 °C, whereas thermal dehydration of the alcohol end-groups occurs upon further heating. In contrast, for cis-1,3-cyclopentanediol, the ester bonds of the cyclopentane end-groups become labile, thereby generating carboxylic acid end-groups, and 3-cyclopentenol already at 180 °C. The thermal dehydration reactions yield double bond end-groups, which in turn facilitate cross-linking through cross-coupling and Diels-Alder reactions, leading to an increase in molecular weight. Despite the limited thermal stability of CPdiol, here we demonstrate that polymerization of CPdiol can successfully be achieved in thin-film polycondensation conditions at 180 °C, yielding molecular weights well above 10 kg mol\u3csup\u3e−1\u3c/sup\u3e.\u3c/p\u3

Thermotropic polyesters from 2,5-furandicarboxylic acid and vanillic acid : synthesis, thermal properties, melt behavior, and mechanical performance

In this work, we address the synthesis of novel aromatic–aliphatic biobased polyesters showing thermotropic behavior in the melt. Successful incorporation of different biobased monomers such as 2,5-furandicarboxylic acid (2,5-FDCA), suberic acid (SuA), and vanillic acid (VA) in thermotropic liquid crystalline polymers (TLCPs) is made possible by performing synthesis at low temperatures. The chemical structures, molecular weights, phase transitions, thermal behavior, and mechanical performance of the synthesized polymers are studied using polarization optical microscopy, WAXD, DSC, TGA, DMTA, solid-state NMR spectroscopy, rheology, and tensile tests. It is shown that the incorporation of the rigid, aromatic 2,5-FDCA moiety enhances the formation of blocky copolymers, whereas the VA moiety tends to decrease the block formation. However, when combined, nonblocky TLCPs containing 2,5-FDCA and VA with high aromatic content can be obtained. These materials show a low temperature transition from the crystalline to the nematic phase, and stable nematic phases up to 300 °C and higher. Furthermore, in such polymers, the 2,5-FDCA and VA moieties require more thermal energy to become mobile compared to the phenyl rings in hydroxybenzoic acid, hydroquinone, and 4,4'-biphenol. Mechanical analysis shows that the performance of these polymers is correlated to their crystallinity. Surprisingly, a higher crystallinity results in ductile behavior, whereas a lower crystallinity results in a higher modulus, a higher stress at break, and a lower strain at break

Synthesis, kinetics, and characterization of bio-based thermosets obtained through polymerization of a 2,5-furandicarboxylic acid-based bis(2-oxazoline) with sebacic acid

The synthesis of renewable 2,5-furandicarboxylic acid-based cross-linked poly(ester amide)s via the polymerization of a 2,5-furandicarboxylic acid based bis(2-oxazoline) monomer (2,5-bis(4,5-dihydrooxazol-2-yl)furan, 2,5-FDCAox) with sebacic acid is reported in this work. It is demonstrated that the amide groups in the 2,5-furandicarboxamide moiety are susceptible to participation in a branching reaction with 2-oxazoline rings. The corresponding enhanced reaction rate decreases the curing times for the preparation of cross-linked polymers compared to systems containing the isophthalic acid based alternative, 1,3-bis(4,5-dihydrooxazol-2-yl)benzene (IAox). The increased tendency to form branches or cross-links in 2,5-FDCAox based systems is attributed to the occurrence of intra-molecular hydrogen bonding of the 2,5-furandicarboxamide moiety. Such an intra-molecular hydrogen bond increases the nucleophilicity of the furanic amide group and makes it more susceptible to participation in an addition reaction with a 2-oxazoline ring. Furthermore, it is demonstrated that the rate of the branching reaction can be enhanced by the addition of triphenyl phosphite as catalyst, resulting in a further decrease of the curing times of the poly(ester amide)s synthesized in this study. Preliminary coating studies indicate that 2,5-furandicarboxylic acid based cross-linked poly(ester amide)s synthesized via the 2-oxazoline ring opening addition reactions with dicarboxylic acids are good candidates for the development of fully renewable cross-linked poly(ester amide)s

Improving stiffness, strength, and toughness of poly(ω-pentadecalactone) fibers through in situ reinforcement with a vanillic acid-based thermotropic liquid crystalline polyester

\u3cp\u3eWe report on the morphology and performance of melt-drawn poly(ω-pentadecalactone) (PPDL) fibers reinforced with a vanillic acid-based thermotropic liquid crystalline polyester (LCP). The in situ reinforced PPDL/LCP fibers developed in this work are considered to be renewable in nature, given the fact that the feedstock for both polymers can be obtained from natural resources. To prepare these fibers, the polymers were mixed in a small scale twin-screw extruder, followed by melt-drawing of the extrudate. It is demonstrated that the tensile modulus and tensile strength of the fibers increase with increasing LCP orientation and concentration. Despite the brittle nature of the pure LCP component, melt-spun PPDL/LCP fibers maintain their ductile deformation for fibers containing up to 30 wt % LCP. The improved stiffness and strength of these PPDL/LCP fibers in combination with their ductile nature ensure improved energy absorption during deformation and effectively increases their toughness compared to the pure PPDL material. A further increase of the LCP content to 40 wt % and higher results in a poor control over the blend morphology, and brittle failure of the fibers is observed after the application of 2-3% strain. Small-angle X-ray scattering data indicate that after processing transcrystallization of PPDL occurs on the surface of the oriented LCP phase. According to DSC analysis, this transcrystallization on the oriented LCP fibrils is accompanied by an increase in the crystallization temperature. These findings have been confirmed through morphological analysis using transmission electron microscopy. It is anticipated that this interfacial crystallization strengthens the PPDL/LCP interface and allows delocalization of stress during deformation.\u3c/p\u3

Effect of self-assembly of oxalamide based organic compounds on melt behavior, nucleation, and crystallization of isotactic polypropylene

\u3cp\u3eWe report on the effect of an aliphatic oxalamide based nucleating agent (OXA3,6) on the melt and crystallization behavior of isotactic polypropylene (iPP) under defined shear conditions. Through polarized optical microscopy, we demonstrate that OXA3,6 self-assembles from the iPP melt into rhombic crystals whereas their size and distribution proved highly dependent on the employed cooling rates. The presence of 0.5 wt % of OXA3,6 in iPP results in a significant suppression in iPP melt viscosity, which could not be explained via molecular modeling. A possible cause for the drop in viscosity in the presence of OXA3,6 is attributed to the interaction (absorption) of high molecular weight iPP chains with the nucleating agent, thereby suppressing their contribution to the viscoelastic response of the melt. This proposed mechanism for the suppression in melt viscosity appears similar to that encountered by the homogeneous distribution of nanoparticles such as CNTs, graphene, and silica. Shear experiments, performed using a slit flow device combined with small-angle X-ray diffraction measurements, indicate that crystallization is significantly enhanced in the presence of OXA3,6 at relatively low shear rates despite its lowered sensitivity to shear. This enhancement in crystallization is attributed to the shear alignment of the rhombic OXA3,6 crystals that provide surface for iPP kebab growth upon cooling. Overall, the suppression in melt viscosity in combination with enhanced nucleation efficiency at low as well as high shear rates makes this self-assembling oxalamide based nucleating agent a promising candidate for fast processing.\u3c/p\u3