Synthesis and characterization of poly(isosorbide-co-butylene 2,5-furandicarboxylate) copolyesters

The search for rigid, tough polyesters with high T g - renewable aromatic polyesters with high isosorbide content

Renewable polyesters with a good balance between impact strength and elastic modulus (stiffness) are not very common, especially when combined with high glass transition temperature (T g). Achieving such high performance properties would enable the substitution of high performance polymers like ABS and polycarbonate with chemically recyclable polyesters from bio-based or recycled sources. One of the challenges in developing these materials is to select the right composition of the right monomers/comonomer ratios and making these materials with high molecular weight, which can be challenging since some of the most promising rigid diols, such as isosorbide, are unreactive. This study comprises aromatic polyesters from (potentially) renewable monomers, using bio-based isosorbide as a means to increase their T g and to inhibit their crystallization, while using flexible co-diols to improve impact strength. To incorporate a high amount of isosorbide into the targeted polyesters, we used the synthesis method with reactive phenolic solvents previously developed in our group. The selected compositions display high T g's (>90 °C) and high tensile modulus (>1850 MPa). We show that more polar monomers such as the stiffer 2,5-furandicarboxylic acid (FDCA) and diethylene glycol cause high stiffness but decreased impact strength (<5 kJ m-2). Combining terephthalic acid and isosorbide with more flexible diols like 1,4-butanediol, 1,4-cyclohexanedimethanol (CHDM) and 1,3-propanediol provides a better balance, including the combination of high tensile modulus (>1850 MPa) and high impact strength (>10 kJ m-2).

Modifications of Furan-Based Polyesters with the Use of Rigid Diols

The replacement of polymers derived from petrochemical resources has been a prominent area of focus in recent decades. Polymers used in engineering materials must exhibit mechanical strength and stiffness while maintaining performance through a broad temperature range. Most of the polyesters used as engineering materials are based on terephthalic acid (TPA) and its derivatives, which provide necessary rigidity to molecular chains due to an aromatic ring. Bio-based alternatives for TPA-based polyesters that are gaining popularity are the polyesters derived from 2,5-furandicarboxylic acid (FDCA). To broaden applicational possibilities, one effective way to achieve specific properties in targeted applications is to adjust the composition and structure of polymers using advanced polymer chemistry techniques. The incorporation of rigid diols such as isosorbide, 1,4-cyclohexanedimethanol (CHDM), and 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO) should result in a greater stiffness of the molecular chains. This review extensively explores the effect of incorporating rigid diols on material properties through a review of research articles as well as patents. Moreover, this review mainly focuses on the polyesters and copolyesters synthesized via two-step melt polycondensation and its alterations due to the industrial importance of this method. Innovative synthesis strategies and the resulting material properties are presented.

Reactive phenolic solvents applied to the synthesis of renewable aromatic polyesters with high isosorbide content

High boiling point phenolic reactive solvents like p-cresol could play a key role in improving the synthesis of aromatic polyesters with a high content of secondary diols such as isosorbide. Previously, our group showed that this method significantly improves the synthesis of poly(isosorbide succinate). In this work, terephthalic acid and 2,5-furandicarboxylic acid were used as building blocks for the synthesis of high T_g polyesters with high isosorbide content (>30 mol% of diols) and high molecular weight (M_n > 24 kg mol^-1). A number of reactive and non-reactive solvents were tested in this work, and the results clearly point to a significant improvement when using reactive solvents, in terms of molecular weight and polycondensation time, especially for the case of p-cresol. The synthesis method was successfully scaled to 1 kg, showing promise for production at industrial scale. A method to remove these solvents (including end groups) from the polymers, which uses small excesses of isosorbide (1.5-3.0%) in the feed, is also presented.

Recent advances in the development of green furan ring-containing polymeric materials based on renewable plant biomass

Fossil resources are rapidly depleting, forcing researchers in various fields of chemistry and materials science to switch to the use of renewable sources and the development of corresponding technologies. In this regard, the field of sustainable materials science is experiencing an extraordinary surge of interest in recent times due to the significant advances made in the development of new polymers with desired and controllable properties. This review summarizes important scientific reports in recent times dedicated to the synthesis, construction and computational studies of novel sustainable polymeric materials containing unchanged (pseudo)aromatic furan cores in their structure. Linear polymers for thermoplastics, branched polymers for thermosets and other crosslinked materials are emerging materials to highlight. Various polymer blends and composites based on sustainable polyfurans are also considered as pathways to achieve high-value-added products.

Recent Progress on Bio-Based Polyesters Derived from 2,5-Furandicarbonxylic Acid (FDCA)

The big challenge today is the upgrading of sustainable materials to replace miscellaneous ones from petroleum resources. Thus, a generic bio-based building block lays the foundation of the huge bio-market to green economy. 2,5-Furandicarboxylic acid (FDCA), a rigid diacid derived from lignocellulose or fructose, represents a great potential as a contender to terephthalic acid (TPA). Recently, studies on the synthesis, modification, and functionalization of bio-based polyesters based on FDCA have attracted widespread attention. To apply furanic polyesters on engineering plastics, packaging materials, electronics, etc., researchers have extended the properties of basic FDCA-based homo-polyesters by directional copolymerization and composite preparation. This review covers the synthesis and performance of polyesters and composites based on FDCA with emphasis bedded on the thermomechanical, crystallization, barrier properties, and biodegradability. Finally, a summary of what has been achieved and the issues waiting to be addressed of FDCA-based polyester materials are suggested.

Melt polycondensation of 2,5-tetrahydrofurandimethanol with various dicarboxylic acids towards a variety of biobased polyesters

The effects of THFDM's structure on its reactivity, polymer molecular chain energy and properties were systematically studied.

Tuning the Properties of Furandicarboxylic Acid-Based Polyesters with Copolymerization: A Review

Polyesters based on 2,5-furandicarboxylic acid (FDCA) are a new class of biobased polymers with enormous interest, both from a scientific and industrial perspective. The commercialization of these polymers is imminent as the pressure for a sustainable economy grows, and extensive worldwide research currently takes place on developing cost-competitive, renewable plastics. The most prevalent method for imparting these polymers with new properties is copolymerization, as many studies have been published over the last few years. This present review aims to summarize the trends in the synthesis of FDCA-based copolymers and to investigate the effectiveness of this approach in transforming them to a more versatile class of materials that could potentially be appropriate for a number of high-end and conventional applications.

Biodegradable Oligoesters of ε-Caprolactone and 5-Hydroxymethyl-2-Furancarboxylic Acid Synthesized by Immobilized Lipases

Following the latest developments, bio-based polyesters, obtained from renewable raw materials, mainly carbohydrates, can be competitive for the fossil-based equivalents in various industries. In particular, the furan containing monomers are valuable alternatives for the synthesis of various new biomaterials, applicable in food additive, pharmaceutical and medical field. The utilization of lipases as biocatalysts for the synthesis of such polymeric compounds can overcome the disadvantages of high temperatures and metal catalysts, used by the chemical route. In this work, the enzymatic synthesis of new copolymers of ε-caprolactone and 5-hydroxymethyl-2-furancarboxylic acid has been investigated, using commercially available immobilized lipases from Candida antarctica B. The reactions were carried out in solvent-less systems, at temperatures up to 80 °C. The structural analysis by MALDI TOF-MS, NMR, and FT-IR spectroscopy confirmed the formation of cyclic and linear oligoesters, with maximal polymerization degree of 24 and narrow molecular weight distribution (dispersity about 1.1). The operational stability of the biocatalyst was explored during several reuses, while thermal analysis (TG and DSC) indicated a lower thermal stability and higher melting point of the new products, compared to the poly(ε-caprolactone) homopolymer. The presence of the heterocyclic structure in the polymeric chain has promoted both the lipase-catalyzed degradation and the microbial degradation. Although, poly(ε-caprolactone) is a valuable biocompatible polymer with important therapeutic applications, some drawbacks such as low hydrophilicity, low melting point, and relatively slow biodegradability impeded its extensive utilization. In this regard the newly synthesized furan-based oligoesters could represent a "green" improvement route.

A facile method to synthesize bio-based and biodegradable copolymers from furandicarboxylic acid and isosorbide with high molecular weights and excellent thermal and mechanical properties

Biobased, biodegradable copolymers containing isosorbide and 2,5-furandicarboxylic acid with high performance are successfully synthesized through a non-solvent and economical pathway.