Polyester from furans

Another class of interesting isohexide polyesters contains furan-2,5-dicarboxylic acid (2,5-FDA or FDCA, Figure 9.5) as the aromatic diacid component. Since FDCA can be obtained from carbohydrates via various routes, this opens up possibilities for fully bio-based semiaromatic polyesters. 

Moore, J.A. and Kelly, J.E. (1978) Polyesters derived from furan and tetrahydrofuran nuclei. Macromolecules, 11 (3), 568-573. 

Interfacial polymerization was employed to produce aromatic polyesters from 2,5-furan dicarbonyl dichloride with various bis-phenols such as resorcinol, pyrocatechol, hydroquinone, and 2,2-bis(4-hydroxy-phenyl) propane. When 2,5-furan dicarbonyl dichloride was combined with 2,2-bis(4-hydroxyphenyl)propane, workers were able to obtain a maximum yield and maximum logarithmic viscosity number of 80% and 0.17, respectively, when the polymerization solvent was benzene at 25 with two equivalents of sodium hydroxide. In a more in-depth study, this same polyester 14... 

ASTM D2996 Standard Specification for Filament-Wound Fiberglass (Glass-Fiber-Reinforced Thermosetting-Resin) Pipe. Applicable to epoxy, polyester, and furan resins in sizes from 1 in. to 16 in. (25 mm to 400 mm)... 

Because of their favourable price, polyesters are preferred to epoxide and furane resins for general purpose laminates and account for at least 95% of the low-pressure laminates produced. The epoxide resins find specialised uses for chemical, electrical and heat-resistant applications and for optimum mechanical properties. The furane resins have a limited use in chemical plant. The use of high-pressure laminates from phenolic, aminoplastic and silicone resins is discussed elsewhere in this book. 

Most of these furan polycondensates are more sensitive to thermal and oxidative degradation than their benzene counterparts. Particularly affected are the polyesters obtained from 2,5 -fci sfhydroxymethyl) furan indicating that one of the vulnerable groups must be the -Fu—CH2—0-, and not the -Fu—CO—O-, since polycondensates obtained from 2,5-dicarboxylic acid are more stable, as expected from the... 

Recent work on the synthesis, structure and some properties of macromolecules bearing furan rings is discussed. Two basic sources of monomers are considered, viz. furfural for monomers apt to undergo chain polymerization and hydroxymethylfurfural for monomers suitable for step polymerization.Within the first context, free radical, catiomc and anionic systems are reviewed and the peculiarities arising from the presence of furan moieties in the monomer and/or the polymer examined in detail. As for the second context, the polymers considered are polyesters, polyethers, polyamides and polyurethanes. Finally, the chemical modification of aU these oligomers, polymers and copolymers is envisaged on the basis of the unique reactivity of the furan heterocycle. 

Furan-2,5-dicarboxylic add also has tremendous industrial potential, because it could replace oil-derived diadds such as adipic or terephthalic acid as monomers for polyesters and polyamides [98, 99]. This diadd can be synthesized by Pt-catalyzed oxidation with 02 of 5-hydroxymethylfurfural the latter is obtained by acid-catalyzed dehydration of D-frudose or frudosans (inulin) the latter, however, are too expensive as starting materials, and yields from glucose-based waste raw materials are no higher than 40%. Therefore, the potential attractive option of furan-2,5-dicarboxylic acid will develop only after an effident generation of 5-hydroxymethylfurfural from forestry waste materials has been developed. The same compound is also the starting material for the synthesis of other interesting chemicals obtained by oxidative processes, such as 5-hydroxymethylfuroic add, 5-formylfuran-2-carboxylic add and the 1,6-dialdehyde. 

Different foundry casting techniques are used. Included are plastic-based binders mixed with sand. Various types of molds and cores are produced that include no-bake or cold-box, hot-box, shell, and oven-cured. Usual binders are phenolic, furan, and thermoset polyester. There is the foundry shell casting, also called dry-mix casting. It is a type of process used in the foundry industry, in which a mixture of sand and plastic (phenolic, thermoset polyester, etc.) is placed on to a preheated metal pattern (producing half a mold) causing the plastic to flow and build a thin shell over the pattern. Liquid plastic pre-coated sand is also used. After a short cure time at high temperature, the mold is stripped from its pattern and combined with a similar half produced by the same technique. Finished mold is then ready to receive the molten metal. Blowing a liquid plastic/sand mix in a core-box also produces shell molds. 

Bis(hydroxymethyl) furan and 5-hydroxymethyl furfural (available from C6 sugars) have been oxidized to furan-2,5-dicarboxylic acid (44)- Linear polyesters, polyurethanes, and polyamides containing these monomers have been described in the literature (45-43) and have been made via condensation polymerization techniques including bulk, solution, and interfacial mixing procedures. Gandini (5,34) reviewed the poly condensation reactions up to 1986 and... 

It has often been proclaimed that 5-hydroxymethylfurfural (HMF, Fig. 8.35) could be an ideal cross-over compound between carbohydrates and petrochemistry [184], as it is a bifunctional heteroaromatic compound that is accessible from fructose in one step. It was expected that HMF could be developed into a valuable synthetic building block and that its derivatives, such as furan-2,5-dicarb-oxylic acid (FDA), would be able to compete with fossil-derived monomers for use in thermostable polyesters and polyamides. 

It is important to point out that in spite of the ease of use, these resinous mortars, like many other chemical compositions, are toxic and adequate precautions must be taken to protect the health of the applicators. For example, the skin should be protected from the setting agents used in phenolic, urea, furan, and epoxy cements and adequate ventilation should be provided during the application of polyurethane and polyester cements to prevent the inhalation of volatile isocyanates and styrene respectively. However, once they are cured, these resinous cements are not hazardous. Actually, they are important energy conserving materials of construction. 

Polyester fibers are composed of linear chains of polyethylene terephthalate (PET), which produces benzene, benzoic acid, biphenyl, and vinyl terephthalate on pyrolysis. Acrylic fibers comprise chains made up of acrylonitrile units, usually copolymerized with less than 15% by weight of other monomers, e.g., methyl acrylate, methyl methacrylate, or vinylpyrrolidone. Thermolysis results in the formation of acrylonitrile monomer, dimers, and trimers with a small amount of the copolymer or its pyrolysis product. In this case, the acrylic is Orion 28, which contains methyl vinyl pyridine as comonomer. Residual dimethyl formamide solvent from the manufacturing process is also found in the pyrolysis products. Cotton, which is almost pure cellulose, comprises chains of glucose units. The pyrolysis products of cellulose, identified by GC/MS, include carbonyl compounds, acids, methyl esters, furans, pyrans, anhydrosugars, and hydrocarbons. The major pyrolysis products are levoglucosan (1,6-anhydro-B-D-glucopyranose) and substituted furans. 

HMF is a suitable precursor for the synthesis of bifunctional furan monomers as summarized in Scheme 4. All these monomers can be used to prepare polycondensates by step-growth reactions with the other corresponding bifunc-tional monomers derived either from petrochemical precursors or from renewable resources. The polycondensates obtained, such as polyesters, polyamides, and polyurethanes, etc. have been characterized [107-113]. Scheme 5 shows another approach for the synthesis of bifunctional monomers through acid-catalyzed condensation of the corresponding mono-functional furan derivatives with an aldehyde... 

Two recent additions to the topic of furan-based polyesters include macromolecular structures synthesized from... 

Among the numerous furan polymers derived from polycondensation involving systems other than polyesters,... 

Table 2. Polyesters Formed from 2,5-Furan Di-carboxyllc Acid and an Aliphatic Acid... 

Considering these differences, it is the purpose of this work to synthesize representative polyesters and polyamides which incorporate derivatives of the four isomeric furan dicarboxylic acids, and to determine if these polymers bear any relationship in properties to similar polymers derived from benzene. Similarity in basic position and distance between carboxyl groups may permit examination and ordering of poljnners containing the isomeric benzene diacids. Some comparisons are shown below. 

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