Furan polymers polyesters

Only some recent contributions to this large field are discussed here, since thorough reviews are available elsewhere. The most interesting studies relate to two very different approaches to furan polymers, namely the synthesis of novel polyesters and the use of the Diels-Alder reaction to prepare thermoreversible materials [37]. 

Furan derivatives, mainly based on furfural or furfuryl alcohol, have been applied in thermosetting resins for almost a century. In contrast, academic and industrial research into furan based polyesters and polyamides took off in the 1950s. Farly papers (up until the 1970s) are usually rather qualitative, generally just describing the polymer synthesis, combined with rudimentary property analysis. Since the 1980s, more quantitative scientific papers have been... 

Moore reacted the acid chloride of FDCA with DHMF, yielding only low molecular weight polyesters [57], Recently, Gomes et al. described a fully furan based polyester via the acid chloride of FDCA by interfacial polymerization, with an Mn of 3800 g.mol , and a Tg of 83 °C (no Tn, is mentioned) [17], The onset of decomposition was determined to be around 205 °C. Based on these results we can conclude that DHMF is too unstable to be used as monomer in step-growth polymers. 

Furan, Furfural, Hydroxymethylfurfural, Furan polymers. Chain polymerizations. Step-growth polymerizations, Furan polyesters, Furan polyamides, Furan polyurethanes, Furan-containing conjugated oligomers, Diels-Alder reaction, Dendrimers, Reversible crosslinking... 

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

It must be emphasized that the presence of carbonyl groups attached to furan rings represents on the contrary an element of stabilization in furan polymers. Thus, for example, furan polyesters and polyamides are white and do not suffer any stmctural modification over very long periods of time. 

The highest mechanical strengths are usually obtained when the fibre is used in fine fabric form but for many purposes the fibres may be used in mat form, particularly glass fibre. The chemical properties of the laminates are largely determined by the nature of the polymer but capillary attraction along the fibre-resin interface can occur when some of these interfaces are exposed at a laminate surface. In such circumstances the resistance of both reinforcement and matrix must be considered when assessing the suitability of a laminate for use in chemical plant. Glass fibres are most commonly used for chemical plant, in conjunction with phenolic resins, and the latter with furane, epoxide and, sometimes, polyester resins. 

A number of cement materials are used with brick. Standard are polymer resin, silicate, and sulfur-based materials. The most widely used resins are furane, vinyl ester, phenolic, polyester, and epoxies. Carbon-filled furanes and phenolics are good against nonoxidizing acids, salts, and solvents. Silicates and silica-filled resins should not be used in hydrofluoric or fluorosilicic acid applications. Sulfur-based cements are limited to 93°C (200°F), while resins can be used to about 180°C (350°F). Silicate-based cements are available for service temperatures up to 1000°C (1830°F). 

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. 

Polyesters come to mind, since PET and some of its more recent homologs play a very prominent role on the polymer market. FDA was therefore used in conjunction with ethylene glycol to synthesize poly(2,5-ethylene furancarboxylate) (PEF), that is, the furan analog of PET [38]. The use of polytransesterification (Figure 1.16) proved particularly effective in generating high-molecular weight semicrystalline polymers. 

The polymer concretes are distinguished by the nature of the binder e.g., furan, polyester, epoxy, phenol formaldehyde, carbamide, and so on. The classification of the main types of polymer concrete according to the kind of synthetic resins involved is shown in Figure 1.2 [7],... 

Polymer concretes based on phenol-formaldehyde, acetone-formaldehyde resins and monomers, and methyl methacrylate are much less common. Phenolic resins are similar to furan in many physical and mechanical properties. However, they are unstable in alkalis like polyester resins [7],... 

Whereas 2,5-dihydroxymethylfuran (DHMF) has been proposed frequently as a diol component for polyester synthesis, the high reactivity of the hydroxymethyl groups under acidic conditions primarily leads to resin formation, which is commercially exploited for the production of thermoset furan resins [55]. Although HMFA is more chemically stable than DHMF, it is also prone to resinification at high temperatures. In contrast, FDCA and derivatives have proven to be chemically stable under conditions relevant to polyester synthesis, making them the most versatile and industrially viable furan monomers for step growth polymers. 

Moore, J.A. and Bunting, W.W. (1985) Polyesters and polyamides containing isomeric furan dicarboxylic acids. Polymer Scienceand Technology, Advanced Polymer Synthesis, 31, 51-91. 

Okada M., Tachikawa K., Aoi K., Biodegradable polymers based on renewable resources. 11. Synthesis and biodegradability of polyesters containing furan rings, J. Poly. Sci. Part A Polym. Chem., 35, 1997, 2729-2737. 

The synthesis of polyesters based on various furan diacids derivatives and dianhydrosugar diols [4d, 39] were reported in the context of biomass-derived polymers with biodegradable properties, but regrettably these studies were not pursued. 

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