Furan-Containing Networks

The fact that furan is only weakly aromatic [463] while, at the same time, substantially dienic [464] leads to its chemistry being rather complex and its polymeric reaction products not fully characterized. The interplay between aromatic and dienic properties leads to a situation where the predominance of either effect depends on the nature and position of the ring substituents, and upon the specificity of the reagents, catalysts and reaction media in each case 

The most commonly used furan resins are those obtained from furfuryl alcohol and/or furfural  

The furfuryl alcohol is reacted with itself under acidic conditions to produce liquid oligomers. 

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Very highly crosslinked, substantially aromatic networks containing methylene bridges fall into several categories hydrocarbon networks, phenol-formaldehyde and similar networks, and furan-based networks. The hydrocarbon networks have not yet found broad industrial applications despite the fact that they have been known for over a century. Traditionally, hydrocarbon aromatic networks were prepared [437, 438] under Friedel-Crafts conditions using monomers such as benzyl chloride [439] ... 

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