Polyformals, aliphatic

After the butyl alcohol was removed, the polymers were built up by heating the melt under reduced pressure. Since these polyformals of aliphatic diols had very low melting points (below 75° C.), their utility was limited. Apparently, no higher melting points have been reported for polyformals. In attempts to obtain higher-melting polyformals, the following alicyclic diols were used cis-, trans-, and 1 to 1 cis-/trans- mixture of 2,2,4,4-tetramethyl-l,3-cyclobutanediol (I) trans-1,4-cyclohexanediol (II) tmiw-l,4-cyclohexanedimethanol (III) and 2,5- or 2,6-norbomanediol (IV). 

The synthesis of aliphatic polyformals (X) been known for many years and is relatively straightforward. As shown in equation 1, aliphatic diols can be reacted directly with formaldehyde or dialkyl formals to produce these polymers. The principal complication of the reaction occurs when the diol used contains 2, 3 or 4 carbon atoms in which case the formation of the cyclic formal is favored. Musser and Jackson have more... 

These preliminary results suggest that aromatic polyformals such as 6 may have better oxidative and chemical stability than would have been predicted based on the reactivity of aliphatic formals. However, the effect of long term aging (either to oxidative or chemical environments) on the properties of have not been determined. 

Telechelic aromatic-aliphatic polyformals containing only primary alcohol chain ends can be conveniently synthesized from a bisphenol and an a,ft>-bis(chloromethoxy)alkane in the presence of a phase transfer catalyst as outlined in Scheme 66. This is in spite of some competing side reactions that are discussed elsewhere. ... 

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