Copolymers of 7-oxabicyclo[2.2.1] heptane with 1,3-dioxane and promesogenic telechelic oligomers thereof

✍ Scribed by Julia Pretula; Krzysztof Kaluzynski; Jan Libiszowski; Ryszard Szymanski; Stanislaw Penczek

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 201 KB
• Volume: 35
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(19970715)35:9<1733::aid-pola14>3.0.co;2-6

✦ Synopsis

Copolymers of 7-oxabicyclo[2.2.1]heptane (B) (and of its 2-methyl derivatives) with 1,3-dioxane (D) were obtained by cationic copolymerization initiated with benzoylium hexafluoroantimonate. Structure of copolymers was determined by 1 H-and 13 C-NMR. The proportion of the acetal bonds in copolymers was additionally confirmed in studies of the products of hydrolysis (only the acetal bonds hydrolyze). D is unable to homopolymerize for the thermodynamic reasons and therefore mostly pseudoperiodic copolymers (-DB x -) y are formed. Nevertheless, the reshuffling reactions are responsible for the appearance of ''wrong'' units. These are: the separate oxymethylene and oxy-1,3-propylene units (P, subunits of D) located between two B units. Only the acetal bonds are cleaved in the acidic hydrolysis with dilute HCl. This gives the promesogenic telechelic oligomers of mostly HO-P-B x -OH structure. This article is the first to describe successful cationic copolymerization of a cyclic acetal with a cyclic ether. Moreover, the inability of D to homopolymerize gives the thermodynamic basis of the pseudoperiodic copolymer formation.