No abstract

Four siloxane-containing benzoxazine monomers and telechelic benzoxazine oligomers were synthesized from 1,3-bis(3aminopropyl)-1,1,3,3-tetramethyldisiloxane, a,x-bis(3-aminopropyl)polydimethylsiloxane, phenol, o-allylphenol, and formaldehyde. The length of the siloxane segment affects the polymerization reaction of the benzoxazine monomers and telechelic benzoxazine oligomers. The dynamic mechanical properties of the corresponding polybenzoxazines depend primarily on the structure of phenol and the length of the siloxane segment. The polybenzoxazines exhibit one-way dual-shape memory behavior in response to changes in temperature. The thermally induced shape memory effects of the polybenzoxazines were characterized by bending and tensile stress-strain tests with a temperature program based on their glass transition temperatures. V C 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44121.

A fluorine‐containing difunctional benzoxazine is synthesized by hydrosilylation of a monofunctional benzoxazine based on o‐allylphenol and p‐fluoroaniline. Besides the intramolecular and intermolecular hydrogen bonding associated with the nitrogen and oxygen atoms in the oxazine ring, specific self‐complementary intermolecular ArF···HO hydrogen bonding is formed in the polymerization of the benzoxazine, which leads to the resultant polybenzoxazine possessing a broad glass transition temperature range and showing two not well‐separated transitions. Based on the two glass transition temperatures, the polybenzoxazine exhibits triple‐shape‐memory behaviors by manipulating temperature and strain in the shape fixing process under tensile and bending modes. The dynamic mechanical and shape‐memory properties of the polybenzoxazine are influenced by the combined effect of the cross‐linking density and the ArF···HO hydrogen bonding.

Three difunctional benzoxazines were synthesized from cresol isomers (o-, m-, and p-methylphenols), 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, and formaldehyde. The ring-opening polymerization temperature decreases in the order of ortho-, para-, and meta-positions of methyl group for the benzoxazine monomers, whereas the glass transition temperature increases in the order of ortho-, para-, and meta-positions of methyl group for the resultant polybenzoxazines. In addition, the polybenzoxazines exhibit one-way dual-shape-memory behavior in response to changes in temperature, and the shape-memory effects are evaluated by tensile and bending tests with a temperature program based on glass transition temperature. The o-and p-cresol-based polybenzoxazines exhibit higher shape-memory performance than their m-cresol-based analogue/counterpart. V C 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45443.