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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.

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Two series of benzoxazine/epoxy copolymers are prepared from polyetheramine-type benzoxazines and diglycidyl ether of bisphenol A (DGEBA) in various weight ratios. Each copolymer appears a single glass-transition temperature (T g ), and the T g shows a systematic increase with increasing DGEBA content for both copolymer systems, but copolymers with low DGEBA content show respectively lower T g s than the corresponding pristine polybenzoxazines. Compared to the corresponding pristine polybenzoxazines, the effect of DGEBA content on the variation in T g of the copolymers depends on the substituent structure of benzoxazines. The two series of copolymers exhibit one-way dual shape memory effect based on T g , and the shape memory effect is affected by both the substituent structure of benzoxazines and the content of DGEBA. Under motion constraints in tensile deformation mode, copolymers with low DGEBA content exhibit high shape recovery ratios (91.0-96.1%) over the corresponding polybenzoxazines (84.5%), whereas copolymers with high DGEBA content show relatively low shape recovery ratios (75.0-84.7%).

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