Polymers (Apr 2014)
Effects of Polybenzoxazine on Shape Memory Properties of Polyurethanes with Amorphous and Crystalline Soft Segments
Abstract
This paper evaluates the role of minor component polybenzoxazine (PB) on shape-memory properties of polyurethanes (PU) with glassy and crystalline soft segments. The polymer compounds were prepared in two steps. In the first step, benzoxazine, polyurethane pre-polymer, and chain extender butanediol (BD) were mixed into a solution followed by chain-extension of the pre-polymer with BD. In the second step, benzoxazine was polymerized at 180 °C for 3 h to obtain shape memory polymer compounds. The atomic force microscopy images revealed that the PB-phase formed uniform dispersions in PU. The presence of PB-phase induced shape-memory behavior in non-shape memory PU with amorphous soft segment and significantly improved the values of shape fixity, recovery ratio, and recovery stress in shape memory polyurethane with crystalline soft segment.
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