Superior shape memory properties and microstructure evolution of poly(ether-b-amide12) elastomer enhanced by poly(ε-caprolactone)

Abstract

In this work, the superior shape memory properties and microstructure evolution of poly (ether-b-amide12) (PEBA) enhanced by poly(3-caprolactone) (PCL) were investigated. The PEBA/PCL blends were prepared by the methods of solution mixing and compression molding. The representative phase-separated morphologies were observed by optical microscopy (OM). The recovery stress and shape memory properties of the samples were determined by dynamic mechanical analysis (DMA). It was found that high loadings of PCL (up to 35 wt%) only marginally worsened the recovery properties of the blends.However, the values of maximum recovery stresses increased greatly with PCL content in spite of deformation temperature, indicating an enhancement effect of PCL on the recovery stress of polymer blends. Moreover, in situ wide angle X-ray scattering (WAXS) investigation revealed the microstructure evolution during the shape memory process. It was notable that during the stretching process, the strain-induced crystallization of soft segments (PTMO) of PEBA shifted to lower strain due to the existence of the PCL phase. The present results provided a reference that the recovery stress could be greatly increased by adding another polymer to the shape memory polymer, which is vital to application in the biomedical field. Fig. 9 The samples 100/0, 80/20 and 65/35 were (a) stretched to 3 ¼ 100% strain at 0 C and (b) cooled from 0 C to À20 C under constant 100% strain and (c) finally heated to 40 C under constant 100% strain; (a1, b1, c1) 4 020 indicate the relative content of (020) plane reflection of PTMO and the 4 020 have been normalized. (a2, b2, c2) PWHH 020 indicate the evaluation of peak width at half height (PWHH) of the corresponding azimuthal scanning profiles for (020) plane reflection of PTMO.This journal is

Double Crystalline Multiblock Copolymers with Controlling Microstructure for High Shape Memory Fixity and Recovery

“…Two rings, located at q = 1.38 nm –1 and 1.58 nm –1 , can be indexed as (020/1̅11) and (110) reflections from a monoclinic α crystal of PBS . The others, located at q = 1.51 nm –1 and 1.67 nm –1 , are related respectively to the (110) and (200) planes of the PCL orthorhombic crystal form. ,− Furthermore, the intensity of the diffraction peaks of one component decreases with decreasing content. Upon heating to 60 °C, PCL crystals melt and PBS crystals are left, evidenced by the remaining two rings related with the monoclinic α crystal of PBS.…”

Shape memory property and underlying mechanism by the phase separation control of poly(ϵ‐caprolactone)/poly(ether‐b‐amide)

“…In our previous work, the shape memory property of PEBA/PCL blends and the corresponding microstructure evolution were studied. It was found that the shape recovery stress of PEBA was enhanced by the addition of PCL . Based on these results, in the current work the blends with weight ratio of PCL/PEBA 35/65 were prepared by solution mixing and the controlling phase separation dynamics were studied.…”

“…SMPs can be divided into two main categories. One is polymer networks, including covalent crosslinked or physical crosslinked semicrystalline or amorphous copolymers; the other is polymer blends and composites . Because the synthesis of SMPs may be difficult, physical blending of polymers is a convenient and effective way to prepare shape memory composites and has potential in industrial applications.…”

“…PCL is a low toxicity, biocompatible and biodegradable semicrystalline polymer which can be used in the biomedical field . Considering the rigid nature of its crystalline state, PCL has been widely studied in SMP research as a block of copolymer or a component for blends . We have already done some research on the shape memory crystalline polymer and its composites .…”

“…Considering the rigid nature of its crystalline state, PCL has been widely studied in SMP research as a block of copolymer or a component for blends . We have already done some research on the shape memory crystalline polymer and its composites . In our previous work, the shape memory property of PEBA/PCL blends and the corresponding microstructure evolution were studied.…”