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A novel thermal-induced shape memory polymer was synthesized by copolymerization of a new kind of epoxy resin-polybutadiene epoxy (PBEP), bisphenol A-type cyanate ester (BACE), and polysebacic polyanhydride (PSPA) with different mass ratios. Fourier transform infrared spectroscopy (FTIR), bending test, dynamic mechanical analysis (DMA), and shape memory property were investigated systematically. It was found that the PSPA significantly enhanced the bending strength and flexural modulus. The DMA results showed that the glass transition temperature reduced with increasing content of PSPA. Furthermore, the shape memory tests proved that the copolymer possessed excellent shape memory properties. The shape recovery time decreased with increasing content of PSPA and temperature. The shape memory rate increased as the PSPA content increased. The shape recovery ratio decreased with increasing cycle times. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42045.

The sensitizing effects of polyfunctional poly(ester acrylate) on the radiation crosslinking of polycaprolactone (PCL) were studied. The influences of the use of the polyfunctional material, the number of functional groups, and the radiation dose on the radiation crosslinking, dynamic mechanical properties, and shape-memory behaviors of PCL, respectively, were investigated. The radiation crosslinking of PCL, under the conditions in which the polyfunctional material was applied, did not follow the classic Charlesby–Pinner equation but instead followed the Chen–Liu–Tang relation. The efficiency of the radiation crosslinking of PCL was distinctly improved with the polyfunctional material. The greater the usage and functional group number were, the greater gel content and the more distinctive the radiation-crosslinking effects were. This also indicated that the polyfunctional material directly participated in the crosslinking reaction. Dynamic mechanical analysis indicated that enhanced radiation crosslinking better raised the heat deformation temperature of PCL and presented a higher and wider rubbery-state plateau; it also produced greater strength at temperatures higher than the melting temperature and provided greater force for recovering the deformation than pure PCL. The shape-memory results revealed that sensitizing crosslinked PCL presented 100% recoverable deformation and a quicker recovery rate. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 634–639, 2005

Poly(ϵ-caprolactone) (PCL) with different molecular weight were crosslinked by γ-radiation. The radiation crosslinking features were analyzed by Soxhlet extraction with toluene and the Charlesby–Pinner equation. The crosslinking degree is relative to molecular weight and radiation dose; the relation between sol fraction and dose follows the Charlesby–Pinner equation. All the samples were crystalline at room temperature, and the radiation crosslinking had a little effect on the crystallinity and the melting behavior of PCL. The shape-memory results indicated that only those specimens that had a sufficiently high crosslinking degree (gel content is higher than about 10%) were able to show the typical shape-memory effect, a large recoverable strain, and a high final recovery rate. The response temperature of the recovery effect (about 55°C) was related to the melting point of the samples. The PCL shape-memory polymer was characterized by its low recovery temperature and large recovery deformation that resulted from the aliphatic polyester chain of PCL. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1589–1595, 2003

A novel biodegradable magnetic-sensitive shape memory poly(ɛ-caprolactone) nanocomposites, which were crosslinked with functionalized Fe3O4 magnetic nanoparticles (MNPs), were synthesized via in situ polymerization method. Fe3O4 MNPs pretreated with γ-(methacryloyloxy) propyl trimethoxy silane (KH570) were used as crosslinking agents. Because of the crosslinking of functionalized Fe3O4 MNPs with poly(ɛ-caprolactone) prepolymer, the properties of the nanocomposites with different content of functionalized Fe3O4 MNPs, especially the mechanical properties, were significantly improved. The nanocomposites also showed excellent shape memory properties in both 60 °C hot water and alternating magnetic field (f = 60, 90 kHz, H = 38.7, 59.8 kA m−1). In hot water bath, all the samples had shape recovery rate (Rr) higher than 98% and shape fixed rate (Rf) nearly 100%. In alternating magnetic field, the Rr of composites was over 85% with the highest at 95.3%. In addition, the nanocomposites also have good biodegradability. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45652.