Biphenyl Containing Shape Memory Epoxy Resin with Post‐heating Adjustable Properties

Shape memory epoxy resin (SMEP) with tailorable properties has gained wide attention. Herein, a series of photocured diphenyl epoxy with excellent shape memory effects, based on the epoxy monomer diglycidyl ether of biphenyl (DGEBP) and M‐xylylenediamine (MXDA), is fabricated. Fourier transform infrared spectrometer (FTIR) is used to verify the mix‐curing process. Differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), polarized light microscope (POM), and X‐ray diffraction (XRD) are applied to analyze the microstructure of the film. The molar ratio of the raw material and the post‐heating could tune the crosslinking density, which allows the prepared epoxy resin to present a tailorable shape memory effect. Besides, this epoxy resin exhibits an excellent triple‐shape memory effect due to the wide transition temperature. It is worth of noting that post‐heating induced the self‐assembly of biphenyl unit of the lamellar structure due to π–π interactions that causes an adjustable shape memory effect. This work offers a novel SMEP with potential application in the thermal history trace field. Biphenyl epoxy resin is prepared by the mixing and curing of aromatic amine and photoinitiator. Due to the fast‐curing process and the biphenyl mesogen, post‐heating can induce self‐assembly of biphenyl units to lamellar structures due to π–π interactions. The layered structure plays the role of additional physical crosslinking netpoints to adjust the shape memory properties of BPEP.