The impact of branching architecture of one continuous uncrosslinked phase on properties of classic shape memory semi‐interpenetrating polymer networks (semi‐IPNs) was explored. Crosslinked poly (methyl methacrylate) (PMMA)/star‐shaped polyethylene glycol (PEG) (PMMA/SPEG) semi‐IPNs and PMMA/linear PEG (PMMA/LPEG) semi‐IPNs were synthesized with the same PEG content. Mechanical properties, phase structure, thermal properties, dynamic mechanical properties, and shape memory properties of these two semi‐IPNs systems were compared. Due to the better compatibility of SPEG in the PMMA network, which was derived from little crystallization compared with PMMA/LPEG semi‐IPNs, PMMA/SPEG semi‐IPNs exhibited a combination of large tensile strength and high elongation at break. PMMA/SPEG semi‐IPNs, which had little crystallization exhibited superior shape recovery versus PMMA/LPEG semi‐IPNs, which had more crystallization. Moreover, the higher the crystallinity in PMMA/PEG semi‐IPNs was the worse long‐term temporary shape retention. Based on tube model theory, the high shape recovery capacity of PMMA/SPEG semi‐IPNs is mainly ascribed to the retraction of free PEG arms, which is entropically favorable and thermally activated due to the fluctuations of the path length. This result is supported by stress relaxation analysis and the influence of long shape fixity time on shape fixity ratio for these two systems.

Nickel/carbon nanocomposite films with different C2H2 flow rate were deposited by filtered cathodic vacuum arc (FCVA) device. The composition and nanostructure of the films were investigated by X-ray diffraction (XRD), Raman scattering spectroscopy, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The grain size increase from 8.7 nm at the C2H2 flow rate of 10 sccm to the maximum of 11.5 nm at 30 sccm, after that it decrease. The mean phase separation is in the range of 0.2-2.6 nm. The hardness of 21.6 Gpa was obtained at 50sccm.