Multiple shape memory effects of trans‐1,4‐polyisoprene and low‐density polyethylene blends

Abstract

A novel series of shape memory blends of trans‐1,4‐polyisoprene (TPI) and low‐density polyethylene (LDPE) were prepared using a simple physical blending method. The mechanical, thermal and shape memory properties of the blends were studied and schemes proposed to explain their dual and triple shape memory behaviors. It was found that the microstructures played an important role in the shape memory process. In TPI/LDPE blends, both the TPI crosslinking network and LDPE crystalline regions could work as fixed domains, while crystalline regions of LDPE or TPI could act as reversible domains. The shape memory behaviors were determined by the components of the fixed and reversible domains. When the blend ratio of TPI/LDPE was 50/50, the blends showed excellent dual and triple shape memory properties with both high shape fixity ratio and shape recovery ratio. © 2017 Society of Chemical Industry

A modified phase‐based constitutive model for shape memory polymers

“…The following assumptions about the evolution of the enthalpy H during the isothermal relaxation process are made. First, during the heating process, the isothermal relaxation is considered as a series of n independent processes and the rate of enthalpy H i change is associated with a time and temperature dependent relaxation time i such that 5) wileyonlinelibrary.com/journal/pi where H ei is the equilibrium value of enthalpy at the present temperature.…”

“…Compared to shape memory ceramics and shape memory alloys, SMPs have many special advantages, e.g. low density, low cost, easily tailored properties and large deformation recovery capacity . These novel properties have drawn increasing attention for utilizing SMPs in many potential applications, such as deployable structures, biomedical devices, smart textiles and self‐healing composite systems …”

“…low density, low cost, easily tailored properties and large deformation recovery capacity. 5,6 These novel properties have drawn increasing attention for utilizing SMPs in many potential applications, such as deployable structures, biomedical devices, smart textiles and self-healing composite systems. [7][8][9][10][11][12][13] SMPs triggered by temperature are known as possessing a thermally induced shape memory effect.…”

Shape memory behavior of carbon nanotube‐reinforced trans‐1,4‐polyisoprene and low‐density polyethylene composites

“…trans ‐1,4‐Polyisoprene (TPI) and polyethylene (PE) could be used as shape memory materials with a moderate degree of cross‐linking. The shape memory properties of TPI, PE, and their blends have been investigated in recent years . However, the disadvantage of most shape memory composites is their poor mechanical properties, and TPI and PE composites are no exception.…”

“…The shape memory properties of TPI, PE, and their blends have been investigated in recent years. [27][28][29][30][31] However, the disadvantage of most shape memory composites is their poor mechanical properties, and TPI and PE composites are no exception. Inorganic fillers are ideal candidate materials with which to improve the mechanical strength of SMPs.…”