Heating Rate Sensitive Multi-Shape Memory Polypropylene: A Predictive Material

Abstract

Here we report on a novel type of smart material that is capable of specifically responding to the changing rate of an environmental signal. This is shown on the example of lightly cross-linked syndiotactic polypropylene that reacts to a temperature increase by adapting its shape change according to the applied heating rate. In general, a material with such properties can be used to predict a system failure when used in a defined environment and is therefore called "predictive material".

Polydopamine Particles Reinforced Poly(vinyl alcohol) Hydrogel with NIR Light Triggered Shape Memory and Self‐Healing Capability

“…Among them, shape memory and self‐healing biocompatible hydrogel attracts much attention due to its biological applications, such as tissue engineering, arthrodial cartilage, and artificial skin . In such a hydrogel, a 3D physically or chemically cross‐linked network is required to maintain the permanent shape, while the fixing of temporary shape generally can be achieved by phase transition temperature T tr (glass transition temperature T g or melting temperature T m ) . Previously, we reported a melamine‐enhanced poly(vinyl alcohol) physical hydrogel and a double‐network polymer hydrogel composed of chemically cross‐linked poly(ethylene glycol) (PEG) and physically cross‐linked poly(vinyl alcohol) (PVA) with shape memory and self‐healing capability, respectively .…”

“…[4][5][6][7][8][9][10][11] In such a hydrogel, a 3D physically or chemically cross-linked network is required to maintain the permanent shape, while the fixing of temporary shape generally can be achieved by phase transition temperature T tr (glass transition temperature T g or melting temperature T m ). [12][13][14][15][16][17] Previously, we reported a melamine-enhanced poly(vinyl alcohol) physical hydrogel and a double-network polymer hydrogel composed of chemically cross-linked poly(ethylene glycol) (PEG) and physically cross-linked poly(vinyl alcohol) (PVA) with shape memory and self-healing capability, respectively. [18,19] In both systems, the temporary shape can be processed by deformation at room temperature and fixed by the Among them, the construction of the second network is widely used to improve the mechanical properties of the hydrogel.…”

Crosslinking of Semiaromatic Polyesters toward High‐Temperature Shape Memory Polymers with Full Recovery

“…Actually, they are capable of exceeding by far well‐established SMAs. Examples are diverse trigger options (heat, pH, chemicals, mechanical stress, UV/IR, electric/magnetic fields), tunable trigger temperatures, narrow trigger ranges, cold programmability, extremely large stored strains, multishape memory, shape memory‐assisted self‐healing, and even heating rate sensitivity . However, the trigger temperatures of most SMPs are considerably lower compared to those of SMAs, which are known for trigger temperatures of more than 700 °C .…”

“…Examples are diverse trigger options (heat, [1][2][3][4][5] pH, [6,7] chemicals, [8][9][10][11] mechanical stress, [12,13] UV/IR, [6,14] electric/magnetic fields [15,16] ), tunable trigger temperatures, [17][18][19] narrow trigger ranges, [20,21] cold programmability, [22] extremely large stored strains, [23,24] multishape memory, [25] shape memory-assisted self-healing, [26,27] and even heating rate sensitivity. [28] However, the trigger temperatures of most SMPs are considerably lower compared to those of SMAs, which are known for trigger temperatures of more than 700 °C. [29] Up to now there are only a few SMPs that exceed a trigger temperature of 200 °C, such as metal salts of sulfonated poly(ether ether ketone), [30,31] polyimides, [32][33][34][35][36][37] polyimide ionomers, [38] and polyester/poly(ester imide) copolymers, [39] but most SMPs exhibit low storable strains (<100%), poor recovery ratios (<80%), or broad trigger temperature ranges (>50 °C).…”

Shock‐ and Energy‐Absorption Capability of Cold‐Programmable Shape Memory Polymers

“…Cold‐programmable shape memory polymers (SMPs) like shape memory natural rubber (SMNR) and lightly cross‐linked syndiotactic polypropylene (x‐sPP) might be promising candidates for mimicking the properties of spider dragline silk. This is due to the crystallization‐inhibition of these polymers and that they transform themselves from a fully amorphous, rubber‐like into a semicrystalline, high modulus state upon stretching to large elongations and retain the latter after removing the stretching force.…”