Bio‐Based, Self‐CrosslinkableEucommia ulmoidesGum/Silica Hybrids with Body Temperature Triggering Shape Memory Capability

Abstract

At present, the synthesis of body temperature triggering shape memory polymers usually requires elaborate structural design, which limits their wide application. Herein, starting from bio-based Eucommia ulmoides gum (EUG), a series of EUG/silica hybrids (ESHs) are prepared through a facile one-pot process, in which EUG is epoxied and then self-crosslinked with SiO 2 by epoxy ring-open reaction. Varying the amount of H 2 O 2 , the shape memory transition temperature (T trans ) of ESHs is adjusted to 47.4-36.6 °C, which is close to human body temperature (37 °C). Among them, ESH-17 exhibited the best body temperature triggering shape memory ability (T trans = 36.6 °C), which can restore the permanent shape within 60 s at 37 °C with a shape fixity ratio of 99% and shape recovery ratio near 100%. In addition, the shape memory mechanism is discussed and shows some application scenarios of ESHs. The as-produced materials can be used as smart biomaterials such as self-tightening sutures, self-sealing root canal filling materials, and so on.

Inverse Vulcanization Polymer-Modified Eucommia ulmoides Gum with Enhanced Shape Memory Capability and Sound Absorption Property

“…Figure S15 shows the shape memory process of EUG and EUG-SP-x at 40 °C. Compared with other polymer materials (Figure b), ,,,,− EUG-SP-8 and EUG-SP-10 displayed lower thermally induced temperature and shorter shape recovery time, indicating that EUG-SP-x is an ideal potential shape memory material in smart biological materials.…”

“…Additionally, the tensile strength increases from 20.58 to 29.54 MPa due to the self-reinforcing effect of crystallization. 52 With the further increase of SP, the crystallization properties were destroyed because of high crosslinking density, and hence, the tensile strength, elongation at break, toughness, and Young's modulus of EUG-SP-10 all decreased sharply, presenting typical stress− strain curves of rubber, standing for the typical elastomer characteristic.…”

Thermomechanical Energy Converters for Harvesting Thermal Energy: A Review

“…The cPEGDA/W 18 O 49 NW hybrid actuators exhibited stable helical deformation (right-handed and left-handed) by utilizing oriented chain segments of the crystalline polymer and vector sum of shape recovery forces. Qi et al demonstrated shape memory triggered at body temperature (T trans = 36.6°C) in bio-based Eucommia ulmoides gum/silica hybrids, which restored the permanent shape within 60 s at 37°C with a shape fixity ratio of 99% and shape recovery ratio near 100% [59]. However, the main drawback of SMPs remains their low mechanical strength and stiffness and also their recovery is accompanied by small forces.…”

Bioinspired Sustainable Polymer with Stereochemistry-Controllable Thermomechanical Properties

“…EUG and NR possess different properties that are dependent on stereochemistry. Since the higher regularity in trans -configuration, EUG crystallizes quickly at room temperature. − Meanwhile, NR is amorphous, soft, flexible, and elastic. , Based on stereochemistry, we hypothesized that if the cis : trans ratios of EUG could be regulated, new materials with different thermomechanical properties could be prepared, even new elastomers with properties comparable to NR. To modulate the cis : trans ratios, Cunneen et al , attempted to isomerize NR and EUG with sulfur dioxide or thiol acid, but the isomerization process is difficult to control, resulting in poor mechanical properties.…”