Biobased Heat-Triggered Shape-Memory Polymers Based on Polylactide/Epoxidized Natural Rubber Blend System Fabricated via Peroxide-Induced Dynamic Vulcanization: Co-continuous Phase Structure, Shape Memory Behavior, and Interfacial Compatibilization

Abstract

A biobased heat-triggered shape memory polymer (HSMP) consisting of polylactide (PLA) and epoxidized natural rubber (ENR) was fabricated by peroxide-induced dynamic vulcanization. The crosslinked ENR phase exhibits a continuous net-like structure embedded in the PLA phase, which is different from conventional plastic/rubber system having typically "sea-island" morphology in which vulcanized rubber particles dispersed in plastic matrix. In-situ interfacial compatibilization was confirmed by FTIR analysis. The shape recovery ratios of the PLA/ENR HSMPs were significantly improved over 90%, compared to that (60~70%) of PLA. The shape fixing and memorizing capability of PLA/ENR HSMPs was realized by the glass transition of PLA phase: crosslinked ENR continuous phase at rubbery state offered strong recovery driving force, improved interface provided effective stress-transferring during shape recovery and PLA continuous phase served as a "control-switch" for recovery. The biobased PLA/ENR HSMP could serve as a promising alternative to the traditional materials for intelligent biomedical devices.

Thermo‐mechanical and shape memory behavior of TPU/ABS/MWCNTs nanocomposites compatibilized with ABS‐g‐MAH

“…Considering the fact that blends of TPU and ABS are immiscible, introduction of ABS‐g‐MAH as a compatibilizer can seriously affect shape memory behavior of the blends. Presence of ABS‐g‐MAH improves interfacial adhesion between TPU and ABS evidently, which affects stress‐transferring throughout the shape recovery .…”

Preparation and properties of novel fluorosilicone thermoplastic vulcanizate with cross‐linking–controlled core‐shell structure

“…Recently, a novel morphology structure in dynamically vulcanized TPVs was reported by Chen et al They found that the cross‐linked rubber phase exhibited a continuous net‐like structure in dynamically vulcanized PLA/NR and PLA/ENR systems . A cocontinuous structure was formed, which was beneficial to obtain outstanding shape memory effect …”

“…6,7 The effective way to prepare TPVs is through dynamical vulcanization, [8][9][10] which is the process of cross-linking an elastomer during its melt mixing with a molten plastic under dynamic condition. 11,12 A significant number of TPVs are produced through this method, such as polylactide (PLA)/natural rubber (NR), 13,14 PLA/epoxidized natural rubber (ENR), [15][16][17] PLA/nitrile butadiene rubber (NBR), 18 poly(vinylidene fluoride) (PVDF)/acrylic rubber (ACM), 19 ethylene-propylene-diene monomer (EPDM)/polypropylene (PP), [20][21][22][23] PVDF/ENR, 24 polyamide 12 (PA12)/hydrogenated acrylonitrile butadiene rubber (HNBR), 25 and ethylene octene copolymer (EOC)/poly dimethyl siloxane (PDMS) rubber. 26 The properties of TPVs strongly depended on the final morphology, which were affected by many factors, such as the cross-linking degree of the rubber phase, composition, viscosity and elasticity of individual components, preparation method, and processing condition.…”

“…16,32 A cocontinuous structure was formed, which was beneficial to obtain outstanding shape memory effect. 17,33 In the previous work, tertiary blends based on PVDF, silicone rubber (SR), and fluororubber (FKM) were prepared. The cross-linked SR was encapsulated by the cross-linked FKM and formed a core-shell particle structure.…”

A triple‐shape memory material fabricated by in situ crosslinking of poly(butylene adipate‐co‐terephthalate)/ε‐polycaprolactone via electron‐beam irradiation and its triple‐shape memory effects

“…SMPs gain a rising attentions from both scientific and technological fields with the requirements for more diverse and intelligent demands. Stimuli manner evolved from the direct heating to remote heating like light, magnetism, and electricity, from thermal manner to athermal manners, physical manner, and chemical manner and so on, dramatically promoting the applications of SMPs. However, the traditional thermal products can memorize just two shapes, namely, dual‐SMPs (DSMPs) and the programmed shape varies only in one‐way model from "B → A", neither more temporary shapes nor the two‐way model "A ↔ B" upon cyclic stimulus are expected for traditional DSMPs.…”