4 research outputs found
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
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 cross-linked ENR phase
exhibits a continuous net-like structure embedded in the PLA phase,
which is different from a conventional plastic/rubber system having
the typical “sea–island” morphology in which
vulcanized rubber particles were 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 the PLA phase: cross-linked 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
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
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 cross-linked ENR phase
exhibits a continuous net-like structure embedded in the PLA phase,
which is different from a conventional plastic/rubber system having
the typical “sea–island” morphology in which
vulcanized rubber particles were 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 the PLA phase: cross-linked 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
Fully Biobased Shape Memory Material Based on Novel Cocontinuous Structure in Poly(Lactic Acid)/Natural Rubber TPVs Fabricated via Peroxide-Induced Dynamic Vulcanization and in Situ Interfacial Compatibilization
Shape
memory polymers (SMPs) based on fully biobased poly(lactide) (PLA)/natural
rubber (NR) thermoplastic vulcanizates (TPVs) were fabricated via
peroxide-induced dynamic vulcanization. Simultaneously, in situ reactive
compatibilization was achieved by PLA molecule grafting onto NR chains.
Differing from the general concept of spherical rubber particles being
formed after dynamic vulcanization, the cross-linked NR was found
to be a “netlike” continuous phase in the PLA matrix.
This novel structure explained the surprising shape memory property
of PLA/NR TPVs well (shape fixities ∼ 100%, shape recoveries
> 95%, and fast recovery speed < 15 s at the switching temperature,
∼60 °C): the cross-linked NR continuous phase offers strong
resilience and the PLA phase serves as the heat-control switch. We
envision that the “green” raw materials and excellent
shape memory properties of the dynamically vulcanized PLA/NR SMPs
will open up a wide range of potential applications in intelligent
medical devices
Additional file 2: of Perfectly matched 20-nucleotide guide RNA sequences enable robust genome editing using high-fidelity SpCas9 nucleases
Rice codon optimized DNA sequences of WT Cas9, eSpCas9(1.0), eSpCas9(1.1), and SpCas9-HF1. (PDF 296 kb