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

Preparation of Superelastic, Durable, and Lightweight Composite Foams Based on Multiple Cross-Linked Network Regulated Structures

The polymer material foaming technology plays an important role in energy conservation and emission reduction. However, modulating the structure of rubber/plastic foams to achieve low weight and high resilience is still a challenge. In this paper, ethylene vinyl acetate polymer (EVA)/epoxidized natural rubber (ENR) foams are prepared by chemical foaming kettle compression molding (KCM) with multiple cross-linked network structures consisting of covalent cross-links of EVA–EVA and ENR–ENR and hydrogen-bonded cross-linked networks between hydroxyl and ester groups. As influenced by the hydrogen-bonded cross-linked networks, the cellular restructuring of EVA/ENR foams is no longer limited to changes in the rubber/plastic content. Compared to pure EVA foams, EVA/ENR foams show advantages such as a low weight (13.95 × 1010 cells/density), a higher ductility (3.42 MJ/m3), a higher resilience (50%), and superior durability (more than 200 cycles at 50% compression). Moreover, due to the binding and anchoring effect of the ENR molecular chains, the thermal stability of EVA/ENR foams is greatly enhanced, with an initial decomposition temperature of around 320 °C, compared to that of EVA foams (∼150 °C). Considering the excellent properties of the EVA/ENR foams and the low cost of the KCM, the present strategy proposes an easy-to-industrialize method of fabricating rubber/plastic composite foams with high mechanical properties

Design of Self-Healing Supramolecular Rubbers by Introducing Ionic Cross-Links into Natural Rubber via a Controlled Vulcanization

Introducing ionic associations is one of the most effective approaches to realize a self-healing behavior for rubbers. However, most of commercial rubbers are nonpolar rubbers without now available functional groups to be converted into ionic groups. In this paper, our strategy was based on a controlled peroxide-induced vulcanization to generate massive ionic cross-links via polymerization of zinc dimethacrylate (ZDMA) in natural rubber (NR) and exploited it as a potential self-healable material. We controlled vulcanization process to retard the formation of covalent cross-link network, and successfully generated a reversible supramolecular network mainly constructed by ionic cross-links. Without the restriction of covalent cross-linkings, the NR chains in ionic supramolecular network had good flexibility and mobility. The nature that the ionic cross-links was easily reconstructed and rearranged facilitating the self-healing behavior, thereby enabling a fully cut sample to rejoin and retain to its original properties after a suitable self-healing process at ambient temperature. This study thus demonstrates a feasible approach to impart an ionic association induced self-healing function to commercial rubbers without ionic functional groups

Table1_Investigating the immune mechanism of natural products in the treatment of lung cancer.XLSX

With the deepening of people’s understanding of lung cancer, the research of lung cancer immunotherapy has gradually become the focus of attention. As we all know, the treatment of many diseases relies on the rich sources, complex and varied compositions and wide range of unique biological properties of natural products. Studies have shown that natural products can exert anticancer effects by inducing tumor cell death, inhibiting tumor cell proliferation, and enhancing tumor cell autophagy. More notably, natural products can adjust and strengthen the body’s immune response, which includes enhancing the function of NK cells and promoting the differentiation and proliferation of T lymphocytes. In addition, these natural products may enhance their anticancer effects by affecting inhibitory factors in the immune system, hormone levels, enzymes involved in biotransformation, and modulating other factors in the tumor microenvironment. The importance of natural products in lung cancer immunotherapy should not be underestimated. However, the specific links and correlations between natural products and lung cancer immunity are not clear enough, and further studies are urgently needed to clarify the relationship between the two. In this paper, we will focus on the correlation between natural products and lung cancer immune responses, with a view to providing new research perspectives for immunotherapy of lung cancer.</p

Bio-Based PLA/NR-PMMA/NR Ternary Thermoplastic Vulcanizates with Balanced Stiffness and Toughness: “Soft–Hard” Core–Shell Continuous Rubber Phase, In Situ Compatibilization, and Properties

Stiffness and toughness are two mutually exclusive attributes of polymer materials that contribute to significant improvements in impact strength, usually accompanied by a reduction in tensile strength. In this study, ternary thermoplastic vulcanizates (TPVs) consisting of poly­(lactic acid) (PLA), poly­(methyl methacrylate)-grafted natural rubber (NR-PMMA), and natural rubber (NR) with balanced stiffness and toughness were successfully prepared via peroxide-induced dynamic vulcanization. With 10 wt% of NR and NR-PMMA, the PLA/NR-PMMA/NR ternary TPV displayed an enhanced yield stress of 41.7 MPa (only 38% loss compared to neat PLA) and a significantly higher impact strength of 91.30 kJ/m² (nearly 32 times that of neat PLA). The in situ compatibilization between PLA and rubber phases was confirmed by Fourier transform infrared spectroscopy. Interfacial, rheological, and calorimetric measurements confirmed that the NR was encapsulated by NR-PMMA in the PLA phase. It was found that the flexibility of the “soft” NR core and outer “hard” NR-PMMA shell with excellent PLA/rubber interfacial adhesion are responsible for the super toughness and considerable tensile strength of the PLA/NR-PMMA/NR ternary TPVs

Self-Healing Natural Rubber with Tailorable Mechanical Properties Based on Ionic Supramolecular Hybrid Network

In most cases, the strength of self-healing supramolecular rubber based on noncovalent bonds is in the order of KPa, which is a challenge for their further applications. Incorporation of conventional fillers can effectively enhance the strength of rubbers, but usually accompanied by a sacrifice of self-healing capability due to that the filler system is independent of the reversible supramolecular network. In the present work, in situ reaction of methacrylic acid (MAA) and excess zinc oxide (ZnO) was realized in natural rubber (NR). Ionic cross-links in NR matrix were obtained by limiting the covalent cross-linking of NR molecules and allowing the in situ polymerization of MAA/ZnO. Because of the natural affinity between Zn²⁺ ion-rich domains and ZnO, the residual nano ZnO participated in formation of a reversible ionic supramolecular hybrid network, thus having little obstructions on the reconstruction of ionic cross-links. Meanwhile, the well dispersed residual ZnO could tailor the mechanical properties of NR by changing the MAA/ZnO molar ratios. The present study thus provides a simple method to fabricate a new self-healing NR with tailorable mechanical properties that may have more potential applications

Image_1_Transcription factors NF-YB involved in embryogenesis and hormones responses in Dimocarpus Longan Lour.jpeg

IntroductionNF-YB transcription factor is an important regulatory factor in plant embryonic development.ResultsIn this study, 15 longan NF-YB (DlNF-YB) family genes were systematically identified in the whole genome of longan, and a comprehensive bioinformatics analysis of DlNF-YB family was performed. Comparative transcriptome analysis of DlNF-YBs expression in different tissues, early somatic embryogenesis (SE), and under different light and temperature treatments revealed its specific expression profiles and potential biological functions in longan SE. The qRT-PCR results implied that the expression patterns of DlNF-YBs were different during SE and the zygotic embryo development of longan. Supplementary 2,4-D, NPA, and PP333 in longan EC notably inhibited the expression of DlNF-YBs; ABA, IAA, and GA3 suppressed the expressions of DlNF-YB6 and DlNF-YB9, but IAA and GA3 induced the other DlNF-YBs. Subcellular localization indicated that DlNF-YB6 and DlNF-YB9 were located in the nucleus. Furthermore, verification by the modified 5'RNA Ligase Mediated Rapid Amplification of cDNA Ends (5' RLM-RACE) method demonstrated that DlNF-YB6 was targeted by dlo-miR2118e, and dlo-miR2118e regulated longan somatic embryogenesis (SE) by targeting DlNF-YB6. Compared with CaMV35S- actuated GUS expression, DlNF-YB6 and DlNF-YB9 promoters significantly drove GUS expression. Meanwhile, promoter activities were induced to the highest by GA3 but suppressed by IAA. ABA induced the activities of the promoter of DlNF-YB9, whereas it inhibited the promoter of DlNF-YB6.DiscussionHence, DlNF-YB might play a prominent role in longan somatic and zygotic embryo development, and it is involved in complex plant hormones signaling pathways.</p

Table_1_Transcription factors NF-YB involved in embryogenesis and hormones responses in Dimocarpus Longan Lour.docx

IntroductionNF-YB transcription factor is an important regulatory factor in plant embryonic development.ResultsIn this study, 15 longan NF-YB (DlNF-YB) family genes were systematically identified in the whole genome of longan, and a comprehensive bioinformatics analysis of DlNF-YB family was performed. Comparative transcriptome analysis of DlNF-YBs expression in different tissues, early somatic embryogenesis (SE), and under different light and temperature treatments revealed its specific expression profiles and potential biological functions in longan SE. The qRT-PCR results implied that the expression patterns of DlNF-YBs were different during SE and the zygotic embryo development of longan. Supplementary 2,4-D, NPA, and PP333 in longan EC notably inhibited the expression of DlNF-YBs; ABA, IAA, and GA3 suppressed the expressions of DlNF-YB6 and DlNF-YB9, but IAA and GA3 induced the other DlNF-YBs. Subcellular localization indicated that DlNF-YB6 and DlNF-YB9 were located in the nucleus. Furthermore, verification by the modified 5'RNA Ligase Mediated Rapid Amplification of cDNA Ends (5' RLM-RACE) method demonstrated that DlNF-YB6 was targeted by dlo-miR2118e, and dlo-miR2118e regulated longan somatic embryogenesis (SE) by targeting DlNF-YB6. Compared with CaMV35S- actuated GUS expression, DlNF-YB6 and DlNF-YB9 promoters significantly drove GUS expression. Meanwhile, promoter activities were induced to the highest by GA3 but suppressed by IAA. ABA induced the activities of the promoter of DlNF-YB9, whereas it inhibited the promoter of DlNF-YB6.DiscussionHence, DlNF-YB might play a prominent role in longan somatic and zygotic embryo development, and it is involved in complex plant hormones signaling pathways.</p