最新刊期
卷 55 ， 期 8 ， 2024
- 摘要：Ionizing radiation has a higher tissue penetration depth than ultraviolet, visible and near-infrared light. It can directly reach tissues and organs inside the human body, making it ideal for clinical applications and as a stimulus to induce drug release or activation for diseased sites in deep tissues. Clinical radiotherapy radiation can potentially cause controlled dissociation of chemical bonds, resulting in the release or activation of biologically active compounds. By exploiting the precision of radiation and the potency of chemotherapeutic agents, this approach allows for spatial and temporal control of drug activation or release, thereby greatly reducing systemic cytotoxicity and potential side effects of the drugs. This review summarizes the recent research progress on ionizing radiation triggered drug release or activation. Herein, we highlight innovative strategies, including conventional polymers vesicles and micelles, novel diselenide or tellurium-containing polymers for drug release, and drug activation using organic small molecules that are responsive to the primary radiolysis species such as hydroxyl radical and hydrated electrons. The pros and cons of different strategies, such as clear mechanism of action, low sensitivity of irradiation response, etc., have been described. In addition, future research directions for ionizing radiation-induced drug release strategies are discussed, providing innovative strategies for tumor therapy.关键词：Radiotherapy;Ionizing radiation;Drug carrier;Pro-drug;Drug release
- 452
- |
- 215
- |
- 0
发布时间：2024-08-14 - 摘要：Porous polymers with azobenzene skeleton (Azo-POPs), which possess good chemical stability, high specific surface area, and easy functionalization and modification, have shown great application prospects in a number of fields and attracted much attention. In this review, we firstly sorted out the ways of introducing azobenzene structural elements into porous polymer skeletons in recent years, including the condensation polymerization of polyaminoaromatics and poly(nitroso)aromatics, the oxidative coupling polymerization of polyaminoaromatics, the reductive coupling polymerization of poly(nitroso)aromatics and the coupling polymerization of electron-rich aromatics with polydiazonium salts, etc. It is pointed out that the coupling polymerization of electron-rich aromatic hydrocarbons with polydiazonium salts has mild conditions, high polymerization efficiency and good functional group tolerance. The examples and characteristics of functional Azo-POPs is briefly described. The electron cloud, polar dipole interactions and alkalinity provided by amino or hydroxyl groups in Azo-POPs, can significantly improve the adsorption capacity of porous polymers for metal ions, polar compounds and CO2. Then the paper analyzes and demonstrates the irreversible isomerization of tris(β-hydroxyazo)benzene structure to tris(β-keto-hydrazone)cyclohexane structure, and analyzes and summarizes the applications of Azo-POPs in the fields of gas and vapor adsorption and storage, multiphase catalysis, removal of pollutants in water, gas membrane separation and electrochemistry. Finally, the challenges to the development of Azo-POPs are analyzed and pointed out, and the future development direction and prospect of Azo-POPs are discussed in the light of the existing research reports.关键词：Porous organic polymers;Azo-benzene;Hydroxyl-azobenzene;Amino-azobenzene;Tris(β-keto-hydrozo)cyclohexane
- 471
- |
- 244
- |
- 0
发布时间：2024-08-14
Review
- 摘要：This study focuses on the development of a sustainable and highly sensitive Antheraea pernyi (A. pernyi) silk paper-based electrochemical sensor, utilizing the excellent solvent resistance of silk paper as the substrate and incorporating molybdenum disulfide (MoS2) functional units. The electrochemical sensing principle of this sensor is based on a transpiration-driven electricity generation mechanism. Different solvents interact distinctly with the sensor, resulting in transpiration-driven electrical signals with varying characteristics. Although these electrical signals display complex band-shaped patterns lacking sharp peaks or specific mutation points, they exhibit highly reproducible trends for specific solvent systems. Consequently, this study further employs a feedforward neural network to construct a solvent identification model based on the oak silk fibroin ultrafine paper electrochemical sensor. This model processes and analyzes these complex yet highly repetitive electrical signals. The AI-driven A. pernyi silk paper-based electrochemical sensor not only accurately identifies solvents with highly similar chemical structures and properties, such as methanol, ethanol, isopropanol, and deionized water, but also recognizes chemically similar mixed solvent systems, like varying proportions of ethanol-water mixtures. In 100 identification tests, the accuracy was 100%. The development of this AI-driven A. pernyi silk paper-based electrochemical sensor offers a convenient, cost-effective method for rapid and accurate solvent detection, holding significant implications in fields such as alcohol testing, environmental monitoring, and chemical analysis.关键词：Silk paper;Eutectic solvent;Depolymerization;Electrochemical sensor;Deep learning
- 323
- |
- 198
- |
- 0
发布时间：2024-08-14 - 摘要：Sulfur dispersion is the most common crosslinking agent for latex vulcanization. However, sulfur dispersion is unstable and its preparation process is complex, and toxic zinc-containing accelerators should be used together for effective crosslinking. In recent years, synthesizing sulfur copolymers through inverse vulcanization of elemental sulfur and vinyl monomers has received widespread attention. Herein, self-emulsified sulfur copolymers (STD) were prepared by inverse vulcanization of elemental sulfur, polysorbide 80 and 1,3-diisopropylbenzene. The effect of monomer feed ratio on the structure and yield of STD was studied. According to laser particle size distribution analyzer and scanning electron microscope measurements, STD emulsion could be stably dispersed in water for a long time with an average size of about 80 nm. Further, STD was used as the crosslinking agent for carboxylated nitrile rubber latex, and the influences of STD content and composition on the properties of crosslinked rubber were systematically studied. The results showed that the fractions of sulfur and polysorbate 80 in STD determine the properties of crosslinked rubber by affecting crosslinking density and plasticizing effect, respectively. Compared with sulfur dispersion, STD emulsion is more stable with smaller micelle size and has higher reactivity, which avoids using toxic zinc-containing accelerators and imparts the crosslinked networks with better mechanical properties, thus exploring new avenue for the green crosslinking of rubber latex and the preparation of high-performance rubber materials.关键词：Inverse vulcanization;Rubber latex;Green crosslinking;Sulfur copolymer
- 439
- |
- 135
- |
- 0
发布时间：2024-08-14 - 摘要：This study reported that an efficient and controllable ring-opening polymerization of ω‑pentadecalactone (PDL) by using cyclic trimeric phosphazene base (CTPB) as a catalyst and benzyl alcohol (BnOH) as an initiator. High molecular weight PPDL was obtained after optimizing the experimental conditions. The PPDL film with high molecular weight not only showed similar mechanical properties, crystallinity and high melting point (Tm=95.5 ℃) as polyethylene, but also exhibited the degradability of aliphatic polyesters. Differential scanning calorimetry (DSC) tests proved that PPDL had good crystallinity. Wide-angle X-ray scattering (WAXS) showed that PPDL had a unit cell structure similar to that of commercial high-density polyethylene (HDPE). Moreover, bishydroxyl-end-capped PPDL (PPDL-diol) can be easily prepared via ring opening polymerization (ROP) of PDL with 1,4-benzenedimethanol (BDM) as initiator. Then the PPDLs with high molecular weights were obtained by chain extension reactions with diisocyanates and showed enhanced mechanical properties. In addition, we synthesized a variety of random copolymers with different ratios of PDL to ε-caprolactone (ε-CL). The melting points and hydrolysis of the copolymers could be adjusted by changing the ratio of ε-CL. The melting points of the obtained random copolymers could be adjusted in the range of 53.0-95.5 ℃ by changing the ratio of ε-CL. Finally, the hydrolysis of PPDL copolyester was achieved under alkaline conditions. Compared with PPDL homopolymer, the hydrolysis of random copolymers showed faster hydrolysis rate and adjustability.关键词：Ring-opening polymerization;Organobase;Polyethylene-like polymers;Degradable polyester
- 428
- |
- 119
- |
- 0
发布时间：2024-08-14 - 摘要：This study presents a simple method for obtaining LCE with high degree of substitution (DS>2.5) by directly utilizing microcrystalline cellulose (MCC), trifluoracetic anhydride (TFAA), and long chain lauric acid (LA). The impact of ball milling speed, grinding time, and feeding ratio on substitution, melting behavior, and thermal stability is thoroughly investigated. The results show that with increasing ball milling speed and time, LCE substitution increased and the melting temperature decreased. When the DS is larger than 2.81, LCE can be completely melted. Optimal conditions involve a feed ratio of 1:6:3, and ball milling at 400 r/min for 4 h yields cellulose laurel ester with a flow temperature (Tf) of 115 ℃ and a decomposition temperature of 324 ℃. In addition, the introduction of PVA into the system is explored to mitigate excessive TFAA and the side product trifluoroacetic acid. The results show that PVA not only fixed trifluoroacetic acid successfully but also had little effect on the melting and processing properties of the product. This strategy has significant advantages over conventional homogeneous methods, such as streamlining the preparation process, reducing monomer quantities, shortening reaction time, and promoting environmental friendliness. Its potential application in large-scale industrial production of thermoplastic cellulose derivatives is promising.关键词：Cellulose;Cellulose laurate ester;Mechanochemistry;Heterogeneous reaction
- 277
- |
- 139
- |
- 0
发布时间：2024-08-14 - 摘要：The ring-opening copolymerization of epoxides and cyclic anhydrides constitutes a straightforward route for synthesizing polyesters. The resultant copolymers are mainly obtained with alternating structures, which might limit their application situations due to their low toughness caused by the high density of ester group. It has been demonstrated that the incorporation of ether segments into the mainchain of polyesters is an efficient strategy to tune the thermal and mechanical properties of polyesters, which is greatly limited by the lack of efficient catalyst. In response to these issues, this study proposed to achieve the random copolymerization of cyclohexene oxide (CHO) and phthalic anhydride (PA) to prepare poly(ether-ester)s via the hetero-bimetallic synergistic catalysis strategy. A series of heterodinuclear Al-K complex has been designed for catalyzing the copolymerization of CHO and PA. The structures of the resultant copolymers are confirmed as poly(ether-ester)s using nuclear magnetic resonance spectroscopy and electrospray ionization mass spectrometry. The exploration of the polymerization process further revealed the randomly structure of obtained poly(ether-ester)s, that is, ester and ether segments were randomly distributed in the polymer mainchain. Systemic studies on the effects of ligand structure, metal ions, reaction temperature and catalyst concentration on the copolymerization were explored, indicating that it is the synergistic cooperation between two metal centers that results in the formation of random copolymers. In addition, thermal property characterization of resultant copolymers indicates that the incorporation of polyether segments into polyester could effectively tune their glass transition temperatures, thus enriching the application of polyester materials.关键词：Poly(ester-ether)s;Heterodinuclear metal complex;Ring-opening copolymerization;Random copolymer
- 430
- |
- 122
- |
- 0
发布时间：2024-08-14 - 摘要：Petroleum-based plastics can cause serious environmental problems such as "microplastics", and common biobased plastics are generally expensive and produced by complex processes. It is thus urgent to develop new biobased materials that are inexpensive, simple to prepare, and possess superior properties. In this work, we used agricultural waste straw bark as raw material, and fabricated microfiber films (SC films) with varied thicknesses by simple hot pressing. Then, cellulose-epoxy films (SC-Ep films) were obtained by pressure casting of epoxy resin into microfiber films. Scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FTIR), and ultraviolet-visible spectrophotometer (UV-Vis) were used to characterize SC and composite SC4-Ep1 films. In addition, their mechanical properties, water resistance, thermal stability, organic solvent stability, and barrier property were investigated. The results showed that the optimal film (SC4-Ep1 films) presented a transmittance as high as 87% and outstanding mechanical strength (tensile stress up to 83.4%, Young's modulus 5.41 GPa) that is much higher than those of similar types plastic materials in the literature as well as in the market. In addition, the water vapor transmission rate was significantly reduced by 75.12% from SC4 films) to SC4-Ep1 films composite film, exhibiting superior barrier property. SC4-Ep1 films also displayed excellent stability in water and various organic solvents. This work provides a new approach to the preparation of composite bio-based films as well as bioplastic products.关键词：Cellulose;Epoxy resin;Transparency;Mechanical properties;Biomass Composites
- 241
- |
- 154
- |
- 0
发布时间：2024-08-14 - 摘要：Sodium lignosulfonate (LSS) with good photothermal property and gold nanoparticles (Au NPs) with excellent localized surface plasmon resonance (LSS) were used as raw materials to fabricate LSS/PVA@Au composite films with synergistic photothermal effect through in situ blending strategy. During the preparation process, the functional groups on the LSS structure play an important role in dispersing, stabilizing, chelating and reducing Au3+. The existence of Au NPs makes the surface of the LSS/PVA@Au composite film rougher, with an average roughness of 30.3 nm, which also endows its stronger and wider absorption in the ultraviolet to near infrared region. The increase of LSS content is beneficial to the enhancement of photothermal property of the LSS/PVA composite material. The maximum temperature of the LSS50/PVA50 composite film can reach (120.6±3.1) ℃ with thermal conversion efficiency of 27.61% under standard 5 sun irradiation. Benefiting from the synergistic photothermal effect of Au NPs, the highest temperature of (190.1±3.5) ℃ can be attained for LSS50/PVA50@Au1 composite film with thermal conversion efficiency of 42.47%. A thermoelectric generator are powered by LSS50/PVA50 and LSS50/PVA50@Au1 composite films successfully, which can convert the heat absorbed into electric energy. The maximum voltage generated by LSS50/PVA50@Au1 is (280.8±4.6) mV and the corresponding current is (48.9±1.9) mA under standard 5 sun irradiation. Due to the good photo-responsiveness to near infrared light (NIR), the LSS50/PVA50@Au1 composite film also show satisfactory photothermal antibacterial performance. After 10 min irradiation of 1.47 W NIR, the antibacterial rates of E.coil and S.aureus can reach 99.5% and 99.2%, respectively. In summary, through a simple, green, and efficient composite blending strategy, abundant solar energy resources can be utilized effectively through the synergistic photothermal effect of LSS and Au NPs. Considering the satisfactory effective antibacterial activity of the LSS50/PVA50@Au1 composite, this work may provide perspectives on the design of green photothermal antibacterial materials via pulp and paper industry waste lignin sulfonate as well as contributes to the enrichment of linin structure and chemistry.关键词：Sodium lignin sulfonate;gold nanoparticles;Photothermal effect;Photothermal-antibacterial
- 296
- |
- 319
- |
- 0
发布时间：2024-08-14 -
Preparation and Research of Polyurethane Based Anti-icing Coating Based on Different Young's Modulus
摘要：Using 4,4'-diphenylmethane diisocyanate (MDI) and polytetrahydrofuran ether diol (PTMEG) as precursors, a one-component wet-cured polyurethane elastomer (PUE) coating with tunable Young's modulus (0.72-5.95 MPa) was synthesized by manipulating the R value. The effect of Young's modulus of coating on ice adhesion strength was studied by comparing polyether diols with different molecular weights. The results show that higher molecular weight series of polyether diols exhibit lower ice adhesion strength (average 57.71 kPa). As the Young's modulus of the coating increases, the corresponding ice adhesion strength initially rises and then declines. The analysis reveals that the surface of the coating with low Young's modulus (for example, PTMEG-1000 as the soft segment, 1.05-2.96 MPa) is easily deformed during water icing expansion, forming uneven structures and providing more adhesion points for the ice structure to adhere, which makes the ice adhesion strength closely related to the surface energy, resulting in the possibility of increasing the ice adhesion strength. However, the decrease interval of ice adhesion strength in coatings with higher Young's modulus (for example, PTMEG-1000 as the soft segment, 2.96-5.95 MPa) is not consistent with the positive correlation between Young's modulus and ice adhesion strength. This is due to the effect of low temperature resilience, the elastic mismatch between the ice and the coating induces micro-cracks and cavitation of the ice-coating interface, resulting in the possibility of reducing the ice adhesion strength. Therefore, understanding how coating's Young's modulus affects ice adhesion can be effectively utilized to reduce such adhesive properties.关键词：Polyurethane elastomer;Young's modulus;Ice adhesion strength;Mechanical property- 279
- |
- 187
- |
- 0
发布时间：2024-08-14 - 摘要：It is a desirable method to develop high energy density supercapacitors without sacrificing power density to prepare electrode materials with both capacitance and battery characteristics by the modification of conductive conjugated polymers. In this study, the intermolecular force is strengthened by electron-withdrawing groups to improve the charge transfer performance of materials, improve the cyclic stability of electrode materials and make them have higher energy density and power density. We use liquid-phase treatment to treat CC and in situ oxidation polymerization to polymerize three D-A type conductive conjugated polymers on the surface of CC with 2,3-dichloro-5,6-dicyano-p-benzoquinone as the acceptor and 3,3-dimethylbenzidine, 3,3-dimethoxybenzidine and 3,3-dihydroxybenzidine as the donors. We studied the capacitance characteristics of three flexible composite electrodes. The P2/CC electrode material with a donor end of 3,3-dimethoxybenzidine exhibits fast electrochemical kinetics characteristics in the range of less than 70 mV·s-1, its discharge specific capacitance reaches 686.27 F·g-1 at a current density of 0.5 A·g-1, and the retention rate of the specific capacitance after 5000 charge discharge cycles is 99.70%. The composite electrode also achieved an energy density of 50.66 Wh·kg-1 at an ultra-high power density of 497.46 W·kg-1. The organic-inorganic synergistic effect between conductive conjugated polymers and CC helps to improve the conductivity and stability of electrodes, and the pseudocapacitive charge storage behavior of conductive conjugated polymers enhances the discharge specific capacity. The preparation of flexible composite electrodes provides a favorable reference for the low-cost development of new electrode materials with high energy density and power density to further improve the performance of supercapacitors.关键词：D-A type conductive polymer;Carbon cloth;Flexible electrodes;High energy density;High power density
- 313
- |
- 249
- |
- 0
发布时间：2024-08-14 - 摘要：An intumescent fireproof sealing system with room temperature vulcanized silicone rubber (SR) as matrix, sodium silicate (NSH) as expansion filler and ammonium polyphosphate (APP) as flame retardant was designed, and the effects of different modulus expansion agents on the properties of the material were investigated. The SR composites were prepared via blending pouring method. The thermal stability and flame retardancy of SR composites were measured by vertical burning test (UL-94), limiting oxygen index (LOI) and thermogravimetric analysis (TGA). Moreover, the important indexes of the sealing material were characterized by expansion test and fire resistance test. The morphology of char residues after UL-94 test and fire resistance test were observed by scanning electron microscopy (SEM). The results showed that the high modulus sodium silicate had better thermal expansion effect, and the 2.8 modulus sodium silicate had the best expansion fireproof performance. The sample with only expansive agent had no grade in the flame-retardant test, but by adding a small amount of flame retardant, the limiting oxygen index increased to 30.9%, and passed the UL-94 test V-0 grade. The study of mechanism found that the outer layer of the material was transformed into a thin-walled hollow microsphere stacking structure when exposed to fire, forming a strong expansion barrier layer. Concomitantly, the expansion barrier layer efficiently exerts the gas phase flame retardant effect of the flame retardant. In addition, the prepared sample can reach the 3 h level of fire sealing test for cracks.关键词：Sealing Material;Room Temperature Vulcanized Silicone Rubber;Ammonium polyphosphate;Sodium Silicat
- 459
- |
- 243
- |
- 0
发布时间：2024-08-14 - 摘要：Biomimetic construction of extracellular microenvironment with dynamic viscoelastic behavior is an important strategy for the design of extracellular matrix (ECM) in tissue engineering. In this study, a poly(vinyl alcohol) (PVA)/cellulose nanofiber (CNF) composite hydrogel with anisotropic structure was constructed through the cooperative strategy of directional freezing (DF) and confined drying and re-swelling (CDR). The prepared composite hydrogel showed the oriented fiber arrangement structure parallel to the directional freezing direction. Rheological experiments showed that PVA/CNF composite hydrogel had anisotropic dynamic modulus (G'∥ = (76.77±1.61) kPa and G'⊥ = (42.93±1.34) kPa; G''∥ = (5.44±0.26) kPa and G''⊥ = (3.71±0.13) kPa). The energy storage modulus (G') and loss modulus (G'') improved with the increase of PVA content in the low frequency and low strain regions, and showed a tendency of increasing and then decreasing with the increase of CNF content. The results of stress relaxation experiments indicated that the composite hydrogel had viscoelastic properties. Therefore, the viscoelastic properties and rules of the composite hydrogel with anisotropic structures summarized in this study have potential applications in guiding the design of tissue-engineered biomimetic ECM and its effect on cell biological behavior.关键词：Anisotropy;Composite hydrogel;Extracellular matrix;Rheological behavior;Stress relaxation
- 375
- |
- 312
- |
- 0
发布时间：2024-08-14 - 摘要：The frictional behaviors of implant soft materials in vivo are important to medical effect. In this study, hydroxyethyl acrylate sodium/acryloyldimethyl taurate copolymer (EMT-10) aqueous dispersions are adopted, acting as lubricants in hydrophobic polydimethylsiloxane elastomer (PDMS) Gemini interfaces or hydrophilic polyamide hydrogel (PAM) Gemini interfaces, respectively. The associations exist in EMT-10 aqueous dispersions via hydrogen bonding, electrostatic and hydrophobic interactions, similar to bio-lubricants. The EMT-10 aqueous dispersions, surface characteristics of Gemini interfaces and the axial force (Na) during frictional experiments in Stribeck curves are studied. Under low and high concentrations of EMT-10 lubricant, the PDMS Gemini interfaces exhibit opposing sensitivity to Na, different from the PAM Gemini interfaces, which always showing lower CoF at higher Na. This phenomenon results from the various degree of perfection for lubrication film between the Gemini interfaces. To further distinguish the lubrication film formation, and correlate frictional surface characteristic and rheological behaviors of lubricant, a new parameter, relative thickness (φ), is established. When φ<1, the lubrication film is discrete, and the boundary lubrication regime plays dominant role during the frictional test. When φ>1, the entire lubrication film forms and the whole system enters hydrodynamic lubrication regime. For PDMS Gemini interfaces, the lubrication film is composed of the confined and adsorbed EMT-10 polymer chains owing to the strong attraction between the hydrophobic surface and the C－C backbone. As a result, the lubrication film is greatly affected by the concentration of the lubricant thus φ increases. The PDMS frictional system gradually converts from the boundary into hydrodynamic lubrication regime. For PAM Gemini interfaces, the film is made of the hydrogel surface mesh and the confined EMT-10 chains, so φ is always larger than 1, exhibiting the characteristic of hydrodynamic lubrication regime. The study tends to probe the frictional behavior of the complex fluids in the soft Gemini interfaces and unveils the mechanism behind the phenomenon.关键词：Lubrication;Gemini interfaces;Polydimethylsiloxane elastomer;Hydrogel
- 339
- |
- 213
- |
- 0
发布时间：2024-08-14
Research Article
- Postal code：100190
- Tel：010-62588927 Email：gfzxb@iccas.ac.cn
- Technical support is provided by Beijing Founder electronics co., LTD 京ICP备05002797号-8
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0