查找使用阿拉丁产品的科研文献

A novel hyperbranched poly(phosphorodiamidate) with high expansion degree and carbonization efficiency used for improving flame retardancy of APP/PP composites

Xinming Ye,Yuanhang Wang,Zhilei Zhao,Hong Yan

A novel P-N containing hyperbranched poly(phosphorodiamidate) (HBPPDA) was synthesized by the A 2 +B 3 polymerization, which had high thermal stability, with greater than 40 wt% of the char residue left at 750 °C. The benzene and triazine rings in HBPPDA contributed to a good char-forming capacity. Furthermore, a large number of terminal primary amines could release incombustible gases to dilute the concentration of oxygen. Thus, HBPPDA could act as blowing agent and carbonization agent simultaneously. Only 6.25 wt% of HBPPDA could greatly enhance the flame-retarding efficiency of ammonium polyphosphate (APP), showing a remarkable synergy to improve flame retardancy and dripping resistance of polypropylene (PP). When 25 wt% of flame retardant (APP:HBPPDA = 3:1) were added into PP matrix, the composite achieved V0 rating for UL-94 test, and its limiting oxygen index (LOI) value was increased to 30.6%. The reduction of 76.2% and 41.5% were available for the peak heat release rate (PHRR) and the total heat release (THR). Meanwhile, the composite showed strong smoke suppression.

Synergistic Enhancement of Antibacterial and Osteo-Immunomodulatory Activities of Titanium Implants via Dual-Responsive Multifunctional Surfaces

Qing Wang,Ya Gao,Yanzheng Chen,Xuan Wang,Qingguo Pei,Taiyu Zhang,Changping Wang,Jinsong Pan

Bone implant-associated infections and inflammations, primarily caused by bacteria colonization, frequently result in unsuccessful procedures and pose significant health risks to patients. To mitigate these challenges, the development of engineered implants with spatiotemporal regulation capabilities, designed to inhibit bacterial survival and modulate immune responses in the early stage, while promoting bone defect healing in the late stage is proposed. The implants are functionalized with ε-poly-l-lysine-phenylboronic acid (PP) via dynamic boronic ester bonds, which facilitate its release through a reactive oxygen species (ROS) and pH-responsive strategy, thereby establishing an antibacterial microenvironment on and around the implants. Additionally, the dynamic metal coordination interaction facilitates the loading and sustained release of Sr 2+ under an acidic environment, providing immunomodulatory and osteogenic effects. The ROS/pH-responsive feature, coupled with the implant-bone tissue integration process, affords precise spatiotemporal regulation of the Ti-TA-Sr-PP implants. This strategy represents a promising approach for the preparation of advanced bone implants.

Novel Core–Shell PS-co-PBA@SiO2 Nanoparticles Coated on PP Separator as “Thermal Shutdown Switch” for High Safety Lithium-Ion Batteries

Haiyang Liao,Haiyan Zhang,Gai Qin,Haoqun Hong,Zhenghui Li,Yingxi Lin,Liuqing Li

Thermal runaway is a hazardous behavior of lithium-ion batteries under extreme conditions and is mainly cause for restraint of its commercial applications in development of high-power and high-rate lithium-ion batteries. In this paper, a new dual-functions coating layer fabricated from polystyrene-poly(butyl acrylate) copolymer encapsulated silica nanoparticles as “thermal shutdown switch” with a reasonable shutdown temperature of ≈80 °C is designed and coated on polypropylene separator. The shell polymer owing to its self-adhesion upon glass transition temperature ( T g ) can retard off the Li + conduction between the electrodes, thus prevents cell from thermal runaway, the core nanoparticles protect the separator from significantly thermal shrinkage when the cell temperature keeps going up. Moreover, the coated separator has no negative affection on the normal electrochemical performance of the batteries, thereby implying that this coating layer provides a simple and effective approach to control the safety of commercial lithium-ion batteries by internal self-protecting.

Dual-mode sunlight/darkness driven composite filtration: Highly efficient self-cleaning based on pre-treated PP/Ag@T-ZIF-8 meltblown nonwoven fabrics

Xiaowan Zhao,Qikai Qiao,Yuanqing Li,Aiqin Zhang,Hong Guo,Jing Guo,Haixia Zhang,Jianjun Lu

To address the issue of secondary contamination caused by the lack of antibacterial properties in polypropylene (PP) meltblown nonwoven fabrics while preserving its core filtration performance, this work employed an immersion-ultrasonic method to construct Ag@T-ZIF-8 antibacterial materials with a core-shell structure. Subsequently, PP/Ag@T-ZIF-8-G composite meltblown fibers was prepared via covalent modification and meltblown spinning technology. The systematic characterization of Ag@T-ZIF-8 was conducted in terms of its chemical structure, microstructure, and photocatalytic antibacterial performance. The effects of Ag@T-ZIF-8 on the antibacterial, filtration and comfort properties of the composite melt-blown nonwoven fabrics were investigated, and the enhancement mechanisms of antibacterial and filtration were revealed. The results indicate that Ag@T-ZIF-8 exhibits a uniform core-shell structure with a particle size of 40∼50 nm and a specific surface area of 531.83 m²/g. At an antibacterial concentration of 200 mg/L, it achieves a 99.99% antibacterial rate against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) within 8 min in the dark or 4 min under illumination. Compared with PP meltblown nonwoven fabrics, it demonstrates 73.31% in filtration efficiency for particles with a pressure drop of only 37.3 Pa. When Ag@T-ZIF-8 loading reaches 1 wt%, the composite meltblown fabrics completely eliminates E. coli and S. aureus after 160 min of illumination or 240 min in the dark. This outstanding comprehensive filtration performance stems from a synergistic filtration mechanism combining mechanical filtration, ionic adsorption, and dual-mode antibacterial action under light or dark condition. Integrating superior filtration capabilities, broad-spectrum antibacterial properties, and wear comfort, PP/Ag@T-ZIF-8-G meltblown nonwoven fabrics deliver a highly efficient integrated antibacterial-filtration solution for the medical protective field.

The EPDM/PP TPV Compatibilized by the In Situ Reaction Product of Bio-Based Itaconic Acid and Magnesium Oxide Possessed Shape Memory Performance

Mengmeng Xu,Liheng Chen,Jujie Sun,Long Han,Shiyu Wang,Chengzhong Zong

EPDM/PP TPV compatibilized by the graft reaction of magnesium itaconate on EPDM and PP chains, which was derived from the in situ reaction of magnesium oxide and bio-based itaconic acid, was successfully obtained. The compatibilized EPDM/PP TPV achieved better shape memory performance and mechanical property compared with the TPV without compatibilization. TPV-4 obtained excellent mechanical property, with the tensile strength and elongation at break of 13.8 MPa and 773%. TPVs compatibilized by the graft products of MgIA owned a higher shape recovery ratio of above 85% compared to 72.6% of TPV-0 without compatibilization. The good compatibility on EPDM and PP interphase was beneficial to the stress delivery that resulted in the outstanding shape memory property of the compatibilized TPV. On the other hand, the ionic interaction of the MgIA graft products in the compatibilized TPV could reinforce TPV, which generated better mechanical performance of TPV. The whole shape memory behavior of TPV-6 measured by DMA was clearly presented in the stress–strain-temperature curve, which further demonstrated the good shape memory performance of TPV. The results of SEM image, FTIR analysis, and DMA curve demonstrated the fine compatibility of EPDM and PP phase in the compatibilized TPVs.

A porous and flame-retardant rGO/PPTA modified PP composite separator suitable for high electrochemical performance and excellent security of lithium metal battery

Zewei Zhang,Xiaoqi Song,Ting Yu,Xiping Lei

Thanks to their high energy density, small size, and light weight, lithium-metal batteries have been widely used over an extended period. However, lithium ions cannot be uniformly deposited, and their poor heat resistance hinders the practical application of lithium-metal batteries. Therefore, it is necessary to design a kind of separator with high electrolyte affinity and good heat resistance in order to improve the problem of a commercial separator. In this study, reduced graphene oxide (rGO) and polyphenylene terephthamide (PPTA) were combined in different ratios and coated onto one side of a commercial polypropylene (PP) separator using a feasible coating technique. A comparison of electrolyte absorptivity and flame retardancy revealed that the composite separator exhibited superior properties compared to those of a PP separator. The rGO2/PPTA3@PP separator with hierarchical porosity and flame-retardant properties, exhibited high ion conductivity (0.59 × 10−3 S cm−1) and an improved lithium-ion transfer number (0.57) at room temperature. By using the composite separator in an LiFePO4‖Li battery, the discharge specific capacity could still reach 125.6 mA h g−1 even after 100 cycles under 1C. After undergoing a high–low temperature cycle, the average discharge specific capacity could remain 151 mA h g−1 at 50 °C and 51 mA h g−1 at −10 °C. In addition, after 1100 h cycles in the assembled Li‖Li symmetric battery, no obvious lithium dendrites appeared on the lithium metal surface, indicating that the composite separator could successfully inhibit the growth of lithium dendrites. This study presents a promising approach for the large-scale production of novel composite separators with high electrochemical performance and safety.

Ionic conductivity and cycling stability-enhanced composite separator using hollow halloysite nanotubes constructed on PP nonwoven through polydopamine-induced water-based coating method

Cheng Wang,Guobin Zhu,Yuqin Hu,Jiuxiao Sun,Jing Xu,Luoxin Wang,Hua Wang,Chunzu Cheng

Ceramic-coating separator can meet the safety requirements of high-power battery through its good thermal tolerance, thus raising more attention recently. During preparation, aqueous coating has been considered as an environmentally friendly method. However, there are some drawbacks for direct coating to be tackled including weak bonding strength and too dense structures of coating layer. In this study, porous sodium alginate/halloysite nanotubes coating was constructed on PP nonwoven by polydopamine-induced water-based coating method to give PHS composite separators. Porous structures were produced by the delayed evaporation of nonsolvent N -methyl pyrrolidone (NMP) in coating slurry. These structures together with hollow structures of halloysite nanotubes (HNTs) were confirmed to boost porosity, wettability and ionic conductivity , thus PHS-4 separator with more HNTs introduced endowing battery with superior discharge performance (159.2 mAh g −1 ) at 0.2 C. Because of more space to store electrolyte, when wetted PHS-4 separator was ignited, it could also give self-extinguishing phenomenon at a shorter time. In addition, the pretreatment of polydopamine before aqueous coating and the overlap among HNTs with high aspect ratio were investigated to increase interfacial peeling strength, therefore PHS-4 separator displayed the best cycling stability with discharge capacity retention achieving 99.1%. Clearly, PHS-4 separator will bring prospect for LIB to pursue high performance and environmentally friendliness.

Chinas Unlimited: Making the Imaginaries of China and Chineseness. By Gregory B. Lee. Honolulu: University of Hawai'i Press, 2003. xi, 121 pp. $45.00 (cloth).

Kathleen Erwin

Regulation on dual-interface of core–shell dispersed phases and mechanical properties of PP blends by rotary evaporation-assisted melt grafted EPDM-g-MAH

Biwei Qiu,Pengfei Qi,Zhongjian Qian,Wenhang Fang,Hua Zou,Xiying Huang

In this study, a series of maleic anhydride-grafted ethylene–propylene–diene rubbers (EPDM-g-MAHs) with different grafting degrees were prepared via the rotary evaporation-assisted melt grafting, which could achieve higher grafting rate and smaller gel content than the traditional melt grafting under the same conditions. Morphological observation, thermal analysis, and rheological measurements confirmed that the interfacial compatibility of the core–shell dispersed phases was enhanced by increasing the composition ratio of EPDM-g-MAH/EPDM or the grafting degree of the prepared EPDM-g-MAHs in the polypropylene (PP) blends. A remarkable improvement in toughness and a little loss in strength and modulus were obtained in the PP blends by regulating the dual interfaces of the core–shell dispersed phases. A new insight into the toughening mechanism of core–shell particles was presented in this work. The balance between toughness and strength could be attributed to the strong dual interfacial interaction of the core–shell dispersed phases, thereby effectively transferring stress. In addition to the conventionally internal cavitation in the rubber phase and the shear yielding of the PP matrix triggered by stress-concentrated dispersed phases, expanded stress field, elongated core phases, and increased cavitation that occurred at dual interfaces by debonding were regarded to contribute to the toughening effect.

alan j. k. sanders: historical dictionary of mongolia. (asian/oceanian historical dictionaries, 42.) lxxiii, 419 pp. lanham and oxford: the scarecrow press, 2003. £40.

george lane

A novel poly (4-methyl-1-pentene)/polypropylene (PMP/PP) thin film composite (TFC) artificial lung membrane for enhanced gas transport and excellent hemo-compatibility

Yiwen Wang,Yang Liu,Qiu Han,Haibo Lin,Fu Liu

Extracorporeal membrane oxygenation is a technique that provides short-term supports to the heart and lungs. It removes CO 2 from the blood and provides enough oxygen, which is a huge help in the fight against COVID-19. As the key component, the artificial lung membranes have evolved in three generations including silicon, polypropylene and poly (4-methyl-1-pentene). Herein, we for the first time design and fabricate a novel poly (4-methyl-1-pentene)/polypropylene (PMP/PP) thin film composite (TFC) membrane with the anticoagulant coating composed of poly (sodium 4-styrenesulfonate) and cross-linked poly (vinyl alcohol). Poly (sodium 4-styrenesulfonate) provides sulfonic acid groups to inhibit the coagulant factors (FVIII and FXII), and cross-linked poly (vinyl alcohol) increase the stability of the anticoagulant coating and further improve the hydrophilicity via abundant hydroxyl groups to depress the protein adsorption. Long-term anticoagulant property was demonstrated by whole human blood for 28 days. Blood compatibility was evaluated by hemolysis rate, anticoagulation activity (APTT, TT and PT), complement activation, platelet activation and contact activation. Pure CO 2 , O 2 and N 2 permeation rates were determined to evaluate the mass transfer properties of PMP/PP TFC membranes. Gas permeation results revealed that gas permeation flux increased in the TFC membranes because of the decrease of crystallinity. Overall, the so prepared PMP/PP membrane shows good CO 2 /O 2 selectivity and blood compatibility as novel TFC artificial lung membrane.

A highly hydrophilic cation exchange nonwoven with a further modifiable epoxy group prepared by radiation-induced graft polymerization

Xiao-han Pan,Jian-hua Zu

Novel cation exchange nonwoven PP-g-SSS/GMA containing epoxy and sulfonic groups was successfully prepared via radiation-induced simultaneous grafting polymerization by attaching glycidyl methacrylate (GMA) and styrene sulfonic sodium (SSS) monomers onto nonwoven polypropylene (PP). The ion exchange capacity of the obtained PP-g-SSS/GMA reached more than 1.5 mmol g−1 and the content of the epoxy groups with potential modifiable properties was above 3 mmol g−1. The relative content of the two functional groups could be adjusted via changing the initial monomer concentration ratio. Scanning electron microscope (SEM) images showed that the polymer surface was fully covered with grafts after modification and those amorphous grafts diluted the crystallinity of the matrix, as revealed via differential scanning calorimetry (DSC). Attenuated total reflection spectroscopy (ATR) confirmed the successful grafting of GMA and SSS onto PP nonwovens. Water contact angle measurements showed that the contact angle decreased from 100.94° for the PP matrix to 0° for PP-g-SSS/GMA with a 56% degree of grafting, indicating the outstanding hydrophilicity of PP-g-SSS/GMA upon the introduction of SSS. Besides this, the epoxy groups on PP-g-SSS/GMA could be further modified via reacting them with chemical compounds with selective adsorption groups. Ag(I) adsorption tests proved that PP-g-SSS/GMA@EDA obtained via the ethanediamine (EDA) modification of epoxy groups on PP-g-SSS/GMA shows excellent selectivity towards Ag(I), and the hydrophilicity brought about by sulfonic groups also ensured a fast adsorption rate. The novel cation exchange nonwoven PP-g-SSS/GMA fabric has potential applications in water treatment, as its strong hydrophilicity could speed up the diffusion rates of adsorbed ions, and further functionalization of the epoxy groups could enable it to selectively adsorb ions in aqueous solutions.