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1.
Complexation of palladium(II) acetate [Pd(OAc)2] or dipotassium tetrachloropalladate [K2PdCl4] to “click” polymers functionalized with phenyl, ferrocenyl and sodium sulfonate groups gave polymeric palladium(II)‐triazolyl complexes that were reduced to “click” polymer‐stabilized palladium nanoparticles (PdNPs). Transmission electron microscopy (TEM) showed that reduction using sodium borohydride (NaBH4) produced PdNPs in the 1–3 nm range of diameters depending on the nature of the functional group, whereas slow reduction using methanol yielded PdNPs in the 22–25 nm range. The most active of these PdNPs (0.01% mol Pd), stabilized by poly(ferrocenyltriazolylmethyl)styrene, catalyzed the hydrogenation of styrene at 25 °C and 1 atm hydrogen, with turnover numbers (TONs) of 200,000. When stabilized by the water‐soluble poly(sodium sulfonate‐triazolylmethyl)styrene, the PdNPs (0.01% mol Pd) catalyze the Suzuki–Miyaura coupling between iodobenzene (PhI) and phenylboronic acid [PhB(OH)2] in water/ethanol (H2O/EtOH) at 25 °C with TONs of 8,200. This high catalytic activity is comparable to that obtained with “click” dendrimer‐stabilized PdNPs under ambient conditions.  相似文献   

2.
A novel polyurethane material containing zwitterionic sulfobetaine groups has been synthesized using the copper‐catalyzed 1,3‐dipolar cycloaddition (azide‐alkyne click chemistry). A standard two‐step polyaddition method was used to produce the well‐defined polyurethane based on polycarbonatediol (PCDL) with alkyne groups. These polyurethanes containing alkyne units were then efficiently clicked using 3‐((2‐azidoethyl)dimethylammonio)propane‐1‐sulfonate (DMPS‐N3). The novel PU material was characterized by 1H NMR, Fourier transform infrared (FTIR) spectrometer, gel permeation chromatography (GPC), elemental analysis, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). This facile “click” reaction provides a useful tool for the development of novel functional polyurethanes for biomedical applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

3.
Water‐soluble 1,2,3‐triazolyl dendrimers were synthesized by “click chemistry” and used to stabilize palladium nanoparticles (PdNPs). These new “click” dendrimer‐stabilized nanoparticles (DSN) are highly stable to air and moisture and are catalytically active for olefin hydrogenation and Suzuki coupling reaction, in aqueous media, under ambient conditions using a low amount of palladium (0.01 mol% Pd). Kinetic studies show high catalytic efficiency and high stability for the new “click” DSN in both reactions. The complexation of potassium tetrachloropalladate (K2PdCl4) to the triazole ligands present in the dendritic structures was monitored by UV/vis and, after reduction, the nanoparticles were characterized by transmission electron microscopy (TEM).  相似文献   

4.
A special “pore/bead” membrane was prepared with a mesoporous inorganic filler (MCM‐41) and a P(VDF‐HFP) binder. The special “pore/bead” structure of the MCM‐41 filler not only enhanced the puncture strength of the membrane but also improved its ionic conductivity. The puncture strength of the dried “pore/bead” membrane (MCM‐41 : P(VDF‐HFP) = 1 : 1.5) was 18 N, and showed a slight decrease (16 N) after the membrane was wetted by liquid electrolyte. Additionally, the composite membrane showed excellent thermal dimensional stability. The composite membrane could be activated by adding 1M LiClO4‐EC/DMC (1 : 1 by volume). The activated membrane displayed a high ionic conductivity about 3.4 × 10?3 S cm?1 at room temperature. Its electrochemical stability window was up to 5.3 V vs. Li/Li+, indicating that it was very suitable for lithium‐ion battery application. The battery assembled using the composite electrolyte also showed reasonably good high‐rate performance. The approach of preparing a “pore/bead” membrane provides a new avenue for improving both the conductivity and the mechanical strength of polymer electrolytes for lithium batteries. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

5.
To investigate linguistic and perceptual boundaries within the “blue” region of the color gamut, we analyzed sorting data from speakers of six languages who sorted color stimuli by similarity. Two of these languages, Russian and Italian, are thought to have a separate basic color term and category for “light blue,” distinguishing it from “blue,” and the third was English, which lacks this distinction. There has been less study of the possible basicness of “light blue” terms in the other three languages: Lithuanian and Estonian (both spoken in Baltic states) and Udmurt (a linguistic enclave in North Russia). Sorting data from each sample of speakers were analyzed with principal component analysis and multidimensional scaling, reducing them to a pattern of interstimulus similarities. In addition, color‐naming data were collected for five of the languages and confirmed that sorting responses were not simply a reflection of the words used by subjects to label the stimuli. A “clustering index” was created, quantifying the extent of light/dark blue separation and the strength of any category boundary between them; this was low for English‐language participants but high for Russian and Italian. Udmurt and Lithuanian values were also high, whereas Estonian responses were closer to English. Thus, when clustering of blue stimuli is used as an additional indicator of basicness, the results are compatible with earlier evidence that “light blue” is a separate basic color category in Russian and Italian, and further indicate that light blue terms are basic in Udmurt and Lithuanian, but not Estonian. It may be that “blue” categories are especially susceptible to splitting into two under the influence of linguistic contact. © 2016 Wiley Periodicals, Inc. Col Res Appl, 42, 362–377, 2017  相似文献   

6.
Exchange of the native promoter to the arabinose‐inducible promoter PBAD was established in entomopathogenic bacteria to silence and/or activate gene clusters involved in natural product biosynthesis. This allowed the “on‐demand” production of GameXPeptides, xenoamicins, and the blue pigment indigoidine. The gene clusters for the novel “mevalagmapeptides” and the highly toxic xenorhabdins were identified by this approach.  相似文献   

7.
Polyacrylamide grafted crosslinked poly (vinyl chloride) beads (PAM‐PVC) were prepared by the surface‐initiated controlled/“living” radical polymerization (SI‐CLRP) methodology from the crosslinked poly(vinyl chloride) beads with surface modification with diethyldithiocarbamyl groups under UV irradiation. The macroiniferter, diethyldithiocarbamyl crosslinked poly(vinyl chloride) beads (DEDTC‐PVC) were prepared by the reaction of the surface C? Cl groups with sodium N,N‐diethyl dithiocarbamate. The “grafting from” polymerization exhibited some “living” polymerization characteristics and the percentage of grafting (PG%) increased linearly with polymerizing time and achieved 47.6% after 6 h UV irradiation. The beaded polymer with polyacrylamide surface was also characterized with Fourier transform infrared (FTIR) and scanning electron microscope (SEM). Its adsorption property for Hg(II) ion was also investigated preliminarily. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:3385–3390, 2006  相似文献   

8.
束状超细纤维聚氨酯合成革的特性与制法   总被引:5,自引:1,他引:4  
简要介绍了束状超细纤维聚氨酯合成革的特性与制法,包括束状超细纤维、高密度三维无纺布、开式微孔结构PU基布等制造方法,并与天然皮革性能作比较。  相似文献   

9.
Esparto “Stipa tenacissima” cellulose esters derivatives: HECA‐COO? C4H8? COOC2H5, HECA‐COO? C8H16? COOC2H5, and HECA‐COO? C6H4? COOC2H5 were successfully prepared in Tetrahydrofuran (THF)/triethylamine system with a degree of substitution (DS), respectively, DSAD‐Et=0.32, DSSB‐Et=0.22, and DSTRP‐Et=0.50 using hydroxyethyl cellulose acetate (HECA; DSAC=0.50) as intermediate product, and we avoided the drawbacks of cellulose solubility. The structural modifications were investigated using Fourier transform infrared spectroscopy (FTIR), Proton nuclear magnetic resonance (1H‐NMR), Carbon‐13 nuclear magnetic resonance (13C‐NMR), and Distortionless Enhancement by Polarization Transfer 135° (DEPT‐135). The results from these analyses revealed the presence of the characteristic groups indicating that the grafting reaction was successful. The crystallinity and the structure order changes during the esterification reactions were recorded by X‐ray diffraction (XRD), it is found that the crystallinity degree decrease from 63.1% for Esparto “Stipa tenacissima” cellulose to 27.74% for HECA. The thermal stability of the esterified and unmodified cellulose samples was studied by thermogravimetric analysis (TGA)‐differential thermal analysis (DTA); the modified HECA exhibits a decrease in thermal stability relatively to the unmodified HECA, and this may be related to the groups grafted. The resulted cellulose esters HECA‐Px (x = 1, 2, or 3) were soluble in THF and present an amorphous structure justified by XRD spectra. It was noted by TGA‐DTA analysis that the cellulose esters with low melting range were proved as thermoplastic polymers. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

10.
The properties of the air-water state diagram, representing the liquid holdups according to gas velocities, in a 0.075 m diameter column are restated. After measurement of the interfacial areas and mass-transfer coefficients, the part of the diagram corresponding to high gas velocities and low liquid contents (10 < UG < 14 m/s and 0.005 < UL < 0.04 m/s) was chosen for the treatment of polluted gas streams. Under these conditions, it was shown that a “droplet column” is very efficient for the treatment of gases polluted by acid vapors (SO2, HCl) and dust (iron oxide, talc, etc.). The cost of energy appeared more favorable than for classical bubble columns.  相似文献   

11.
本文对碳纤维增强铸型尼龙(CF/MC 尼龙)复合材料在不同吸湿介质中的吸湿行为进行了研究。结果表明,对于纤维体积分数为10%的碳纤维增强铸型尼龙复合材料(10%CF/MC尼龙复合材料),随着吸湿介质的PH值减小,它的吸湿率增大。同时,经过吸湿后,10%CF/MC尼龙复合材料的弯曲强度有明显的下降。随着吸湿介质的PH值减小,试样的弯曲强度下降。使用环境扫描电子显微镜观察在10%HCl溶液中吸湿的试样的剪切断口形貌,得到的结果与吸湿实验的结果一致。  相似文献   

12.
Short fiber–elastomer composites with 10 vol % fiber, nylon 6–CR and PET–CR composites, absorbed water either in the moisture atmosphere or in water. The effect of absorbed water on the viscoelastic properties for these composites was investigated. The temperature dependence of tan σ for the nylon–CR composite showed that the α-dispersion peak of nylon shifted to lower temperatures with increasing absorbed water content and that after displacement of the α-dispersion peak the additional small hump appeared at about 90°C. For the PET composite, the α-dispersion peak of PET shifted slightly to lower temperatures and the small shoulder at 90°C diminished with increasing absorbed water. The additional dispersion probably was caused by the interface between fiber and CR matrix and was independent of fiber orientation. The results suggested that nylon fiber absorbed a larger amount of water than CR matrix, while the water absorption for PET fiber was considerably less than for nylon fiber. The absorbed water in nylon fiber bonded stronger than that in CR matrix and was only slightly diminished by heat treatment under 100°C.  相似文献   

13.
Fully degradable cationic poly(ester‐phosphoester)s with antibacterial properties were prepared by a combination of ring‐opening polymerization (ROP) and “click” reaction. First, poly(ester‐phosphoester)s‐bearing alkynyl groups were synthesized by the ring‐opening copolymerization of 2‐(2‐propynyloxy)?2‐oxo‐1,3,2‐dioxaphospholane (propynyl ethylene phosphate, PEP) and ε‐caprolactone (CL) using lanthanum tris(2,6‐di‐tert‐butyl‐4‐methylphenolate)s (La(DBMP)3) as the catalyst. 2‐Azido‐N,N‐dimethylethanamine (DMEAN3) was then attached to the copolymers by “click” reaction, resulting in poly(ester‐phosphoester)s with pendant tertiary amines. After the quaternization reactions between the copolymer and various alkyl bromides, cationic poly(ester‐phosphoester)s containing ammonium groups were obtained. Optical density (OD) measurement shows that the cationic copolymers have excellent antibacterial activity, which makes them potential candidates as biomaterials. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42647.  相似文献   

14.
Successful polymerization of nylon 12 6 was accomplished in two‐steps, the preparation of nylon salts and involvement of the salts with a pressure vessel followed by high temperature melt polymerization. Chemical composition, thermal properties, crystal structure, mechanical properties, and moisture absorption were characterized in detail. Melting temperature and glass transition temperature were recorded at 234°C and 75°C, respectively, while the β‐relaxation peak was determined to be ?64°C. The results indicated that nylon 12 6 could be used at a broad range of temperatures. Characterization of the mechanical properties showed that nylon 12 6 exhibited a better flexibility and elongation compared with other industrially important nylons. The moisture absorption of nylon 12 6 decreased by 36.7% compared with that of nylon 6 12, suggesting that nylon 12 6 will exhibit a better dimensional stability in the humid environment. Overall, in this research, the novel nylon, that is, the nylon 12 6, shows a relatively low water absorption and excellent toughness contributing to its potential technological application in the future. POLYM. ENG. SCI., 59:192–197, 2019. © 2018 Society of Plastics Engineers  相似文献   

15.
A comprehensive mathematical model is developed for “living” free‐radical polymerization carried out in tank reactors and provides a tool for the study of process development and design issues. The model is validated using experimental data for nitroxide‐mediated styrene polymerization and atom transfer radical copolymerization of styrene and n‐butyl acrylate. Simulations show that the presence of reversible capping reactions between growing and dormant polymer chains should boost initiation efficiency when using free nitroxide in conjunction with conventional initiator and also increase the effectiveness of thermal initiation. A study shows the effects of the value of the capping equilibrium constant and capping reaction rate constants for both nitroxide‐mediated styrene polymerization (using alkoxyamine as polymer chain seeds) and atom transfer radical polymerization of n‐butyl acrylate (using methyl 2‐bromopropionate as chain extension seeds). Also the effect of introducing additional conventional initiator into atom transfer radical polymerization of n‐butyl acrylate is studied. It is found that the characteristics of long chain growth are determined by the fast exchange of radicals between growing and dormant polymer chains. Polymerization results in batch, semibatch, and a series of continuous tank reactors are analyzed. The simulations also show that a semibatch reactor is most flexible for the preparation of polymers with controlled architecture. For continuous tank reactors, the residence time distribution has a significant effect on the development of chain architecture. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1630–1662, 2002  相似文献   

16.
Life Cycle Analysis (LCA) of Renewable Raw Materials Using “Palm Oil” as an Example Renewable raw materials provide ecological advantages such as renewability, protection of limited resources, unlimited availability, ease of decomposition of end-products, as well as reintegration of material. In the public discussion the above-mentioned characteristics are increasingly examined from an ecological point of view. Do they require too much fertilizer and pesticides? Are there any impacts on the ecological system such as emissions to the groundwater and damages by erosion? Within certain limits - as the social-economic sector is not taken into account - the LCA-method proves to be a means of investigation whereby ecological processes can be evaluated in a comprehensive way from “cradle to grave”. It is, however, stressed that LCA is not always carried out uniformly. Especially the LCA of renewable raw material shows considerable deviations resulting from the different evaluation of agricultural residue. The term “waste” in agricultural and industrial systems is discussed. By using the example of the Malaysian agricultural production of oil palms in plantations and palm oil in oil mills it is demonstrated that there exists an almost closed recycling system of all the agricultural residue and by-products. Furthermore, the paper deals with the closed CO2 loop in agricultural systems.  相似文献   

17.
LDH/P supramolecule with exfoliated and intercalated structure by exfoliation/adsorption and in situ polymerization method is prepared, respectively. Afterward, the LDH/polymer supramolecule with exfoliated (LDH/P‐E, exfoliation/adsorption) and intercalated (LDH/P‐I, in situ polymerization) and partial exfoliated and partial intercalated (LDH/P‐B, physical blending, reported in the previous work) is used in leather tanning and retanning process to evaluate the structure–activity relationship between LDH/P and leather application performance. LDH/P supramolecule with exfoliated structure shows the best intensification ability to most of the leather performances, and the sequence of intensification ability of LDH/P is LDH/P‐E > LDH/P‐B > LDH/P‐I. This is related to the size and penetration property of LDH/P. For the leather performance intensification, the positively charged LDH layers can promote the absorption of negatively charged leather chemicals, and thus the dyeing and softness of leather can be intensified. The nanolayered structure of LDH filled between leather gaps can play a toughening and block effect, and thus the physical and mechanical strength, thickening rate, and the inhibition of volatilization of small organic molecule property of leather can be intensified. Furthermore, the reduction of chemical oxygen demand value of dyeing waste water is also an evidence that the LDH/P is an environmental retanning auxiliary.  相似文献   

18.
First, the second‐generation hyperbranched poly(amine‐ester) (G2‐OH) was successfully prepared by thiol‐ene “click” chemistry. Subsequently, a series of photosensitive hyperbranched oligomers (G2‐ORs) were synthesized by facile modifications of the G2‐OH with acryloyl chloride, methacryloyl chloride, IPDI‐HEA, and IPDI‐HEMA, respectively. The structures of hyperbranched oligomers were characterized by element analysis, FT‐IR, 1H NMR, GPC and viscosity measurement. It was shown that these synthesized oligomers have narrow molecular weight distribution and low intrinsic viscosity at 30°C. UV–vis spectra results showed that the G2‐ORs had sharp absorption bands at around 202 nm. The results of photosensitivities measurement indicated that the G2‐Macr shows the highest photosensitive than other hyperbranched oligomers in the absence of photoinitiator. In addition, these UV‐cured photosensitive G2‐ORs had good thermal properties. The solubilities of the synthesized hyperbranched oligomers were also examined. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

19.
This article reports the mechanical and thermal properties of poly(butylene succinate) (PBS) biocomposites reinforced with industrially available waste silk fibers, fabricated with varying fiber contents and lengths. The result indicates that use of waste silk fibers may be a potential as reinforcement for effectively improving the static and dynamic mechanical properties of a biodegradable polymer matrix resin, depending on the waste silk fiber content and length in the present biocomposite system. The “as‐separated” waste silk/PBS biocomposites showed the maximum tensile and flexural properties at a fiber loading of 40 wt %, and the “chopped” waste silk/PBS biocomposites showed the optimal strength and modulus with waste silk fibers of 12.7 mm length. The chopped waste silk fibers play a more contributing role in improving the mechanical properties of waste silk/PBS biocomposites than the as‐separated waste silk fibers at a fixed fiber loading. Above the glass transition temperature, the storage modulus of waste silk/PBS biocomposites was significantly greater than that of PBS resin, especially in the higher temperature region. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4972–4980, 2006  相似文献   

20.
通过对卧管式尼龙66(PA66)缩聚系统关键部位的再次改造和工艺优化,生产出质量更为稳定的聚合物,为超细旦多孔尼龙66纤维的开发奠定了物质基础。  相似文献   

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