排序方式: 共有12条查询结果,搜索用时 15 毫秒
1.
亚麻等麻类纤维与乙烯基类单体接枝共聚反应的研究进展 总被引:2,自引:1,他引:2
近年来,乙烯基类单体与亚麻、大麻、苧麻等麻类纤维的接枝共聚反应已得到关注。本文着重总结接枝的引发方法,包括:1.辐射引发接枝;2.光引发接枝;3.Ce(Ⅳ)离子引发接枝;4.锰盐引发接枝;5.V(Ⅴ)离子引发接枝;6.Fenton's 试剂(Fe~(2+)-H_2O_2)引发接枝;7.过硫酸盐氧化还原引发体系接枝。上述各类引发体系及接枝纤维的结构与性能表征均在本文中作了述评。 相似文献
2.
3.
《Journal of Saudi Chemical Society》2022,26(4):101514
A facile, single-step hydrothermal route is followed to prepare ZnS nanowires with large aspect ratios. The obtained ZnS nanowires deposited on nickel foam (ZnS/Ni-foam) exhibit a specific capacitance of 781 F/g at a current density of 0.5 A/g. An asymmetric supercapacitor fabricated from ZnS/Ni-foam as a positive electrode and jute derived activated carbon coated on Ni-foam (JAC/Ni-foam) as a negative electrode attains a high specific capacitance of 573 F/g at a current density of 0.5 A/g, with an accompanying high energy density of 51 Wh/kg at a power density of 200 W/kg in an extensive operating potential window of 1.2 V. In addition, the ZnS//JAC asymmetric supercapacitor reveals long-term cyclic stability, after 10,000 GCD cycles the device sustain around ~87 % of the initial specific capacitance. These results shed enlighten a new opportunity for promising electrode materials in supercapacitors. 相似文献
4.
《Arabian Journal of Chemistry》2022,15(11):104265
In this paper, we used green and hydrothermal methodology to prepare zinc oxide (ZnO) nanoflakes (NFs) with jute stick extract (J–ZnO NFs) as growth substrate. The prepared materials were characterized using different analytical techniques including ultraviolet–visible spectroscopy (UV–vis), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The characteristic absorption peak for ZnO NFs and J–ZnO NFs were observed from the UV–vis spectrum at 373 and 368 nm respectively. The hexagonal wurtzite crystal structure of ZnO NFs and J–ZnO NFs was confirmed by XRD analysis. FESEM and TEM analyses of synthesized J–ZnO NFs confirmed their NFs shape and collectively flower-like structure formation by the assembly of NFs of J–ZnO on cellulose of jute stick extract substrate. The FTIR analysis revealed the functional groups of jute stick extract biomolecules, mainly cellulose, are responsible for the formation of collectivel flower like J–ZnO NFs structure. The XPS analysis revealed the surface and chemical compositions (Zn, C, and O) of J–ZnO NFs. The photocatalytic performance of ZnO NFs and J–ZnO NFs samples was carried out by the degradation of methylene blue (MB) dye solution under UV light irradiation. The degradation efficiency of ZnO NFs and J–ZnO NFs was obtained 79 % and 89 %, respectively, for 5 h. Notably, the degradation efficiency of the J–ZnO NFs was 98 % after 8 h of irradiation, which is very inspiring. The both NFs exhibited first-order kinetics with MB photodegradation. We also examined the possible antibacterial activity of both samples against Escherichia coli (E. coli) pathogens, which demonstrated a significant result with a 17 mm and 19 mm zone of inhibition by ZnO NFs and J–ZnO NFs respectively. 相似文献
5.
Pretreatments (water-soaking, pre-mercerization, mercerization under a pressure of 15 bars and steam explosion) were used
to improve the accessibilities and reactivities of celluloses of bleached flax, hemp, sisal, abaca and jute pulps for the
synthesis of methylcellulose. Degrees of crystallinity were determined by X-ray Diffraction (XRD) spectra. The iodine adsorption
accessibilities of pulps were low and accessible fractions ranged from 1.3 to 5.2%. Accessible fractions in amorphous cellulose
were calculated in the 5–18% range. The accessibilities of these pulps were hemp pulp > flax pulp > sisal pulp > jute pulp > abaca
pulp. Fourier Transform Infrared (FTIR) spectra showed that mean hydrogen bond strengths were weakened and relative crystallinity
indexes were decreased by pretreatments. The accessibility and reactivity of the abaca pulp were improved by water soaking,
mercerization under 15 bars pressure, steam explosion and preliminary mercerization, of which steam explosion and pre-mercerization
were the best treatments. Species was the main factor for the accessibility and reactivity. 相似文献
6.
Claudia Barba Daniel Montané Marguerite Rinaudo Xavier Farriol 《Cellulose (London, England)》2002,9(3-4):319-326
This paper explores the production of carboxymethylcellulose (CMC) fromseveral bleached cellulose pulps obtained from non-wood species. The chemicalcomposition (-cellulose, hemicellulose and lignin content), the degreeofswelling, viscosity, solubility in concentrated NaOH and crystallinity ofsoda/AQ cellulose pulps from abaca, jute, sisal, linen and Miscanthussinensis were determined. The pulps were carboxymethylated by one andtwo successive reaction steps in aqueous medium under identical conditions. Thedegree of substitution (DS) of CMC was found to be dependent upon the source ofthe cellulose pulp, but generally it was close to 1 with one etherificationtreatment and around 2 after the second. The molar mass of CMC was found to bedependent on the initial intrinsic viscosity of the cellulose pulp. The weightaverage molar mass of our CMCs ranged from 1.5×105 to2.8×105. Increasing the DS up to 2 improved the CMC solubility, butviscosity slightly decreased due to a slight degradation of the polymer. 相似文献
7.
Raw and refined flax, hemp, abaca, sisal, jute and ramie fibres are dipped into N-methylmorpholine N-oxide (NMMO)–water with various contents of water and into hydroxide sodium (NaOH)–water. The swelling and dissolution mechanisms
of these plant fibres are similar to those observed for cotton and wood fibres. Disintegration into rod-like fragments, ballooning
followed or not by dissolution and homogeneous swelling are all observed as for wood and cotton fibres, depending on the quality
of the solvent. Balloons are not typical of wood and cotton and they seem to be present in all plant fibres. Another interesting
result is that the helical feature seen on the balloon membrane is not related to the microfibrillar angle. Plant fibres are
easier to dissolve than wood and cotton. This is not related to the molar mass of the cellulose chain. Raw plant fibres keeping
most its non-cellulosic components do not show the formation of balloons.
Patrick Navard is a Member of the European Polysaccharide Network of Excellence (EPNOE) 相似文献
8.
Biodegradability of poly(butylene succinate) (PBS) composite reinforced with jute fibre 总被引:2,自引:0,他引:2
Lifang Liu Jianyong Yu Longdi Cheng Xiaojie Yang 《Polymer Degradation and Stability》2009,94(1):90-94
Poly(butylene succinate) (PBS)/jute composites were prepared, and the effects of fibre content, diameter, surface modification and arrangement forms on the biodegradability were evaluated by compost-soil burial test. The weight losses of PBS/jute composites are higher than that of pure PBS film and bulk jute fibre, and decreased with increasing fibre content. The weight loss of PBS/10% jute composite after 180 days is 62.5%. In the case of the effect of fibre diameter, the weight loss is found to decrease with decreasing fibre diameter. For the effect of fibre surface modification, the order of higher weight loss is PBS/untreated jute > PBS/alkali treated jute > PBS/coupling agent treated jute. Furthermore, the composite of PBS/woven fabric has the highest weigh loss, followed by that of PBS/nonwoven fabric and PBS/bulk jute fibre, respectively. 相似文献
9.
A. Bismarck J. Springer A. K. Mohanty G. Hinrichsen M. A. Khan 《Colloid and polymer science》2000,278(3):229-235
ζ-potential measurements using the streaming potential method were performed on several differently modified jute fibers.
The time dependence of the ζ-potential measured in 1 × 10−3 M KCl solution offers the possibility to characterize the water-uptake behavior and the velocity constant of this process
for almost all the jute fibers investigated. All the jute fibers contain, as expected, dissociable acidic surface functional
groups as could be verified by measuring the pH dependence of the ζ-potential. Remarkably a peak (increase in the negative
ζ-potential values) was detected while measuring the ζ–pH dependency. The origin of this peak is still questionable; however,
it could be observed that this peak is a function of the degree of surface coverage of additional components, such as fats,
waxes or grafted polymers, i.e. the accessibility of ether functions in the jute fiber surface.
Received: 26 May 1999/Accepted in revised form: 28 September 1999 相似文献
10.
M. M. H. Khan A. T. M. Mijanur Rahman Md. Salim Uddin Shahanaz Khatun F. Pervin N. Absar 《中国化学会会志》2008,55(5):1171-1177
Three lectins were isolated from an extract of jute leaves (Chorchorus olitorius) and purified by gel filtration on Sephadex G‐50 of the 100% ammonium sulfate saturated crude extract, followed by ion‐exchange chromatography on DEAE‐cellulose were designated as JLL‐1, JLL‐2 and JLL‐3. All the lectins were homogeneous as judged by SDS‐polyacrylamide slab gel electrophoresis and gave single bands. The molecular weights of the three lectins were estimated by the same method were 35000, 38000 and 42000, respectively. The lectins specifically agglutinated rat red blood cells. The agglutination of JLL‐1 was inhibited by D‐mannose/D‐glucose and their derivatives, whereas D‐galactose was found to be the potent inhibitor for the agglutination of JLL‐2 and JLL‐3. The lectins were glycoprotein in nature with a neutral sugar content of 1.3%, 1.2% and 0.8% for JLL‐1, JLL‐2 and JLL‐3, respectively. The hemagglutinating activity of JLL‐2 was also investigated after the treatment of physico‐chemical agents. The lectin showed maximum activity between the range of pH 7.2–8.0 and the range of temperature of 20‐30 °C. The activity of lectin decreased after treatment with a higher concentration of acetic acid and urea. In the presence EDTA the activity was inhibited while the presence of Ca+2, Mn+2 and K+ increased the activity of the lectin moderately. 相似文献