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排序方式: 共有3337条查询结果,搜索用时 171 毫秒
81.
Mashael Alshabanat 《Journal of Saudi Chemical Society》2019,23(3):355-364
In this study, date palm waste that was naturally treated as a filler in a linear-low density polyethylene (LLDPE) matrix was recycled to prepare green composites. Two types of LLDPE, based on basic additives, were used. UV stabilizer and the slip and anti-block were added as basic additives. The objective of this study was to examine the effect of these basic additives and the treated filler on the biodegradation, morphological, and thermal properties of the prepared samples by a soil burial test. The samples were characterized by Fourier-transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD). Weight loss was calculated to investigate the biodegradation of the sample, and SEM and thermogravimetric analyses were performed to reveal the morphology and thermal properties before and after burial, respectively. Results showed that the presence of the bio-filler accelerated the biodegradation of the composites. The UV stabilizer had a positive impact on biodegradation factors whereas anti-block additives appeared resistant to biodegradable factors. The morphology and thermal stability of all the prepared samples changed after burial due to the effects of biodegradation during the burial. 相似文献
82.
Hasan M. El Ghanem Saa’Di Abdul Jawad Yazan A. Hussain Adnan S. Abu-Surrah 《Journal of Macromolecular Science: Physics》2014,53(5):878-892
Impedance spectroscopy was utilized to investigate the dielectric properties, ac conductivity and charge transport mechanisms in propylene-alt-CO/ethylene-alt-CO (EPEC) random terpolymer filled with multi-walled carbon nanotubes (MWCNT) as a function of nanofiller content, frequency, and temperature. Equivalent resistor-capacitor (RC) circuit models were proposed to describe the impedance characteristics of the unfilled terpolymer and the nanocomposite at different temperatures. For the nanocomposites, the ac conductivity tended to be frequency independent at low frequencies. At high frequencies, the ac conductivity increased with frequency. The dc conductivity (i.e., plateau of the ac conductivity at low frequencies) at room temperature increased from 10?9 (Ω·m)?1 for the unfilled polymer to l0?3 (Ω·m)?1 for the 6 wt% MWCNT/EPEC nanocomposite. At low temperatures, the equivalent RC model for EPEC-0 and EPEC-2 was found to consist of a parallel RC circuit. However, for 6 wt% MWCNT/EPEC nanocomposite, an RC model consisting of an R/constant phase element (CPE) circuit and a resistor in series was required to describe the impedance behavior of the nanocomposite. 相似文献
83.
Quasi-static tensile test of UHMWPE fiber-reinforced composite laminate is challenging to perform due to low interlaminar shear strength and low coefficient of friction. Tensile tests proposed in the literature were conducted and limitations associated with each method led to the evolution of a new method. Tensile test of single-ply was realized as the best representative of tensile strength of a composite than tensile test of UHMWPE laminate. A fixture was developed for single-ply tests which increased friction and provided the mechanical constraint to slipping. The fixture is easy to fabricate and has provided repeatable results for eight grades of UHMWPE fiber-based (0/90) fabrics. Reported tensile strengths are in quite high range of 900–1500 MPa. 相似文献
84.
Yushu Liu Chun Gao Qing Li Prof. Dr. Huan Pang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(9):2141-2160
Nickel oxide (NiO) has emerged as one of the most promising transition-metal oxides (TMOs) for electrochemical capacitors, batteries, catalysis, and electrochromic films, owing to its cost-effectiveness, abundance, and well-defined electrochemical properties. Recent studies have identified that mixing NiO with graphene or graphene derivatives results in novel composites with synergistic effects and superior electrochemical performance. This review summarizes the latest advances in composites of NiO with graphene or graphene derivatives. The synthetic strategies, morphologies, and electrochemical performance of these composites are introduced, as well as their electrochemical applications in supercapacitors, batteries, sensors, catalysis, and so forth. Finally, tentative conclusions and assessments regarding the opportunities and challenges for the future development of these composites and other TMOs/graphene or graphene-derived composites are presented. 相似文献
85.
合成了氯代1-(2-羟乙基)-3-甲基咪唑离子液体[He MIM]Cl、溴代1-乙胺基-3-甲基咪唑离子液体[Ae MIM]Br和氯代1-羧乙基-3-甲基咪唑离子液体[Ce MIM]Cl 3种功能化咪唑离子液体,并分别进行了红外与氢核磁结构表征.然后用3种离子液体液化木粉,液化3 h后向体系直接加入苯酚、甲醛和氢氧化钠,制备酚醛复合材料,并采用FTIR、XRD、DSC和SEM对酚醛复合材料进行结构、性能与形貌测试,研究离子液体种类对木粉液化率及酚醛树脂性能的影响.结果表明,离子液体及其液化木粉产物制备的酚醛复合材料性能得到明显改善.[Ce MIM]Cl液化效果最好,90℃液化率高达24.6%,当[Ce MIM]Cl与木粉质量比为10∶1时,制备的酚醛复合材料的游离醛释放量由原来的3.64%降低到0.92%.离子液体[Ae MIM]Br能将酚醛复合材料的冲击强度由原来的0.93 k J/m2提高到6.96 k J/m2,而[Ae MIM]Br及其液化的木粉产物制备的酚醛复合材料拉伸强度从原来的3.28 MPa提高到9.70 MPa. 相似文献
86.
This study explores the effects of 3-glycidoxypropyltrimethoxysilane (3-GPTS) modified Na-montmorillonite (Na-Mt) nanoclay addition on mechanical response of unidirectional basalt fiber (UD-BF)/epoxy composite laminates under tensile, flexural and compressive loadings. Fourier transform infrared (FT-IR), X-ray diffraction (XRD) and simultaneous thermal analysis (STA) data confirmed the reaction mechanism between the silane compound and Mt. It was demonstrated that addition of 5 wt % 3-GPTS/Mt resulted in 28%, 11% and 35% increase in flexural, tensile and compressive strengths. Scanning electron microscopy (SEM) clarified the improvement in the adhesion between the basalt fibers and matrix in the case of Mt-enhanced epoxy specimens. Also, a theoretical route based on a Euler-Bernoulli beam-based approach was employed to estimate the compressive properties of the composites. The results demonstrated good agreement between theoretical and experimental approaches. Totally, the results of the study show that matrix modification is an effective strategy to improve the mechanical behavior of fibrous composites. 相似文献
87.
Multifunctional mesoporous silica nanoparticles in poly(ethylene‐co‐vinyl acetate) for transparent heat retention films 下载免费PDF全文
Md Abdul Mumin Kazi Farida Akhter Sara Dresser Sasha T. van Dinther Wei Wu Paul A. Charpentier 《Journal of Polymer Science.Polymer Physics》2015,53(12):851-859
Transparent inorganic‐polymer nanocomposite films are of tremendous current interest inemerging solar coverings including photovoltaic encapsulants and commercial greenhouse plastics, but suffer from significant radiative heat loss. This work provides a new and simple approach for controlling this heat loss by using mesoporous silica/quantum dot nanoparticles in poly(ethylene‐co‐vinyl acetate) (EVA) films. Mesoporous silica shells were grown on CdS‐ZnS quantum dot (QDs) cores using a reverse microemulsion technique, controlling the shell thickness. These mesoporous silica nanoparticles (MSNs) were then melt‐mixed with EVA pellets using a mini twin‐screw extruder and pressed into thin films of concentration variable controlled thickness. The results demonstrate that the experimental MSNs showed improved infrared and thermal wavebands retention in the EVA transparent films compared to commercial silica additives, even at lower concentrations. It was also found MSNs enhanced the quantum yield and photostability of the QDs, providing high visible light transmission and blocking of UV transmission of interest for next generation solar coatings. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 851–859 相似文献
88.
Mariem Ghali Chaima Brahmi Mahmoud Benltifa Cyril Vaulot Aissam Airoudj Philippe Fioux Frédéric Dumur Corine Simonnet-Jégat Fabrice Morlet-Savary Salah Jellali Latifa Bousselmi Jacques Lalevée 《Journal of polymer science. Part A, Polymer chemistry》2021,59(2):153-169
Different inorganic/organic photocomposites based on polyoxometalate (POM) nanoparticles have been developed for photocatalytic applications. Currently, polyoxometalate nanoparticles have been successfully in-situ embedded into an acrylate polymer network by photopolymerization upon mild visible light irradiation at 405 nm. The proposed POM/polymer photocomposites have been characterized using complementary techniques for a better understanding of their photocatalytic activity. Interestingly, the obtained photocomposites exhibit high rigidity, excellent thermal stability, a non-negligible porosity and new functionalities such as light reactivity and redox properties. Moreover, developed composites showed efficient catalytic activity for the color removal of aqueous solutions of erythrosine and rose Bengal under Light Emitting Diodes LED@375 nm irradiation reaching 80 and 90% as a final color removal, respectively. 相似文献
89.
Reducing gas contaminants by affordable and effective adsorbents is a major challenge in the 21st century. In the present study, thorium metal organic framework (Th‐MOF) nanostructures are introduced as highly efficient adsorbents. These compounds were manufactured via a novel route resulting from the development of microwave assisted reverse micelle (MARM) and ultrasound assisted reverse micelle (UARM) methods. The products were characterized utilizing XRD, SEM, TGA/DSC, BET, and FT‐IR analyses. Based on the results, the samples synthesized by MARM had uniform size distribution, high thermal stability, and significant surface area. Calculations using DFT/B3LYP indicated that the compounds have a tendency to the polymeric form, which could theoretically confirm the formation of Th‐MOF. Results of analysis of variance (ANOVA) showed that synthesis parameters played a critical role in the manufacturing of products with distinctive properties. Response surface methodology (RSM) predicted the possibility of creating Th‐MOF adsorbents with the surface area of 2579 m2/g, which was a considerable value in comparison with the properties of other adsorbents. Adsorption studies showed that, in the optimum conditions, the Th‐MOF products had high adsorption capacity for CO and CH4. It is believed that the synthesis protocol developed in the present study and the systematic studies conducted on the samples which lead to products with ideal adsorption properties. 相似文献
90.
Cu‐doped Ni‐based metal–organic frameworks (MOFs) nanomaterials fabricated through a one‐pot hydrothermal reaction were characterized, and their performance as supercapacitor electrode materials was further studied for the first time. The results indicated that the doping of foreign metals and the introduction of K3[Fe(CN)6] in the KOH electrolyte significantly improve the performance of the supercapacitor. The results indicated that the Ni2.6Cu0.4 MOFs material shows the highest specific capacitance (1282 F g?1 at 1 A g?1 in mixed 2 M KOH and 0.1 M K3[Fe(CN)6]) and optimal capacitance retention (85.7% after 2000 cycles). This work provides a feasible optimization strategy for the construction of MOFs‐based supercapacitor electrode materials with excellent performance, and also provides a reliable experimental and theoretical basis for practical industrial production. 相似文献