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排序方式: 共有3373条查询结果,搜索用时 15 毫秒
1.
Colin Robert Witiwat Best Thitasiri Dimitrios Mamalis Zakareya Elmo Hussein Muhammad Waqas Dipa Ray Norbert Radacsi Vasileios Koutsos 《应用聚合物科学杂志》2021,138(5):49749
The through-thickness conductivity of carbon fiber reinforced polymer (CFRP) composite was increased by incorporating multiwalled carbon nanotubes in the interlaminar region. Carbon nanotubes (CNTs) were dispersed in a polyethylenimine (PEI) binder, which was then coated onto the carbon fiber fabric. Standard vacuum-assisted resin infusion process was applied to fabricate the composite laminates. This modification technique aims to enhance the electrical conductivity in through-thickness direction for the purpose of nondestructive testing, damage detection, and electromagnetic interference shielding. CNT concentrations ranging from 0 to 0.75 wt% were used and compared to pristine CFRP samples (reference). The through-thickness conductivity of the CFRP exhibited an improvement of up to 781% by adopting this technique. However, the dispersion of CNT in PEI led to a viscosity increase and poor wetting properties which resulted in the formation of voids/defects, poor adhesion (as shown in scanning electron micrographs) and the deterioration of the mechanical properties as manifested by interlaminar shear strength and dynamic mechanical analysis measurements. 相似文献
2.
Orebotse Joseph Botlhoko Dimakatso Makwakwa Suprakas Sinha Ray James Ramontja 《应用聚合物科学杂志》2019,136(17):47387
Commodity polymers are the most widely used materials for electronic packaging applications. However, they are nondegradable and causing serious environmental damage. Addressing this challenge, the relative effects of graphite (G) and graphene oxide (GO) dispersion on the enzymatic degradation, electronic properties, thermal degradation, and crystallization behavior of enzyme degradable polylactide/poly(ε-caprolactone) blend composites is investigated. Owing to the oxygenated surface functionalities and excellent thermal conductivity arising from the carbon structure, the randomly dispersed GO particles do not provide electrical pathways and facilitate large enhancements in the electrical resistivity (126%) and thermal conductivity (72%) of the blend composites. However, while the G particles enhanced the thermal conductivity of the composites, they had little effect on enzymatic degradation. Furthermore, they reduced the electrical resistivity, particularly at high concentration (0.25 wt % G), as a result of the conducting delocalized electrons in the G structure and due to network formation. We also find that the energy required to initiate and propagate the thermal degradation process for GO-filled blend composites is relatively lower than that of G-filled blend composite. However, the former composites show higher crystallization rate coefficients value than that of G-filled composites and the neat blend, thereby providing better crystallization ability and miscibility with the matrix. In summary, the GO-filled blend composites are observed to show potential for use in sustainable materials for thermal management applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47387. 相似文献
3.
Lokesh Kulhari Kanad Ray Ankit Paptan Nikhil Suri Pramod K Khanna 《International Journal of Applied Ceramic Technology》2020,17(3):1430-1439
Low temperature co-fired ceramic (LTCC) micro-hotplates show wide applications in gas sensors and micro-fluidic devices. It is easily structured in three-dimensional structures. This paper presents the low power consumption micro-hotplates which were developed with PTC (positive temperature coefficient) temperature sensor and inter-digitated electrodes. The paper presents two different structures for micro-hotplate with platinum as a heating element. The PTC temperature sensor using two different materials viz. PdAg and platinum paste are developed with micro-hotplates. The simulation has been achieved through COMSOL for LTCC and alumina micro-hotplates. The temperature variation with power consumption has been measured for the developed LTCC micro-hotplates. The change in resistance of PTC temperature sensors was measured with micro-hotplate temperature. The aim of this study was to place a temperature sensor with the gas sensor module to measure and control the temperature of micro-hotplate. A SnO2 sensing layer is coated on LTCC micro-hotplate using screen printing and characterized for the sensing of carbon monoxide gas (CO). This study will be beneficial for designing hotplates based on LTCC technology with low power consumption and better stability of temperature for gas-sensing applications. 相似文献
4.
B N V S Ganesh Gupta K Mritunjay Maharudrayya Hiremath Rajesh Kumar Prusty Bankim Chandra Ray 《应用聚合物科学杂志》2020,137(43):49318
Polymer hybridization technique, consisting of an interlayer arrangement of different polymers, acts as the most economical and promising technique in augmenting the glass fiber-reinforced polymer composite's mechanical properties. This investigation focuses on the effect of cure kinetics on the flexural behavior of glass-polymer hybrid (GPH) composite, and also elucidates the comparative analysis on the mechanical behavior of glass-epoxy (GE) composite, glass-vinyl ester (GVE) composite, and GPH composite. The optimal postcuring temperature has been found to be 200°C for GPH composite among the other postcuring temperatures conducted at 140, 170, and 230°C. Among all these abovementioned composites, highest flexural strength and interlaminar shear strength properties have been recorded by the 200°C postcured GPH composite leading to 10.87 and 18.76% increment, respectively, compared with GE composite. Furthermore, thermomechanical characterization has been done to know the viscoelastic behavior of the GPH composite postcured at different temperatures using dynamic mechanical thermal analysis. The fracture morphology of flexural tested composite samples demonstrated a combination of failure modes. Relevant information on the chemical restructuring and fracture morphology of experimented composite material using Fourier-transform infrared (FTIR) spectroscopy and Scanning electron microscopy (SEM) has also been studied. 相似文献
5.
This reported paper presents the design and analysis of wideband nature inspired planar antenna of 46 × 18 × 1.6 mm3 size, designed using FR4 (Flame Retardant) substrate. The antenna patch is delineated from the growth pattern of sneezewort plant with supplementary notion of golden ratio in branching and branch width. The total number of branches in each stage follows the Fibonacci series and the branch width is calculated from the golden ratio concept. Starting from one feed line and two branches, the maximum numbers of branches are increased to 20. There has been significant enhancement in the radiation performance of proposed geometry by increasing the number of branches to 21 and by modifying ground with T‐shaped slot. The antenna covers wide impedance bandwidth of 8.2 to 16.5 GHz by possessing stable radiation characteristics. 相似文献
6.
A novel crosslinkable supramolecular poly(cyclotriphosphazene) functionalized graphene oxide (FGO) is synthesized and melt‐processed with polypropylene (PP), which results in a PP composite with simultaneously improved flame retardancy, smoke‐suppression, and thermal and viscoelastic properties. The cone‐calorimetry test results reveal that the peak heat‐release rate and total heat release of the composite (2 wt% FGO) are reduced by 39.7% and 29.9%, respectively, compared to those of the neat PP. Meanwhile, the total smoke released and total smoke production of PP are significantly (42.7% and 34.9%, respectively) reduced after composite formation with 2 wt% FGO. Similarly, the PP/FGO composite shows an improved maximum weight loss temperature of 392.4 °C, compared to that of neat PP (361.4 °C). Thermogravimetric Fourier‐transform infrared spectroscopy (TG‐FTIR) analysis further confirms that the composite reduces the evolution of the flammable components and toxic gases, especially CO gas, indicating that the FGO significantly decreases the fire hazards of the PP. The thermomechanical and melt‐rheological analyses reveal that the composite has higher mechanical stiffness and viscoelastic properties than the neat polymer. In summary, FGO is shown to have potential as an advanced additive to obtain PP composites with multifunctional properties; however, higher FGO loading would be needed to improve UL‐94 rating from V‐2 to V‐0. 相似文献
7.
Clean Technologies and Environmental Policy - Renewable energy and sustainable development are widely discussed and highly debated topics. The current and majority opinion is that for sustainable... 相似文献
8.
9.
Jincy Joy Jessica Pereira Rachida Aid‐Launais Graciela Pavon‐Djavid Alok R Ray Didier Letourneur Anne Meddahi‐Pell Bhuvanesh Gupta 《Polymer International》2019,68(7):1367-1377
The work reported involved the fabrication of an electrospun tubular conduit of a gelatin and polycaprolactone (PCL) blend as an adventitia‐equivalent construct. Gelatin was included as the matrix for increased biocompatibility with the addition of PCL for durability. This is contrary to most of the literature available for biomaterials based on blends of gelatin and PCL where PCL is the major matrix. The work includes the assiduous selection of key electrospinning parameters to obtain smooth bead‐free fibres with a narrow distribution of pore size and fibre diameter. Few reports elucidate the optimization of all electrospinning parameters to fabricate tubular conduits with a focus on obtaining homogeneous pores and fibres. This stepwise investigation would be unique for the fabrication of gelatin–PCL electrospun tubular constructs. The fabricated microfibrous gelatin–PCL constructs had pores of size ca 50–100 μm reportedly conducive for cell infiltration. The measured value of surface roughness of 57.99 ± 17.4 nm is reported to be favourable for protein adhesion and cell adhesion. The elastic modulus was observed to be similar to that of the tunica adventitia of the native artery. Preliminary in vitro and in vivo biocompatibility tests suggest safe applicability as a biomaterial. Minimal cytotoxicity was observed using MTT assay. Subcutaneous implantation of the scaffold demonstrated acute inflammation which decreased by day 15. The findings of this study could enable the fabrication of smooth bead‐free microfibrous gelatin–PCL tubular construct as viable biomaterial which can be included in a bilayer or a trilayer scaffold for vascular tissue engineering. © 2019 Society of Chemical Industry 相似文献
10.