Epoxy Resin Composite Reinforced with Carbon Fiber and Inorganic Filler: Overview on Preparation and Properties

Among carbon fillers, carbon fiber is considered to be an ideal reinforcement for epoxy because of its outstanding electrical, mechanical, and thermal features. Several inorganic fillers such as zinc oxide, titania, and silica are also used in epoxy matrix for property enhancement. The review initially focuses the preparation methods and physical characteristics of epoxy/carbon fiber composite. Afterward, fabrication and properties of epoxy/zinc oxide/titania/silica composites are also conversed. Moreover, the effect of filler dispersion on polymer properties’ improvement is also highlighted. Epoxy/carbon fiber composites are employed more frequently and effectively in defense-related applications compared with epoxy/inorganic nanofiller composite.     

Recent Developments in Different Types of Flame Retardants and Effect on Fire Retardancy of Epoxy Composite

In this review, main focus is on the different types of fire retardants, their properties, and pertinent potential. Both inorganic (titania, silica, and zinc oxide) and organic (graphite, graphene, and graphene nanoplatelet) compounds have been discussed as flame inhibitors. Among various sorts of fire retardants, halogen-based flame inhibitors possess outstanding features. Consequently influence of fire retardant on the performance of epoxy composite has been discussed. It was noted that significant enhancement occurs by addition of organic and inorganic fillers in epoxy matrix. However, halogen additives impart better flame resistance to epoxy composite. Toward the end of this review, potential of halogen-containing fire retardant is discussed.     

Advances in Epoxy/Graphene Nanoplatelet Composite with Enhanced Physical Properties: A Review

In this review, development from graphene nanoplatelet, that is, comprised of short bulk of single layer graphene, into modified-polymer/graphene nanoplatelet composite is presented. Preparation methods of graphite, graphene, and graphene nanoplatelets have also been discussed. Graphene nanoplatelet and modified graphene nanoplatelet commend unique properties to composites such as excellent thermal and electrical conductivity as well as mechanical and barrier properties. Graphene nanoplatelet fabrication techniques by solution mixing, melt blending, and in situ polymerization are also discussed. Excellent dispersion of nanoplatelets in polymer/graphene nanoplatelet depends upon the selection of suitable fabrication technique. Moreover, the corresponding significance, exploitation, challenges, and future aspect of polymer/graphene nanoplatelet-based material is overviewed.     

Palynological investigation of some selected species of family Fabaceae from Pakistan,using light and scanning electron microscopy techniques

Pollen morphology of 11 species of family Fabaceae that is, Trifolium alexandrinum, Trifolium resupinatum, Arachis hypogaea, Lathyrus aphaca, Medicago lupulina, Vicia sativa, Lathyrus odoratus, Pongamia pinnata, Melilotus indicus, Medicago polymorpha, Medicago sativa from Pakistan has been investigated by light and scanning electron microscopy. Pollen were generally tricolporate, radially symmetrical, isopolar, elliptic in equatorial view and triangular in polar view under LM. Results showed that pollens were per‐prolate (T. alexandrinum), prolate (T. resupinatum, V. sativa, L. odoratus, Melilotus indicus, M. polymorpha, M. sativa) and sub‐prolate (A. hypogaea, L. aphaca, M. lupulina, P. pinnata). The larger polar/equatorial (P/E) ratio was found in T. alexandrinum (2.26 μm) and the smallest was found in M. lupulina (1.21 μm). The exine of T. resupinatum was 3.00 μm in thickness while others posses smaller exine thickness. The larger pore diameter was found in P. pinnata (16.01 μm) while others have smaller. The length of colpi was larger in Arachis hypogaea (32.24) while others posses smaller. Eight types of surface ornamentation (Psilate, faintly rugulate). Perforate and rugulate to verrucate have been observed under SEM. The pollens were europalynous type. Pollen morphology proved to be useful for the specific delimitation and serve as a tool for the identification and classification of taxa at specific and generic levels and can also be used as a key for the taxonomic features. Diversity in exine sculpture is helpful indicative characters for the isolation of closely related species. Hence, it is clear that both qualitative and quantitative characters of pollen can be useful for differentiating between taxa at specific level.     

A cluster-based key agreement scheme using keyed hashing for Body Area Networks

In recent years, Body Area Networks (BANs) have gained immense popularity in the domain of healthcare as well as monitoring of soldiers in the battlefield. Security of a BAN is inevitable as we secure the lives of soldiers and patients. In this paper, we propose a security framework using Keyed-Hashing Message Authentication Code (HMAC-MD5) to protect the personal information in a BAN. We assume a network in which nodes sense physiological variables such as electrocardiography (EKG), electroencephalography (EEG), pulse oximeter data, blood pressure and cardiac output. Heterogeneous wireless sensor network is considered which consists of a powerful High-end sensor (H-sensor) and several Low-end sensors (L-sensors). EKG is used for secure communication between nodes as it introduces plug and play capability in BANs. The process is made secure by applying HMAC-MD5 on EKG blocks. Key agreement is done by comparing HMAC of feature blocks between sensors resulting in a more secure network. The analysis is done by calculating the entropy of keys and checking the randomness of EKG data using NIST-randomness testing suite.     

Exploration of Epoxy Resins,Hardening Systems,and Epoxy/Carbon Nanotube Composite Designed for High Performance Materials: A Review

Epoxy resins, is an important class of reactive polymers, have been reported to be toughened by nanoparticles. Carbon nanotube is a tubular cylinder ofcarbonatoms having extraordinary mechanical, electrical, and thermal properties. In this article, present state of epoxy/carbon nanotube composite is given. Types of epoxy and hardening agents commonly used in composite processing have been thrashed out. Frequently used fabrication techniques are discussed with particular emphasis on evaluating dispersion state of nanotube. Epoxy/carbon nanotube composites offer substantially improved properties compared to traditional fiber-reinforced epoxy composites. Finally, potential relevance for efficiently transforming filler properties to matrix facilitating aerospace relevance is conversed.     

Effect of NiO on organic framework functionalized ZnO nanoparticles for energy storage application

Functionalization of metal oxides nanomaterial by different organic and inorganic species could considerably enhance the electrochemical performance of a supercapacitor. Here, we have synthesized and functionalized ZnO nanoparticles (NPs) via organic compounds of E. cognate and then doped the synthesized nanomaterials by NiO following hydrothermal route involving the bioactive compounds. As synthesized ZnO@NiO was analyzed by field emission-scanning electron microscopy at nanoscale. The organic functional groups were delineated by X-ray photoelectron spectroscopy as well as by Fourier transform infrared spectroscopy. What is more, Tauc plot revealed drastically decreased band gap energy of ZnO@NiO to 2.48 eV resulting in an enhanced electrochemical properties. Therefore, organic framework derived ZnO@NiO nanomaterial was scrutinized as an electrode for supercapacitor by galvanostatic charge-discharge, cyclicvoltammetry and electrochemical impedance spectroscopy. ZnO@NiO electrode demonstrated specific capacitance of 185 Fg⁻¹ by cyclicvoltammetry, proposing its potential towards supercapacitor due to nanoscale particles and incorporated C, O, and N atoms of organic compounds.     

Perspectives of Epoxy/Graphene Oxide Composite: Significant Features and Technical Applications

In this article, advancement in epoxy/graphene oxide composites is presented. These materials are comprised of graphene oxide (GO) as filler (carbon-based material, thermodynamically stable, two-dimensional, planar and layered structure). Due to improved properties (mechanical response, low density, electrical resistance, and thermal stability), epoxy resins are used in several applications. Graphene oxide proposes unique properties to epoxy composites as high surface area, thermal and electrical conductivity as well as mechanical and barrier properties, relative to neat matrix. The corresponding significance of epoxy/GO-based materials, related challenges, and potential exploitation regarding technical applications (aerospace, gas sensor, electronic devices, etc.) have been overviewed.     

Composite of DGEBA/TBA epoxy blend and amine-functionalized carbon nanotube: Structural,thermal, nonflammability,and EMI shielding studies

Novel blend of diglycidyl ether of bisphenol-A (DGEBA) and tetrabromo bisphenol-A (TBA) was reinforced with acid-functionalized (MWCNT-F) and amine-functionalized multi-walled carbon nanotube (MWCNT-A). DGEBA/MWCNT-A displayed fine tubular morphology with open nanotube ends, while DGEBA/TBA/MWCNT-A displayed somewhat aggregated morphology due to lesser filler content. DGEBA/TBA/MWCNT-A system showed maximum enhancement in decomposition temperature (T₀ = 404°C, T_max = 583°C). Glass transition temperature and Limiting oxygen index of DGEBA/TBA/MWCNT-A were also higher (221°C and 55%) compared with other systems. DGEBA/TBA/CNT-A 0.1 had crystalline morphology with diffractions at 12.7° and 26.09°. Novel nanocomposite revealed EMI shielding effectiveness of ～15.05–15.18 dB, i.e., suitable for aerospace applications.     

Aerospace Application of Polymer Nanocomposite with Carbon Nanotube,Graphite, Graphene Oxide,and Nanoclay

In this review, potential and properties of carbon nanotube, graphite, graphene oxide, and clay nanofiller have been deliberated with reference to aerospace application. The polymers discussed as matrices are polypropylene, polyaniline, polyurethane, polystyrene, and polyamide. Main focus of the review is to converse space competency of polymer/carbon nanotube, polymer/graphite, polymer/graphene oxide, and polymer/clay nanocomposite. The effect of nanofiller addition on the desired aerospace properties of polymeric nanocomposite has been conversed. Attractive features are high glass transition temperature, thermal stability, high modulus, chemical resistance, and nonflammability. Toward the end, challenges in the enhancement of materials’ properties for aerospace relevance have been considered.