Effect of grain boundaries on the interfacial behaviour of graphene-polyethylene nanocomposite

Aim of this article was to investigate the effect of grain boundaries on the interfacial properties of bi-crystalline graphene/polyethylene based nanocomposites. Molecular dynamics based atomistic simulations were performed in conjunction with the reactive force field parameters to capture atomic interactions within graphene and polyethylene atoms, whereas non-bonded interactions were considered for the interfacial properties. Atoms at the higher energy state in bi-crystalline graphene helps in improving the interaction at the nanocomposite interphase. Geometrical imperfections such as wrinkles and ripples helps the bi-crystalline graphene in increasing the number of adhesion points between the nanofiller and matrix, which eventually improves the strength and toughness of nanocomposite. These outcomes will help in opening new opportunities for defective nanofillers in the development of nanocomposites for future applications

Magnesium based alloys for reinforcing biopolymer composites and coatings: A critical overview on biomedical materials

Magnesium (Mg) & its alloys are favourable for orthopaedic & cardiovascular medical device fabrication applications, but holds a natural ability to degrade biologically when put with aqueous solution of the substances and/or water-saturated tissue in the context of a living organism. Mg alloys nature to corrode inside the living organism body is mainly attributed to the excessive rates of corrosion of Mg. Poor corrosion resistance possessed by Mg decreases the mechanical properties of the implants, and adds toxic effects on the bone metabolism. A potential method for increasing Mg alloy resistance to corrosion without changing its properties is by the protective polymeric deposit coatings. Moreover, to impart better mechanical and biocompatible aspects to Mg based materials biopolymers have been used as a composite constituent. This review is based on such composite materials constituting Mg and biopolymers. Their resulting favourable mechanical and osteopromotive properties in conjunction with biocompatibility may help the clinicians to fix the existing orthopaedic related issues

Starch-jute fiber hybrid biocomposite modified with an epoxy resin coating: fabrication and experimental characterization

In this article, biocomposites derived from a starch-glycerol biodegradable matrix reinforced with jute fibers were fabricated using the wet hand lay-up and compression moulding techniques. Samples having different weight percentages of jute fiber in the starch matrix were analyzed. The fiber’s surface was chemically treated by alkaline sodium hydroxide to improve the interphase bonding between the fiber and the matrix. Tensile tests for the composites were done and the sample with highest tensile strength was selected for further tests that included water absorption (WA), scanning electron microscopy (SEM) and thermal analysis (TA). It has been concluded that the ultimate tensile strength was found to be maximum for the composition of 15% fiber by weight composite as 7.547 MPa without epoxy coating and 10.43 MPa with epoxy coating. The major disadvantage of the biocomposite is its high WA property, which in this study was inhibited by the epoxy resin layer. Herein, the results of various tests done disclose a noteworthy improvement in the overall properties of bio-composite, in comparison to the neat biodegradable starch matrix

Recent progressive developments in conductive-fillers based polymer nanocomposites (CFPNC's) and conducting polymeric nanocomposites (CPNC's) for multifaceted sensing applications

Conducting polymer nanocomposites (CPNC's) are promising materials for sensor devices possessing design pliability, good sensitivity, and low temperature operation. For producing conducting polymer nanocomposites with tunable morphology, the soft template procedure is one of the advantageous aspects as reported from in-depth literature. Since the diameter and aspect ratio of conducting-polymer nanomaterials have affected the charge-transport properties, hence, the fine tuning of their structures is important to enhance sensitivity. This review has focused on the CPNC's membranes, insulative-polymers with conductive-fillers based CPNC's (IPCFCPNC's) and conductive-fillers based polymer nanocomposites (CFPNC's) which have been incorporated in many prior literary sources including the usage of strain sensors in some sensing applications for detection pressure, gas humidity, etc. As the review sheds light on incorporating specific types of nanofillers, such as graphene or carbon nanotubes or conducting filling-agents, into the CPNC's membrane matrix and insulative-polymeric-matrices, it will be possible to improve their mechanical stability, enabling them to be used for high-performance sensing applications. In addition, the review has evident that by using advanced fabrication techniques, such as electrospinning, it is possible to create thin, flexible CPNC's membranes that exhibit high sensitivity and stability towards target analytes. Therefore, the feasibility of CPNC's, IPCFCPNC's, and CFPNC's in sensor applications has thoroughly been reviewed for the purpose to realize the novel flexible CPNC structures and their other aspects of applications that may cater to new horizons in high-end smart flexible sensing applications. Additionally, the advanced discovery is to combine conductivity measurement and rheology analysis using a new emerging class of CPNC's, IPCFCPNC's, and CFPNC's for remarkable electrical properties. It is highly appealing to find out more about novel CPNC's, IPCFCPNC's, and CFPNC's, and their role in sensor matrices, considering their unique properties. Based on conducting polymers (CPs), and insulative-polymers with conductive filling-agents that have been reported during the past forty years, the properties and performance of sensing matrices have been investigated by incorporating the diverse carbon-based nano-additives and other nano filling-agents. Furthermore, another area of interest is the use of CPCs, and insulative-polymers with conductive filling-agents for the development of bio-sensors. CPCs, and insulative-polymers with conductive filling-agents can be functionalized with biological molecules such as enzymes, antibodies, and nucleic acids, to create highly sensitive sensors for the detection of various biological markers, including glucose, lactate, and pH. Along with myriads of illustrations in accordance with the CPs and their composites with nanoparticles, carbon materials, or conductive filling-agents with insulative-polymeric-matrices etc., their salient characteristics have been enumerated in this comprehensive review. Additionally, CPNC's, IPCFCPNC's, and CFPNC's-sensing devices will have to improve their analytical performance for a widespread spectrum of multifaceted sensing applications in future research trends

PVA biopolymer-acidic functionalized graphene hybrid nano composite for vibration isolation application: An experimental approach with variable reflux and vacuum timings

In this research work, polyvinyl alcohol (PVA)-graphene (Gr) nano composite films were fabricated by incorporating the functionalized graphene (f-Gr) for different periods of refluxing and vacuum oven time. The graphene particles were functionalized through nitric acid (HNO3). Various tests were conducted to estimate the properties and characteristics of this composite. Fourier transform infrared spectroscopy (FTIR) results confirm the bonds of carboxyl, hydroxyl and carbonyl groups, manifested of functionalization of graphene. Scanning electron microscopy was performed to investigate morphology and transparency of f-Gr nano-particles in nano-composite films. Water absorption test was carried out to evaluate water absorption (%) in the PVA based composite films. The result revealed that water absorption rate of the composite decreased with increasing refluxing time at constant vacuum oven time of f-Gr reinforced composite. Dynamic mechanical analysis (DMA) showed that the value of storage modulus was higher for PVA-f-Gr nano-composite films compared to neat PVA and PVA-Gr composite over the entire range of temperature, which lead to explore this composite material for the vibration isolation applications. Glass transition state (Tg), loss modulus and the damping factor (tan δ) of the PVA-f-Gr nano composites films were highly affected by the addition f-Gr nano crystals in the PVA matrix. The value of tan δ for f-Gr nano composite is obtained both higher as well as lower compared to PVA-Gr film for the varying vacuum oven time and refluxing time. Electrical analysis indicates an enhancement in conductivity of PVA with introduction of f-Gr nano particles. After evaluating the high damping characteristics of this composite, the authors perceive that it may be utilized to reduce noise transmission and as a shock absorber vibration isolator

Fabrication and Experimental Testing of Hybrid Composite Material Having Biodegradable Bagasse Fiber in a Modified Epoxy Resin: Evaluation of Mechanical and Morphological Behavior

Natural fibers such as bagasse, jute, sisal and coir are biodegradable as well as non-toxic in nature, so the use of natural fiber is safe. Bagasse contains about 50% cellulose, 25% hemicellulose, and 25% lignin. The present work has been undertaken to develop a composite using bagasse fiber as reinforcement and to study its mechanical properties, morphology, water absorption capacity and performance. The composites were prepared with different weight percentage of bagasse fiber by hand lay-up method. In the present research work, it can be concluded that with increase in wt% of bagasse fiber in matrix material the rate of water absorption increases. Ultimate tensile strength, ultimate compressive and flexural strength of the composite are less than the pure epoxy while Young’s modulus is higher for composite. Ultimate tensile, ultimate compressive strength and flexural strength of composite is decreasing at all cross head speed with increase in wt% of bagasse fiber while flexural strain is increasing. Scanning Electron Microscopy (SEM) showed that for 5 wt% of bagasse fiber the binding between epoxy and bagasse fiber is better than the 10 and 15 wt% of bagasse fiber configuration. This was because of the increase in wt% of bagasse fiber, which results in cavities and improper binding in the composite domain. Thus, as we increase the wt% of bagasse fiber, it causes the decrease in mechanical properties of composite