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American Society for Testing and Materials

Recently, there has been a rapid growth in research and innovation in the natural fibre composite (NFC) area. Interest is warranted due to the advantages of these materials compared to others, such as synthetic fibre composites, including low environmental impact and low cost and support their potential across a wide range of applications. Much effort has gone into increasing their mechanical performance to extend the capabilities and applications of this group of materials. This review aims to provide an overview of the factors that affect the mechanical performance of NFCs and details achievements made with them.

A review of recent developments in natural fibre composites and their mechanical performance

This paper is a review on the tensile properties of natural fiber reinforced polymer composites. Natural fibers have recently become attractive to researchers, engineers and scientists as an alternative reinforcement for fiber reinforced polymer (FRP) composites. Due to their low cost, fairly good mechanical properties, high specific strength, non-abrasive, eco-friendly and bio-degradability characteristics, they are exploited as a replacement for the conventional fiber, such as glass, aramid and carbon. The tensile properties of natural fiber reinforce polymers (both thermoplastics and thermosets) are mainly influenced by the interfacial adhesion between the matrix and the fibers. Several chemical modifications are employed to improve the interfacial matrix–fiber bonding resulting in the enhancement of tensile properties of the composites. In general, the tensile strengths of the natural fiber reinforced polymer composites increase with fiber content, up to a maximum or optimum value, the value will then drop. However, the Young’s modulus of the natural fiber reinforced polymer composites increase with increasing fiber loading. Khoathane et al. [1] found that the tensile strength and Young’s modulus of composites reinforced with bleached hemp fibers increased incredibly with increasing fiber loading. Mathematical modelling was also mentioned. It was discovered that the rule of mixture (ROM) predicted and experimental tensile strength of different natural fibers reinforced HDPE composites were very close to each other. Halpin–Tsai equation was found to be the most effective equation in predicting the Young’s modulus of composites containing different types of natural fibers.

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A review on the tensile properties of natural fiber reinforced polymer composites

Physical and mechanical properties of PLA, and their functions in widespread applications - A comprehensive review.

Poly(lactic acid) (PLA), so far, is the most extensively researched and utilized biodegradable aliphatic polyester in human history. Due to its merits, PLA is a leading biomaterial for numerous applications in medicine as well as in industry replacing conventional petrochemical-based polymers. The main purpose of this review is to elaborate the mechanical and physical properties that affect its stability, processability, degradation, PLA-other polymers immiscibility, aging and recyclability, and therefore its potential suitability to fulfill specific application requirements. This review also summarizes variations in these properties during PLA processing (i.e. thermal degradation and recyclability), biodegradation, packaging and sterilization, and aging (i.e. weathering and hygrothermal). In addition, we discuss up-to-date strategies for PLA properties improvements including components and plasticizer blending, nucleation agent addition, and PLA modifications and nanoformulations. Incorporating better understanding of the role of these properties with available improvement strategies is the key for successful utilization of PLA and its copolymers/composites/blends to maximize their fit with worldwide application needs.

Physical and mechanical properties of PLA, and their functions in widespread applications — A comprehensive review

This review article describes the recent developments of natural fiber reinforced polypropylene (PP) composites. Natural fibers are low-cost, recyclable, and eco-friendly materials. Due to eco-friendly and bio-degradability characteristics of these natural fibers, they are considered as strong candidates to replace the conventional glass and carbon fibers. The chemical, mechanical, and physical properties of natural fibers have distinct properties; depending upon the cellulosic content of the fibers which varies from fiber to fiber. The mechanical properties of composites are influenced mainly by the adhesion between matrix and fibers. Chemical and physical modification methods were incorporated to improve the fiber—matrix adhesion resulting in the enhancement of mechanical properties of the composites. The most important natural fibers are jute, flax, and coir and their novel processing technics to develop natural fiber reinforced composites are also described.

Recent Development in Natural Fiber Reinforced Polypropylene Composites

Sugarcane bagasse (SCB) is abundantly available agro-waste world-wide and has been used in different applications and its utilization as a source of cellulose attracting attention in the area of biomedical and other applications. The present study investigates the surface morphology, topography, structural, elemental and thermal properties of cellulose nanocrystals (CNCs) extracted by acid-hydrolysis from sugarcane bagasse as agro-waste. Morphological (field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM)), structural (fourier transformed infrared (FTIR) spectroscopy, X-ray diffraction (XRD)), elemental analysis (energy dispersive x-ray diffraction (EDX)) and thermal characterization (TG-DTG-DTA) of CNCs was carried out. Morphological characterization clearly showed the formation of rod-shaped CNCs having size in the range of 250-480 nm (length) and 20-60 nm (diameter). Elemental analysis (EDX) showed 0.72 wt% sulfur impurity in CNCs along with other main components. X-ray diffraction and thermal analysis revealed that CNCs have higher crystallinity (72.5%) than that of chemically purified cellulose (CPC) (63.5%) but have lower thermal stability. These lab extracted CNCs supposed to have a high potential as nano-reinforcement into bionanocomposite for biomedical and other value-added products in industrial applications.

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Characterization of Cellulose Nanocrystals Produced by Acid-Hydrolysis from Sugarcane Bagasse as Agro-Waste

Melt–solid polycondensation of lactic acid and its biodegradability

Organic thin film transistor (OTFT) based device modeling and circuit application is a rapidly emerging research area. Taking cognizance of this fact, our paper reviews various basic to advanced OTFT structures, their performance parameters, materials of individual OTFT layers, their molecular structures, OTFT charge transport phenomena, and fabrication techniques. The performance of p- and n-type conducting polymer and small molecule organic semiconductors are reviewed primarily in terms of field effect mobility, current on/off ratio, and operating voltage for various OTFT structures. Moreover, different organic/inorganic materials for realizing the dielectric layer, electrodes, and the substrate in an OTFT are analyzed. Some of the compact models that are essential for predicting and optimizing the device performance are described that takes into account the mobility enhancement factor and channel length modulation. A detailed study of the single gate, dual gate, vertical channel, and cylindrical gate O...

Yuvraj Singh Negi

Papers

Recent Development in Natural Fiber Reinforced Polypropylene Composites

Characterization of Cellulose Nanocrystals Produced by Acid-Hydrolysis from Sugarcane Bagasse as Agro-Waste

Melt–solid polycondensation of lactic acid and its biodegradability

Organic Thin Film Transistors: Structures, Models, Materials, Fabrication, and Applications: A Review

Chitosan film incorporated with citric acid and glycerol as an active packaging material for extension of green chilli shelf life