Narendra Yadav

Hybrid Composites Made from Jute/Coir Fibers: Water Absorption, Thickness Swelling, Density, Morphology, and Mechanical Properties

The action of water in natural fiber-reinforced composite material was studied so as to produce great swelling with resultant changes in the fine structure, dimensional stability, and mechanical properties. Water absorption and thickness swelling test reveal that hybrid composite shows water absorption moderately, which is 15.3% for hybrid coir/jute/coir composite and 11.2% for hybrid jute/coir/jute composite. The thickness swelling, water absorption, and mechanical properties of the hybrid composites slightly increased as the layering pattern of hybrid composites changed. Hybridization of coir fibers composites with jute fibers can improve the dimensional stability, extensibility and density of pure coir composites. Microstructures of the composites were examined to understand the mechanisms for the fiber-matrix interaction in relation to mechanical properties.

Growth of spherulitic crystal patterns in a Belousov–Zhabotinski type reaction system

The growth of spherulitic crystal patterns in a Belousov–Zhabotinski (BZ) type reaction system by using acetyl acetone (AA)–succinic acid (SA) as dual organic substrates has been reported. The reaction system in the liquid phase has been found to show concentric ring-like wave patterns. A colloidal phase composed of numerous fine particles has also been observed during reaction. The solid phase nucleation has been found to occur in the colloidal phase, which leads to the formation of some stable nucleus centers. The solid phase nucleus has been found to grow in symmetric crystal patterns, with the progress of reaction, exhibiting spherulitic morphology. The possible growth behavior of spherulites has also been discussed. The spherulitic structure composed of fine crystal fibrils diverging from a common center have been observed by a scanning electron microscopy (SEM) technique. The polymorphic crystalline phase, found in spherulites has been supported by thermal characterization (TGA/DTA) and X-ray diffraction (XRD) patterns of crystal materials.

Summary of the Research Work

This chapter summarizes and concludes the entire work carried out under the scope of this book.

Growth and Form of Spherulitic Crystal Pattern

This chapter gives the detailed experimental procedure adopted for the growth of selforganized nanostructured spherulitic patterns and their morphological investigation. The chapter also elucidates the roles of the various possible factors behind such phase transformation along with the plausible explanation of the corresponding reaction pathways

Growth and Formation of Diffusion-Limited-Aggregation Crystal Pattern

This chapter described that the DLA crystal patterns have been characterized by optical microscope (OPM), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric (TG) analysis. The oscillatory behaviour, exhibited by UV-Visible spectroscopy, is found to be interrelated to the DLA structures formed in the reaction system.

Growth and Form of Self-organized Branched Crystal Pattern in Nonlinear Chemical System

Self-organization phenomenon and various types of pattern formation, involving diffusion-driven mechanism might be observed in biological, chemical, and geochemical systems. Exciting phenomena such as precipitation, electric potential oscillations, chaos, fractal growth, etc., which are far from equilibrium, have captivated considerable attention in recent years. The spontaneous formation of nano-scale patterns seems to be a significant way to control the structure and morphology of various functional materials. Self-organization, based on interplay between reactions and diffusion, has been found to occur in a range of physical and chemical systems. The recent development of non-equilibrium crystallization phenomenon enables one to form spontaneous, coherent, and periodic patterns which are accompanied by molecular interactions. Among the different nanostructures, the dendrite (DLA and spherulitic) crystal patterns attract the attention of scientific community due to their importance in connection to some fractal growth phenomena and crystallography research. The growth of dendrite crystals is also an example which mimics several pattern-forming phenomena encountered in nature and biology. In this connection, the BZ reaction is one of the best prototype systems for exploring such self-organization based phenomenon. The most widely studied oscillatory reaction is the BZ reaction that became model for investigating a wide range of intriguing pattern formations in chemical systems. So many modifications in classic version of BZ reaction have been carried out under various experimental conditions that demonstrate rich varieties of temporal oscillations and spatiotemporal patterns in non-equilibrium conditions. Mixed-mode versions of BZ reactions, which comprise a pair of organic substrates or dual metal catalysts, have displayed very complex oscillating behaviors and novel space–time patterns during reaction processes. These characteristic spatiotemporal properties of BZ reactions have attracted increasing attention of the scientific community in recent years because of its comparable periodic structures in electrochemical systems, polymerization process, and non-equilibrium crystallization phenomena. Instead non-equilibrium crystallization phenomenon which leads to the development of novel crystal morphologies in constraint of thermodynamic equilibrium conditions have been investigated and are said to be stationary