J. Jayaramudu

Preparation and characterization of nano-cellulose with new shape from different precursor

Three different precursor materials - 1. China cotton, 2. South African cotton, 3. Waste tissue papers were used to produce nano-cellulose by acid hydrolysis route. No chemical pretreatment has been done for the production of nano-cellulose from these precursors. Prepared nano-cellulose and their corresponding precursor materials were characterized by transmission electron microscopy (TEM), particle size analysis, X-ray diffraction (XRD) study, thermo gravimetric analysis (TGA), differential scanning calorimetric (DSC) analysis and Fourier transformed infra red (FTIR) spectroscopy. A comparative study of the characteristics was done with the properties of raw materials and with that of nano-cellulose. Shape and size of the nano cellulose generally depends on nature of the precursor and hydrolysis condition. Morphology study of nano-cellulose from different sources revealed range of length from 50 to 200 nm and diameter from 10 to 90 nm. Higher thermal stability and crystallinity of nano-cellulose were observed compared to that of precursor from TGA/DSC study.

Structure and properties of poly (lactic acid)/Sterculia urens uniaxial fabric biocomposites

Uniaxial cellulose fabric Sterculia urens reinforced poly (lactic acid) (PLA) matrix biocomposites were prepared by a two-roll mill. In order to assess the suitability of Sterculia fabric as reinforcement for PLA matrix, the PLA/Sterculia fabric biocomposites were prepared. Tensile parameters, such as maximum stress, Youngs modulus and elongation-at-break, were determined using the Universal Testing Machine. The effect of alkali treatment and silane-coupling agent on the tensile properties of PLA-based biocomposites was studied. The results of thermogravimetric analysis show that uniaxial treatment of the fabric can improve the degradation temperature of the biocomposites. Moreover, morphological studies by scanning electron microscopy confirmed that better adhesion between the uniaxial fabric and the matrix was achieved. It was established that standard PLA resins are suitable for the manufacture of S. urens uniaxial fabric reinforced biocomposites with excellent engineering properties, useful for food packaging.

Preparation and Properties of Biodegradable Spent Tea Leaf Powder/Poly(Propylene Carbonate) Composite Films

The aim of the present work is to develop novel bio-based lightweight material with improved tensile and thermal properties. Spent tea leaf powder (STLP) was used as a filler to improve the tensile and thermal properties of polypropylene carbonate (PPC). Tea is an important material used in hotels and households, and spent tea leaf is a resulting solid waste. Composite films with STLP were obtained by the solution casting method. These films were characterized by optical and scanning electron microscopy, Fourier transform-infrared spectroscopy, thermogravimetric analysis, and tensile testing to examine the effect of filler content on the properties of the composites. The results showed that composite films have increased tensile strength due to enhanced interfacial adhesion between the filler and the matrix. In addition, the composite films also exhibited higher thermal degradation temperatures than pure polypropylene carbonate. The morphology results indicate that there is a good interface interaction between STLP and PPC. Results of the study reveal STLP to be a promising green filler for polymer plastics.

Extraction and Characterization of Natural Cellulose Fibers from Maize Tassel

This article reports on the extraction and characterization of novel natural cellulose fibers obtained from the maize (tassel) plant. Cellulose was extracted from the agricultural residue (waste biomaterial) of maize tassel. The maize tassel fibers were obtained after treatment with NaOH and were carefully characterized while the chemical composition was determined. The chemical composition of the maize tassel fibers showed that the cellulose content increased from 41% to 56%, following alkali treatment. FT-IR spectroscopic analysis of maize tassel fibers confirmed that this chemical treatment also shows the way to partial elimination of hemicelluloses and lignin from the structure of the maize tassel fibers. X-ray diffraction results indicated that this process resulted in enhanced crystallinity of the maize tassel fibers. The thermal properties of the maize tassel fibers were studied by the TGA technique and were found to have improved significantly. The degradation temperature of the alkali-treated maize tassel fiber is higher than that of the untreated maize tassel fibers. This value convincingly showed the potential of maize tassel fibers for use in reinforced biocomposites and waste water treatment.

A review of natural fibres, their sustainability and automotive applications

In recent years, the amount of research on natural fibres and natural-fibre-based products has increased substantially. The reason for this increase is due to a greater awareness of the environment and the ever depleting trend of petroleum supplies. Natural fibre composites and in general, natural fibres have a big role to play towards a sustainable environmentally friendly future. The automotive industry is taking big steps toward a more eco-friendly product chain by implementing natural fibres as a base for making various components, such as seat backs, door panels, spare tyre and boot linings. The world production of natural fibres is increasing since the product base is increasing. Each year, more synthetic fibres and high energy consuming products are being replaced by natural-fibre-based products. The reason for this trend is not only due to an increased environmental awareness but also because natural fibres have excellent properties, such as light weight, and they have relatively low costs. This study attempts to review the most commercially important natural fibres and their automotive application and also looks at the properties, chemical composition and cost of some natural fibres being used in industry.

Mechanical properties of uniaxial natural fabric Grewia tilifolia reinforced epoxy based composites: Effects of chemical treatment

The effects of chemical treatment on the mechanical, morphological, and chemical resistance properties of uniaxial natural fabrics, Grewia tilifolia/epoxy composites, were studied. In order to enhance the interfacial bonding between the epoxy matrix and the Grewia tilifolia fabrics, two different types of treatment: alkali treatment (5 % NaOH) and (3-aminopropyl)-triethoxysilane coupling agent (CA), were used. The epoxy composites containing 0–15 wt% of Grewia tilifolia fabric were prepared by hand lay-up technique, at room temperature. The tensile and flexural properties of the untreated, alkali-treated and coupling agent treated Grewia tilifolia reinforced epoxy composites were determined as a function of fabric loading. The 9 % wt Grewia tilifolia fabric reinforced epoxy composites showed improved tensile and flexural modulii when compared to the neat epoxy matrix. Significant improvement in the mechanical properties was obtained when both alkali and coupling agent treated fabrics were used as reinforcement. Morphological studies demonstrated that better adhesion between the fabrics and the matrix was achieved especially when the alkali-treated and coupling agent treated Grewia tilifolia fabrics were used in the composites. For the water absorption and chemical resistance studies, various solvents, acids and alkalis were used on the epoxy composites. This study has shown that Grewia tilifolia fabric/epoxy composites are promising candidates for structural applications, where high strength and stiffness are required.

A New Series of Two-Ring-Based Side Chain Liquid Crystalline Polymers: Synthesis and Mesophase Characterization

A new series of side chain liquid crystalline polymers containing a core, a butamethylenoxy spacer, ester groups, and terminal alkoxy groups were synthesised and their structures were confirmed. The core was constructed with two phenyl rings and an ester linking unit. All the polymers were characterised by hot-stage polarising optical microscopy, differential scanning calorimetry, variable temperature X-ray diffraction, thermogravimetric analysis, and gel permeation chromatography. The polymers were found to be liquid crystalline. The nematic and smectic A (SA) phases were observed for the homologues with short-terminal chains (C2 and C6), whereas the homologues with longer chains (C8 to C12) exhibited a smectic C phase. The thermal stability of the polymers was found to be in the range of 293 to 326 0 C and the molecular weights of the polymers were found to vary from 6_10 3 to 1.3_10 4 .

Tensile Properties of Polycarbonate Coated Natural Fabric Grewia tilifolia

The natural fabric from the tree of Grewia tilifolia was coated with polycarbonate. The tensile properties of both the uncoated and polycarbonate coated fabrics were studied. The tensile parameters such as maximum stress, Young’s modulus and percentage elongation at break were determined using a Universal Testing Machine. The effect of alkali treatment and the polycarbonate coating on tensile properties was studied. The improvement in the tensile properties on polycarbonate coating was attributed to the filling up of the void regions of the uniaxial fabrics with polycarbonate facilitating continuity.

Immiscible Polymer Blends Stabilized with Nanophase

The importance of phase morphology in immiscible blend makes the issue of stability also very important. In this chapter, we try to explain the role of nanoparticles in the stabilization of dispersed phases from the experimental and theoretical point. As inorganic particles, it might seem impossible from the classical chemistry point of view. However, their sizes and shapes have them some very important advantages, such that interactions that may not have been possible with microsize particles now are with nanoscale particles. However, it is not as straightforward as it sounds. Therefore, factors that are necessary for these particles to act as compatibilizers and those required of the polymer blends are discussed here so that first timers in material science of polymer blends can follow through.

Hydrophobic/Hydrophilic Nanostructured Polymer Blends

It is the objective of this chapter to review the hydrophobically modified water-soluble and other hydrophilic nanostructured polymer systems and their biocompatibility for potential use in biomedical applications. The nanostructured polymer systems reviewed include block copolymers, amphilic copolymers, nanostructured polymer blends, and networks that exhibit hydrophilic/hydrophobic micro-/nanophase domain structures. Enhanced biocompatibility and mechanical strength appear to be a general characteristic of such systems as compared to single phase hydrophilic polymers. Fabrication of solid surfaces in terms of chemical affinity including hydrophilicity is a technology of importance in the development of various devices and functional materials. In particular, super-hydrophobic/super-hydrophilic patterning is crucial because it is applicable to the control of liquid flow and the immobilization of functional materials into specific areas. The ability to create superhydrophilic-superhydrophobic micro patterns and arrays on nanostructured polymer blends is essential for a variety of applications ranging from micro fluidics to cell microarrays. Despite a lot of research done on the development of new superhydrophobic and superhydrophilic surfaces on nanostructured polymer blend films, creating precise, and stable micro patterns of superhydrophilic and superhydrophobic areas has proved challenging. To the best of our knowledge, most of the existing methods are based on the surface modification of a rough superhydrophobic and or superhydrophilic substrate through a mask to reverse hydrophobicity of the exposed areas.