Natural plant fibers have unequivocally contributed economic prosperity and sustainability in our daily lives. Particularly, bamboo fibers have been used for industrial applications as diverse as textiles, paper, and construction. Recent renewed interest in bamboo fiber (BF) is primarily targeted for the replacement or reduction in use of glass fiber from non-renewable resources. In this review, various mechanical, chemical, and biological approaches for the preparation and separation of macro-, micro-, and nano-sized fibers from raw bamboo are summarized. The differences in the mechanical, thermal, and other properties of fibers from different materials are linked to their size, aspect ratio, surface charge and groups, and their function in nature. Biocomposites made of BF are considered to be green, environmentally responsible eco-products. Different processing parameters such as fiber extraction, surface modification, and synthesis of the composites affect the characteristics of composites. Fiber length, orientation, concentration, dispersion, aspect ratio, selection of matrix, and chemistry of the matrix must all be considered during fabrication in order to achieve desirable functionalities and performance. Because of the hydrophilic nature of BF, different methods may be adopted to improve interfacial surface adhesion. A better understanding of the fiber structure and characteristics that influence composite performance could lead to the development of additives, coatings, binders, or sizing suitable for natural fiber and a variety of polymeric matrices.

Bamboo fiber and its reinforced composites: structure and properties

The tensile strength and modulus of short, randomly oriented hybrid-natural fiber composite was found out experimentally and also predicted using Rule of Hybrid Mixture (RoHM). Hybrid composites were prepared using banana/sisal fibers of 40:0, 30:10, 20:20, 10:30, and 0:40 ratios, while overall fiber volume fraction was fixed as 0.4 V f . The comparison between experimental and RoHM showed that they are in good agreement.

Prediction of tensile properties of hybrid-natural fiber composites

Traditional, state-of-the-art and renewable thermal building insulation materials: An overview

The effects of chemical modification of fiber surface in sisal–oil palm reinforced natural rubber green composites have been studied. Composites were prepared using fibers treated with varying concentrations of sodium hydroxide solution and different silane coupling agents. The vulcanisation parameters, processability conditions and tensile properties and swelling characteristics of these composites were analysed. The fiber reinforcing efficiency of the chemically treated biocomposites was compared with that of untreated composites. The extent of fiber alignment and strength of fiber–rubber interfacial adhesion was analysed from the swelling measurements. Composites containing chemically treated fibers were found to possess enhanced mechanical properties. The hardness and abrasion resistance of the untreated and treated composites were also analyzed. Surface characterization of treated and untreated sisal fibers by XPS showed the presence of numerous elements on the surface of the fiber. The fracture mechanism of treated and untreated fiber reinforced rubber biocomposites was investigated from SEM studies.

Effect of chemical modification on properties of hybrid fiber biocomposites

The natural fibers nowadays play a major role as reinforcement in composites due to their important properties like lightweight, biodegradability and non-toxicity. Borassus fruit fiber is one such type possessing high cellulose which is inexpensive and available in plenty. The Borassus fruit fibers were extracted and its physical, chemical and mechanical properties such as density, diameter, cellulose, hemicellulose, lignin, wax, denier, tenacity and tensile force were experimentally determined. In this study, the Borassus fruit fibers were treated with 5%, 10% and 15% NaOH and the effect of alkali treatments on the fiber properties were explored. It is interesting to note that 5% NaOH treatment yielded significant improvement in tensile properties of the fibers than the others. The Fourier Transform Infrared Spectrometry (FT-IR) analysis was made to identify the chemical compounds of the raw and alkali treated fibers. The morphological study on raw and alkali treated fibers by Scanning Electron Microscope (SEM) revealed the existence of the impurities on the raw fiber surface and the removal of the same on the treated fibers.

Investigation of physical, chemical and mechanical properties of raw and alkali treated Borassus fruit fiber

The untreated and 2%aqueous NaOH treated bamboo fibers (Dendrocalamus strictus) were coated with epoxy, unsaturated polyester (UP) and their blends. The chemical resistance of these fibers to acetic acid, nitric acid, hydrochloric acid, sodium hydroxide, ammonium hydroxide, sodium carbonate, benzene, toluene, carbon tetrachloride and water was studied. The blend coated fibers showed better resistance to the chemicals mentioned above. The blend coated fibers had higher tensile strength. This was attributed to the hydrogen bonding between the unsaturated polyester and epoxides group.

Chemical Resistance and Tensile Properties of Epoxy/Unsaturated Polyester Blend Coated Bamboo Fibers

Short, natural fibers belonging to the species Hildegardia populifolia were reinforced in styrenated polyester matrix. The mechanical properties of these polymer composites such as tensile modulus, compression strength at first deformation, flexural modulus, and izod impact strength were determined. The effect of alkaline treatment of the natural fiber on the mechanical properties of the composites has been reported. The fractured surfaces of these composites were investigated by scanning electron microscopic technique (SEM) to investigate the interfacial bonding between matrix and the reinforcement. The present work has been carried out in order to make partially biodegradable and eco-friendly composites.

Mechanical Properties of Short, Natural Fiber Hildegardia populifolia-reinforced Styrenated Polyester Composites

The uniaxial natural fabric from the tree Hildegardia populifolia was treated with 5% aqueous NaOH solution for 0, 2, 4, 6, and 8 h, and the resulting changes were analyzed by density, Fourier infrared spectroscopic, X-ray, polarized microscopic, and scanning electron microscopic techniques. On alkali treatment, absorption of water and elimination of hemicellulose in the fabric were observed. In each case, the tensile strength, modulus, and percent elongation at break were determined. The tensile strength, modulus, and density were found to be maximum at 4 h of alkali treatment. Hemicellulose was found on the surface of the untreated fabric. After 6 and 8 h of alkali treatment, some microcracks developed in the fabric. The area of the void region in the fabric increased with the duration of alkali treatment. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1604–1608, 2003

Effect of alkali treatment on properties of the lignocellulose fabric Hildegardia

Miscibility studies of blends of epoxy with unsaturated polyester resin in chloroform were carried out by viscosity, ultrasonic velocity, and refractive methods at 30°C. By using viscosity data, the interaction parameters were computed, which indicated that epoxy/unsaturated polyester resin blends were miscible. The miscibility was further confirmed by the ultrasonic velocity and refractive index methods. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2970–2972, 2003

Miscibility studies of epoxy/unsaturated polyester resin blend in chloroform by viscosity, ultrasonic velocity, and refractive index methods

The primary thermogram of the bamboo fibers of Dendrocalamus strictus family was recorded. Using the primary thermogram and its derivative, the initial degradation, inflection point and final degradation were determined. The refractoriness and integral procedural degradation temperatures were also determined. These studies revealed the suitability of bamboo fibers as reinforcement even with thermoplastic polyolefin matrix materials.

L. Ganga Devi

Papers

Chemical Resistance and Tensile Properties of Epoxy/Unsaturated Polyester Blend Coated Bamboo Fibers

Mechanical Properties of Short, Natural Fiber Hildegardia populifolia-reinforced Styrenated Polyester Composites

Effect of alkali treatment on properties of the lignocellulose fabric Hildegardia

Miscibility studies of epoxy/unsaturated polyester resin blend in chloroform by viscosity, ultrasonic velocity, and refractive index methods

Thermogravimetric analysis of Dendrocalamus strictus bamboo fibers