G. M. Arifuzzaman Khan

Estimation of Main Constituents of Ananus comosus (Pineapple) Leaf Fiber and Its Photo-Oxidative Degradation

An estimation of main constituents of pineapple leaf fiber (PALF) by conventional method was attempted and the values of 74.44% α-cellulose, 13.39% hemicellulose, 7.12% lignin, 2.89% pectic matter, and 0.58% aqueous extract were obtained. So, the main constituents of PALF are α-cellulose, hemicelluloses, and lignin. The molecular weight of raw, bleached PALF and α-cellulose of PALF were 1.517 × 105, 1.303 × 105, and 1.225 × 105, respectively. Bleached PALF was dyed with two dyes, Direct Green 27 and Acid Orange 52. Maximum dye exhaustion was found to be 98.97% for Direct Green 27 under the conditions of 3% dye concentration, 5% electrolyte concentration, and 70°C temperature, and 93.27% dye exhaustion was found for Acid Orange 52, where dyeing conditions were 4% dye concentration, 6% electrolyte concentration, and 80°C temperature. Dyeing time was fixed for 60 min for both dyes. The color fastness of PALF on exposure to sunlight has also been studied. It was observed that color fastness of raw fiber is higher than bleached fiber. The degradation of PALF under sunlight was studied by tensile strength and molecular weight measurements. Bleached fiber exhibited lesser loss of tensile strength and molecular weight than raw fiber. Infrared spectra (IR) of PALF were measured for different exposure times under sunlight. The PALF containing higher α-cellulose has good characteristics, similar to materials of higher molecular weight. For this, it gives high tensile strength, more dyeability, and better color fastness properties.

Renewable Okra Bast Fiber Reinforced Phenol Formaldehyde Resin Composites: Mechanical and Thermal Studies

Okra bast fiber (OBF) reinforced thermoset phenol formaldehyde (PF) resin composites were prepared by compression molding methods. In order to found better wetting of filler and matrix, OBF was treated with NaOH. The properties of composites were studied by mechanical tests, thermal methods and water uptake. The mechanical properties such as tensile strength (TS), Young’s modulus (YM), tensile elongation, flexural strength (FS) and flexural modulus of composites were varied with NaOH concentration, treatment time and fiber loading. TS and FS were found to increase for fiber loading upto 30% and then decreased whereas YM, FM and tensile elongation were increased with increase of weight fraction. About 21% more TS and 85% more FS was found for 10% alkali treated fiber composite than untreated fiber composite. Treated fiber composites also showed greater thermal stability and lower water absorption property

Surface Chemical Treatments of Jute Fiber for High Value Composite Uses

In order to confer hydrophobicity, higher mechanical and thermal properties, jute fiber has been chemically modified by means of NaClO2 bleaching, acrylonitrile (AN) grafting and diphenylmethanediisocyanate (DPMIC) treatment. The extent of modification reaction is evaluated by FTIR measurement. Morphologies and crystalline index of jute fibers are investigated using scanning electron microscopy (SEM) and wide angle X-ray diffractometer (WAXD). A significant variation in fibre surface occurred by chemical treatments is clearly observed in SEM images. It has been found that tensile properties (tensile strength, extension at break and Youngs modulus) are substantial improved by AN-grafting and DPMIC treatment. Based on findings of hydrophobicity, the DPMIC treated fiber has been showed better properties than other fibers. Chemical treatment also increases the thermal stability. The TG and DTA curves show two-stages of decomposition for all the fibres; first below 100°C indicating the moisture loss and the second between 320°C and 360°C due to major degradation of fibre.

Utilization of Sawmill By-Product for Making Cellulose and Its Valuable Derivatives

Nowadays, biomass is a valuable raw material not only for energy but also achieving the goal of sustainable development by converting into various life saving, decorative, structural and nonfood consumer products such as pharmaceuticals, paints, adhesives, textile products, polymer composites, cosmetics, papers, and various commodity specially cellulose derivatives. The main constituent of most biomass is cellulose. Sawdust is a good representative of abundant residual forest biomass and consists of 40–50 % of cellulose, 25–35 % of hemicelluloses, and 20–30 % lignin, approximately. It is frequently used for direct combustion in our subcontinent resulting in energy loss and environmental pollution. As it contains higher percentage of cellulose, it can be value-added by producing plenty of precious cellulose derivatives, for instance, carboxymethylcellulose (CMC) which is extensively used as emulsion stabilization, binder, thickener of paints, film-former in textiles, etc. A number of researches have been published on the preparation of cellulose derivatives from wood and sawdust. This chapter will accumulate some basic synthesis reactions and scope of applications of valuable cellulose derivatives.

Studies on Okra Bast Fibre-Reinforced Phenol Formaldehyde Resin Composites

Bast fibres are mainly composed of lignocellulosic materials. It is extracted from the outer cell layers of the stems of different plants species. In ancient times, bast fibres were used for making various products like rope, bags, mats and coarse textile materials to mitigate daily demands. However, such trendy usages of bast fibres were decreased behind the invention of cheap synthetic fibre. Although synthetic fibres have good strength and longibility, they are causing serious environmental pollution for their nonbiodegradable nature. To achieve the ‘sustainable development’, the usages of bast fibres are explored again. Diversified use of bast fibres as reinforcements of polymer matrix composites becomes popular due to its satisfactory engineering properties. The plant kingdom has a vast source of bast fibres. Few of them are utilized for reinforcing polymer composites and many species remain unexplored. Okra (Abelmoschus esculentus) bast fibre has no commercial value currently. It is considered as agricultural waste product after collecting vegetable. In fact, its chemical composition is almost similar to other commercial bast fibres, such as α-cellulose (60–70 %), hemicelluloses (15–20 %), lignin (5–10 %) and pectins (3–5 %) along with trace amount of water-soluble materials. The fibre exhibited high breaking tenacity (40–60 MPa) and high breaking elongation (3–5 %). In this chapter, okra bast fibre is introduced as a reinforcement material for fabrication of phenol formaldehyde resin composites. Manufacturing techniques and effect of fibre modification on their mechanical, thermal and biodegradation properties are discussed.