A Study on Cannabis Sativa L. Hemp Reinforced Polymer Composites for Marine Applications

Abstract

Traditional engineering materials pose a great challenge for marine environment due to their corrosive nature leading to ocean acidification. This further poses a great threat to marine creatures destroying their environment. Since decades, polymer composites started replacing traditional materials like metals for making marine structures due to their high strength to weight ratio, low elongation, and low life cycle cost because of fewer problems associated with wear and corrosion. Over the time, the use of fiber reinforced polymer (FRP) composites have grown from manufacturing pleasure boats, boat hulls etc. to large scale applications like submarines, military vessels, propellers and propulsion shafts. Apart from traditional marine ship and boat structures, FRP composites have gained popularity in the field of offshore industries like lifeboats, buoys, floats etc., and renewable marine energy such as tidal and floating wind turbines. The utilization of natural fiber over synthetic fiber as reinforcement in polymer composites have been growing recently, as the world becomes more environmentally conscious. So, this work is undertaken to study the potential of a natural fiber for marine applications. Natural plant fibers are primarily composed of cellulose, hemicellulose, lignin, pectin, and wax, with small amounts of other constituents. These constituents have an impact on the fiber’s physical, mechanical, thermal, and other characteristics. Therefore, the careful selection of suitable natural fiber for the desired application is required. The researchers’ estimations or limited evaluation perspectives still govern the selection of natural fibers for composite fabrication. By applying multi-criteria decision making (MCDM) methods to the properties of natural fibers, one can make a statistically sound decision about which fiber to use. However, this can be a disadvantage in terms of the complexity of testing for determining fiber properties when introducing a new fiber. Determination of chemical constituents is an easy and straightforward procedure. A novel technique is designed in MATLAB for natural plant fiber selection based on the chemical constituents of the fibers as well as the correlation between the properties of the fibers and their chemical constituents using MCDM techniques. The correlation matrix is used to convert the weights given to properties into the weights of chemical constituents by weighted scoring model. Hemp is one of the strongest and most durable commercially available natural fiber. Its biodegradability, low density, high fiber length, availability, low weight-to-strength ratio and more yield per acre makes it an ideal fiber for marine applications. Before reinforcing any fiber/fabric into the matrix to form composites, its characteristics should be investigated. The strength of fiber has significant effect on the performance of a composite because it bears majority of the load. The present work describes the modern and systematic methods for examining the physical and mechanical properties of Cannabis sativa L. hemp fiber and its fabric. The hemp fiber is characterized in this study based on its constituents. Additionally, thermal stability, crystallinity, elemental analysis, and Fourier transform infrared spectroscopy has also been determined. The physical, mechanical and dynamic mechanical properties, thermal stability, water absorption of hemp fiber reinforced polymer composites have been studied. A numerical simulation was performed to determine the loads on a surfboard in a marine environment. MCDM techniques are utilized to select the best suitable hemp composite among the alternatives for fabrication of surfboard. The findings of this study provide valuable insight into the potential use of hemp fiber for surfboard fabrication.