Description:Field of Invention
The present invention pertains to fabrication of coir based green composite comprising jaggery and calcium carbonate.
Background of the Invention
The need for newer composite materials has been increasing. Elevated environmental awareness of the general public in reducing carbon footprints and the use of non-naturally decomposed solid wastes has resulted in an increasing use of natural materials, biodegradable and recyclable polymers, and their composites for a wide range of engineering applications.
Fiber reinforced polymer composites play key roles in various applications and reduce carbon footprint on the environment. Researchers are keenly interested on the study and fabrication of fiber reinforced polymer composites. Natural fibers are researched to be good reinforcement due to their ability of decreasing density and cost of composites.
The polymeric composites where reinforcements are natural fibers and bio-polymers as matrix are called green composites. Some natural fibers are coir, flax, sisal, hemp etc. Examples of bio-polymer matrix are starch, PLA, PBAT, CNSL, furan etc.
Natural fiber composite is an emerging material that has great potential to be used in engineering application. Oil palm, sugar palm, bagasse, coir, banana stem, hemp, jute, sisal, kenaf, roselle, rice husk, betel nut husk and cocoa pod are among the natural fibers reported to be used as reinforcing materials in polymer composites. Natural fiber composites were used in many industries such as automotive, building, furniture, marine and aerospace industries. The advantages of natural fiber composites include low cost, renewable, abundance, light weight, less abrasive and they are suitable to be used in semi or nonstructural engineering components. Research on various aspects of natural fiber composites such as characterization, determination of properties and design have been extensively carried out.Natural fiber-reinforced polymers have advantages such as low cost, low density, high strength and stiffness, good absorption, and high energy absorption. The purpose of using recycled natural fiber reinforced polymers is one way that can be done to reduce the increasing waste of plastic waste and use abundant natural resources by combining the two component properties to produce a reinforcing component that can improve bio composite properties at low cost and good strength. The main issues in the using of natural fibers are poor strength between the fibers and matrix that lead to microcracking on the surface as well as inside of the composite causing a decrease in the mechanical properties.
Preparation of green composites are known in the prior art. For instance,US9499686B2 discussesthe preparation of bacterial cellulose based green composites. The green composite produced is Acetobacter xylinum, which is a sustainable and biodegradable fibrous material having same chemical structure as plant based cellulose fibers. BC fibers have diameters in range of a few nano meters yet display higher tensile strength. The production of these BC fibers is not economic as the cost of sugar is high and not considered for large scale production. The preparation of carbon-carbon composite was disclosed in US7332112B1. The invention discusses the apparatus and method for impregnating the carbonized part with a substantially curing by-product free, high carbon yield resin.US9512304B2 discloses the production of modified plant fiber and plant fiber-based resin to overcome the previous drawbacks. However, there is less work conducted of naturally available fiber without pre-treatment or modification.
Accordingly, there is an urgent need and demand for a green composite prepared using naturally available fibers. The present invention overcomesthe gap in use of naturally available fibers in the prior art and discloses herein the preparation of green composite with naturally available coir fiber, jaggery and calcium carbonateconsiderate of the above-mentioned drawbacks.
Summary of the Invention
Considering the above-mentioned drawbacks in the prior art, the present invention aims to create a green composite with naturally available fiber coir, jaggery and limestone.
The specific objective of the invention is to research and fabricate a composite using naturally occurring substances without any chemical pre-treatment or chemical use.
A further specific objective of the invention is to remove the drawbacks while aiming to increase structural strength of the composite fabricated.
Brief Description of Drawings
The invention will be described in detail with reference to the exemplary embodiments shown in the figures wherein:
Figure 1 Photograph of fabricated coir green composite
Detailed Description of the Invention
The embodiments of the present disclosure provide fabrication of composite which satisfies the following criteria, i) Fiber, resin and all the constituents to be occurring naturally. ii) No chemical treatment of the fiber, resin required
Coir is a hard biodegradable Fiber that is obtained from the outer layer of coconut fruits and makes up about 25% of it. Coir has more life compared to other natural Fibers due to its high lignin content. Due to the high lignin content of coir Fibers, they are durable, weather resistant and relatively waterproof and be chemically modified. The fibers also have high elongation at break i.e. they can also be stretched beyond the elastic limit without rupture. Coir Fibers possess several advantageous properties such as low cost, high lignin content, low density, availability, high elongation at break and low elastic modulus.Coir fibers are the only naturally occurring fibers resistant to salt water damage.
Coir fibers are processed by pulling them apart (carding) to remove any impurities. Carding helps in separating the fibers in coir which increase the fiber matrix adhesion. It gives individual fibers that are narrow and hollow. They have thick walls of cellulose. Coir fibers are the only naturally occurring fibers resistant to salt water damage.
Jaggery is a traditional non-centrifugal cane sugar consumed in the Indian Subcontinent, Southeast Asia, and Africa. It is a concentrated product of cane juice and often date or palm sap without separation of the molasses and crystals, and can vary from golden brown to dark brown in color. It contains up to 50% sucrose, up to 20% invert sugars, and up to 20% moisture, with the remainder made up of other insoluble matter, such as wood ash, proteins, and bagasse fibers. Jaggery is heated to its boiling point i.e., 2000C. This helps remove the moisture from jaggery to increase its binding capacity. When jaggery is brought to this temperature, it becomes a thick semi solid which acts as resin to coir reinforcement.
CaCO3 (Limestone) is a molecular formula that defines a white or transparent mineral in the form of crystals. Calcium carbonate (customary name – calcite) consists of a carbonic acid calcium salt. The water solubility of CaCO3 is poor and the powder is perfect for the production of cement, an essential ingredient of masonry and plastering mortar. Calcite forms high-quality durable binders that last for years whether used outdoors or indoors. CaCO3 stones are crushed into fine powder with uniform size less than 100 nm.
The Jaggery and CaCO3 are stirred together rapidly beforethe jaggery to cools down. The mixture is stirred well to achieve uniform composition. The stirring also releases the trapped CO2, released while heating limestone.When CO2 is released, the residual CaO in the mixture increases the strength of matrix. This increases the shear load bearing capacity of the composite acquired. Limestone increases the strength of jaggery while showing less effect on its binding capacity.
Coir fibers are cut into 5-10 mm length with coconut husk (which have high cellulose). They are then introduced into the mixture and stirred in clockwise and anti-clockwise direction. This stirring decreases the void formation and helps aid in increasing fiber-matrix interface adhesion. It helps create a uniform composition of constituent materials in the whole specimen fabricated. Coir fibers are the reinforcement which are the major load carrying member of the composite responsible for tensile strength.
The mold is prepared with vegetable oil in order to create a layer between mold and composite. This layer helps in easier removal of the cured composite. The cured composite is then poured into a flat mold. The mold is closed with a top force or plug member, pressure is applied to force the material into contact with all mold areas, while heat and pressure are maintained until the molding material has cured.
The mold is placed in hydraulic press and pressure above 1000 psi is applied. Pressure in the range of 1200-1500 psi proved to be the best. The cast specimen is left in the press to cure naturally. It is then removed from the mold.
The reinforcement percentage determine the composite properties obtained. In this case, limestone and coir fibers act as reinforcement in the composite while jaggery acts as matrix. The percentage of limestone even determines the fiber matrix adhesion. The limestone percentage alteration helped in adhesion and strength determination.
Equal amounts of coconut fibers and matrix were taken in volume ratio i.e., 1:1=Vc(volume of coconut fibers): Vm (volume of matrix).
Limestone powder was measured as 6% of total weight of the jaggery and added to create the resin matrix.
4 Claims & 1 Figure
Equivalents
Coir reinforced jaggery composite of the present invention discloses fabrication and method of preparation of green composite. The above material can be used in automobiles and aircrafts as decorative parts. The scope of the invention was not limited to its usage as decorative item, rather can be used to replace most of the materials which bear less loads. , Claims:The scope of the invention is defined by the following claims:

Claim:
1. The fabrication of coir reinforced jaggery composite comprising:
a) The major constituents are coir fiber, lime stone and jiggery. The reinforcement is coir fiber and the matrix is jaggery. The equal amount of fiber and matrix are taken in volume ratio of 1:1.
b) The Jaggery and CaCO3 are stirred together rapidly before the jaggery to cools down. The mixture is stirred well to achieve uniform composition.
c) The coir fibers are cut into 5-10 mm length with coconut husk (which have high cellulose) and introduced into the matrix mixture and stirred in clockwise and anti-clockwise direction. This Coir fibers are the reinforcement which are the major load carrying member of the composite responsible for tensile strength.
d) The mold is prepared with vegetable oil in order to create a layer between mold and composite. This layer helps in easier removal of the cured composite.
2. As mentioned in claim 1, the stirring of jaggery and CaCO3 releases the trapped CO2 while heating the limestone. The residual CaO in the mixture increases the strength of matrix in turn the shear load bearing capacity of the composite increased.
3. According to claim 1, the stirring of fiber and matrix decreases the void formation and helps aid in increasing fiber-matrix interface adhesion. It helps create a uniform composition of constituent materials in the whole specimen fabricated. The Coir fibers are the reinforcement which are the major load carrying member of the composite responsible for tensile strength.
4. As per claim 1, the cured composite is poured into a flat mold. The mold is closed with a top force, pressure is applied to force the material into contact with all mold areas, while heat and pressure are maintained until the molding material is cured.