Vetiver root based sustainable ecofrindly electro-acoustic stealth material

Abstract

ABSTRACT VETIVER ROOT BASED SUSTAINABLE ECOFRINDLY ELECTRO-ACOUSTIC STEALTH MATERIAL The present invention relates to an eco-friendly bio composite electro-acoustic stealth material and a method (400) for fabricating thereof. The bio composite electro-acoustic stealth material comprising ethanol treated vetiver roots in a bath of ultrasonication along with a blend of epoxy and hardener. The bio composite electro-acoustic stealth material has improved properties of electro-acoustic, thermal insulating, dielectric, mechanical strength along with low cost for fabrication thereof. Figures 1 and 4

Description

Description:FIELD OF INVENTIONThe present disclosure generally relates to the field of electro-acoustic materials. More specifically, the present disclosure relates to bio composite and biodegradable radar-absorbing materials (RAM) with improved properties of electro-acoustic, thermal insulating, dielectric, mechanical strength along with low cost for preparation thereof. The present disclosure also relates to a method for preparing the bio composite and biodegradable RAM.BACKGROUND OF THE INVENTIONElectro-acoustic stealth material- Radar-absorbing material (RAM) is a class of material which is coated on a surface of structures stealth military aircrafts such as F-22 Raptor to avoid radar detection i.e. invisibility to a radar. In stealth technology, RAMs are used to reduce radar cross-section (RCS). A RAM actually absorbs the incident electromagnetic (EM) energy, thereby reducing the energy reflected or scattered back to the radar which further reduces the RCS signature of the coated object; thereby camouflaging it from enemy eyes. Apart from defence related matters, RAMs also have benefits of minimizing the problem of electromagnetic interference (EMI) pollution. The EMI problem has been on the rise; owing to the astronomical increase in the microwave operated electronic devices. The EMI pollution interferes with the circuitry of the device rendering its function unsatisfactory. Most of the conventional RAMs consist of ferromagnetic particles embedded in a polymer matrix having a high dielectric constant. For example, iron ball paint containing tiny metal-coated spheres suspended in an epoxy-based paint. The spheres are coated with ferrite or carbonyl iron. Another conventional RAM consists of neoprene sheet containing ferrite or carbon black particles. Both the conventional RAMs work on the principle of converting the radar waves to heat. Some other conventional arts employ composition of Ram material paints made from ferrofluidic and nonmagnetic materials. Some conventional arts involve fireproofed urethane foam loaded with conductive carbon black [carbonyl iron spherical particles, and / or crystalline graphite particles] in mixtures between 0.05% and 0.1% (by weight in finished product), and cut into square pyramids with dimensions set specific to the wavelengths of interest. Some latest RAMs involve carbon nanotubes in the composition; ceramic materials thereof. The conventional arts work towards achieving maximum radar absorption. However, there are certain disadvantages associated therewith. It is always been difficult for the existing conventional arts to decompose or degrade to full extent, thereby causing damage to environment. Another challenge is with high cost for manufacturing such materials-based RAMs. Still there have been challenges associated in achieving high strength of such materials to reduce high level of noise. Even though the synthetic and ceramic material has potential to attain highest reduction in high level of noise, however biodegradability thereof is an important concern.Therefore, there exists a need for developing eco-friendly electro-acoustic stealth materials i.e. RAM with enhanced properties of electro-acoustic, thermal insulating, dielectric, mechanical strength along with low cost.OBJECTS OF THE INVENTIONThe main object of the present invention is to provide an eco-friendly electro-acoustic stealth material.Another object of the present invention is to provide a low-cost and eco-friendly method for preparing the eco-friendly electro-acoustic stealth material.Another object of the present invention is to enhance electro-acoustic properties of the existing electro-acoustic stealth materials in addition to more properties such as mechanical strength, thermal insulating, dielectric, mechanical strength along with low cost.SUMMARY OF THE INVENTIONIn one aspect of the present disclosure, an eco-friendly bio composite electro-acoustic stealth material is disclosed. The stealth material includes vetiver roots in the range of 30-45 wt% treated with 8-14 wt% of ethanol in a bath of ultra-sonication along with blend of 40-55 wt% of hardener and 3-6 wt% of epoxy. In some embodiments, the vetiver roots may be untreated. The frequency of ultra-sonication bath is 125 kHz and 60W power output. In an embodiment, the epoxy is LY-556 and the hardener is HY-951. In another embodiment, other examples of the epoxy include such as but not limited to Melamine formaldehyde, Polyester resin, Urea formaldehyde, Polyurethane, and Phenol formaldehyde resin, and so on. In the embodiment, the hardener can be of different grades including such as but not limited to hardeners of different grade like HY- 950, HY-951, HY-952, HY-952, HY-953, etc. can be used with polymers basing on the requirement. The electro-acoustic stealth material is radar absorbing material (RAM).In another aspect of the present disclosure, a method (400) for fabricating an eco-friendly bio composite electro-acoustic stealth material is disclosed. The method (400) involves pre-processing vetiver roots (204), followed by putting 30-45 wt% of the pre-processed vetiver roots (204) inside a beaker (202) kept in a steel tank (206) of ultrasonic bath sonicator (214). The steel tank (206) is filled with at least 1.5 liters of water. The method (400) involves pouring 8-14 wt% of ethanol (216) into the beaker (202) containing the vetiver fiber roots (204), followed by blending thereof for at least one hour along with exposure to ultrasonication thereby providing surface treatment to vetiver roots (204) in ethanol (216). The method (400) involves pouring 3-6 wt% of epoxy into a separate beaker, followed by adding 40-55 wt% of hardener into the beaker containing epoxy in the ratio of 10:1 to form a mixture and stirring the mixture with a mechanical stirrer with a speed of at least 500 RPM for at least 30 minutes until removal of water bubbles therefrom. The above mixture is mixed with the treated vetiver roots (204) in ethanol (216) inside a steel mold of dimension 15cm X 15cm X 1cm. The mold is put with the composite mixture inside a compression molding machine and undergoes release after at least 15 hours.In this respect, before explaining at least one embodiment of the present invention in detail, it is to be understood that the invention is not limited to in its application to the details of processing and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practised and carried out in various ways. Also, it is to be understood that the phraseology terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting.STATEMENT OF THE PRESENT INVENTIONThe present disclosure provides an eco-friendly bio composite electro-acoustic stealth material is disclosed. The stealth material includes vetiver roots in the range of 30-45 wt% treated with 8-14 wt% of ethanol in a bath of ultra-sonication along with blend of 40-55 wt% of hardener and 3-6 wt% of epoxy.The present disclosure also provides a method for fabricating the eco-friendly bio composite electro-acoustic stealth material. The method is low cost and environment friendly.BRIEF DESCRIPTION OF THE DRAWINGSOther objects, features, and advantages of the embodiment will be apparent from the following description when read with reference to the accompanying drawings. In the drawings, wherein like reference numerals denote corresponding parts throughout the several views:Other objects, features, and advantages of the embodiment will be apparent from the following description when read with reference to the accompanying drawings. In the drawings, wherein like reference numerals denote corresponding parts throughout the several views:Referring to Figures 1A-1C, illustrated herewith picture of vetiver root in Figure 1A, along with lateral cross section under microscope in Figure 1B, and approximate diameter of 1 mm measured with scale in Figure 1C, in accordance with an embodiment of a present disclosure;Referring to Figures 2A-2C, illustrated is a schematic of the vetiver roots being blended with ethanol and exposure of such blend to ultrasonication in Figure 2A, Figures 2B and 2C show post effects of ultrasonication treatment on the vetiver roots blended with ethanol, in accordance with the embodiment of the present disclosure;Referring to Figures 3A-3C, illustrated are SEM images of (i) untreated vetiver composite in Figure 3A, (ii) treated vetiver composite in Figure 3B, and cross-section of the vetiver root after surface treatment in Figure 3C, in accordance with the embodiment of the present disclosure;Referring to Figure 4A-4I, illustrated is a series of flowchart steps representing steps of a method (400) for preparing the eco-friendly electro-acoustic stealth material, in accordance with another embodiment of the present disclosure;Referring to Figure 5, illustrated is Energy dispersive X-ray spectroscopy (EDS) of the vetiver composite, in accordance with the embodiment of present disclosure;Referring to Figure 6, illustrated is FTIR Spectra graphs (602) and (604) for untreated and treated vetiver composite respectively, in accordance with the embodiment of present disclosure;Referring to Figure 7, illustrated is variation of sound absorption coefficient with frequency graphs (702) and (704) of untreated and treated vetiver composite respectively, in accordance with the embodiment of present disclosure;Referring to Figure 8, illustrated is variation of dielectric constant with frequency of the vetiver composite, in accordance with the embodiment of present disclosure;Referring to Figure 9, illustrated is variation of dielectric loss with frequency of the vetiver composite, in accordance with the embodiment of present disclosure;Referring to Figure 10, illustrated is variation of tangent loss with frequency of the vetiver composite, in accordance with the embodiment of present disclosure;Referring to Figure 11, illustrated is variation of reflection loss with frequency of the vetiver composite, in accordance with the embodiment of present disclosure; andReferring to Figure 12, illustrated is variation of hardness with load on the vetiver composite, in accordance with the embodiment of present disclosure.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTSThe embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.Many modifications will be apparent to those skilled in the art without departing from the scope of the present invention as hereinbefore described with reference to the accompanying drawings. Throughout this specification and the claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.As used herein, the singular forms “a”, “an”, “the” include plural referents unless the context clearly dictates otherwise. Further, the terms “like”, “as such”, “for example”, “including” are meant to introduce examples which further clarify more general subject matter, and should be contemplated for the persons skilled in the art to understand the subject matter. The reference in this specification to any prior art publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgement or admission or any form of suggestion that the prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavor to which this specification relates.The present disclosure discloses an eco-friendly bio composite electro-acoustic stealth material. bio composite electro-acoustic stealth material is Radar absorbing material (RAM). The bio composite electro-acoustic stealth material has improved properties of electro-acoustic, thermal insulating, dielectric, mechanical strength along with low cost for fabrication thereof. The stealth material includes vetiver roots in the range of 30-45 wt% treated with 8-14 wt% of ethanol in a bath of ultra-sonication along with blend of 40-55 wt% of hardener and 3-6 wt% of epoxy.The vetiver roots have been collected from kirba village of Burla, Sambalpur, India.Figures 1A and 1B show vetiver roots with lateral cross section under microscope. Before treatment of the vetiver roots, the vetiver roots undergo pre-processing. The vetiver roots are cleaned properly with normal water and then with distilled water. The roots are cut into 3 cm length and diameter of 1mm and dried with hot air oven at 80 deg C for 1 hour as shown in Figure 1C. Figure 2A shows a set up (200) for fabricating the bio composite electro-acoustic stealth material. The set up (200) includes a beaker (202) containing the pre-processed vetiver roots (204). The vetiver roots (204) fibres are measured in the range of 30-45 wt% and put inside the beaker (202). The beaker (202) is of 500 ml capacity. The beaker (202) is kept in a steel tank (206). The steel tank (206) is exposed to bath of ultra-sonicator (214). The steel tank (206) is filled with cold water of at least 1.5 litres. The steel tank (206) is surrounded by heating coils (208A, 208B) on either side thereof. There are multiple transducers (210) containing piezoelectric crystal beneath the steel tank (206). The transducers (210) are in continuous communication with an ultrasonic generator (212). The ultrasonic generator (212) produces electrical signals and provide them to the transducers (210). As shown in Figure 2A, ethanol in the range of 8-14wt% is poured into the beaker (202) containing the vetiver roots (204). Blending of the vetiver roots and ethanol is performed for at least one hour. The temperature of the ultra-sonicator (214) is set to room temperature of 27 deg C while the operating frequency is set to 125 kHz and 60 W power output. In some embodiments, the operating frequency can be set up in the 120-240 kHz and power output is in the range of 50 W-120 W. After the treatment of the vetiver roots in ethanol, the vetiver roots are washed in distilled water and dried under room temperature and ultimately the treated vetiver roots are obtained. By utilizing the piezoelectric crystal, the transducers (210) transform a high-frequency electrical signal to ultrasound waves. When such ultrasonic pulse travels through the steel tank (206), compression (218) and rarefaction (220) develop as shown in Figure 2B. By pressing molecules closer, the compression (218) creates a positive tension in the beaker (202) while the rarefaction (220) creates a negative pressure by dispersing molecules. Negative pressure is produced, resulting in the formation of tiny air bubbles (222). Such tiny air bubbles (222) grow in size until they reach unstable dimensions, at which they rupture abruptly and fragment (226), thereby causing cavitation (224). The air bubbles operate as small high-speed brushes, moving quicker and enhancing the speed of aggregation of the vetiver roots (204) in ethanol (216).Figure 2C shows a detailed schematic of the surface of the vetiver roots (204) fibres after ultrasonication. Before ultrasonication, the vetiver root (204) is in natural state having cellulose, lignin and hemicellulose. When the vetiver root (204) is treated with ethanol, the mechanism of ultrasonication causes a rise in the medium's acoustic pressure and temperature, which creates deboning of CH+ and hydroxyl ion owing to cavitation. This hydroxyl ion reacts with the OH group of the cellulose of vetiver roots (204) and eliminates water as vapor, rendering the roots hydrophobic. So due to loss of OH- ions porous structures are formed on the fibre surface. This is confirmed from the scanning electron microscope image shown in Figure 2C.High frequency and small wavelength of ultrasonic wave enables interaction of molecules of the blend at atomic and subatomic region of solvent, by changing the thermodynamic characteristics of optimum blend. Though the ultrasonic wave is unable to dissociate into raw vetiver fibres but increases the available exposed area on the surface of the vetiver fibre by creating a large number of active sites. The presence of large number of active site due to available of more number of activated carbon and interaction of ultrasonic wave with the surfactant to remove the foreign material as well as moisture creates large number of pores on the surface of the fibre so as to make the vetiver composite a good absorber.Figures 3A and 3B show SEM images of untreated vetiver composite and treated vetiver composite. Untreated vetiver composite is fabricated with the raw vetiver fibre without any surface treatment and chemical. In such a situation, the raw fibers undergo washing and cut into 3 cm length and mixed with the matrix of epoxy and the hardener. The mixture is put into the mold and with the help of compression molding, the stealth material is fabricated. Figure 3C shows a cross-section of the vetiver root after surface treatment. The surface treatment is done to improve fiber properties and interfacial bonding with polymeric matrix and to reduce their hydrophilic character. Figures 4A-4I show series of detailed steps of method (400) of fabricating the stealth material. The method (400) involves pouring the predetermined amount of epoxy in a beaker, to which a predetermined amount of the hardener is poured as shown in Figure 4A. Both the components are mixed to form a matrix through a mechanical stirrer at 500 RPM for 30 minutes as shown in Figure 4B. The matrix is mixed with the treated or untreated vetiver roots (204) in Figure 4C, followed by mechanical stirring again in Figure 4D for 30 minutes till a clear mixture of the vetiver roots fibre and the matrix is ready. As shown in Figure 4E, the mixture is put inside a steel mold of dimension 15 cm*15 cm*1 cm. Then the mold is covered with a flat steel plate along with applying pressure thereon as shown in Figure 4F. Thereafter, a load may be applied on the covered mold to keep the composite tight and bound as shown in Figure 4G, the composite may further be demolded as shown in Figure 4H, and the composite for the stealth material may be finally released after 15 hours as shown in Figure 4I.Experimental detailsVetiver roots were cleaned properly with normal water and then with distilled water. The roots were cut into 3 cm and dried with a hot air oven at 80°C for 1hour. 40 wt% (322.20 gm) of vetiver fibres were measured and put inside a beaker of 500ml. 1.5 Litres of water was filled in the steel tank of Ultrasonic Bath Sonicator. 10 wt% (80.55 ml) of Ethanol was poured into the beaker containing vetiver fibre. The fibre and ethanol blending was performed for 1 hour. The temperature of the sonicator was set to room temperature (27°C). The operating frequency was set to 125 kHz and 60 W power output. 45 wt% (366.15 gm) of Epoxy was poured into the beaker and 4.54 wt% (36.61 gm) of hardener was added into it in the ratio 10:1. The mixture of epoxy and hardener was stirred with the mechanical stirrer with a speed of 500 RPM for 30 mins till removal of all the water bubbles from the mixture. The ethanol treated vetiver roots are then mixed with the mixture of epoxy and hardener and again stir with mechanical stirrer for 30 mins till a clear mixture of fiber and matrix (Epoxy and hardener) was ready. The fiber and matrix mixture was put inside a steel mold of dimension 15cm*15cm*1cm. Then the mold was covered with a flat steel plate and a load of 15 kg was kept on it so as to keep the composite tight and bound. The mold with composite mixture was put under inside the compression molding machine. After 15 hours the composite was released from the mold and was ready for characterization and testing.Figure 5 shows Energy dispersive X-ray spectroscopy (EDS) of the vetiver composite for the stealth material. The EDS determines concentration of each and every component of the vetiver composite. Figure 6, illustrated shows FTIR Spectra graphs (602) and (604) for untreated and treated vetiver composite respectively. Figure 7, illustrated shows how sound absorption coefficient varies in case when the vetiver roots used are untreated and when the vetiver roots used are treated with ethanol. The frequency graphs (702) and (704) of untreated and treated vetiver composite respectively depict more increase in absorption of sound for the treated vetiver composite as compared to that of the untreated vetiver composite.Figure 8, illustrated is variation of dielectric constant with frequency of the vetiver composite. As there is increase in the frequency, the dielectric constant of the vetiver composite decreases.Figure 9, illustrated is variation of dielectric loss with frequency of the vetiver composite. Upon comparison of properties of the vetiver roots with other possible organic materials, following are the values highlighting betterment of the vetiver root over the other materialsSl. no Composites Dielectric constant Dielectric Loss Tangent Loss Reflection Loss (dB) Hardness (HV) Sound absorption coefficient1 Graphite 2.8 0.13 0.045 -6.00 NA NA2 Mango Leaves 5.73 0.90 0.14 -4.00 NA NA3 Coco-peat 6.24 5.58 0.89 -9.00 NA NA4 Rice husk 2.89 0.22 0.07 -12.00 NA NA5 Sugarcane baggage 3.35 0.50 0.14 -5.40 NA NA6 Vetiver 2.99 0.25 0.086 -14.00* 23.6 0.91Furthermore, the efficiency of Radar Absorbing Material (RAM) depends on its reflection loss of any composite in X-band frequency range for stealth application which is the key factor of the investigation for any carbon-based material. In the present disclosure, the reflection loss of the RAM found to be higher than the other carbonaceous material. The dielectric loss of the material shows an increasing trend with frequency displayed in Figure 9. At 10GHz frequency, the material shows the highest dielectric loss i.e. 0.22 – 0.26. With increase in frequency from 8-12 GHz, relaxation mechanism also increases and shifts towards right. So, there is an increase in mobility of molecules in the bulk composite. Dielectric property of the composite is affected by both ion mobilization and the electrical conductivity of the composite at lower frequency. But in microwave frequency, the dielectric loss factor depends on the vibration of the ions and the dipole relaxation caused by the inner molecules. The mechanism of dielectric loss in polymers is due to their complex chemical structure that includes continuous molecular chain of various segments in length, polar group, and crystalline phase.Figure 10, illustrated is variation of tangent loss with frequency of the vetiver composite. The tangent loss of the material shows an increasing trend with frequency. The graph plotted between frequency and tangent loss shows that at 10GHz, the fabricated vetiver composite exhibits the highest tangent loss of 0.080 – 0.090. During dielectric measurements, the epoxy polymer based composite exhibits two types of relaxation. With the increase of frequency in microwave range, the peaks get broader and finally merge into a single peak showing relaxation. The single peak is obtained due to the increase in volume of the composite allowing dipolar relaxation. The variation of dielectric loss is contributed by the fact that with increase of frequency, the intrinsic tangent moment and relaxation processes between the ionizing atoms increases tremendously which leads to more absorption within the material.Figure 11, illustrated is variation of reflection loss with frequency of the vetiver composite. The reflection loss of the material decreases with increase of frequency. It has a value of -13.5 dB to -16 dB which is below -10dB at frequency 10GHz. As the material has high dielectric loss, it decreases the amplitude of the electromagnetic wave. This indicates that material have good response to electromagnetic wave and completely attenuates inside it. Figure 12 is variation of hardness with load on the vetiver composite. For hardness test, the vetiver composite was cut into a square shape of size 3-6 cm. Figure 12 shows the graph of the hardness value of the composite with increasing indenter load. The hardness of vetiver composite was found to be 22-24HV. This occurs primarily due to the collapsing of pores under the load. From Figure 12, it can be clearly observed that the composite surface is filled with large numbers of pores which confirms that hardness has a good involvement in increasing the absorptive of the material. From the hardness, value it can be suggested that the vetiver composite can be a better microwave absorbing material.The foregoing descriptions of exemplary embodiments of the present disclosure have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the disclosure to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to best explain the principles of the disclosure and its practical application, to thereby enable others skilled in the art to best utilize the disclosure and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions, substitutions of equivalents are contemplated as circumstance may suggest or render expedient but is intended to cover the application or implementation without departing from the spirit or scope of the claims of the present disclosure.

Claims

, Claims:We Claim1. An eco-friendly bio composite electro-acoustic stealth material comprising vetiver roots in the range of 30-45 wt% with blend of 40-55 wt% of hardener and 3-6 wt% of epoxy.

2. The eco-friendly bio composite electro-acoustic stealth material as claimed in claim 1, wherein the vetiver roots are treated with 8-14 wt% of ethanol in bath of ultra-sonication.

3. The eco-friendly bio composite electro-acoustic stealth material as claimed in claim 1, wherein the vetiver roots are untreated.

4. The eco-friendly bio composite electro-acoustic stealth material as claimed in claim 1, wherein the epoxy is selected from LY-556, Melamine formaldehyde, Polyester resin, Urea formaldehyde, Polyurethane, and Phenol formaldehyde resin.

5. The eco-friendly bio composite electro-acoustic stealth material as claimed in claim 1, wherein the hardener is of different grade selected from one or more of HY- 950, HY-951, HY-952, HY-952, and HY-953,6. The eco-friendly bio composite electro-acoustic stealth material as claimed in claim 1, wherein frequency of ultra-sonication bath is 120-240 kHz and power output in the range of 50-120 W7. The eco-friendly bio composite electro-acoustic stealth material as claimed in claim 1, wherein the electro-acoustic stealth material is radar absorbing material (RAM).

8. A method (400) for fabricating an eco-friendly bio composite electro-acoustic stealth material, the method (400) comprising:(i) pre-processing vetiver roots (204);(ii) putting 30-45 wt% of the pre-processed vetiver roots (204) of step (i) inside a beaker (202) kept in a steel tank (206) of ultrasonic bath sonicator (214), the steel tank (206) filled with at least 1.5 liters of water;(iii) pouring 8-14 wt% of ethanol (216) into the beaker (202) containing the vetiver fiber roots (204), followed by blending thereof for at least one hour along with exposure to ultrasonication thereby providing surface treatment to vetiver roots (204) in ethanol (216);(iv) pouring 3-6 wt% of epoxy into a separate beaker;adding 40-55 wt% of hardener into the beaker containing epoxy in the ratio of 10:1 to form a mixture;(v) stirring the above mixture with a mechanical stirrer with a speed of at least 500 RPM for at least 30 minutes until removal of water bubbles therefrom;(vi) mixing the mixture of step (iv) with the treated vetiver roots (204) in ethanol (216) of step (iii) inside a steel mold or mixing the mixture of step (iv) with untreated vetiver roots (204);(vii) putting the mold with the composite mixture obtained at step (vi) inside a compression molding machine; and(viii) releasing the composite from the mold after at least 15 hours.

9. The method (400) as claimed in claim 6, wherein the method (400) comprising setting temperature of an ultrasonic bath sonicator (214) to room temperature of at least 27 deg C and frequency set in the range of 120 KHz-240 KHz and power output in the range of 50 W-120 W.