Indian Patents. 252553:METHOD OF MAKING ALIGNED ROPE LIKE NANOCARBON STRUCTURES WITH PLATELET LIKE CARBON UNITS FROM CASHEW NUT SHELL PYROLYSIS VAPOURS

Title of Invention	METHOD OF MAKING ALIGNED ROPE LIKE NANOCARBON STRUCTURES WITH PLATELET LIKE CARBON UNITS FROM CASHEW NUT SHELL PYROLYSIS VAPOURS
Abstract	ABSTRACT Method of making aligned rope like nanocarbon structures with platelet like carbon units from cashew nut shell pyrolysis vapours. The pyrolysis vapours are cracked at 750°C to 900°C and at atmospheric pressure over a supported bi- metallic catalyst comprising Fe-Ni supported on MgO and the nanocarbon structures formed are purified with an acid.

Full Text	FORM 2 THE PATENTS ACT, 1970 (39 of 1970) As amended by the Patents (Amendment) Act, 2005 & The Patents Rules, 2003 As amended by the Patents (Amendment) Rules, 2006 COMPLETE SPECIFICATION (See section 10 and rule 13) TITLE OF THE INVENTION Method of making aligned rope like nanocarbon structures with platelet like carbon units from cashew nut shell pyrolysis vapours APPLICANTS Indian Institute of Technology, Bombay, an autonomous research and educational institution established in India by a special Act of the Parliament of the Republic of India under the Institutes of Technology Act 1961, Powai, Mumbai 400076, Maharashtra, India INVENTORS Ganesh Anuradda and Das Piyali, both of Indian Institute of Technology, Bombay, Energy Systems Engineering, Powai, Mumbai 400076, Maharashtra, India, both Indian nationals PREAMBLE TO THE DESCRIPTION The following specification particularly describes the invention and the manner in which it is to be performed: FIELD OF INVENTION This invention relates to a method of making aligned rope like nanocarbon structures with platelet like carbon units from cashew nut shell pyrolysis vapours. BACKGROUND OF INVENTION Due to their fascinating broad range of electronic, thermal and structural properties, carbon nanotubes (CNTs), the tubular fullerenes, are envisaged as the key to potentially revolutionary technologies and have attracted a lot of attention from the industries and research communities. They are highly versatile, with a range of applications, which extend from super strong composites to nanoelectronics. The experimental characterisation and applications of the nanotubes have been hampered because of problems with alignment of tubes. Attainment of alignment in synthesised nano-tubes is still being worked upon, through application of external fields, electrical, magnetic or mechanical in nature [ Ingo Dierking, Giusy Scalia, Piero Mo rales, Darren LeCl ere," Aligning and re-orienting carbon nanotubes by nematic liquid crystals",Advanced Materials,Volume 16,lssue 11, pages 865-869, 30 April 2004, 2. http://macdiarind.ac.nz/institute.php-news/success stories/Alan Kaiser]. Carbon nanotubes are seamless tubes of graphite sheets with full fullerene caps, which were first synthesised in 1991 as multilayer concentric tubes called as multi-walled carbon nanotubes and were later synthesised in 1993 as single walled carbon nanotubes. Since then, numerous attempts have been made to syntbesise such products on a large scale and at low cost. Carbon nanotubes are synthesised by methods like arc discharge, laser ablation or catalytic chemical vapour deposition (CVD). Among the various methods, CVD has become more popular and is considered to be the best method for low cost and large scale synthesis of high quality nanotube materials (Moon, C Y, Kim, Y S, Lee, E C, Jin, Y G, Chang, K J, "Mechanisms for Oxidative Etching in Carbon Nanotubes" Physical Review B, Vol. 65, Issue 15, 2002). Gaseous hydrocarbons like methane, ethylene or acetylene are conventionally used for making carbon nanotubes and nanofibres. Aromatic compounds like benzene are also reported as carbon precursor (Teo, B K K, Singh, C, Chhowalla, M, Milne, I W, "Catalytic Synthesis of Carbon Nanotubes and Nanofibers" Encyclopedia of Nanoscience and Nanotechnology, Vol. X, pp 1-22, 2004). Conducting carbon nanofibres and nano thin films from kerosene, which is a mixture of various short and long chains of aromatic and aliphatic hydrocarbons, were also produced (Kumar, M, Kichambare, P D, Sharon, M, Ando, Y, Zhao, X, "Synthesis of Conducting Fibers, Nanotubes and Thin Films of Carbon from Commercial Kerosene", Vol. 34, No. 5, pp 791-801, 1999). Formation of different forms of novel carbon nanomaterials using organic camphor, a natural precursor of carbon is also reported. (Mukhopadhyay, K, Sharon, M, "Glassy Carbon from Camphor-—a natural source", Materials Chemistry and Physics, Vol 49, pp 105-109, 1997). Carbon nanomaterial has also been made from turpentine oil, which consists of hydrocarbon terpenes (C10H16) as the major component (Chaterjee A.K., Maheshwar Sharon and Rangan Banerjee,"Alkaline fuel cellxarbon nanobeads coated with metal catalyst over porous ceramic for hydrogen electrode", Journal of Power Sources, Volume 117, Issues 1-2, pp 39-44, 15 May 2003). Oxygenated materials like alcohol (Maruyama, S, Miyauchi, Y, Murakami, Y and Chiashi, S, "Optical Characterization of Single Walled Carbon Nanotubes Synthesized by Catalytic Decomposition of Alcohol", New Journal of Physics, Vol 5, pp 149, 1-149.12, 2003) and carbon dioxide (Xu, X J, Huang, S M, "Huang Carbon Dioxide as a Carbon Source for Synthesis of Carbon Nanotubes by Chemical Vapour Deposition" Materials Letters, Volume 61, Issue 21, pp 4235-4237, 2007) have also been reported as precursors for making carbon nanotubes. Amorphous carbon bags, which are non-aligned and noncrystalline have been reported from chlorination of ferrocene (Garrote, E U, Brande, D A, Katcho, N A. Herrero, A G, Canovas, A R L, Diaz, L C O, "Amorphous Carbon Nanostructures from Chlorination of Ferrocene", Carbon, Vol 43, pp 978-985, 2005). Wantanabe et al has described in JP Publication No 2007-070166 preparation of nanocarbon materials from biomass namely woodymass as a carbon source. The woodymass is thermally decomposed by heating to produce a carbon-rich gas mixture which is purified and reacted with catalyst to produce the CNTs. Although woodymass, a forest residue, is a renewable source for CNTs, it is costly and it leads to thinning and degradation of forests and deforestation. In order to ensure continued availability of the woodymass rigorous and sustained afforestation is required. The catalytic activity of different transition metal catalysts in the formation of carbon nanotubes has been studied extensively. Besides the commonly used Fe, Co, Ni, catalysts, bimetallic mixtures like Fe-Ni, Fe-Co, Fe-Mo or Co-Ni have been reported to be more effective over single metal catalysts in producing high yield and highly crystalline CNTs (Teo, B K K, Singh, C, Chhowalla, M, Milne, I W, "Catalytic Synthesis of Carbon Nanotubes and Nanofibers" Encyclopedia of Nanoscience and Nanotechnology, Vol X, pp 1-22, 2004). The catalyst-support material also plays a role in the synthesis of carbon nanotubes using the CVD method (Kong, J, Soh, H T, Cassel, A M, Quate, C F, Dai, H J, "Chemical Vapor Deposition of Methane for Single Walled Carbon Nanotubes", Chemical Physics Letters, Vol 292, Issue 4-6, pp 567-574, 1998; Casell, A H, Raymakers, J A, Kong, J, and Dai, H J, "Large Scale Synthesis of Single Walled Carbon Nanotubes" journal of Physical Chemistry, B, Vol 103, 6484-6492, 1999). The catalyst on porous silica support like silica gel or zeolite has been found to be excellent for CNTs production (Hernadi, K, Fonseca, A, Piedigrosso, P, Delvaux, M, Nagy, J B, Bernaerts, D, Riga, J, "Carbon Nanotubes Production over Co/Silica Catalysts", Catalysis Letters, Vol 48, No 3-4, pp 229-238, 1997; Hernadi, K, Fonseca, A, Nagy, J B, Bernaerts, D, Fudala, A, Lucas, A, "Catalytic Synthesis of Carbon Naotubes using Zeolite Support", Zeolites, Vol 17, p416-423, 1996). However, the catalytic process requires multistep purification procedure which is substantially time consuming and expensive (Couteau, E, Hernadi, K, Seo, J W, Nga, L T, Miko, C, Gaal, R, Forro, L, "CVD Synthesis of High Purity Multiwalled Carbon Nanotubes using CaCC>3 Catalyst Support for large Scale Production", Chemical Physics Letter, Vol 378, pp9-17, 2003). It is also reported to damage the graphite walls. Use of non-porous supports like CaC03 and MgO has an advantage of requiring a single step purification instead of a two step purification as in when using porous supports like that of silica based supports. ((Couteau, E, Hernadi, K, Seo, J W, Nga, L T, Miko, C, Gaal, R, Forro, L, "CVD Synthesis of High Purity Multiwalled Carbon Nanotubes using CaCCh Catalyst Support for large Scale Production", Chemical Physics Letter, Vol 378, pp9-17, 2003; Seo, J W, Couteau, E, Umek, P, Hernadi, K, Marcoux, P, Lukic, B, Miko, Cs, Milas, M, Gaal, R, Forro, L, "Synthesis and Manipulation of Carbon Nanotubes", New Journal of Physics, Vol 5, 120, 2003). Cashew tree, Anacardium occidentale Linn, is cultivated in various tropical areas like East Africa, South and Central America or Far East. India alone accounts for nearly half the cashew production in the world. On heating the cashew nut shells (CNS), an agroindustrial residue, upto about 100°C, the pericardium fluid present in the shells oozes out and is collected (about 14-16% by weight). This is generally used for making resins and adhesives. The partially de-oiled cashew nut shells are further heated upto about 280°C to remove gases like carbon dioxide, carbon monoxide and water vapour. Subsequent heating of the shells upto about 500°C produces pyrolysis vapours which are condensed to recover oil rich in cardariol. Pyrolysis temperature can be between 400-600°C; however, 500°C gives the maximum yield. The pyrolysis vapours are mainly composed of unique long chain compounds like carbonol, cardol, di-n-decyl phthalate, di-n-octgl phathalate or bis(2-ethyl hexyl) phathalate. These long chain compounds have a unique head and tail like structure with phenolic group being on the head and the long linear aliphatic chain forming the tail. CNS is found to contain very high carbon content unlike other biomasses. (Das P, Sreelatha T, Ganesh A, "Bio-oil from pyrolysis of cashew nut shell - characterisation and related properties", Biomass and Bioenergy, Vol 27, pp- 265-275,2004). OBJECTS OF INVENTION An object of the invention is to provide aligned rope like nanocarbon structures with platelet like carbon units. Another object of the invention is to provide aligned rope like nanocarbon structures with platelet like carbon units from cashew nut shell pyrolysis vapours. Another object of the invention is to provide a method of making aligned rope like nanocarbon structures with platelet like carbon units from cashew nut shell pyrolysis vapours. Another object of the invention is to provide aligned rope likk nanocarbon structures with platelet like carbon units from cashew nut shell pyrolysis vapours obtained by the above method. DETAILED DESCRIPTION OF THE INVENTION According to the invention there is provided a method of making aligned rope like nanocarbon structures with platelet like carbon units of the figure la, lb or lc of the accompanying drawings from cashew nut shell pyrolysis vapours, the method comprising cracking the pyrolysis vapours at 750°C to 900°C and at atmospheric pressure over a supported bi- metallic catalyst comprising Fe-Ni supported on MgO and purifying the nanocarbon structures formed with an acid. The nanocarbon structures formed are purified with an acid selected from nitric acid or hydrochloric acid. The purification of the nanocarbon structures is carried out to remove impurities like spent catalysts, support matrix of the catalysts or the like present. According to the invention there is also provided nanocarbon structures obtained from cashew nut shell pyrolysis vapours. According to the invention there is also provided nanocarbon structures obtained from cashew nut shell pyrolysis vapours by the above method. According to the invention there is also provided aligned rope like nanocarbon structures with platelet like carbon units of figure la, lb or lc of the accompanying drawings. According to the invention there is also provided aligned rope like nanocarbon structures with platelet like carbon units of figure la, lb or lc of the accompanying drawings from cashew nut shell pyrolysis vapours. According to the invention there is also provided aligned rope like nanocarbon structures with platelet like carbon units of figure la. lb or lc of the accompanying drawings obtained from cashew nut shell pyrolysis vapours by the above method. Preferably the pyrolysis vapours are cracked at 850 °C. According to the invention nanocarbon structures including novel aligned rope like nanocarbon structures with platelet like carbon units are obtained by supported bimetallic catalyst cracking of cashew nut shell pyrolysis vapours. Cashew nut shell is an agroindustrial waste or residue and a very cheap and renewable source of carbon with a high percentage of carbon. It does not cause any ecological problems as in the case of woody biomass. Therefore, nanocarbon structures can be produced according to the invention in a cheap and economic manner. The nanocarbon structures obtained by the invention can be used for a wide range of applications including as reinforcement for biocomposites. According to the invention there is also provided a polymer nanocomposite comprising aligned rope like nanocarbon structures with platelet like carbon units of figure la, lb or lc of the accompanying drawings obtained from cashew nut shell pyrolysis vapours. Such nanocomposites have improved mechanical, electrical and rheological properties. Cashew nut shell pyrolysis vapours were cracked in a gas cracker at 850°C and at atmospheric pressure using various supported bi-metallic catalysts as given in the following Table 1. The nanocarbon structures were purified by treatment with hydrochloric acid. Table 1 Exam pi eNo Catalyst Catalyst loading Catalyst support Product characteristics Structure of Product 1 Fe-Ni 5 wt. % of each metal MgO Highly aligned nano carbon p latelets—rope like Diameter: of single platelet unit: 60-140 nm Wall Thickness of single platelet: 14-20 nm Diameter of Rope: 0.2-1 um Length of Rope: 11.85-18 jam (maximum) Figure la, lb and lc of the accompanying drawings The higher values correspond to the longer chains 2 Fe-Ni 5 wt. % of each metal Silica Long straight chain nanotubes Diameter: 10-20nm Wall Thickness: 10-12nm Figure 2 of the accompanying drawings 3 Co-Ni 5 wt. % of each metal MgO Long chain nanotubes Diameter: 11-12nm Wall thickness: ll-12nm Figure 3 of the accompanying drawings 4 Co-Ni 5 wt. % of each metal Silica Long dense straight nanotubes Diameter: ll-12nm Wall Thickness: 10-12nm Figure 4 of the accompanying drawings 5 Co-Mo 5 wt. % of each metal MgO Long nanotubes coiled up Diameter: 10-50nm Wall Thickness: 5-30 nm Figure 5 of the accompanying drawings 6 Co-Mo 5 wt. % of each metal Silica Long straight chain nanotubes Diameter: 35-70 Wall Thickness: 10-12 Figure 6 of the accompanying drawings The aligned crystalline rope like nanostructures with platelet like carbon units in Figs la, lb and lc are novel nanocarbon structures. Mechanical properties of biocomposities of polyetheretherketone (PEEK) filled with aligned nano-carbons of Example 1 were as shown in the following Tables 2 and 3. Table 2 shows the variations in tensile strength, percent elongation, flexural strength, flexural modulus, impact strength and hardness of varying concentrations (0.1-2 wt.%) of nanocarbon filled PEEK nano composites. Table 3 represents the change in dielectric strength, arc resistance, heat distortion temperature and melt flow index (MFI) of nanocarbon filled PEEK nanocomposites. Table 2 ^^^^ Filler fwt.%) 0 0.1 0.5 1.0 1.5 2.0 Properties ^^^^ Tensile strength (MPa) 90.0 97.0 102.0 111.0 98.0 99.0 Rate of change of Tensile Strength - 70.0 12.5 18,0 -26.0 2.0 Tensile Modulus (MPa) 3552.0 3691.0 3723.0 4185.0 3713.0 3885.0 Rate of change of Tensile Modulus - 1390.0 80.0 924.0 -944.0 344.0 Elongation at Break (%) 80.0 100.0 96.0 86.0 45.0 45.0 Rate of change of Elongation at Break (%) - 200.0 -10.0 -20.0 -82.0 0.0 Flexural Strength (MPa) 126.0 133.0 147.0 152.0 129.0 131.0 Rate of change of Flexural Strength - 70.0 35.0 10.0 -46.0 4.0 Flexural Modulus (MPa) 3093.0 3318.0 3390.0 3400.0 3380.0 3420.0 Rate of Change of Flexural Modulus - 2250.0 180.0 20.0 -40.0 80.0 Izod Impact Strength (KJ/m2) 3.0 3.2 3.7 4.3 3.3 3.2 Rate of Change of Izod Impact Strength - 2.0 1.25 1.2 -2.0 -0.2 Hardness (M scale) 100.0 107.0 114.0 119.0 121.0 122.0 Rate of Change of Hardness - 70.0 17.5 10.0 4.0 2.0 Table 3 0 0.1 0.5 1 1.5 2.0 ' N. Filler \. fwt.%) ProDerties ^K Dielectric Strength 11.0 20.0 23.0 27.0 28.0 28.0 Rate of change of Dielectric Strength - 90.0 7.5 8.0 2.0 0.0 Arc Resistance (sec) 126.0 156.0 165.0 196.0 T78.0 68.0 Rate of change of Arc Resistance - 300.0 22.0 62.0 -36.0 -20.0 Heat Distortion Temperature (°C) 153.0 161.0 164.0 169.0 172.0 174.0 Rate of change of Heat Distortion Temperature - 80.0 . 7.5 10.0 6.0 4.0 Mechanical properties of nanocomposites of Polyethersulfone (PES) filled with aligned nanocarbons of Example ! were as shown in the following Tables 4 and 5. Table 4 shows the variations in tensile strength, percent elongation, flexural strength, flexural modulus, impact strength and hardness of varying concentrations (0.1-2 wt.%) of nanocarbon filled PES nanocomposites. Table 5 represents the change in dielectric strength, arc resistance, heat distortion temperature and melt flow index (MFI) of nanocarbon filled PES nanocomposites. Table 4 ^^^Filler fwt.%) 0 0.1 0,5 1.0 1.5 2.0 Properties ^^^^ Tensile strength (MPa) $6 94 97 99 103 108 Rate of change of Tensile Strength -- 80.0 7.5 10 8 10 Tensile Modulus (MPa) 2800 3129 3103 3235 3547 4064 Rate of change of Tensile Modulus - 3290 -65 264 624 1034 Elongation at Break (%) 25 6.1 5 4.3 4 3.8 Rate of change of Elongation at Break {%) - -189 -2.75 -1.4 -0.6 -0.4 Flexural Strength (MPa) 120 141 148 156 162 170 Rate of change of Flexural Strength - 210 17.5 16 12 .16 Flexural Modulus (MPa) 2600 3207 3174 3285 3674 4365 Rate of Change of Flexural Modulus - 6070 -82.5 222 178 1382 Izod Impact Strength (KJ/m2) 4.0 6.3 7 7.8 8.6 10.2 Rate of Change of Izod Impact Strength - 2.3 3.25 1.6 1.6 3.2 Hardness (M scale) 83.0 92 99 105 110 121 Rate of Change of Hardness - 90 17.5 12 10 22 Table 5 0 0.1 0.5 1 1.5 2.0 \. Filler \v (Wt.%) Properties ^v Dielectric Strength 8 13 18 22 28 32 Rate of change of Dielectric Strength - 50 12.5 8 12 8 Arc Resistance (sec) 70 121 134 148 158 165 Rate of change of Arc Resistance - 51.0 32.5 28 20 14 Heat Distortion Temperature (°C) 200 226 238 253 268 282 Rate of change of Heat Distortion Temperature - 260 30 30 30 28 It is evident from the Tables 2 and 3 and Tables 4 and 5 that the nanocomposites of Polyetheretherketone (PEEK) as well as Polyethersulfone (PES) with the nanocarbons of Example 1 give better mechanical, electrical and rheological properties as compared to PEEK and PES respectively even at very low concentrations (as low as 0.1-2.0%) of the nanostructures of the invention. The nanocarbons of the invention are excellent reinforcement for biocomposites. The above examples are to be understood to be illustrative of the invention and not limitative of the invention. We claim : 1. A method of making aligned rope like nanocarbon .structures with platelet like carbon units of the figure la, lb or lc of the accompanying drawings from cashew nut shell pyrolysis vapours, the method comprising cracking the pyrolysis vapours at 750°C to 900°C and at atmospheric pressure over a supported bi- metallic catalyst comprising Fe-Ni supported on MgO and purifying the nanocarbon structures formed with an acid. 2. The method as claimed in claim 1, wherein each of the metals of the catalyst is in 5% by weight. 3. The method as claimed in claim 1 or 2, wherein the cracking is carried out at 850 4. The method as claimed in anyone of claims 1 to 3, wherein the nanocarbon structures are purified with an acid selected from nitric acid or hydrochloric acid. 5. A polymer nanocomposite comprising aligned rope like nanocarbon structures with platelet like carbon units of figure 1a, 1b or 1c of the accompanying drawings obtained from cashew nut shell pyrolysis vapours.

Full Text

FORM 2
THE PATENTS ACT, 1970 (39 of 1970)
As amended by the Patents (Amendment) Act, 2005
& The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION (See section 10 and rule 13)
TITLE OF THE INVENTION
Method of making aligned rope like nanocarbon structures with platelet like carbon units from cashew nut shell pyrolysis vapours
APPLICANTS
Indian Institute of Technology, Bombay, an autonomous research and educational institution established in India by a special Act of the Parliament of the Republic of India under the Institutes of Technology Act 1961, Powai, Mumbai 400076, Maharashtra, India
INVENTORS
Ganesh Anuradda and Das Piyali, both of Indian Institute of Technology, Bombay, Energy Systems Engineering, Powai, Mumbai 400076, Maharashtra, India, both Indian nationals
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF INVENTION
This invention relates to a method of making aligned rope like nanocarbon structures
with platelet like carbon units from cashew nut shell pyrolysis vapours.
BACKGROUND OF INVENTION
Due to their fascinating broad range of electronic, thermal and structural properties, carbon nanotubes (CNTs), the tubular fullerenes, are envisaged as the key to potentially revolutionary technologies and have attracted a lot of attention from the industries and research communities. They are highly versatile, with a range of applications, which extend from super strong composites to nanoelectronics. The experimental characterisation and applications of the nanotubes have been hampered because of problems with alignment of tubes. Attainment of alignment in synthesised nano-tubes is still being worked upon, through application of external fields, electrical, magnetic or mechanical in nature [ Ingo Dierking, Giusy Scalia, Piero Mo rales, Darren LeCl ere," Aligning and re-orienting carbon nanotubes by nematic liquid crystals",Advanced Materials,Volume 16,lssue 11, pages 865-869, 30 April 2004, 2. http://macdiarind.ac.nz/institute.php-news/success stories/Alan Kaiser].
Carbon nanotubes are seamless tubes of graphite sheets with full fullerene caps, which were first synthesised in 1991 as multilayer concentric tubes called as multi-walled carbon nanotubes and were later synthesised in 1993 as single walled carbon nanotubes. Since then, numerous attempts have been made to syntbesise such products on a large scale and at low cost. Carbon nanotubes are synthesised by methods like arc discharge, laser ablation or catalytic chemical vapour deposition (CVD). Among the various methods, CVD has become more popular and is considered to be the best method for

low cost and large scale synthesis of high quality nanotube materials (Moon, C Y, Kim, Y S, Lee, E C, Jin, Y G, Chang, K J, "Mechanisms for Oxidative Etching in Carbon Nanotubes" Physical Review B, Vol. 65, Issue 15, 2002).
Gaseous hydrocarbons like methane, ethylene or acetylene are conventionally used for making carbon nanotubes and nanofibres. Aromatic compounds like benzene are also reported as carbon precursor (Teo, B K K, Singh, C, Chhowalla, M, Milne, I W, "Catalytic Synthesis of Carbon Nanotubes and Nanofibers" Encyclopedia of Nanoscience and Nanotechnology, Vol. X, pp 1-22, 2004). Conducting carbon nanofibres and nano thin films from kerosene, which is a mixture of various short and long chains of aromatic and aliphatic hydrocarbons, were also produced (Kumar, M, Kichambare, P D, Sharon, M, Ando, Y, Zhao, X, "Synthesis of Conducting Fibers, Nanotubes and Thin Films of Carbon from Commercial Kerosene", Vol. 34, No. 5, pp 791-801, 1999). Formation of different forms of novel carbon nanomaterials using organic camphor, a natural precursor of carbon is also reported. (Mukhopadhyay, K, Sharon, M, "Glassy Carbon from Camphor-—a natural source", Materials Chemistry and Physics, Vol 49, pp 105-109, 1997). Carbon nanomaterial has also been made from turpentine oil, which consists of hydrocarbon terpenes (C10H16) as the major component (Chaterjee A.K., Maheshwar Sharon and Rangan Banerjee,"Alkaline fuel cellxarbon nanobeads coated with metal catalyst over porous ceramic for hydrogen electrode", Journal of Power Sources, Volume 117, Issues 1-2, pp 39-44, 15 May 2003).
Oxygenated materials like alcohol (Maruyama, S, Miyauchi, Y, Murakami, Y and Chiashi, S, "Optical Characterization of Single Walled Carbon Nanotubes Synthesized by Catalytic Decomposition of Alcohol", New Journal of Physics, Vol 5, pp 149, 1-149.12,

2003) and carbon dioxide (Xu, X J, Huang, S M, "Huang Carbon Dioxide as a Carbon Source for Synthesis of Carbon Nanotubes by Chemical Vapour Deposition" Materials Letters, Volume 61, Issue 21, pp 4235-4237, 2007) have also been reported as precursors for making carbon nanotubes. Amorphous carbon bags, which are non-aligned and noncrystalline have been reported from chlorination of ferrocene (Garrote, E U, Brande, D A, Katcho, N A. Herrero, A G, Canovas, A R L, Diaz, L C O, "Amorphous Carbon Nanostructures from Chlorination of Ferrocene", Carbon, Vol 43, pp 978-985, 2005). Wantanabe et al has described in JP Publication No 2007-070166 preparation of nanocarbon materials from biomass namely woodymass as a carbon source. The woodymass is thermally decomposed by heating to produce a carbon-rich gas mixture which is purified and reacted with catalyst to produce the CNTs. Although woodymass, a forest residue, is a renewable source for CNTs, it is costly and it leads to thinning and degradation of forests and deforestation. In order to ensure continued availability of the woodymass rigorous and sustained afforestation is required.
The catalytic activity of different transition metal catalysts in the formation of carbon nanotubes has been studied extensively. Besides the commonly used Fe, Co, Ni, catalysts, bimetallic mixtures like Fe-Ni, Fe-Co, Fe-Mo or Co-Ni have been reported to be more effective over single metal catalysts in producing high yield and highly crystalline CNTs (Teo, B K K, Singh, C, Chhowalla, M, Milne, I W, "Catalytic Synthesis of Carbon Nanotubes and Nanofibers" Encyclopedia of Nanoscience and Nanotechnology, Vol X, pp 1-22, 2004). The catalyst-support material also plays a role in the synthesis of carbon nanotubes using the CVD method (Kong, J, Soh, H T, Cassel, A M, Quate, C F, Dai, H J, "Chemical Vapor Deposition of Methane for Single Walled Carbon Nanotubes", Chemical Physics Letters, Vol 292, Issue 4-6, pp 567-574, 1998; Casell, A H, Raymakers,

J A, Kong, J, and Dai, H J, "Large Scale Synthesis of Single Walled Carbon Nanotubes" journal of Physical Chemistry, B, Vol 103, 6484-6492, 1999). The catalyst on porous silica support like silica gel or zeolite has been found to be excellent for CNTs production (Hernadi, K, Fonseca, A, Piedigrosso, P, Delvaux, M, Nagy, J B, Bernaerts, D, Riga, J, "Carbon Nanotubes Production over Co/Silica Catalysts", Catalysis Letters, Vol 48, No 3-4, pp 229-238, 1997; Hernadi, K, Fonseca, A, Nagy, J B, Bernaerts, D, Fudala, A, Lucas, A, "Catalytic Synthesis of Carbon Naotubes using Zeolite Support", Zeolites, Vol 17, p416-423, 1996).
However, the catalytic process requires multistep purification procedure which is substantially time consuming and expensive (Couteau, E, Hernadi, K, Seo, J W, Nga, L T, Miko, C, Gaal, R, Forro, L, "CVD Synthesis of High Purity Multiwalled Carbon Nanotubes using CaCC>3 Catalyst Support for large Scale Production", Chemical Physics Letter, Vol 378, pp9-17, 2003). It is also reported to damage the graphite walls. Use of non-porous supports like CaC03 and MgO has an advantage of requiring a single step purification instead of a two step purification as in when using porous supports like that of silica based supports. ((Couteau, E, Hernadi, K, Seo, J W, Nga, L T, Miko, C, Gaal, R, Forro, L, "CVD Synthesis of High Purity Multiwalled Carbon Nanotubes using CaCCh Catalyst Support for large Scale Production", Chemical Physics Letter, Vol 378, pp9-17, 2003; Seo, J W, Couteau, E, Umek, P, Hernadi, K, Marcoux, P, Lukic, B, Miko, Cs, Milas, M, Gaal, R, Forro, L, "Synthesis and Manipulation of Carbon Nanotubes", New Journal of Physics, Vol 5, 120, 2003).
Cashew tree, Anacardium occidentale Linn, is cultivated in various tropical areas like East Africa, South and Central America or Far East. India alone accounts for nearly half

the cashew production in the world. On heating the cashew nut shells (CNS), an agroindustrial residue, upto about 100°C, the pericardium fluid present in the shells oozes out and is collected (about 14-16% by weight). This is generally used for making resins and adhesives. The partially de-oiled cashew nut shells are further heated upto about 280°C to remove gases like carbon dioxide, carbon monoxide and water vapour. Subsequent heating of the shells upto about 500°C produces pyrolysis vapours which are condensed to recover oil rich in cardariol. Pyrolysis temperature can be between 400-600°C; however, 500°C gives the maximum yield. The pyrolysis vapours are mainly composed of unique long chain compounds like carbonol, cardol, di-n-decyl phthalate, di-n-octgl phathalate or bis(2-ethyl hexyl) phathalate. These long chain compounds have a unique head and tail like structure with phenolic group being on the head and the long linear aliphatic chain forming the tail. CNS is found to contain very high carbon content unlike other biomasses. (Das P, Sreelatha T, Ganesh A, "Bio-oil from pyrolysis of cashew nut shell - characterisation and related properties", Biomass and Bioenergy, Vol 27, pp- 265-275,2004).
OBJECTS OF INVENTION
An object of the invention is to provide aligned rope like nanocarbon structures with
platelet like carbon units.
Another object of the invention is to provide aligned rope like nanocarbon structures with platelet like carbon units from cashew nut shell pyrolysis vapours.

Another object of the invention is to provide a method of making aligned rope like nanocarbon structures with platelet like carbon units from cashew nut shell pyrolysis vapours.
Another object of the invention is to provide aligned rope likk nanocarbon structures with platelet like carbon units from cashew nut shell pyrolysis vapours obtained by the above method.
DETAILED DESCRIPTION OF THE INVENTION
According to the invention there is provided a method of making aligned rope like nanocarbon structures with platelet like carbon units of the figure la, lb or lc of the accompanying drawings from cashew nut shell pyrolysis vapours, the method comprising cracking the pyrolysis vapours at 750°C to 900°C and at atmospheric pressure over a supported bi- metallic catalyst comprising Fe-Ni supported on MgO and purifying the nanocarbon structures formed with an acid.
The nanocarbon structures formed are purified with an acid selected from nitric acid or hydrochloric acid. The purification of the nanocarbon structures is carried out to remove impurities like spent catalysts, support matrix of the catalysts or the like present.
According to the invention there is also provided nanocarbon structures obtained from cashew nut shell pyrolysis vapours.
According to the invention there is also provided nanocarbon structures obtained from cashew nut shell pyrolysis vapours by the above method.

According to the invention there is also provided aligned rope like nanocarbon structures with platelet like carbon units of figure la, lb or lc of the accompanying drawings.
According to the invention there is also provided aligned rope like nanocarbon structures with platelet like carbon units of figure la, lb or lc of the accompanying drawings from cashew nut shell pyrolysis vapours.
According to the invention there is also provided aligned rope like nanocarbon structures with platelet like carbon units of figure la. lb or lc of the accompanying drawings obtained from cashew nut shell pyrolysis vapours by the above method.
Preferably the pyrolysis vapours are cracked at 850 °C.
According to the invention nanocarbon structures including novel aligned rope like nanocarbon structures with platelet like carbon units are obtained by supported bimetallic catalyst cracking of cashew nut shell pyrolysis vapours. Cashew nut shell is an agroindustrial waste or residue and a very cheap and renewable source of carbon with a high percentage of carbon. It does not cause any ecological problems as in the case of woody biomass. Therefore, nanocarbon structures can be produced according to the invention in a cheap and economic manner. The nanocarbon structures obtained by the invention can be used for a wide range of applications including as reinforcement for biocomposites.

According to the invention there is also provided a polymer nanocomposite comprising aligned rope like nanocarbon structures with platelet like carbon units of figure la, lb or lc of the accompanying drawings obtained from cashew nut shell pyrolysis vapours. Such nanocomposites have improved mechanical, electrical and rheological properties.
Cashew nut shell pyrolysis vapours were cracked in a gas cracker at 850°C and at atmospheric pressure using various supported bi-metallic catalysts as given in the following Table 1. The nanocarbon structures were purified by treatment with hydrochloric acid.

Table 1

Exam pi
eNo Catalyst Catalyst loading Catalyst support Product characteristics Structure of Product
1 Fe-Ni 5 wt. % of each metal MgO Highly aligned nano carbon p latelets—rope like
Diameter: of single platelet unit: 60-140 nm Wall Thickness of single platelet: 14-20 nm Diameter of Rope: 0.2-1 um
Length of Rope: 11.85-18 jam (maximum) Figure la, lb and lc of the accompanying drawings The higher values
correspond to the longer chains
2 Fe-Ni 5 wt. % of each metal Silica Long straight chain nanotubes
Diameter: 10-20nm
Wall Thickness: 10-12nm Figure 2 of the
accompanying
drawings
3 Co-Ni 5 wt. % of each metal MgO Long chain nanotubes Diameter: 11-12nm Wall thickness: ll-12nm Figure 3 of the
accompanying
drawings
4 Co-Ni 5 wt. % of each metal Silica Long dense straight nanotubes
Diameter: ll-12nm
Wall Thickness: 10-12nm Figure 4 of the
accompanying
drawings
5 Co-Mo 5 wt. % of each metal MgO Long nanotubes coiled up
Diameter: 10-50nm Wall Thickness: 5-30 nm Figure 5 of the
accompanying
drawings
6 Co-Mo 5 wt. % of each metal Silica Long straight chain nanotubes
Diameter: 35-70 Wall Thickness: 10-12 Figure 6 of the
accompanying
drawings

The aligned crystalline rope like nanostructures with platelet like carbon units in Figs la, lb and lc are novel nanocarbon structures.
Mechanical properties of biocomposities of polyetheretherketone (PEEK) filled with aligned nano-carbons of Example 1 were as shown in the following Tables 2 and 3. Table 2 shows the variations in tensile strength, percent elongation, flexural strength, flexural modulus, impact strength and hardness of varying concentrations (0.1-2 wt.%) of nanocarbon filled PEEK nano composites. Table 3 represents the change in dielectric strength, arc resistance, heat distortion temperature and melt flow index (MFI) of nanocarbon filled PEEK nanocomposites.
Table 2

^^^^ Filler fwt.%) 0 0.1 0.5 1.0 1.5 2.0
Properties ^^^^

Tensile strength (MPa) 90.0 97.0 102.0 111.0 98.0 99.0
Rate of change of Tensile Strength - 70.0 12.5 18,0 -26.0 2.0
Tensile Modulus (MPa) 3552.0 3691.0 3723.0 4185.0 3713.0 3885.0
Rate of change of Tensile Modulus - 1390.0 80.0 924.0 -944.0 344.0
Elongation at Break (%) 80.0 100.0 96.0 86.0 45.0 45.0
Rate of change of Elongation at Break (%) - 200.0 -10.0 -20.0 -82.0 0.0
Flexural Strength (MPa) 126.0 133.0 147.0 152.0 129.0 131.0
Rate of change of Flexural Strength - 70.0 35.0 10.0 -46.0 4.0
Flexural Modulus (MPa) 3093.0 3318.0 3390.0 3400.0 3380.0 3420.0
Rate of Change of Flexural Modulus - 2250.0 180.0 20.0 -40.0 80.0
Izod Impact Strength (KJ/m2) 3.0 3.2 3.7 4.3 3.3 3.2
Rate of Change of Izod Impact Strength - 2.0 1.25 1.2 -2.0 -0.2
Hardness (M scale) 100.0 107.0 114.0 119.0 121.0 122.0
Rate of Change of Hardness - 70.0 17.5 10.0 4.0 2.0

Table 3

0 0.1 0.5 1 1.5 2.0
' N. Filler \. fwt.%)
ProDerties ^K

Dielectric Strength 11.0 20.0 23.0 27.0 28.0 28.0
Rate of change of Dielectric Strength - 90.0 7.5 8.0 2.0 0.0
Arc Resistance (sec) 126.0 156.0 165.0 196.0 T78.0 68.0
Rate of change of Arc Resistance - 300.0 22.0 62.0 -36.0 -20.0
Heat Distortion Temperature (°C) 153.0 161.0 164.0 169.0 172.0 174.0
Rate of change of Heat Distortion Temperature - 80.0 . 7.5 10.0 6.0 4.0
Mechanical properties of nanocomposites of Polyethersulfone (PES) filled with aligned nanocarbons of Example ! were as shown in the following Tables 4 and 5. Table 4 shows the variations in tensile strength, percent elongation, flexural strength, flexural modulus, impact strength and hardness of varying concentrations (0.1-2 wt.%) of nanocarbon filled PES nanocomposites. Table 5 represents the change in dielectric strength, arc resistance, heat distortion temperature and melt flow index (MFI) of nanocarbon filled PES nanocomposites.

Table 4

^^^Filler fwt.%) 0 0.1 0,5 1.0 1.5 2.0
Properties ^^^^

Tensile strength (MPa) $6 94 97 99 103 108
Rate of change of Tensile Strength -- 80.0 7.5 10 8 10
Tensile Modulus (MPa) 2800 3129 3103 3235 3547 4064
Rate of change of Tensile Modulus - 3290 -65 264 624 1034
Elongation at Break (%) 25 6.1 5 4.3 4 3.8
Rate of change of Elongation at Break {%) - -189 -2.75 -1.4 -0.6 -0.4
Flexural Strength (MPa) 120 141 148 156 162 170
Rate of change of Flexural Strength - 210 17.5 16 12 .16
Flexural Modulus (MPa) 2600 3207 3174 3285 3674 4365
Rate of Change of Flexural Modulus - 6070 -82.5 222 178 1382
Izod Impact Strength (KJ/m2) 4.0 6.3 7 7.8 8.6 10.2
Rate of Change of Izod Impact Strength - 2.3 3.25 1.6 1.6 3.2
Hardness (M scale) 83.0 92 99 105 110 121
Rate of Change of Hardness - 90 17.5 12 10 22

Table 5

0 0.1 0.5 1 1.5 2.0
\. Filler
\v (Wt.%)
Properties ^v

Dielectric Strength 8 13 18 22 28 32
Rate of change of Dielectric Strength - 50 12.5 8 12 8
Arc Resistance (sec) 70 121 134 148 158 165
Rate of change of Arc Resistance - 51.0 32.5 28 20 14
Heat Distortion Temperature (°C) 200 226 238 253 268 282
Rate of change of Heat Distortion Temperature - 260 30 30 30 28
It is evident from the Tables 2 and 3 and Tables 4 and 5 that the nanocomposites of Polyetheretherketone (PEEK) as well as Polyethersulfone (PES) with the nanocarbons of Example 1 give better mechanical, electrical and rheological properties as compared to PEEK and PES respectively even at very low concentrations (as low as 0.1-2.0%) of the nanostructures of the invention. The nanocarbons of the invention are excellent reinforcement for biocomposites.
The above examples are to be understood to be illustrative of the invention and not limitative of the invention.

We claim :
1. A method of making aligned rope like nanocarbon .structures with platelet like
carbon units of the figure la, lb or lc of the accompanying drawings from cashew nut shell pyrolysis vapours, the method comprising cracking the pyrolysis vapours at 750°C to 900°C and at atmospheric pressure over a supported bi- metallic catalyst comprising Fe-Ni supported on MgO and purifying the nanocarbon structures formed with an acid.
2. The method as claimed in claim 1, wherein each of the metals of the catalyst is in 5% by weight.
3. The method as claimed in claim 1 or 2, wherein the cracking is carried out at 850
4. The method as claimed in anyone of claims 1 to 3, wherein the nanocarbon structures are purified with an acid selected from nitric acid or hydrochloric acid.
5. A polymer nanocomposite comprising aligned rope like nanocarbon structures with platelet like carbon units of figure 1a, 1b or 1c of the accompanying drawings obtained from cashew nut shell pyrolysis vapours.

METHOD OF MAKING ALIGNED ROPE LIKE NANOCARBON STRUCTURES WITH PLATELET LIKE CARBON UNITS FROM CASHEW NUT SHELL PYROLYSIS VAPOURS

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