A leading centre in India dedicated to research in both pure and applied science of Carbon with principal motives i) to develop the process technology of newer carbon products which hold strategic importance and are not available to the country at any cost, ii) to develop products which can be made cost-effective by innovative process suitable to available infrastructure, expertise and resources in India, iii) to promote overall growth of carbon science and technology in the country through sustained R&D, research publications, patents, technology transfer, consultancy to industry, national & international conferences and refresher courses etc.

1. Development of carbo-graphite material for aeronautical application

This project is sponsored by Defence Materials and Stores R&D Establishment (DMSRDE), Kanpur. The carbo-graphite material is to be used as a seal for the defence application. This material possesses a high density of 1.90 gcm-3, high shore hardness of 85, high compressive strength of 2000 kgcm-2, besides being stable in air at 650oC. The high density carbo-graphite of almost required characteristics using modified NPL green coke has been developed in this project. A high pressure-high temperature impregnation assembly was designed, fabricated and employed for impregnation of high density graphite with suitable boron and phosphorus salts to make it heat stable at 650 oC. Process parameters for impregnation of graphite were optimized. It is interesting to note that high-density graphite without impregnation loses 40% of its weight at 650 oC within four hours, whereas the impregnated graphite does not lose any weight and is stable at 650 oC for periods upto 10 hours. The report of the R&D work done was submitted and presented at DMSRDE, Kanpur. Further work is in progress to develop isostatic moulds of carbo-graphite for supplying to DMSRDE.

2. Development of mesophase pitch for high performance carbon fibers

This project is again sponsored by DMSRDE, Kanpur as a sub-project of their major programme on development of advanced composites and fibres. Mesophase pitches of high softening point were prepared at NPL using QI free pitches (developed by us at NPL) and commercial petroleum pitches by suitable thermal treatment. These pitches were characterized for various parameters including mesophase content (liquid crystal development) using polarizing optical microscope. The samples of mesophase developed in such pitches has been shown in fig. 3.5 (a-d). Further work on the optimization of process parameters and composition of pitches is in progress. Few mesophase pitch samples have been supplied to DMSRDE, Kanpur for spinning into fibres. Two interim reports were prepared and submitted to DMSRDE, Kanpur during the year.

3. Development of carbon-ceramic composites and influence of oxidation at elevated temperatures

Carbon-ceramic composites were developed by incorporating SiC (through the reaction of Si and carbon or SiC particles as such) and B4C in the green coke (developed inhouse). It was observed that carbon-ceramic composite plates have a density of 1.95 gm/cm-3 at HT of 1400 oC and were resistant to oxidation at 800oC - 1200oC for about 10 hours. The bending strength of the composite plates before and after oxidation at 800oC for 10 hrs was found to be the same
thereby showing the oxidation of the composite has little effect on the mechanical properties.

4. Development of fuel cells based on hydrogen (CSIR-NMITLI Project)

A batch of 50 numbers of carbon paper samples of size 20cm x 15cm and 30 nos. of carbon composite bipolar plates of similar size were supplied to CECRI to be used in a 1 kW fuel cell stack being assembled at CECRI using all indigenous components. Fig. 3.6 shows the I-V performance of the unit PEM fuel cells assembled at CECRI using Porous carbon paper and the Bipolar plates developed at NPL. The results were highly ecouraging.

5. Development of speciality carbon materials for novel nuclear reactor

Work under the sponsored project from BARC was continued to develop Carbon/ carbon composite tubes for new generation high temperature nuclear reactors (CHT). Prototype tubes with dimensions OD 60mm, ID 20mm and Length 100 mm were fabricated by filament winding technique or using 3-D perform using Hot Isostatic Pressing (HIP) to achieve the desired bulk density of 1.75 to 1.85 g/cc (Fig 3.7). The sample tubes were characterized for physical and mechanical properties and microstructure before supplying to BARC for neutron diffraction studies.

6 Carbon nanotubes based polymer composites

Carbon nanotubes were grown by chemical vapour deposition (CVD) on different carbon fibre substrates namely, unidirectional (UD) carbon fibre tows, Bi-directional(2D) carbon fibre cloth (Fig.3.8) and threedimensional( 3D) carbon fibre felt. These substrates were used as the reinforcement in phenolic resin matrix to develop hybrid CFCNT composites. The flexural strength (FS) and Flexural modulus(FM) of the CNT-CF cloth hybrid composite improved with increasing amount of CNT contents. The FS and FM improved by 75% and 54 % respectively as compared to that prepared by neat reinforcements (without CNT growth) under identical conditions with ~ 8% by weight of CNT growth on the substrate(Fig.3.9).

7. Development of high quality impregnating grade coal tar pitch

A state of the art process for the production of high quality impregnating pitch was developed by us at NPL and transferred to industry earlier. The industry has now put up an industrial plant shown in Fig.3.10 with a capacity of 2400 MT/p.a. worth about Rs.15 crores. The pitch is used for densification of graphite electrodes for steel industry and CC composites for defence/other high technology applications besides having other important applications. A novel process has
been recently developed now to produce this pitch with a high coking value of 50-62% compared 42-46% produced from the earlier process. This will reduce the number of impregnation cycles required for the densification of graphite electrodes and C-C composites. A patent for the invention has been applied for during the year.

pecifications of Impregnating Grade Coal

Tar Pitch

8. Development of high purity - high density - isotropic graphite

R&D work was continued to improve the process of producing high density - high strength - isotropic graphite from green coke. A new technique of coating the green coke powder was done to improve the properties and shelf life of the green coke prepared for the production of high density high strength graphite. A patent application with complete specifications of the process is being drafted. Efforts are continuing to transfer the technology of this high-density graphite to an
industry.

9. Development of high-density graphite for multistage depressed collection of electron tubes (XI th Plan Network project)

This is a part of the XI Plan CSIR sponsored network project on Design and fabrication capabilities for very high power microwave tubes with CEERI, Pilani as the nodal agency. The objective in the project is to develop two types of graphites with stringent specifications namely (i) high density graphite, (ii) copper reinforced graphite suitable for multistage depressed collection of electron tubes useful for space applications. Imported samples of both types of graphites, supplied by CEERI, Pilani were characterized and some preliminary R&D work were also initiated.

10. Support of industry

A. Consultancy project

A consultancy project entitled “consultancy for improvement of quinoline insoluble and coking value properties of QI free coal tar pitch” sponsored by a major pitch producing industry in India was undertaken. Suitable experiment was conducted for improving the coking value of the impregnating grade coal tar pitch. The final technical report has been completed for onward transmission to industry.

B. Industrial Testing

The carbon blocks received from different industries / R&D institutes were tested for apparent porosity, Kerosene density, bulk density ,bending strength, shore hardness and thermal conductivity. The test reports were prepared and submitted to parties.

C. Liquid Crystal and Self Assembled Monolayer Section Design, Development and Fabrication of Array Sensor Chip For Biological Applications Micropatterning of biological molecules (proteins, immunoglobulins, peptides) onto various surfaces using softlithographic techniques

Development of biomedical microdevices (BioMEMS) has received tremendous attention in recent years as they are more sensitive, accurate, reliable and inexpensive and use very small quantities of expensive reagents and solvents. Consequently, there is a strong need to develop simple microfabrication technology that will be central to the development of miniaturized devices for biological/ biomedical/ biotechnology/ chemical analysis. We have developed a number of techniques to create two-dimensional patterns of different biological sensing elements (proteins, nucleotides, immunoglobulins, cells etc.) with micrometer sizes on different solid substrates, which in turn would be used to develop arraybiosensors.

One of the simplest ways to selectively adsorb proteins to the designated regions of a substrate is to create regions with contrasting hydrophobic and hydrophilic properties. Microcontact printing (ìCP) of alkane thiols (HDT) and PEG-thiol on gold coated substrate and alkane silanes and PEG silane on glass/ silicon substrates, respectively has been used to create highly hydrophobic and highly hydrophilic regions with feature sizes ranging from a few tens of microns to a few hundred microns. The hydrophobic regions exhibit strong adsorption of proteins while hydrophilic regions strongly resist the protein adsorption. The proteins selectively adsorb immunoglobulins / cells and act as biosensing elements. It has been found through fluorescence microscopy that selectively adsorbed proteins exhibit strong bioactivity and has been reported in previous year annual report.