Improvements in the Structural Integrity of Resin Based Combustible Cartridge Cases (CCC) at Elevated Temperatures

• Autorzy: Dey A. , Athar J. , Gogoi S. , Navle P. B. , Sikder A. K.
• Języki publikacji: EN

Abstrakty

EN

An advanced, solvent-less resin based Combustible Cartridge Case (CCC), designed to resolve the inherent problems of shrinkage and limited mechanical strength associated with the gelatinisation of nitrocellulose, has already been developed. The felt-moulded components contain thermoplastic polyvinyl acetate (PVAc) resin as the binder and the enhanced mechanical strength is achieved by carrying out hot compaction of dry felts at an elevated temperature (105 ± 2 °C). Presently, resin based technology is adopted for tank gun ammunition and also for the developed modular CCCs, i.e. the Modular Combustible Case (MCC) for different types of artillery gun ammunition. However, during exhaustive trials conducted with the resin based CCCs in 120 mm tank gun ammunition at three temperatures, i.e. -10, 27 and 55 °C, severe geometrical deformation was noticed when the rounds were conditioned at 55 °C for 24 h., adversely affecting the loading of rounds into the gun chamber. This was attributed to the combined effects of softening of the resin at that temperature and the load of the projectile/ shell (14.4 kg) experienced by the CCC region during conditioning of the round in the horizontal mode. In order to resolve this problem of deformation, PVAc resin was required to be modified. The PVAc resin was modified to the form of a nanocomposite. PVAc nano composite was prepared by dispersing organically modified nano clay, i.e. Cloisite 30B, into the resin before making the CCCs. The nanocomposite of PVAc resin was characterized by FTIR, DMA, softening point measurement etc. The results showed a remarkable improvement in the glass transition temperature (Tg) and in the softening temperature of the modified PVAc resin. This modified PVAc resin was used to prepare CCCs. Furthermore, these CCCs were coated with hexamethylene diisocyanate (HMDI) on the inner and the outer surfaces. The isocyanate coating becomes crosslinked in the matrix, thereby improving the softening point as well as the mechanical properties of the CCCs. These modified CCCs were repeatedly tested at 55 and 60 °C for 24 h. After testing, it was found that no deformation had taken place and the assembled rounds were easily loaded into the gun chamber. The use of the PVAc nanocomposite in the preparation of resin based CCCs, followed by isocyanate coating, is an effective means of achieving the required improvement in structural integrity of the resin CCCs at elevated temperatures.

Słowa kluczowe

EN

CCC; deformation; PVAc; ammunition; cartridge; gun

• Czasopismo: Central European Journal of Energetic Materials
• Rocznik: 2015
• Tom: Vol. 12, no. 1
• Strony: 117--127
• Opis fizyczny: Bibliogr. 15 poz., rys., tab.

Twórcy

autor

Dey A.

• High Energy Materials Research Laboratory, DRDO, Sutarwadi, Pune, 411 021, India

autor

Athar J.

• High Energy Materials Research Laboratory, DRDO, Sutarwadi, Pune, 411 021, India

autor

Gogoi S.

• High Energy Materials Research Laboratory, DRDO, Sutarwadi, Pune, 411 021, India

autor

Navle P. B.

• High Energy Materials Research Laboratory, DRDO, Sutarwadi, Pune, 411 021, India

autor

Sikder A. K.

• High Energy Materials Research Laboratory, DRDO, Sutarwadi, Pune, 411 021, India

Bibliografia

• [1] Sayal R.K., Narr P.S., Study of Brass Obturator Design for Combustible Cartridge Case for 105 mm Tank Gun Ammunition, Def. Sci. J., 1997, 47(3), 373-381.
• [2] Shedge M.T., Patel C.H., Tadkod S.K., Murthy G.D., Polyvinyl Acetate Resin as a Binder Effecting Mechanical and Combustion Properties of Combustible Cartridge Case Formulations, Def. Sci. J., 2008, 58, 390-397.
• [3] Kurulkar G.R., Syal R.K., Singh H., Combustible Cartridge Case Formulation and Evaluation, J. Energ. Mater., 1996, 14, 127-149.
• [4] Brasiques A., Maures M., Spirally Winding Combustible Paper Tapes Containing NC, US Patent 4649827, 1987.
• [5] Boblinski J., Picard J.P., Novel Combustible Cartridge Case and Process Therefore, US Patent 3706280, 1972.
• [6] Dutta M.L., Report on visit to Isagchemie, Synthen, West Germany, 1986.
• [7] Luebben M., Witt W., Ammunition with Protective Surface Layer and Method of Making Same, US Patent 4363273, 1982.
• [8] Haley J.E., Design and Manufacture of 155 mm Modular Propelling Charges, US Army Armament Research & Development Center, Dover, New Jersey, Armtec Defence Products Co., 1984.
• [9] Deluca P.L., Manufacturing Process for Various Shaped Consumable Ordnance Products, US Gov. Report AD-A 121 656, 1982.
• [10] Maures M., Pasdeloup J., Lespinasse P., Process for the Manufacture of Combustible Articles by Embossing Combustible Paper and Combustible Articles thus Produced, US Patent 4705 655, 1985.
• [11] Barbets R.I., Combustible Cartridge Case Characterization, US Gov. Report, AD-A 140664, 1984.
• [12] Societe Nationale des Poudres et Explosifs, French Corporate Body, France, Mouldable Compositions Comprising Polyvinyl Nitrate, France Patent 1443289, 1973.
• [13] Nelson M.B., Remaly R.F., Shefcik W. P., Felting Process for Making Combustible Cartridge Cases, US Patent 3474702, 1969.
• [14] Godfrey J.N., Myron G., Cartridge Cases from Fibrous Nitrocellulose and Alkaline Catalysed Phenolic Resin, US Patent 3260203, 1966.
• [15] Beal K.F., Combustible Cartridge Case and Method of Making Same, US Patent 2982211, 1961.