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Novel methodology introduced to incorporate peroxide in the rubber matrix led to successful development of peroxide cured EPDM insulation based on precipitated silica, a conventional filler. Effect of Silica Filler on the physical, mechanical, thermal, ablative properties and thermal degradation of such an insulation has been recently published. As an outcome of above study, peroxide cured EPDM insulation with 25 PHR of Silica, has been promulgated as potential low density insulation meeting all the requirements of Large Rocket Motor, while having a density as low as 0.997 g/cm3 and Tg as low as −55°C. Effect of aging on mechanical, thermal properties and thermal degradation behavior of low density peroxide cured EPDM insulation has been studied and the findings have been corroborated by FTIR Spectroscopy and morphological Examination by SEM. [ABSTRACT FROM AUTHOR]

Non‐compatibility with double base propellant and nitrate ester plasticized polyether based propellant and poor aging resistance limit the overall life of sulfur cured EPDM insulation and warranted the development of peroxide cured EPDM insulation in order to reap the full benefits of EPDM insulation. This article describes the effect of silica filler on the physical, mechanical, thermal, and ablative properties of peroxide cured EPDM insulation, free from chlorosulphonated polyethylene and filled with conventional precipitated silica, which has been validated for the requirements of large composite rocket motor casing. Significant findings, which have been corroborated by instrumental techniques viz. DSC, TGA, FTIR, and SEM are presented in this article. [ABSTRACT FROM AUTHOR]

Even though literature available on EPDM is abundant, the data on physical, mechanical, thermal, interface properties and ablative performance as specifically required for the design and acceptance of internal insulation of large Composite Rocket Motor Casing is scant in the plethora of literature available in the subject of EPDM insulation. This gave the impetus to take up this experimental work wherein most promising formulation of EPDM with Kevlar and silica as reinforcing fillers and with only silica as reinforcing filler were thoroughly characterized for the insulation requirements of large Composite Rocket Motor Casing and compared with the performance of proven Nitrile rubber based insulation. The significant findings which are unique, are discussed in this paper. [ABSTRACT FROM AUTHOR]

Natural rubber (NR)-based elastomer, by virtue of its amenability to yield shear modulus at 3.5 kg/cm2 shear stress as low as 1.6–2.0 kg/cm2, is the most preferred elastomer for the realization of flex seals that are used for the thrust vector control of large rocket motors. Despite the utmost care taken during compounding, there exists a high degree of uncertainty in achieving required shear modulus primarily because of complexity involved in compounding to obtain high degree of homogeneity of the NR compound. Assessing the quality of NR compound is a tedious and time-taking process since it involves the preparation and testing of standard quadruple lap shear (QLS) specimens. Any non-conformance in shear modulus calls for fine-tuning of NR formulation; remaking of QLS specimens to recheck shear modulus leads to huge time delay and wastage of materials. The authors have meticulously generated oscillatory disc rheometer (ODR) data in comparison with QLS test results for various NR compounds and introduced ODR as an effective quality assurance tool. This article demonstrates how, based on ODR data, shear modulus can be predicted, thereby corrective actions can be taken in NR compound quickly and the appropriate vulcanization scheme can be prescribed for the given NR compound, which will prevent reversion and ensure optimum vulcanization, thereby eliminate the causes for shear modulus increase during storage of flex seals. [ABSTRACT FROM AUTHOR]