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Resumo: Neste trabalho é apresentado o estudo da formação de reticulações na temperatura ambiente, de borracha natural epoxidada (ENR) de 25% de grau de epoxidação, com um agente de cura contendo o tiol trimetilolpropano tris(2-mercaptoacetato) (TMP-SH). As composições foram realizadas a partir de solubilização da ENR e, posterior reação com o TMP-SH. Foram preparadas composições com 5, 10 e 20 phr de ENR e controles contendo NR e ENR. Também foi preparada uma composição com NR e 10 phr de TMP-SH para comprovar o efeito do grupo epóxido. A formação de reticulação dos filmes foi determinada pelas propriedades físico-mecânicas como grau de inchamento no equilíbrio, resistência à tração e propriedades dinâmico-mecânicas. Os resultados mostraram a eficiência do agente de cura e a influência do teor incorporado de TMP-SH nas propriedades determinadas, e a composição de ENR com 10 phr do agente de cura foi a que apresentou melhor desempenho físico-mecânico. Palavras-chave: Borracha natural epoxidada, cura, resistência à tração, DMA, grau de inchamento. Physical-Mechanical Characterization of Epoxidized Natural Rubber Films Curable at Ambient TemperatureAbstract: This paper presents the crosslinking study at room temperature of epoxidised natural rubber (ENR), of 25% of epoxidation level, with a curing agent containing thiol trimethylolpropane tris(2-mercaptoacetate) (TMP-SH). The compositions were made from solubilization of ENR, and subsequent reaction with TMP-SH. Compositions with 5, 10 and 20 phr of TMP-SH, NR and ENR controls were prepared. It was also prepared a composition with NR and 10 phr of TMP-SH to demonstrate the effect of epoxide group. The crosslinking formation of the films was determined by physicalmechanical properties as equilibrium swelling index, tensile strength and dynamic-mechanical properties. The results showed the efficiency of the cure agent and the influence of TMP-SH content incorporated, in the studied properties, and the ENR composition with 10 phr of curing agent presented the best physical-mechanical performance.

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This paper describes the synthesis and characterization of a copper-based ballistic modifier, copper subsalicylate (monobasic copper salicylate), and its performance in green-type propellants. New lead-free ballistic modifiers and phthalatefree plasticizers with reduced toxicity, less harmful to the environment, have been employed to replace their traditional additives in green-type double-base propellant preparations. The characterization of the chemical compound was performed by FTIR, TGA-DSC, and WAXS, indicating that copper subsalicylate was obtained. The results of the characterization of propellant compositions showed that copper subsalicylate, in combination with a bismuth salt, could be a substitute for the traditional lead-based ballistic modifier producing green-type propellants without reducing ballistic performance.