Utilização de NBR Modificada com Grupos 2-Oxazolina em Misturas de NBR/EVA
Utilization of 2-Oxazoline Modified NBR in NBR/EVA Blends
Almeida, Mauricio S. M.; Soares, Bluma G.; Guimarães, Pedro Ivo C.
http://dx.doi.org/10.1590/S0104-14282003000200010
Polímeros: Ciência e Tecnologia, vol.13, n2, p.119-124, 2003
Resumo
Misturas envolvendo borracha nitrílica e copolímeros de etileno–acetato de vinila na proporção 70:30 % em peso, foram preparadas na presença de borracha nitrílica funcionalizada com 2-oxazolina isoladamente ou combinada com EVA funcionalizado com grupos hidroxila, carboxila ou mercaptana. A reação entre os grupos funcionais foi verificada por análise de FTIR da fração insolúvel de amostras não vulcanizadas e pelo decréscimo nos valores de tan δ nos ensaios dinâmico-mecânicos. A utilização desses copolímeros funcionalizados não influenciou significativamente as propriedades mecânicas, provavelmente devido à proporção da mistura utilizada (rica em NBR) o que facilita a localização da NBR funcionalizada no interior da fase elastomérica.
Palavras-chave
Borracha nitrílica, 2-oxazolina, copolímeros de EVA, misturas poliméricas
Abstract
Nitrile rubber/ethylene-vinyl acetate copolymer (NBR/EVA) blends with ratio of 70/30 wt% were prepared in the presence of functionalized NBR with 2-oxazoline groups. This functionalized copolymer was employed alone or in combination with EVA copolymer functionalized with hydroxyl, carboxyl or mercaptan groups. The reaction between the functional groups was confirmed by FTIR analysis of the unvulcanized samples insoluble fraction, and by the decrease in the tan δ values. The mechanical properties were not substantially affected by the presence of these functionalized copolymers, probably due to the proportion of blend composition (with high amount of NBR), thus forcing the location of functionalized NBR inside the elastomer phase.
Keywords
Nitrile rubber, 2-oxazoline, EVA copolymer, polymer blends
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