Caracterização físico-mecânica de filmes de borracha natural epoxidada curáveis em temperatura ambiente

Abstract

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.

Study of the Foaming Kinetics in Epoxidized Natural Rubber Foams Crosslinked by Electron Beam Irradiation

“…On the other hand, this could be attributed to the structural changes induced in the ENR matrix during the blending process, which could lead to the formation of ether crosslinks and other epoxy ring products which are more prone to crosslinking processes, as stated in previous works found in literature . Moreover, these works showed that the increase in gel fraction of ENR is associated with the interchain interactions by H bonding through ring‐opened products of ENR such as hydroxyl group, hydrofuran, and carbonyl group formations and also by ether‐type crosslink formations . All these facts allowed the ENR matrix to present more free radicals and more possibilities to produce crosslinking than the NR rubber.…”

“…The introduction of epoxide groups within the polymer chain allows improvements of certain natural rubber properties such as oil resistance, gas impermeability, wet grip, and damping . For these reasons, this type of rubber, epoxidized natural rubber (ENR), is a subject of investigation as a potential substitute for several synthetic elastomers …”

Electrospun natural rubber latex biocomposite for scaffolds in tissue engineering

“…The epoxide group is very reactive and is considered one of the most important intermediates in organic synthesis, as its introduction not only reduces the number of double bonds but also increases the rubber hydrophilicity. 6 Due to the high reactivity of the epoxide groups, they can be easily functionalized or modified by the attachment of bioactive compounds, in addition, these epoxidized groups increase the chemical compatibility between load-polymers or in physical polymer mixture. 7 As a new material, the PLGA/PIepox mixture has only a few works done and its properties, characteristics and processing possibilities have not been fully explored.…”

Tissue-engineered solution containing cells and biomaterials—an in vitro study: A perspective as a novel therapeutic application

“…12,13 Mixing epoxidized polyisoprene with other polymers is an alternative means of preparing biocompatible polymer blends with versatile characteristics and advanced mechanical properties for use in tissue engineering. 14 However, this technique requires careful in vitro study to analyze the potential risks and benefits that such a biomaterial can offer. 15…”