Caracterização de artefatos elastoméricos obtidos por revulcanização de resíduo industrial de SBR (copolímero de butadieno e estireno)

Abstract

Resumo: A reciclagem de resíduos de borracha é de extrema importância nos dias de hoje, tanto em relação aos impactos ambientais quanto à conservação de energia. Considerando que a maioria dos trabalhos publicados atualmente se refere à reciclagem de pneus, o objetivo deste trabalho foi desenvolver e caracterizar formulações contendo um tipo de resíduo industrial, proveniente da fabricação de perfis automotivos, à base de copolímero de butadieno e estireno (SBR) para possível aplicação na própria empresa. As composições foram preparadas e caracterizadas pela determinação das propriedades térmicas (calorimetria diferencial de varredura), reológicas (analisador de processamento de borracha), reométricas (reômetria de disco oscilatório), mecânicas (resistência à tração e ao rasgamento), químicas (densidade de ligações cruzadas) e morfológicas (microscopia eletrônica de varredura). Os resultados obtidos para as composições foram comparados aos de uma amostra controle, de mesma composição, que foi fornecida pela empresa geradora do resíduo de SBR. Os resultados mecânicos indicaram que o processo de revulcanização proposto foi efetivo. Os valores dos parâmetros de tensão na ruptura e resistência ao rasgamento foram de 70 e 50%, respectivamente, em relação aos valores encontrados para a amostra controle, indicando a possibilidade do uso desse resíduo em artefatos de menor exigência técnica. Palavras-chave: Resíduo industrial de SBR, revulcanização, propriedades mecânicas. Characterization of Elastomeric Artifacts obtained by Revulcanization of SBR Industrial Waste (Styrene-butadiene Rubber)Abstract: The recycling of waste rubber has very important significances, such as protection of the environment and conservation of energy. Considering that most of published works concerning this subject are about tire recycling, the objective of this work was to develop and characterize formulations containing a type of industrial waste, from the manufacture of automotive profiles, based on styrene-butadiene rubber (SBR) for possible application in the industry. The compositions were formulated and characterized by thermal (differential scanning calorimetry), rheological (rubber processor analyzer), rheometrical (oscillatory disc rheomether), mechanical (tensile strength and tear resistance), chemical (cross-link density) and morphological properties (scanning electron microscopy). The results obtained for these compositions were compared to a control sample purchased for the industry, with the same formulation of the SBR scraps. Obtained results show that the revulcanization process was effective. Values for tensile strength and tear resistance were 70 and 50%, respectively, compared to values found for the control sample, indicating the possibility of using this residue as artifacts of lower technical requirement.

Relationship among Vulcanization, Mechanical Properties and Morphology of Blends Containing Recycled EPDM

“…In the recovery of elastomers, the first step of any recycling process is the milling of the material, which is necessary to increase the surface contact area and to produce a more uniform product [23][24][25]. According to the literature [26], ground particles in the range of 28 to 35 mesh (0.425-0.600 mm) are ideal for incorporation in compounds.…”

“…In general, the ML values increased as the concentration of EPDM-r increased in the blends. These values reflect the initial viscosity of the compounds and provide information about the processability of the compounds [24,25]. It is known that the residue is vulcanized, which increases the initial viscosity of the blend.…”

“…In order to reduce this problem, some devulcanization techniques have been largely used in the recycled phase such as microwave devulcanization. It is a promising way of recycling since the results presented by the literature depicted the ability of the devulcanized elastomers to flow and to be remolded [9,23,28,29,46,47]. Figure 7 shows the SEM micrographs of some samples.…”

The Influence of UV-Accelerated Aging Process on Industrial Waste Containing EPDM

“…Additionally, its reuse into new compositions promoted improvements of the studied mechanical properties without compromising the vulcanization characteristics due to the higher molecular stiffness of the samples. This procedure can be used to lower costs, but only small amounts of residue can be incorporated into raw rubber without altering the material properties, due to the weak interaction of vulcanized rubber with raw rubber [1,2,5]. Some methods aim to improve this interaction by de-vulcanization.…”

“…Among the most-studied methods, the ultrasound method uses ultrasound waves to produce cavitation in the rubber, which generates tensions that are able to break the chemical bonds [3,5,[11][12][13][14][15][16][17][18]. Another de-vulcanization method based on the action of microwaves presents some advantages that make it one of the most promising for the recycling of rubber [2][3][4]13,15,[18][19][20][21][22], including its physical nature, the volumetric heating of the material by the microwaves, and the possibility of high productivity [23].The aging of elastomers can be defined as the degradation process produced by the interaction between a material and an environment, modifying their structure and properties (i.e., mechanical, electrical, chemical, and/or thermal). It is a complex chemical process that occurs under the influence of heat, oxygen, light, ozone, and mechanical tension, and it results in time-dependent modifications of the chemical and physical properties [24].…”