Nanofibers, which have high surface area to volume ratio and better mechanical properties, are nanomaterials that both industry and scientists have started to show great attention in the last two decades. They are used in many areas such as life and filtration sciences, sensors, and composite reinforcement etc. Among five main production types, electrospinning is the best candidate for further development with a wide range of opportunities to be applied to all types of polymers and ceramics. This method uses electrically charged jet of polymers or liquid states of polymers to produce fibers from micro dimensions down to nano dimensions. Electrospinning setup has mainly three parts / (i) an AC/DC high voltage equipment which creates high electrical potential, (ii) a syringe, and (iii) a collecting screen. The purpose of this study is to electrospin polystyrene/butyl rubber blends and to investigate the effects of electrospinning parameters on the fibers produced. In this study, polystyrene/butyl rubber blends were electrospun by changing the applied voltage, the tip-to-collector distance, the flowrate, and the butyl rubber content in the fiber. Finally, morphology of electrospun fibers was characterized by SEM. The average fiber diameters varied from 760 nm to nearly 10 &micro / m. Increasing butyl rubber content in the fiber resulted in a decrease in the final fiber diameter. Increasing applied voltage also caused a decrease in the final fiber diameter. The tip-to-collector distance did not affect the average fiber diameter. Increasing flowrate yielded fibers with larger diameters. Finally, the addition of non-ionic surfactant decreased the average fiber diameter.

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Materiais poliméricos (plásticos e borrachas) abrangem uma proporção continuamente crescente de resíduos urbanos e industriais descartados em aterros, seus impactos no meio ambiente são cada vez mais preocupantes. A implementação de novas tecnologias em prol da redução dos resíduos poliméricos, aceitáveis do ponto de vista ambiental e a um custo eficaz, provou ser um grande problema, face às complexidades inerentes para a reutilização dos polímeros. A radiação ionizante tem capacidade para alterar a estrutura e propriedades dos materiais poliméricos. As borrachas butílicas e halobutílicas têm sido usadas em larga escala, numa variedade de aplicações tais como partes de pneus e artefatos diversos. O principal efeito do fóton de alta energia, como raios gama nas borrachas butílicas e butílicas halogenadas é a geração de radicais livres, acompanhada por mudanças nas propriedades mecânicas. O objetivo deste trabalho é desenvolver processos de degradação controlada (desvulcanização) de borrachas butílicas e halobutílicas (cloro e bromo), de modo a caracterizar sua disponibilidade para transformação e alteração de suas propriedades. Os resultados experimentais obtidos mostraramm que as borrachas butílica e halobutílicas irradiadas a 25 kGy e posteriormente cisalhadas podem ser usadas como ponto de partida para misturas com borracha virgem. / Polymeric materials (plastics and rubbers) attain a continuous and raising proportion of urban and industrial scraps discarded in landfills; their impact on environment are more and more concerning. The implementation of new technologies in order to reduce impacts of plastic waste on the environment, at an effective cost, proved to be a great problem, due to inherent complexity for polymers re-using. Ionizing radiation is capable to modify structure and properties of polymeric material. Butyl and halobutyl rubbers have been used within a comprehensive scale, applications such as tires spare parts and diverse artifacts. The major high energy photon effect, as gamma-rays in butyl and halo butyl rubbers consists in free-radicals generation along changes in mechanical properties.This work aims to the development of controlled degradation processes (devulcanization) of butyl and halo butyl (chlorine and bromine) rubbers, in order to characterize their availability for transformation and modification of properties. Experimental results obtained showed that butyl and halobutyl rubbers,irradiated at 25 kGy and further sheared, are able to be used as an initial point for mixtures with pristine.

Materiais poliméricos (plásticos e borrachas) abrangem uma proporção continuamente crescente de resíduos urbanos e industriais descartados em aterros, seus impactos no meio ambiente são cada vez mais preocupantes. A implementação de novas tecnologias em prol da redução dos resíduos poliméricos, aceitáveis do ponto de vista ambiental e a um custo eficaz, provou ser um grande problema, face às complexidades inerentes para a reutilização dos polímeros. A radiação ionizante tem capacidade para alterar a estrutura e propriedades dos materiais poliméricos. As borrachas butílicas e halobutílicas têm sido usadas em larga escala, numa variedade de aplicações tais como partes de pneus e artefatos diversos. O principal efeito do fóton de alta energia, como raios gama nas borrachas butílicas e butílicas halogenadas é a geração de radicais livres, acompanhada por mudanças nas propriedades mecânicas. O objetivo deste trabalho é desenvolver processos de degradação controlada (desvulcanização) de borrachas butílicas e halobutílicas (cloro e bromo), de modo a caracterizar sua disponibilidade para transformação e alteração de suas propriedades. Os resultados experimentais obtidos mostraramm que as borrachas butílica e halobutílicas irradiadas a 25 kGy e posteriormente cisalhadas podem ser usadas como ponto de partida para misturas com borracha virgem. / Polymeric materials (plastics and rubbers) attain a continuous and raising proportion of urban and industrial scraps discarded in landfills; their impact on environment are more and more concerning. The implementation of new technologies in order to reduce impacts of plastic waste on the environment, at an effective cost, proved to be a great problem, due to inherent complexity for polymers re-using. Ionizing radiation is capable to modify structure and properties of polymeric material. Butyl and halobutyl rubbers have been used within a comprehensive scale, applications such as tires spare parts and diverse artifacts. The major high energy photon effect, as gamma-rays in butyl and halo butyl rubbers consists in free-radicals generation along changes in mechanical properties.This work aims to the development of controlled degradation processes (devulcanization) of butyl and halo butyl (chlorine and bromine) rubbers, in order to characterize their availability for transformation and modification of properties. Experimental results obtained showed that butyl and halobutyl rubbers,irradiated at 25 kGy and further sheared, are able to be used as an initial point for mixtures with pristine.

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