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Silicone rubber (SR) and ethylene-propylene-diene monomer (EPDM) are widely-used polymers as housing for high voltage insulators. In this work, SR/EPDM/clay nanocomposites were obtained by two-roll mill mixing for outdoor polymeric insulators. Morphology, dielectric properties, dielectric breakdown strength (DBS), and surface and volume resistivity of different weight contents of nanoclay (Cloisite 15A) incorporated in SR, EPDM, and SR/EPDM hybrid nanocomposites were characterized. In addition, the distribution of breakdown voltages was fit to the distribution of Weibull and estimated the scale and shape parameters. The polar groups of the clay particles enhanced the polarization capability of the nanocomposites. Moreover, DBS results showed an enhancement of the dielectric strength proportional to clay content. Finally, the surface and volume resistance of all nanocomposites decreases but maintains very high electrical resistance. The experimental data presented in this study will be useful for designing and manufacturing the outdoor insulators. Fil: Bazli, Leila. Nano and Smart Polymers Center of Excellence. Iran Polymer & Petrochemical Institute; Irán Fil: Eskandarinezhad, Sara. Yazd University. Department of Mining and Metallurgy; Irán Fil: Kakur, Naresh. Indian Institute of Technology Madras. Department of Aerospace Engineering; India Fil: Ramachandran, Velmurugan. Indian Institute of Technology Madras. Department of Aerospace Engineering; India Fil: Bacigalupe, Alejandro. Instituto Nacional de Tecnología Industrial. Centro de Materiales Avanzados (INTI); Argentina Fil: Mansilla, Marcela. Instituto Nacional de Tecnología Industrial. Centro de Materiales Avanzados (INTI); Argentina Fil: Escobar, Mariano. Instituto Nacional de Tecnología Industrial. Centro de Materiales Avanzados (INTI); Argentina

This work presents the synthesis and characterization of oriented nanofibers made of polycaprolactone (PCL) and multiwalled carbon nanotubes (MWCNT) obtained by electrospinning. The preparation of MWCNT/PCL solutions and electrospinning conditions were studied in order to maximize electrical conductivity of the composite and fiber alignment. The characterization of MWCNT/PCL solutions and fibers revealed the occurrence of different dispersion states for MWCNTs for different loads, which in turn affected the properties of the electrospun composite, such as its double electrical percolation and the in-fiber orientation of the PCL crystals. As the same dispersion states of MWCNT were present in both PCL/MWCNT dispersions and fibers, the rheology of the former can be correlated to the final properties of the latter.

El negro de humo es el refuerzo más utilizado de la industria del caucho. Debido a que se trata de un material derivado de la industria del petróleo, se prevé un aumento en el costo. El objetivo del presente trabajo es estudiar el efecto de la adición de caolín y montmorillonita para formar un sistema híbrido de refuerzo sobre una matriz de SBR, y reducir el uso de negro de humo en las formulaciones de caucho. Se observa que la presencia de montmorillonita aumenta el alargamiento a la rotura, la tracción y el desgarre. El estudio por microscopía detecta un cambio morfológico que justifica la mejora en las propiedades mecánicas. La reología indica que los sistemas híbridos presentan mayor grado de entrecruzamiento. Por otra parte, la montmorillonita retrasa las reacciones de vulcanización, mientras que el caolín no influye en la cinética de curado. Carbon black is the most used additive in rubber industry. However the future shortage of petrochemical-based products could lead to an increase in costs. The aim of the present work is to study the effect of the addition of kaolin and montmorillonite to form a hybrid reinforcement system on a matrix of SBR, and reduce the use of carbon black in rubber formulations. Analyses show that the presence of montmorillonite increases elongation, tensile strength, and tear strength. Microscopy detects a morphological change which justifies the improvement in mechanical properties. Rheology indicates that hybrid systems have a higher degree of cross-linking. Moreover, montmorillonite retards vulcanization reactions while kaolin does not affect the curing kinetics. Fil: Pereletegui, Marcelo. Instituto Nacional de Tecnología Industrial; Argentina Fil: Crisnejo, Matias. Instituto Nacional de Tecnología Industrial; Argentina Fil: Valdez, Ignacio. Instituto Nacional de Tecnología Industrial; Argentina Fil: Bacigalupe, Alejandro. Instituto Nacional de Tecnología Industrial; Argentina Fil: Leszman, Carlos. Universidad Nacional del Oeste; Argentina Fil: Torres Sanchez, Rosa Maria. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; Argentina Fil: Escobar, Mariano Martin. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Oeste; Argentina. Instituto Nacional de Tecnología Industrial; Argentina