Nanocompósitos híbridos de borracha natural (NR) com argila mineral montmorilonita (MMT) e celulose II (CEL II) foram obtidos partindo de látex elastomérico, xantato de celulose e suspensão aquosa de MMT. O conteúdo de MMT foi variado de 1 a 5 phr (per hundred resin) e a quantidade de celulose II utilizada foi mantida constante em 15 phr. Foi comprovada por microscopia eletrônica de transmissão (TEM) a formação de nanocompósitos, na ausência e presença de xantato de celulose, mostrando a eficiência da técnica utilizada. Além do resultado de TEM, a viscosidade e relaxação Mooney, e propriedades mecânicas foram estudadas em todas as composições desenvolvidas. A adição da argila mineral promoveu aumento nas propriedades mecânicas estudadas, sendo que o aumento na viscosidade Mooney e a redução na capacidade de relaxação indicaram boa interação entre a montmorilonita e o sistema NR/CEL II.

Hybrid nanocomposites of natural rubber (NR), clay (MMT) and cellulose II (CEL II) were obtained with elastomeric latex, cellulose xanthate and aqueous suspension of the clay. The content of MMT varied from 1 to 5 phr (per hundred resin) while cellulose II was kept as 15 phr. The formation of nanocomposites from co-coagulation of natural rubber latex and MMT aqueous suspension, in the presence and absence of cellulose xanthate, was confirmed by transmission electron microscopy (TEM), thus showing the efficiency of the technique used. In addition to the TEM investigation, all compositions were studied with measurements of the Mooney viscosity and relaxation and mechanical properties. The MMT addition improved the mechanical properties, causing an increase in Mooney viscosity and a reduction in relaxation capability, which indicate a good interaction between MMT and NR/CEL II system.

Poly(ether ether ketone) nanocomposites containing vapour-grown carbon nanofibres (CNF) were produced using standard polymer processing techniques. At high shear rates no significant increase in resin viscosity was observed. Nevertheless, the addition of the CNFs results in a higher melt strength at 360°C. Electron microscopy confirmed the homogeneous dispersion and alignment of nanofibres in the polymer matrix. Evaluation of the mechanical composite properties revealed a linear increase in tensile stiffness and strength with nanofibre loading fractions up to 15 wt% whilst matrix ductility was maintained up to 10 wt%. An interpretation of the composite performance by short-fibre theory resulted in rather low intrinsic stiffness properties of the vapour-grown CNF. Differential scanning calorimetry was used to investigate crystallization kinetics and degree of crystallinity. The CNFs were found not to act as nucleating sites. Furthermore, unidirectional sliding tests against two different counterpart materials (100Cr6 martensitic bearing steel, X5CrNi18-10 austenitic stainless steel) were performed. The carbon nanofibres were found to reduce the wear rate of PEEK significantly.