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The preparation procedure of epoxy and benzoxazine multi-walled carbon nanotube buckypaper composites is described. The morphology of the buckypaper is characterized by scanning electron microscopy and porosimetry, revealing a non-uniform porous structure. The wetting behavior of epoxy and benzoxazine resins in the buckypaper surface is studied by contact angle measurements. Scanning electron microscopy photographs of the composites obtained by infiltration of the buckypaper with epoxy and benzoxazine resins and subsequent curing reveal that a good impregnation is achieved. Thermal conductivity results reveal higher values for pristine buckypaper than for the composites, which is explained by the extremely small thermal conductance of the nanotube–polymer interface. The thicker resin layer surrounding the nanotubes observed in the buckypaper/epoxy composite justifies its lower conductivity, as compared with the buckypaper/benzoxazine composite. [ABSTRACT FROM AUTHOR]

Joule’s first-law dictates that when electric current passes through a conductor heat is generated. The scope of this work is to investigate the Joule heating effect of two types of carbon fiber tows in dry form. The tows are used as primary heating elements on various preform structures that require accurate and uniform temperature control, using a DC power supply. The investigated temperatures, ranged from 300 K up to 650 K. A finite difference scheme was developed, in order to predict and quantify the transient phenomenon and is verified against experimental results. In order to exploit in-depth the phenomenon and achieve very good agreement between numerical and experimental results, temperature dependence of thermal and electrical properties (specific heat capacity, total hemispherical emissivity, and volume resistivity) was examined under controlled vacuum environment, ensuring no fiber oxidation. [ABSTRACT FROM PUBLISHER]