Carbon nanotubes filler-matrix interaction

More recently nanoscale fillers such as clay platelets, silica, nano-calcium carbonate, titanium dioxide, and carbon nanotube nanoparticles have been used extensively to achieve reinforcement, improve barrier properties, flame retardancy and thermal stability, as well as synthesize electrically conductive composites. In contrast to micron-size fillers, the desired effects can be usually achieved through addihon of very small amounts (a few weight percent) of nanofillers [4]. For example, it has been reported that the addition of 5 wt% of nanoclays to a thermoplastic matrix provides the same degree of reinforcement as 20 wt% of talc [5]. The dispersion and/or exfoliahon of nanofillers have been identified as a critical factor in order to reach optimum performance. Techniques such as filler modification and matrix functionalization have been employed to facilitate the breakup of filler agglomerates and to improve their interactions with the polymeric matrix. 

Yang, K., Gu, M. The Effects of triethylenetetramine grafting of multi-walled carbon nanotubes on its dispersion, filler-matrix interfacial interaction and the thermal properties of epoxy nanocomposites. Polym. Eng. Sci. 49, 2158-2167 (2009)... 

Specific interfacial interactions in multi-component systems such as composites improve the chemical compatibility between the filler and the matrix, prevent the fiUer from aggregating and strengthen the interface. Marom et al. [136] prepared carbon nanotube based... 

Powders are commonly used as fillers for rubber mixes. The most popular are carbon black, silica, kaolin, or more modem like graphene, fullerenes and carbon nanotubes. The nature of their surface is the main attribute of fillers, as surface energy and specific area determine the compatibility of filler with mbber matrix and the affinity to other c ingredients. One of the major problems is the tendency of fillers to agglomeration - formation of bigger secondary stmctures, associated with lower level of filler dispersion, what is reflected by the decrease of mechanical properties of mbber vulcanizates [1]. Surface modification of powder can improve interaction between mbber matrix and filler. Application of low-temperature plasma treatment for this purpose has been drown increasing attention recently [2, 3]. 

The carbon nanotubes have a very stable surface structure and hard surface interaction so when the carbon nanotubes are used as nanofiller in polymer matrices, this high stability becomes a problem in the interaction between matrix and filler. 

Incorporating carbon black and carbon nanotubes into the polymer matrix leads to conductive materials. A lot of work has been devoted to investigations of the electrical properties of these filled materials. The electrical conduction process depends on several parameters such as processing techniques used to mix fillers with rubber, fiUer content and filler characteristics (particle size and structure) as well as polymer-filler interactions. 

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