Increasing the Dispersibility of Multi-walled Carbon Nanotubes and Their Uniform Distribution in the Polymer Matrix Using Soft Acid Treatment
Abstract
Introduction. Modern polymer composites modified with carbon nanotubes open up new possibilities for creating materials with improved mechanical, electrical and thermal conductivity properties. The key problem limiting wide application of these materials is the uneven distribution of nanotubes in the polymer matrix and their tendency to aggregate. To solve this problem, there can be used chemical functionalization of carbon nanotubes, in particular acid treatment. When scaling up the technology, evaluating the effect of this treatment on the distribution of carbon nanotubes in a polymer matrix will allow reducing the cost of manufacturing masterbatches and products based on polymer composite materials. Aim of the Study. The study is aimed at developing a gentle carbon nanotubes functionalization regime that ensures the production of polymer composite materials with a uniform filler distribution. Materials and Methods. The object of the study was multi-walled carbon nanotubes LUCAN BT 1001M in their original and treated (with a mixture of nitric and sulfuric acids) forms. The specific surface area of the samples was determined by the adsorption methods and analyzed with the use of the Brunauer-Emmett-Teller method. The distribution of the original and treated multi-walled carbon nanotubes was investigated by the optical microscopy method. Results. It has been found that the specific surface area of multi-walled carbon nanotubes increases after functionalization. It has shown that the treatment of carbon nanotubes in a gentle mode makes it possible to obtain stable aqueous dispersions and distribute them uniformly in a polymer matrix. Conclusion. The results obtained indicate the need for a functionalization procedure of carbon nanotubes for their practical application and indicate the effectiveness of a gentle nanotube treatment regime for obtaining composite materials with uniformly distributed filler.