Effect of Coating of Carbon Nanotubes on Mechanical Properties of Polymer Composites: A Review

Carbon nanotubes (CNTs) possess superior mechanical properties in addition to other functional features. The last decade has seen rapid growth in the usage of CNTs in polymer matrix composites. This has led to the development of novel dispersion and functionalization techniques. Though the CNTs exhibit excellent properties, their use in commercial applications has been restricted by the problem of dispersion in polymers. Perfect bonding of CNTs and polymer interphase with uniform distribution of CNTs are required for fully utilizing the reinforcement effect of the CNTs. In this review, the techniques and principles of CNT dispersion and functionalization/coating have been discussed in depth. The readers will be able to further their understanding of the field of CNT-reinforced polymer composites. Functionalization of CNTs and their dispersion effects are highlighted for polymer-based composites to observe the changes that occur in their mechanical behavior. The issues that require further work include the need to develop the tools and techniques to analyze the extent of dispersion or cluster of CNTs in a matrix of polymer, the need to optimize the process variables, and the need to resolve the inconsistency among the studies involving functionalization of CNTs. Comprehensive studies are needed to determine the association between different variables, such as surface treatment, degree of functionality, conditions of processing, and thermal, mechanical, optical, and electrical properties.