Halloysite for clay-polymer nanocomposites: effects of nanofillers on the anti-corrosion, mechanical, microstructure, and flame-retardant properties-a review

Polymer-clay nanocomposites are the most remarkable nanomaterials of the current decade with broad range of applications, because they attempt a great competence to impart outstanding properties when compared to pure polymers even at a very less percentage of nanofiller inclusion. Montmorillonite, vermiculite, halloysite, sepiolite, laponite, bentonite, and attapulgite are the dominant classes of clay used as reinforcement in polymer-clay nanocomposites. Clay is easily accessible, easily processed, inexpensive, and non-toxic, and clay nanocomposites have seen significant commercial interest due to improvements in processing. Clay nanocomposites show distinctive properties of outstanding thermal stability, enhanced flame retardancy, high dimensional stability, decreased gas permeability, and enhanced anticorrosive and improved mechanical properties. This review reveals the polymer-based nanocomposites reinforced with halloysite nanotubes, for high-performance promising applications. The qualities of the nanofiller can be changed by chemically modifying exterior surface and interior lumen. Chemical alteration of the halloysite nanotube surface, in particular, results in nanoarchitecture with targeted affinity through functionalization of the outer surface and potential for drug transport through functionalization of the nanotube lumen. The various functionalization techniques of altering the nanofillers to allow interaction with polymers are discussed. The significance of filler dispersion in the polymeric matrix is also featured. The consequences of functionalized nanofillers on the microstructure and morphology, mechanical strength, thermal stability, drug encapsulation and sustained release abilities, and flame retardancy as well as barrier properties can be summarized. Subsequently, the challenges, key problems, future prospects, and feasible mechanism for polymeric clay nanocomposites are also reviewed. [GRAPHICS] .