Nanodiamond reinforcement in polyamide and polyimide matrices: Fundamentals and applications

Nanodiamond is an emerging nanocarbon material having several advantageous properties (high surface area, mechanical properties, optical features, wear resistance, low friction coefficient, etc.) as a nano-sized filler for polymer matrices. Polyamides and polyimides are two important thermoplastic polymers which are among important matrices for nanodiamond composites. Polyamides have high thermal stability, mechanical strength, wear resistance, superior tribological properties, and fine processability. Many aliphatic polyamides, such as polyamide 6, polyamide 6,6, polyamide11, polyamide 12, and several aromatic polyamides have been reinforced with nanodiamond to further enhance their engineering properties. Similarly, outstanding mechanical, thermal, optical, and electrical properties of aromatic polyimides have been enhanced by using nanodiamond particles. Surface nanodiamond modification with various functional groups has been achieved to enhance interfacial adhesion with the matrix, which in turn, improved the physical properties. Polyamide/nanodiamond nanocomposites and polyimide/nanodiamond nanocomposites have been prepared using in situ reactive polymerization, melt extrusion, solution processing, and other techniques. The improved electrical, mechanical, thermal, and biomedical properties render them potentially important materials for various technical applications including energy storage, membrane technology, coatings, and biomedical.