Mechanical Reinforcement of Polymers Using Carbon Nanotubes

Abstract

Owing to their unique mechanical properties, carbon nanotubes are considered to be ideal candidates for polymer reinforcement. However, a large amount of work must be done in order to realize their full potential. Effective processing of nanotubes and polymers to fabricate new ultra‐strong composite materials is still a great challenge. This Review explores the progress that has already been made in the area of mechanical reinforcement of polymers using carbon nanotubes. First, the mechanical properties of carbon nanotubes and the system requirements to maximize reinforcement are discussed. Then, main methods described in the literature to produce and process polymer–nanotube composites are considered and analyzed. After that, mechanical properties of various nanotube–polymer composites prepared by different techniques are critically analyzed and compared. Finally, remaining problems, the achievements so far, and the research that needs to be done in the future are discussed.

Liquid‐Phase Exfoliation of Nanotubes and Graphene

“…This diameter reflects the 1nm diameter nanotubes and a 1nm thick shell of functional groups. At low concentration (~10 -4 mg/ml) we observed rms bundle diameters of ~3-4 nm indicative of extensive exfoliation As the concentration was increased to 1 mg/ml, the rms diameter increased only to [5][6] nm. This represents a very small degree of aggregation over 4 decades of concentration change, illustrating the very good quality and stability of these dispersions.…”

“…Bundle properties are inferior to those of isolated SWNT. It is non-trivial to separate SWNT from bundles making this issue a serious hurdle in the way of real applications [5,14,15] .…”

“…For example, single walled carbon nanotubes (SWNT) have mechanical [4,5] , electrical [6] and thermal [7] properties unheard of in any other material. They are extremely stiff, displaying Young's modulus close to 1 TPa, and are among the world's strongest materials, with strength between 50 and 100 GPa.…”

Analysis of the structure and chemical properties of some commercial carbon nanostructures

“…With a Young's modulus of approximately 1 TPa and a tensile strength of approximately 50 GPa, carbon nanotubes are the strongest and stiffest nanomaterials [21,25,27,28]. Their advantages for polymer reinforcement have been recently reviewed by Miyagawa et al and Coleman et al [29,30]. Koziol et al spun fibers from CNTs much stronger than in previous studies [31].…”

Design and fabrication of colloidal polymer nanocomposites

“…Nanocomposites with nanoscale fillers, e.g. nanoclay [4] and carbon nanotubes [5,6], have pronounced properties that are not realized with traditional micro-scale fillers. The mechanical properties, electrical and thermal conductivity, and flammability resistance all differ in nanocomposites in comparison to conventional composites.…”