Small but strong: A review of the mechanical properties of carbon nanotube–polymer composites

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.

Mechanical Reinforcement of Polymers Using Carbon Nanotubes

Metal Matrix Composites

We report the observation of single nanotube fragmentation, under tensile stresses, using nanotube-containing thin polymeric films. Similar fragmentation tests with single fibers instead of nanotubes are routinely performed to study the fiber-matrix stress transfer ability in fiber composite materials, and thus the efficiency and quality of composite interfaces. The multiwall nanotube-matrix stress transfer efficiency is estimated to be at least one order of magnitude larger than in conventional fiber-based composites.

Stress-induced fragmentation of multiwall carbon nanotubes in a polymer matrix

One-dimensional carbon nanotubes and two-dimensional graphene nanosheets with unique electrical, mechanical and thermal properties are attractive reinforcements for fabricating light weight, high strength and high performance metal-matrix composites. Rapid advances of nanotechnology in recent years enable the development of advanced metal matrix nanocomposites for structural engineering and functional device applications. This review focuses on the recent development in the synthesis, property characterization and application of aluminum, magnesium, and transition metal-based composites reinforced with carbon nanotubes and graphene nanosheets. These include processing strategies of carbonaceous nanomaterials and their composites, mechanical and tribological responses, corrosion, electrical and thermal properties as well as hydrogen storage and electrocatalytic behaviors. The effects of nanomaterial dispersion in the metal matrix and the formation of interfacial precipitates on these properties are also addressed. Particular attention is paid to the fundamentals and the structure–property relationships of such novel nanocomposites.

Recent progress in the development and properties of novel metal matrix nanocomposites reinforced with carbon nanotubes and graphene nanosheets

T ensile tests at a variety of temperatures have been carried out on composites consisting of tungsten or molybdenum wires, uniaxially aligned in a copper matrix. Both continuous and discontinuous wires have been used, and both brittle and ductile tungsten wires. It is found that the breaking strength is a linear function of the wire content. A simple theory to explain this is developed and auxiliary experiments to check the theory are described. Some simple predictions about the behaviour of fibre reinforced metals are made from the results.

Tensile properties of fibre-reinforced metals: Copper/tungsten and copper/molybdenum

Measurements of the strain-time curve have been made on silver specimens containing 40 per cent by volume of aligned tungsten wires at temperatures between 400°C and 600°C. The wires greatly reduce the rate of creep of the matrix. The rate of creep of composites containing discontinuous wires appears to be governed by the rate of creep of the matrix under the action of the shear stresses which arise close to the fibre-matrix interface.

Tensile properties of fibre reinforced metals—II. Creep of silver-tungsten

Calculations of the cleavage strength σmax and of the shear strength τmax of ideally perfect crystals have been reviewed by Kelly (1966), and Tyson (1966) has carried out some accurate calculations...

W.R. Tyson

Papers

Tensile properties of fibre-reinforced metals: Copper/tungsten and copper/molybdenum

Tensile properties of fibre reinforced metals—II. Creep of silver-tungsten

The Theoretical Strengths of Crystals and the Tip of a Crack