Applications of Polymer Matrix Composites

December 2018

Polymer matrix composites are defined as materials comprising a matrix polymer and inclusions within that matrix polymer. 

Both thermoset polymers and thermoplastic polymers can be used as matrix polymers.  The term binder is also often used to describe the matrix polymer since it holds together (and thus it “binds”) the inclusions. 

The inclusions may include continuous fibers (such as glass, carbon, aramid, basalt, or polymer fibers), short fibers (such as chopped glass fibers or chopped carbon fibers), platy inclusions (such as exfoliated clay platelets), spherical particles (such as glass microspheres), particles with irregular shapes (such as carbon black particles or fumed silica particles which are aggregates of very small primary particles), or combinations of two or more types of such materials.  The term filler is also often used to describe an inclusion since it “fills” the polymer matrix.

Composites provide properties and performance characteristics, such as higher stiffness, strength, impact resistance, heat resistance, abrasion and wear resistance, and gas barrier, that cannot be attained by the matrix polymer in the absence of inclusions.  A composite may be designed to manifest such improvements either isotropically or anisotropically depending on the application needs. 

For example, in the vast majority of the continuous fiber-reinforced composites used today, individual layers (plies), where each ply contains unidirectionally oriented continuous fibers in a polymer matrix, are stacked with different angles to form laminates that possess isotropic in-plane properties but are weak in the orthogonal (through-thickness) direction.  If it is crucial to also have excellent properties in the through-thickness direction, a 3-dimensional woven fabric is often used as the reinforcement instead of stacking layers of plies containing unidirectionally oriented fibers.

Composites where nanofillers (such as carbon nanotubes, exfoliated clay platelets, or carbon black nanoparticles) have been dispersed in a polymer are commonly called nanocomposites.  There is no single universally accepted criterion for defining nanofillers and nanocomposites.  We define a nanofiller as an inclusion that possesses a length that is less than 0.5 microns (500 nanometers) in at least one principal axis direction and a polymer matrix nanocomposite as a composite where a nanofiller is dispersed within a polymer matrix.

The benefits sought in designing nanocomposites include any one or combination of (often dramatically) increased stiffness (modulus), strength, dimensional stability, thermal stability, electrical conductivity, flame retardancy, chemical resistance, and/or optical clarity; decreased gas, water, and oil permeability; and more attractive surface appearance.

At Bicerano & Associates, our expertise in polymers and composites helps our clients to develop polymers and composites for any application they may require.

Examples of Applications

The following industry and application highlights provide a sampling of the vast range of applications of polymer matrix composites.  More detailed discussions are provided for several industries on separate webpages, as indicated.

Transportation vehicles:  Polymer matrix composites find many uses in automotive, aerospace, and marine applications.  Some examples of these uses are provided below.  See Polymers and Composites in the Transportation Industry for a more detailed discussion.

• Automotive vehicles: Examples of polymer matrix composite use include tires and various belts and hoses as well as polymer matrix composite components in automotive bodies.  Some very expensive sports cars, such as Bugatti, use carbon fiber reinforced polymer matrix composite as the main material of construction of the body of the car.  It is interesting to note also that the first polymer matrix nanocomposite ever used in a commercial product was a timing belt cover launched in 1993 for the Toyota Camry.  This breakthrough was followed over the decades with other applications, such as bumpers, body panels, engine parts, fuel tanks, and mirror housings.  The technology has, by now, expanded to reduce the rolling resistance of tires, as well as provide ultra-hard protective coatings for paintwork, windscreen glass, and headlamps.
• Aerospace vehicles: Polymer matrix composites are also used in aircraft tires and interiors.  Of even greater value, however, is the ability of polymer matrix composites to help satisfy the relentless drive in the aerospace industry to enhance performance while reducing weight.  Most importantly, fiber-reinforced polymer matrix composites can be optimized to combine high strength, stiffness, and toughness, and low density, and thus to obtain exceptional strength-to-density and stiffness-to-density ratios along with superior physical properties, so that they are often the structural materials of choice for use in aircraft components.
• Marine vehicles: Polymer matrix composites find many uses in marine vehicles.  Fiberglass boats are among the most familiar examples since fiberglass is a composite where a matrix polymer is reinforced by glass fibers which may be arranged randomly, or as a chopped strand mat, or as a woven fabric.  The growing use of lighter, stiffer, and stronger carbon fibers instead of glass fibers is an emerging trend in boatbuilding. 

Medical devices:  Polymers and composites are essential components of many medical devices and applications.  Some examples of these uses are provided below.  See Polymers and Composites in the Medical Device Industry for a more detailed discussion.

• Polymer matrix composites are used as components in a wide range of medical devices; such as MRI scanners, C scanners, X-ray couches, mammography plates, tables, surgical target tools, wheelchairs, and prosthetics.
• Polymer matrix nanocomposites containing carbon nanotubes or TiO₂ nanotubes reduce the healing time of broken bones by acting as a “scaffold” which guides the growth of replacement bone.
• The potential uses of nanocomposites in diagnostics and therapy are being explored. For example, the combination of magnetic nanoparticles and fluorescent nanoparticles in nanocomposite particles that are both magnetic and fluorescent appears to make a tumor easier to see during MRI tests performed prior to surgery and may also help the surgeon to see the tumor better during surgery.

Personal protective equipment:  Polymer matrix composites are used in protective equipment for use in harsh environments (as in extreme heat or cold), when exposed to fire (as firefighters often are), when facing deadly weapons (as soldiers and law enforcement personnel often face), and in many other hazardous situations.  Protection against temperature extremes, moisture, rain, chemical exposure, fire, clothing puncture, projectiles, abrasion, biohazards, radiation, explosions, high voltage, static electricity, and more can be achieved through the use of composites.

Footwear:  The performance and comfort of footwear, as well as the durability of shoe interiors and exteriors, can be improved with the help of polymer matrix composites.  In addition, biologically resistant or reactive composites may be used to counteract the typical drawbacks of conventional shoe textiles, such as odor, bacteria, and fungi.    Synthetic (artificial) leather prepared from polyurethane formulations and often used as an alternative to natural (most often cow) leather in performance footwear is also often a composite made of two layers, including a backing layer that is most often made of woven or nonwoven polyester fibers.  The optimum use of polymer matrix composites is essential for manufacturing footwear that can be used for prolonged periods in harsh environments.  See Polymers and Composites in the Sporting Goods Industry for a more detailed discussion.

Sporting goods:  Polymer matrix composites find many uses in sporting goods.  The following are some examples.  See Polymers and Composites in the Sporting Goods Industry for a more detailed discussion

• Polymer matrix composites are used in performance footwear.
• Some versions of synthetic leather, a polyurethane-based material which is often used as an alternative to natural leather in performance footwear, are composite made of two layers, including a backing layer that is most often made of woven or nonwoven polyester fibers.
• Biologically resistant or reactive composites can provide protection against the hazards posed by sports equipment use, primarily excessive moisture, which promotes the growth of bacteria and fungi.
• Fiber-reinforced polymer matrix composites are used as materials of construction in high-performance sports gear because of their light weight, high strength, many degrees of freedom of design, and easy processing and forming characteristics. Examples of sports gear where such composites are used include skis, baseball bats, golf clubs, tennis rackets, and bicycle frames.

Industrial equipment:   Polymer matrix composites are used in a vast range of industrial equipment.  They are used as the main material of construction, or as components of equipment, or in some instances both as the main material of construction and as components.  The uses of equipment in which polymer matrix composites are incorporated span almost all industries.

Packaging:  Polymer matrix composites are used in many packaging applications.  The following are some examples.  See Polymers and Composites in the Consumer Packaged Goods Industry for a more detailed discussion.

• Polymer matrix nanocomposite films where exfoliated clay nanoplatelets are dispersed with a high degree of orientation parallel to the plane of the film offer excellent barrier to oxygen and other gases. Hence such nanocomposites are useful as packaging materials for foods and other products that need protection against exposure to gases.
• It is also possible to design versions of such protective packaging films which provide high resistance to water vapor transmission.
• Work is in progress to develop biodegradable versions of such barrier packaging films. Such versions must remain stable and able to protect the packaged food but undergo biodegradation after being discarded.
• Work is in progress to develop “active” nanocomposite food packaging materials incorporating nanofiller particles with antimicrobial and/or antioxidant activity so that the package inhibits and retards food spoilage even more effectively than would be expected from its gas barrier performance by itself.
• Work is in progress to develop “intelligent” food packaging materials incorporating reactive nanoparticles that can serve as nanosensors and manifest visible changes that warn the consumer of spoilage of the packaged food.

Building, construction, and civil engineering:  Examples of polymer matrix composite use include the replacement, repair, retrofitting, or reinforcement of a structural component manufactured from a traditional structural material with fiber-reinforced polymers, as well as the emerging technology of composite panels used for the modular construction of buildings.  See Polymers and Composites in the Building, Construction, and Civil Engineering Industry for a more detailed discussion.

Impellers, blades, housings, and covers:

• Windmill blades are among the many types of products where the high strength-to-weight ratio achievable by using polymer matrix composites is essential for providing the necessary end use performance. Examples include blades manufactured from carbon nanotubes or graphene nanoplatelets in an epoxy thermoset matrix polymer. 
• Such nanocomposites conduct electricity. Their electrical conductivity depends on the distance between the nanofiller components.  This distance changes when strong wind gusts cause the blades to bend.  Hence these structural components also serve as stress sensors which warn the windmill operator when the windmill should be shut down to protect it from serious damage.
• Polymer matrix nanocomposites are also used as the materials of construction of impellers for many applications, including vacuum cleaners.
• Polymer matrix nanocomposites are also used as the materials of construction of many housings and covers; such as power tool housings, lawn mower hoods, and covers for portable electronic equipment such as mobile phones and pagers.

Energy storage devices:  Polymer matrix composites are used in many energy storage devices.  The following are some examples.  See Electrical and Electronics Applications of Polymers and Composites for a more detailed discussion.

• Anodes manufactured from a nanocomposite of silicon nanospheres and carbon nanoparticles provided lithium ion batteries with greater power output. After this initial work, other nanocomposite formulations were also evaluated with favorable results.  It should be noted that, although they are mentioned here because of their importance, these particular nanocomposites do not possess a polymeric matrix.
• Carbon nanotubes can be incorporated into paper to manufacture a conductive paper which can then be soaked in an electrolyte to obtain flexible batteries. Since cellulose (a polymer) is the main component of paper, the conductive paper is a polymer matrix nanocomposite.  This work is a significant step forward in the emerging field of flexible (bendable) electronics.
• Polymer matrix nanocomposites are used in thin film capacitors for computer chips.

Electronics and optics:  Polymer matrix composites are used in many electrical and electronics applications.  The following are some examples.  See Electrical and Electronics Applications of Polymers and Composites for a more detailed discussion

• As was discussed above, under the heading of “Energy storage devices”, nanocomposites are used in lithium ion batteries, flexible batteries, and thin film capacitors.
• As was discussed above, under the heading of “Impellers, blades, housings, and covers”, polymer matrix nanocomposites are used as covers for portable electronic equipment such as mobile phones and pagers. They provide outstanding mechanical properties and excellent protection of electronic equipment while being of low weight.  They can also be formulated to impart the cover with much better antistatic performance than that of the matrix polymer.
• The electrical conductivity of a polymer possessing low density and excellent mechanical properties can be increased by orders of magnitude by the incorporation of small amounts of certain nanofillers. Such polymer matrix nanocomposites then become candidates for use as components in electronics applications where the matrix polymer by itself would be useless.
• The incorporation of optimum quantities of certain nanofillers, such as nanoclays, enhances the transparency and reduces the haze of many polymer films. These nanofillers also improve the strength, toughness, hardness, and abrasion resistance of the film to levels that are unattainable by films of the matrix polymer by itself.  The applications of such polymer matrix nanocomposites include coatings that provide both protection and enhanced aesthetic appeal.

Oil and gas exploration, production, transport, and storage:  Polymer matrix composites are used in many oil and gas industry applications.  The following are some examples.  See Applications of Polymers and Composites in the Oil and Gas Exploration and Production Industry for a more detailed discussion. 

• Fiber-reinforced polymer matrix composites are used as materials of construction in structures, such as offshore oil platforms and components on such platforms, used for oil and gas exploration and production. Much lighter weight and greater corrosion resistance are among the major advantages of polymer matrix composites over metals for such applications.
• The use of fiber-reinforced thermoset polymer matrix composites for repairing oil and gas transport and storage media ranging from high-pressure equipment and piping to oil storage tanks has been growing rapidly over the last two decades. Such composite repair systems are being used as alternatives to replacing damaged steel pipeline components or repairing them by installing heavy metal sleeves.
• The use of thermoset nanocomposite beads as nearly neutrally buoyant proppants, gravel pack materials, and solid lubricants during oil and gas drilling and completion operations is growing rapidly.