Lecture 11: Polymer Matrix Composites

Flashcards covering the key vocabulary and concepts from Lecture 11 on Polymer Matrix Composites (PMC).

Carbon (in modern skis)

A relatively complex composite structure that is light, lively, and strong under compression, but very expensive.

Kevlar (in modern skis)

A relatively complex composite structure that is strong, reasonably light, good under tension, and a good dampener.

Aluminium Honeycomb (in modern skis)

A relatively complex composite structure that is very light and strong, but is expensive and has reduced damping capabilities.

Fibreglass (in modern skis)

A relatively complex composite structure that is relatively strong, light, and inexpensive.

Titanium (in modern skis)

A relatively complex composite structure that is very light and strong, with good damping properties, but expensive.

Air (in modern skis)

When used correctly, it can decrease the weight of a ski core without having any major effect on the core's strength.

Foam (in modern skis)

If large amounts of it are used in a core, it is often done by using a composite torsion box to create most of the ski's strength and flex characteristics.

Principle of combined action

Material property combinations and ranges have been, and are yet being, extended by the development of composite materials.

Composite

Any multiphase material that exhibits a significant proportion of the properties of both constituent phases.

Principle of combined action

Better property combinations are fashioned by the judicious combination of two or more distinct materials.

Composite (in the present context)

A multiphase material that is artificially made, as opposed to one that occurs or forms naturally; constituent phases must be chemically dissimilar and separated by a distinct interface.

Matrix phase

The continuous phase that surrounds the other phase in a composite material.

Dispersed phase

The phase that is surrounded by the matrix phase in a composite material.

Dispersed phase geometry

The shape of the particles and the particle size, distribution, and orientation.

Polymer Based Composites

Polymer imbedded with a reinforcing item such as fibers or powders.

Thermosetting (TS) polymers

Thermosetting polymers that are the most common matrix materials; examples include phenolics, polyesters, and epoxies.

Reinforcing Agent

Possible materials include ceramics, metals, other polymers, or elements such as carbon or boron; possible geometries include fibers, particles, and flakes.

Particle-reinforced composites

Composite type where particle dimensions are approximately the same in all directions.

Fiber-reinforced polymer composites

Composite type where the dispersed phase has geometry of a fiber (i.e., a large length-to-diameter ratio).

E-glass (electrical glass)

The standard glass composition used for most glass fibers.

Small-particle reinforcement (dispersion-strengthened composites)

Particles diameter is between 0.01 and 0.1 mm (10 and 100 nm), particle–matrix interactions occur on the atomic or molecular level.

Rubber

Automobile tire matrix.

Carbon black

Automobile Rire particles.

Glass Fiber-Reinforced Polymer (GFRP) Composites

Glass fibers (referred to as E-glass) + polymer matrix.

200 oC

Most fiberglass materials are limited to temperatures below.

Carbon Fiber-Reinforced Polymer (CFRP) Composites

Carbon fibers + polymer matrix.

Carbon fibers

Have highest specific modulus & strength of all fibers, retain their properties at elevated temperatures and are not affected by moisture or a wide variety of solvents, acids, etc.

Aramid Fiber-Reinforced Polymer Composites

Outstanding strength-to-weight ratios, examples Kevlar™ & Nomex™.

Aramid Fiber-Reinforced Polymer Composites

Known for its toughness, impact resistance, and resistance to creep and fatigue failure; used in ballistic products, sporting goods, tires, ropes, missile cases, pressure vessels, and automotive brakes.

Polymer matrix

Holds fibers in place, protects fiber surfaces protects from abrasion, transfers load to fibers.

Pultrusion Processes

Like extrusion but workpiece is pulled through die.

Pultrusion

Continuous fiber rovings are dipped into a resin bath and pulled through a shaping die where the impregnated resin cures.

Pultrusion

Pultrusion is limited to straight sections of constant cross section.

Pultrusion Products

Solid rods, tubing, long flat sheets, structural sections (such as channels, angled and flanged beams), tool handles for high voltage work, and third rail covers for subways.

Filament Winding Process

Resin-impregnated continuous fibers are wrapped around a rotating mandrel that has the internal shape of the desired FRP product.

Prepreg

A fibrous material pre-impregnated with a particular synthetic resin, used in making reinforced plastics.