Advanced Materials: Composites Lecture 29

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What is the result of combining matrix and reinforcement in materials science?

New materials with excellent properties

What type of composites are used for applications that require high strength materials?

Composites with crosslinked polymers and inorganic reinforcement

What is a characteristic of a composite material?

Showing properties different from its constituents

What are the two main phases that make up a composite material?

Matrix phase and Dispersed phase Signup and view all the answers

What are some advantages of composite materials?

High strength, light weight, high strength/weight ratio, good toughness, good mechanical properties, and corrosion resistance Signup and view all the answers

What is an example of a composite material found in nature?

Bone (a composite of collagen fibres in hydroxyapatite) Signup and view all the answers

What are the three main categories of composite materials?

Particle-reinforced composites, Fiber-reinforced composites, and Structural Composites Signup and view all the answers

What are some examples of composite materials used in engineering applications?

Steel reinforced cement structures (concrete), Aramid fibre composites in bulletproof jackets, and composite materials used in aircrafts and automobiles Signup and view all the answers

What is the advantage of using composite materials in certain applications?

They are lightweight and have high strength Signup and view all the answers

What is the purpose of adding reinforcement to a polymer matrix?

To improve the properties of the matrix Signup and view all the answers

What is a characteristic of composite materials that makes them useful in certain applications?

They have exceptionally good mechanical properties Signup and view all the answers

What are the components of a composite material?

Two or more distinct phases with an interface separating them Signup and view all the answers

What is the typical diameter of filaments used in reinforcement?

5-10 µm Signup and view all the answers

What are the typical properties of carbon fibers?

High modulus, high specific strength, and stiffness at elevated temperatures Signup and view all the answers

What are the benefits of using aramid fibers in composites?

High modulus, high tensile strength, and thermal stability, resulting in composites with high strength Signup and view all the answers

What is the main advantage of using particulates as a dispersed phase in composites?

Results in tough materials with improved thermal and electrical properties Signup and view all the answers

What is the characteristic of whiskers that makes them useful for reinforcement?

High degree of crystalline perfection, resulting in exceptionally high strength Signup and view all the answers

What is the advantage of using flakes over fibers in composite materials?

Packing of flakes is more efficient, resulting in increased strength in a plane and unidirectional reinforcement Signup and view all the answers

What is the main characteristic of the fibers in the filament-winding operation?

Good fibre orientation Signup and view all the answers

What is the composition of wood?

Composite of cellulosic fibres in lignin as matrix Signup and view all the answers

What are the benefits of the structure of plywood?

Lightweight, strong, and consistent strength in all directions Signup and view all the answers

What is the difference between cellulose and hemicellulose in terms of strength and hydrolysis?

Cellulose has good strength and is resistant to hydrolysis, while hemicellulose has less strength and can be easily hydrolyzed Signup and view all the answers

What is the characteristic of polyimide sheets?

Excellent impact strength and tensile strength Signup and view all the answers

What are the two main components of composites?

Matrix and reinforcement Signup and view all the answers

What is the advantage of using carbon fibre reinforced polyimide?

It is light weight and has high strength. Signup and view all the answers

What are the factors that affect the mechanical properties of fibre reinforced polymers?

The nature of the fibre, length of fibre, amount of fibre, and orientation of fibre. Signup and view all the answers

What is the principle behind fibre reinforced polymers?

The principle of combined action. Signup and view all the answers

What is the characteristic of fibre reinforced polymers that distinguishes them from conventional materials?

They show properties that cannot be met with conventional materials, such as high strength, light weight, and high corrosion resistance. Signup and view all the answers

What is the significance of fibre reinforcement in improving mechanical properties?

It allows for the creation of materials with high strength and light weight, meeting mechanical strength requirements for specific applications. Signup and view all the answers

What is the term used to describe materials created by combining two or more distinct materials?

Composites. Signup and view all the answers