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Composite Materials

8.4 Composite Materials and Its Importance
CHEMISTRY • Form 4 • Chapter 8: Manufactured Substances in Industry

8.4Composite Materials and Its Importance

A composite material is created by combining two or more non-homogeneous substances: a matrix substance and a strengthening substance. The matrix surrounds and binds the strengthening substance together. The resulting composite material exhibits superior physical and chemical properties compared to its individual original components.

Learning Objectives

  • State the meaning and properties of composite materials.
  • Describe with examples the uses of composite materials.
  • Compare and contrast the properties of a composite material with its constituent materials.

Comparison of Composite Materials and Their Constituent Substances

Identify the matrix and strengthening components of each composite material and observe how their combined properties outperform the individual components.

Reinforced Concrete

Matrix: Concrete
Strengthening: Steel bars / wire mesh

Combined property: High compression strength, high stretching strength, resistant to corrosion.

Fibre Glass

Matrix: Plastic
Strengthening: Glass fibres

Combined property: High stretching strength, heat and electrical insulator, resistant to corrosion, durable.

Optical Fibre

Matrix: Cladding (glass/plastic) + protective jacket (plastic)
Strengthening: Silica glass fibres (core)

Combined property: High compression strength, flexible, transmits data as light.

Photochromic Glass

Matrix: Glass
Strengthening: Silver chloride and copper(I) chloride

Combined property: Transparent, absorbs UV rays depending on light intensity.

Superconductor (YBCO)

Matrix: Yttrium(III) carbonate, barium carbonate, copper(II) carbonate
Strengthening: Oxygen

Combined property: No electrical resistance at very low temperature.

Brief Explanation

Understand the key ideas behind composite materials.

A composite material is formed by combining a matrix substance and a strengthening substance. Neither substance dissolves or blends homogeneously into the other; instead, they work together. By combining them, the weakness of one substance is compensated by the strength of the other.

Natural Composite Materials

Wood: Formed from lignin and cellulose fibres. It is strong and sturdy.

Teeth: Made up of hydroxyapatite and collagen.

Reinforced Concrete Example

Concrete is strong under compression but weak under tension, whereas steel is strong under tension but prone to rust. When combined into reinforced concrete, the resulting composite is resistant to compression, strong against stretching, and protected from corrosion.

Composite Material Matrix Substance Strengthening Substance Uses
Reinforced Concrete Concrete Steel bars or wire mesh Construction of bridges, dams, and buildings
Fibre Glass Plastic Glass fibres Helmets, car bumpers, and printed circuit boards
Optical Fibre Cladding (glass/plastic) + protective jacket (plastic) Silica glass fibres (core) Replaces copper wires in video cameras and connects computers in Local Area Networks (LAN)
Photochromic Glass Glass Silver chloride and copper(I) chloride Car windows, building windows, and camera lenses
Superconductor (YBCO) Yttrium(III) carbonate, barium carbonate, copper(II) carbonate Oxygen Particle accelerators, NMR machines, and MRI machines

Try to Answer First

Answer mentally, then check the explanation.

1

Name the matrix substance and strengthening substance found in natural wood.

Answer: The matrix substance is lignin and the strengthening substance is cellulose fibres.
2

Why does photochromic glass darken when exposed to sunlight?

Answer: Exposure to sunlight causes the formation of silver atoms from silver chloride, which prevents the passage of light.
3

What is the key electrical property difference between YBCO superconductor and its original carbonate components?

Answer: The original carbonate components have high electrical resistance at room temperature, whereas the YBCO superconductor has no electrical resistance at very low temperatures.

Common Mistakes

Avoid these errors when studying composite materials.

!
Confusing the matrix substance with the strengthening substance, for example stating that glass fibres act as the matrix in fibre glass instead of plastic.
!
Stating that photochromic glass contains elemental silver metal from the start, rather than silver chloride which forms silver atoms only upon UV exposure.
!
Forgetting that the reversible clearing of photochromic glass in dim light is catalysed by copper(I) chloride.
!
Assuming superconductors conduct electricity with zero resistance at room temperature, whereas they only exhibit zero electrical resistance at very low temperatures.

Concept Misunderstandings

Compare each misconception with the correct fact.

Misconception

A composite material is a chemical compound or a homogeneous mixture like an alloy.

Correct Fact

A composite material consists of two or more distinct, non-homogeneous phases (matrix and strengthening substances) that remain physically separate while acting together.

Misconception

Optical fibres transmit data using electric currents.

Correct Fact

Optical fibres transmit information and data in the form of light via total internal reflection, not electric current.

Summary

Key facts to remember.

  • A composite material combines a matrix substance (binder) and a strengthening substance (reinforcement) to produce superior properties.
  • Natural examples: Wood (lignin + cellulose fibres) and Teeth (hydroxyapatite + collagen).
  • Reinforced concrete: Concrete + steel bars/wire mesh (high compression and stretching strength).
  • Fibre glass: Plastic + glass fibres (high stretching strength, durable, insulator).
  • Optical fibre: Core of silica glass fibres + cladding of glass/plastic + protective jacket of plastic (transmits data as light, high compression strength, flexible).
  • Photochromic glass: Glass + silver chloride and copper(I) chloride (darkens in sunlight, UV protection).
  • Superconductor (YBCO): Metal carbonates + oxygen (zero electrical resistance at very low temperatures).

Short Activity

Complete all parts before checking your score.

A. Objective Quiz

1

Which of the following correctly pairs the composite material with its strengthening substance?

2

What is the function of copper(I) chloride in photochromic glass?

B. Fill in the Blanks

3

Light moves through the core section of an optical fibre in a series of total internal ________.

4

A superconductor composite such as YBCO ceramic conducts electrical current with zero electrical resistance at very ________ temperature.

C. Match the Composite Material with Its Use

Drag each composite material on desktop. On mobile, tap a material and then tap the matching box.

Composite Material

Reinforced concrete Fibre glass Optical fibre Superconductor (YBCO)

Application / Use

1Construction of bridges, dams, and buildings
2Helmets, car bumpers, and printed circuit boards
3Connecting computers in Local Area Networks (LAN)
4Magnetic Resonance Imaging (MRI) machines
Complete every answer before checking.
 

Keywords

Tap or hover over a term to read its meaning.

Composite material Matrix substance Strengthening substance Reinforced concrete Fibre glass Optical fibre Photochromic glass Superconductor
The views expressed in the notes here are those of the contributor and don’t necessarily represent the views of Pandai.

Composite Materials

8.4 Composite Materials and Its Importance
CHEMISTRY • Form 4 • Chapter 8: Manufactured Substances in Industry

8.4Composite Materials and Its Importance

A composite material is created by combining two or more non-homogeneous substances: a matrix substance and a strengthening substance. The matrix surrounds and binds the strengthening substance together. The resulting composite material exhibits superior physical and chemical properties compared to its individual original components.

Learning Objectives

  • State the meaning and properties of composite materials.
  • Describe with examples the uses of composite materials.
  • Compare and contrast the properties of a composite material with its constituent materials.

Comparison of Composite Materials and Their Constituent Substances

Identify the matrix and strengthening components of each composite material and observe how their combined properties outperform the individual components.

Reinforced Concrete

Matrix: Concrete
Strengthening: Steel bars / wire mesh

Combined property: High compression strength, high stretching strength, resistant to corrosion.

Fibre Glass

Matrix: Plastic
Strengthening: Glass fibres

Combined property: High stretching strength, heat and electrical insulator, resistant to corrosion, durable.

Optical Fibre

Matrix: Cladding (glass/plastic) + protective jacket (plastic)
Strengthening: Silica glass fibres (core)

Combined property: High compression strength, flexible, transmits data as light.

Photochromic Glass

Matrix: Glass
Strengthening: Silver chloride and copper(I) chloride

Combined property: Transparent, absorbs UV rays depending on light intensity.

Superconductor (YBCO)

Matrix: Yttrium(III) carbonate, barium carbonate, copper(II) carbonate
Strengthening: Oxygen

Combined property: No electrical resistance at very low temperature.

Brief Explanation

Understand the key ideas behind composite materials.

A composite material is formed by combining a matrix substance and a strengthening substance. Neither substance dissolves or blends homogeneously into the other; instead, they work together. By combining them, the weakness of one substance is compensated by the strength of the other.

Natural Composite Materials

Wood: Formed from lignin and cellulose fibres. It is strong and sturdy.

Teeth: Made up of hydroxyapatite and collagen.

Reinforced Concrete Example

Concrete is strong under compression but weak under tension, whereas steel is strong under tension but prone to rust. When combined into reinforced concrete, the resulting composite is resistant to compression, strong against stretching, and protected from corrosion.

Composite Material Matrix Substance Strengthening Substance Uses
Reinforced Concrete Concrete Steel bars or wire mesh Construction of bridges, dams, and buildings
Fibre Glass Plastic Glass fibres Helmets, car bumpers, and printed circuit boards
Optical Fibre Cladding (glass/plastic) + protective jacket (plastic) Silica glass fibres (core) Replaces copper wires in video cameras and connects computers in Local Area Networks (LAN)
Photochromic Glass Glass Silver chloride and copper(I) chloride Car windows, building windows, and camera lenses
Superconductor (YBCO) Yttrium(III) carbonate, barium carbonate, copper(II) carbonate Oxygen Particle accelerators, NMR machines, and MRI machines

Try to Answer First

Answer mentally, then check the explanation.

1

Name the matrix substance and strengthening substance found in natural wood.

Answer: The matrix substance is lignin and the strengthening substance is cellulose fibres.
2

Why does photochromic glass darken when exposed to sunlight?

Answer: Exposure to sunlight causes the formation of silver atoms from silver chloride, which prevents the passage of light.
3

What is the key electrical property difference between YBCO superconductor and its original carbonate components?

Answer: The original carbonate components have high electrical resistance at room temperature, whereas the YBCO superconductor has no electrical resistance at very low temperatures.

Common Mistakes

Avoid these errors when studying composite materials.

!
Confusing the matrix substance with the strengthening substance, for example stating that glass fibres act as the matrix in fibre glass instead of plastic.
!
Stating that photochromic glass contains elemental silver metal from the start, rather than silver chloride which forms silver atoms only upon UV exposure.
!
Forgetting that the reversible clearing of photochromic glass in dim light is catalysed by copper(I) chloride.
!
Assuming superconductors conduct electricity with zero resistance at room temperature, whereas they only exhibit zero electrical resistance at very low temperatures.

Concept Misunderstandings

Compare each misconception with the correct fact.

Misconception

A composite material is a chemical compound or a homogeneous mixture like an alloy.

Correct Fact

A composite material consists of two or more distinct, non-homogeneous phases (matrix and strengthening substances) that remain physically separate while acting together.

Misconception

Optical fibres transmit data using electric currents.

Correct Fact

Optical fibres transmit information and data in the form of light via total internal reflection, not electric current.

Summary

Key facts to remember.

  • A composite material combines a matrix substance (binder) and a strengthening substance (reinforcement) to produce superior properties.
  • Natural examples: Wood (lignin + cellulose fibres) and Teeth (hydroxyapatite + collagen).
  • Reinforced concrete: Concrete + steel bars/wire mesh (high compression and stretching strength).
  • Fibre glass: Plastic + glass fibres (high stretching strength, durable, insulator).
  • Optical fibre: Core of silica glass fibres + cladding of glass/plastic + protective jacket of plastic (transmits data as light, high compression strength, flexible).
  • Photochromic glass: Glass + silver chloride and copper(I) chloride (darkens in sunlight, UV protection).
  • Superconductor (YBCO): Metal carbonates + oxygen (zero electrical resistance at very low temperatures).

Short Activity

Complete all parts before checking your score.

A. Objective Quiz

1

Which of the following correctly pairs the composite material with its strengthening substance?

2

What is the function of copper(I) chloride in photochromic glass?

B. Fill in the Blanks

3

Light moves through the core section of an optical fibre in a series of total internal ________.

4

A superconductor composite such as YBCO ceramic conducts electrical current with zero electrical resistance at very ________ temperature.

C. Match the Composite Material with Its Use

Drag each composite material on desktop. On mobile, tap a material and then tap the matching box.

Composite Material

Reinforced concrete Fibre glass Optical fibre Superconductor (YBCO)

Application / Use

1Construction of bridges, dams, and buildings
2Helmets, car bumpers, and printed circuit boards
3Connecting computers in Local Area Networks (LAN)
4Magnetic Resonance Imaging (MRI) machines
Complete every answer before checking.
 

Keywords

Tap or hover over a term to read its meaning.

Composite material Matrix substance Strengthening substance Reinforced concrete Fibre glass Optical fibre Photochromic glass Superconductor
The views expressed in the notes here are those of the contributor and don’t necessarily represent the views of Pandai.
Chapter : Manufactured Substances in Industry
Topic : Composite Materials and Its Importance
Form 4 Chemistry
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