Plastics Properties and Recycling

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Questions and Answers

Which testing method is used to determine the modulus of rigidity for structural beams made of wood?

ASTM D70

ASTM D695M

ASTM D143 (correct)

ASTM F1306

What does ASTM D638 specifically test in relation to plastics?

Torsional properties of plastic composites

Flexural strength of unreinforced plastics

Compressive strength of rigid plastics

Tensile properties of unreinforced and reinforced plastics (correct)

What type of specimen is used in ASTM D70 for testing flexural strength of plastics?

Rectangular bars of at least 2 in. width

Dogbone shaped specimens (correct)

Cylindrical samples with a diameter of 14 mm

Thin sheets no thicker than 10 mm

What aspect of wood testing does the reference to slenderness ratio pertain to?

Compression parallel to grain testing Signup and view all the answers

Which testing standard determines the tensile properties of polymer matrix composite materials reinforced by high modulus fibers?

ASTM D3039 Signup and view all the answers

Which property of plastics is essential for their use as thermal insulators?

Low thermal conductivity Signup and view all the answers

What is the primary advantage of using wood in construction?

It is renewable Signup and view all the answers

What differentiates lumber from timber?

Lumber pieces are smaller than 5 inches in width or thickness Signup and view all the answers

What is a common method used to test the quality of wood materials?

Bending strength test Signup and view all the answers

Which statement correctly describes the optical properties of plastics?

Plastics have high optical clarity Signup and view all the answers

Which of the following is a significant disadvantage of wood as a construction material?

Susceptibility to insects Signup and view all the answers

What characteristic of plastics makes them suitable for recycling?

They can be reshaped without losing properties Signup and view all the answers

What is a primary thermal property of composite materials?

High thermal stability Signup and view all the answers

At what approximate temperature do some plastics begin to melt?

50°C Signup and view all the answers

Which optical property describes plastics that allow light but change its direction?

Translucent Signup and view all the answers

What is a common use for recycled plastics?

Furniture Signup and view all the answers

What property of plastics makes them effective thermal insulators?

Low thermal conductivity Signup and view all the answers

What method is used to determine the mechanical properties of wood?

ASTM D198 Signup and view all the answers

What happens to most plastics when exposed to ultra violet rays from sunlight?

They become brittle Signup and view all the answers

Which of the following best describes the weight of plastics in relation to their specific gravity?

Lightweight, specific gravity 1.3 to 1.4 Signup and view all the answers

Which material is commonly produced from the saturation of phenolic resins?

Acoustic boards Signup and view all the answers

Study Notes

Humidity

Cellulosic plastics are affected by moisture
PVC pipes are highly resistant to moisture

Maintenance

Plastics are easy to maintain
Plastics do not require surface finishing coats or paints

Melting Point

Plastics have low melting points
Some plastics melt at 50°C
Plastics cannot be used in high temperature environments

Optical Property

Some plastics are transparent, allowing light to pass through in its original direction
Some plastics are translucent, allowing light to pass through but changing its direction

Recycling of Plastics

Plastic waste can be used to create drainage pipes, fencing, handrails, carpets, benches, etc.

Sound Absorption

Acoustic boards are made by saturating phenolic resins
Acoustic boards absorb sound and provide sound insulation

Strength

Plastics are strong materials
There is no ideal plastic design for structural components
Plastics are not preferred over metal despite similar strength-to-weight ratios

Thermal Property

Plastics have low thermal conductivity, similar to wood
Foamed and expanded plastics are used as thermal insulators

Weather Resistance

Most plastics resist weathering, except for a few types
Sunlight exposure can damage plastics, causing them to become brittle due to ultraviolet rays

Weight of Plastics

Plastics have low specific gravity, generally ranging from 1.3 to 1.4
This makes them lightweight and easily transportable in large quantities

ASTM D198

Determines the flexural, compression, tension, torsion, and shear modulus of wood for structural members

ASTM D143

Determines the flexural properties of wood for small specimens

Flexure

Test method for determining the flexural properties of structural beams
Material can be solid wood, laminated wood, or a composite construction of wood or wood combined with plastics or metals

Compression (parallel to grain)

Test for determining the compressive properties of structural members made of solid or laminated
Applies to elements with a slenderness ratio (length to least radius of gyration) of less than 17 and greater than a nominal 2 by 2-in. (38 by 38-mm) cross-section

Tension (parallel to grain)

Test for determining the tensile properties of structural elements made primarily of lumber
Applies to elements equal to and greater than a nominal 1 in. (19 mm) thick

Torison

Test for determining the torsional properties

Shear Modulus

Test for determining the modulus of rigidity (G) or shear modulus of structural beams made of solid or laminated wood

ASTM D638 (Tensile Strength)

One of the most common plastic strength specifications
Covers the tensile properties of unreinforced and reinforced plastics
Uses a "dogbone" shaped specimen, 14mm in thickness

ASTM D70 (Flexural Strength)

Uses a universal testing machine and a three-point bend fixture to bend plastic test bars

Compression

ASTM D695M (Rigid plastics)

Puncture

ASTM F1306

ASTM D3039 (Tensile Strength)

Determines the in-plane tensile properties of polymer matrix composite materials reinforced by high modulus fibers

Woods, Plastics, and Composites

Identify different types of wood materials used in construction
Identify different construction materials using paper products
Determine the plastic properties of materials used in construction
Identify different methods of testing woods, plastics, and composite materials

Different Types of Wood Materials Used in Construction

Wood has been used as a building material for thousands of years
Commonly used to build houses, shelters, boats, furniture, and home décor
Wood is a renewable, durable, readily available, and has a high strength-to-weight ratio
It is also a good insulator and can be easily shaped, repaired, and altered
Disadvantages of wood include flammability, susceptibility to decay due to moisture and insects, volumetric instability, variation in strength within the cross-section of a tree log, non-homogeneous and non-uniform properties

Timber as a Structural Material

Beams and girders
Columns
Railway foundation
Trusses

Lumber or Timber?

Lumber: pieces of wood smaller than 5 inches wide by 5 inches thick (regardless of length), machine-planed and sawn to fit certain dimensions, primarily used in residential construction
Timber: pieces of wood over 5 inches wide by 5 inches thick (regardless of length), larger in dimension

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Description

Explore the various properties of plastics, including their interaction with moisture, maintenance requirements, melting points, and optical characteristics. Additionally, discover the recycling possibilities of plastic waste and the advantages of acoustic boards made from phenolic resins. Test your understanding of these important aspects of plastics in this quiz.