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What are the Mechanical Propertoes of Plastic Materials?
Hello people, Today, we’ll be looking at the mechanical properties of all mainstream plastic materials. Below is the easiest bifurcation of all mechanical properties possessed by plastics.
| Materials | Tensile Strength | Tensile Elongation | Compression Strength | Tensile Modulus of Elasticity | Flexural Strength | Flexural Modulus of Elasticity | Hardness | Izod Impact |
| ASTM TEST | psi D638, 73°F | % D638, 73°F | psi D695, 73°F | psi D638, 73°F | psi D790, 73°F | psi D790, 73°F | Scales – D785, D2240, 73°F |
ft-lbs/in D256, 73°F
|
| ABS | 4100 | 32 | – | 294,000 | 9100 | 304,000 | R102 | 7.7 |
| Acetal | 10000 | 75 | – | 450,000 | 14300 | 420,000 | M89, R121, Shore D 83 | 1.5 |
| Acrylic | 10000 | 4.5 | 17,000 | 400,000 | 17,000 | 480,000 | M95 | 0.4 |
| CAB – cellulose acetate butyrate | 5,221 | 33.9 | – | 400,000 | – | 230,000 | – | 4.4 |
| CE – Canvas Phenolic | 9,000 | – | 34,000 | – | 15,000 | 1,500,000 | M100 | 1.5 |
| Polyamide | 12,400 | 90 | – | 470,000 | 17,000 | 410,000 | M85, R121, Shore D 80 | 1.2 |
| ECTFE – Ethylene Chlorotrifluoroethylene | 8,000 | 300 | – | 250,000 | – | 145,000 | Shore D 73 | No breaking |
| HDPE | 4,000 | 600 | 30,000 | – | – | 200,000 | Shore D 69 | – |
| PBT | 8,690 | 300 | – | 416,000 | 12,000 | 330,000 | M72 | 1.5 |
| PEEK | 14,000 | 60 | – | 400,000 | 24,600 | 590,000 | M105, R126, Shore D 85 | 1.6 |
| PET | 11,500 | 70 | – | 400,000 | 15,000 | M93, R125, Shore D 87 | 0.7 | |
| PETG | 7,700 | 210 | – | 320,000 | 11,200 | 310,000 | R115 | 1.7 |
| Polycarbonate | 9,500 | 135 | 12,500 | 345,000 | 135,000 | 345,000 | M70, R118, Shore D 80 | 12.0 – 16.0 |
| Polypropylene | 5,400 | – | – | – | – | 225,000 | Shore D 75 | 1.2 |
| PTFE | 2,500 | 150 | – | – | – | 72,000 | Shore D 55 | 3.5 |
| PVC | 7,500 | – | – | 411,000 | 12,800 | 481,000 | R115, Shore D 89 | 1 |
| PVDF | 7,800 | 35 | – | 350,000 | 10,750 | 310,000 | M75, R84, Shore D 77 | 3 |
| TPE | 1,740 | 31 | – | – | – | – | – | – |
| UNMW | 3,100 | 350 | – | – | – | 110,000 | Shore D 64 | * |
All the values and technical information mentioned above are for information purposes only. All the value shave been figured out after extensive research, but still consulting with your material supplier is advised for accurate figures.
Definition – The meaning of mechanical property is the physical attributes shown by a material upon application of forces.
The Purpose Mechanical Properties in Plastics-
Mechanical Properties are a crucial part of a product’s integrity. Factors like tensile strength, tensile elongation, compression strength, flexural strength, hardness, and elasticity can make or break things for a product’s quality and applications.
Let’s look at the purpose and importance of some of the above attributes.
Impact Strength:
The impact strength in thermoplastics is measured by either Charpy or Izod impact tests. The string method is simple but effective. A rectangular rod is placed in a pendulum at high speed and the energy absorbed while breaking the sample is measured.
The higher the number, the greater the impact resistance. In certain cases, plastics with high resistance values do not break, resulting in no usability. The test will be repeated serval times with a north made on the sample to obtain details under a more dreadful condition.
The plastics with high impact strength are:
- ABS
- Polycarbonate
- EVA
- CAB
- ETFE
- ECTFE
Compressive Strength:
Compression strength is measured by applying a constantly increasing force on cubical or cylindrical samples placed between two plates, thereby measuring elongation and pressure.
One important thing to note is that the compression property at break is not always accurate because ductile materials sample tends to deform without clear breakage. Unrestrained deformation under load isn’t a reliable indication for success under real-life industrial applications.
Following those reasons, compressive street si not determined at the break but determined at defined deformation point (Usually 1,2, or 10%). Another smart move would be to check the test conditions before comparing compression values from different sources.
A reliable method to improve or enhance the compression strength of any thermoplastic polymer is to add carbon fiber or glass fiber reinforcements. However, apparent effects on the load performance are noticeable in the long term rather than short-term (That means patience is the key) due to enhancements in creep properties.
The thermoplastics with impressive compressive strength are:
- ABS
- Acrylic
- Acetal
- Polycarbonate
- HDPE
- Polyethylene
Engaging Read – Physical Properties of Plastic Materials | The Complete Guide
Hardness:
While there are several methods to measure hardness in a thermoplastic, the most common method used is known as “ball indentation hardness.” A sphere-shaped metallic ball of standard dimensions is pressed into material with a certain force; for a certain amount of time, the residual mark will define the hardness value.
There is another method named “Rockwell Hardness testing,” which is also popular for determining hardness.
Carbon fiber and glass fiber-filled materials show the highest surface hardness.
The materials exhibiting excellent hardness are:
- Polypropylene
- Polycarbonate
- HDPE
Tensile and Flexural Strength:
Flexural strength for any thermoplastics is yielded thorough flexure test. In that test, a sample with rectangular or circular is bent until a fracture occurs. The flexural strength represents the highest stress experienced by material in its moment of yield.
Talking about tensile strength, it is the maximum stress a plastic material can resist while being stretched before breaking. Tensile strength is more important in brittle materials than ductile materials.
Materials showing phenomenon tensile strength are:
Flexural Modulus of Elasticity:
Flexural modulus of elasticity means the equation of stress applied to the material along the axis of the sample tested and deformation, determined on the same axis. It is also called young’s modulus and elastic modulus. The flexural modulus of elasticity is determined using Hooke’s law.
In Hooke’s law, force is applied to an object which extends it and puts on a behavior pattern using a stress-strain curve in the elastic deformation region. The dimensions such as length and thickness also play a major role in determining the extension of the force.
Flexural modulus is an important mechanical property for selecting the material, product design, and performance analysis.
- To decrease the material costs, looking for batch quality and long-term consistency in manufacturing.
- To assist the design process.
- Handy in selecting materials for various purposes by testing them in different circumstances under different types of forces.
FAQs –
1. What are the general properties of polymers?
Ans. The general properties of any polymer are decided by its applications. Toughness, reliance, high strength, modulus to weight ratios, corrosion resistance, electrical conductivity, and transparency are general properties of plastics.
2. What are the most important mechanical properties of plastics used in construction?
Ans. Tensile and flexural strength is the most important mechanical properties.
3. Which plastic material has the highest Young’s modulus?
Ans. EVOH – Ethylene Vinyl Alcohol – has the highest young’s modulus.
4. What makes mechanical properties so important for any material?
Ans. If determined correctly, mechanical properties can help in the product’s design process and decrease material costs with more valuable and quality manufacturing.
5. Which is the strongest plastic?
Ans. Polycarbonate is the strongest plastics in the market. It is 200 times stronger than plastics and crack-free.
Suggested Read –
- Thermal Properties of Plastics | The Ultimate Guide
- Polystyrene Repeat Unit | Polystyrene Properties
- PVC Melting Point, Properties, Applications, Advantages & Disadvantages
- What is Ultrasonic Welding? | Ultrasonic Welding for Injection Molded Parts | Common Welding Problems and Solutions | Ultrasonic Welding Advantages
- What is Rotational Molding | Rotational Molding Process | Advantages & Disadvantages | Best Material for Rotational Molding
- 6 Best Plastic Molding Techniques | A Complete Analysis
- Extrusion Molding Process ; A Detailed Guide
- Plastic Thermoforming Mold: Information about Male Vs. Female Molds
Final Thoughts –
That was all I had t say about mechanical properties in plastic materials. I believe determining the right mechanical properties is a must for any plastic manufacturer to curing out the supreme quality of products.
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Have a wonderful day.
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