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What are the Physical Properties of Plastic Materials?
Let’s discuss the physical properties of all the mainstream plastic materials. Without further due, here we go.
Specific Gravity: 73°F, Water Absorption: Immersion 24 hours
| Physical Properties | ||
| Materials | Water Absorption | Specific Gravity |
| ABS | 0.3 | 1.04 |
| Acetal | 0.25 | 1.42 |
| Acrylic | 0.2 | 1.19 |
| CAB – cellulose acetate butyrate | 1.4 | 1.2 |
| CE – Canvas Phenolic | – | 1.37 |
| Polyamide | 0.24 | 1.43 |
| ECTFE – Ethylene Chlorotrifluoroethylene | <0.10 | 1.68 |
| HDPE | 0.1 | 0.96 |
| Nylon | 1.2 | 1.14 |
| PBT | 0.08 | 1.3 |
| PEEK | 0.5 | 1.32 |
| PET | 0.1 | 0.38 |
| PETG | 0.2 | 1.27 |
| Polycarbonate | 0.15 | 1.2 |
| Polypropylene | – | 0.91 |
| PTFE | 2.15 | <0.01 |
| PVC | 0.06 | 1.42 |
| PVDF | 0.02 | 1.78 |
| TPE | – | 0.95 |
| UNMW | – | 0.93 |
The Importance of Physical Properties –
Adequate physical properties can make or break things for the integrity of a product. Specific gravity and water absorption are an integral part of a product’s quality.
Water Absorption:
Talking about water absorption abilities, a material that properly becomes very useful for manufacturers, increasing its potential applications significantly.
Water absorption is the ability of plastic material to absorb water or moisture from the atmosphere. Absorbed water acts as a plasticizer, reducing the strength and glass temperature of the plastic. It can be reversed, but absorbed moisture can also trigger unalterable degradation of polymer structure.
Factors affecting water Absorption:
- Type of plastic
- The proportion of additives, filaments, fillers, and reinforcements used
- Morphology
- Length of exposure
- Relative humidity of temperature
- Composites – fiber fraction and orientation
Below I have shared the water absorption values:
| Water Absorbtion Values | ||
| Materials | Max Value (% weight) |
Min value (% weight)
|
| ABS | 0.8 | 0.1 |
| CAB | 2.2 | 1.9 |
| ETFE | 0.03 | 0.03 |
| HDPE | 0.01 | 0.005 |
| LDPE | 0.015 | 0.005 |
| Nylon | 1.9 | 1.6 |
| PBT | 0.2 | 0.1 |
| PC | 0.2 | 0.1 |
| PE | 0.06 | 0.02 |
| PEEK | 0.5 | 0.1 |
| PET | 0.2 | 0.1 |
| PETG | 0.1 | 0.1 |
| PP (Both homopolymer and copolymer) | 0.1 | 0.01 |
| PVDF | 0.05 | 0.03 |
| PVC | 0.4 | 0.04 |
Surface Quality:
Polymers normally have a “Benchmark” Density that can provide a value of the surface gravity of a particular material. However, there are a number of factors that can affect the surface gravity such as absorption of solvent, and crystallinity. The density can differ within portions of the same sample such as thermal history, porosity, crystallinity, and changes in material composition.
The surface gravity of a material can be determined using two main methods.
Method A is used for testing solid plastic in water and the method is used in any other liquid other than water.
Method A is more common than the other and can be implemented with rod, sheet, tube, and molded chunks of plastic materisl not contrived by water. The same is weighted in air, first and then in distilled water at 23°C.
Now the following formulas will be used for determining the surface gravity
Specific Gravity = (Weight A / Weight B)
Density = (Weight A / Weight B) * 0.9976 g/cm3 , where 0.9976 g/cm3 is equal to the density of distilled water at 23°C
Density and surface gravity determination is crucial for the custom plastic sheet industry as the plastic sheets are sold on a cost per pound basis. The lower the surface area of a specific material the more material you will get on a per pound basis.
Let me give you an example to understand that better, Polypropylene and PET have different densities and surface gravity. PP has a surface density of 0.90 and PET – 1.40. When comparing both materials, accounting size, and constant gauge, customers can witness a 30% reduction in density from PET to PP and an increased yield on pounds purchased.
All the information and values written above are for information purposes only. To know the perfect value consulting the material supplier would be the best option.
Engaging Read – Melting Point of Plastics | The Ultimate Guide
FAQs –
1. Can water pass through plastic?
Ans. The amount of moisture absorbed by plastic is limited. The moisture absorption density can be attributed to ambient conditions such as temperature, humidity and contact time, etc. The highest water/moisture absorption is exhibited by Nylon, aka polyamide.
2. What are the common properties of plastic?
Ans. A few of the common properties are Chemical resistance, corrosion resistance, ductility/malleability, fracture toughness, hardness, plasticity, density, thermal conductivity, formability, impact resistance, etc
3. What properties make using plastic material a smart choice?
Ans. Plastics are resistant to many atrocities like corrosion, chemical attacks, high strength-to-weight ratio, thermal conductivity, good durability, excellent shock resistance, low cost, easily available in both low and high quantities, etc. That bouquet of beneficial properties makes using plastic material for manufacturing purposes a very smart choice.
4. What are the two types of plastics?
Ans. There are two main types of plastics – Thermoplastics and thermosets.
5. What is the toughest plastic?
Ans. In terms of durability, strength, and impact resistance Polycarbonate is the toughest plastic material out there.
The Takeaway –
That was all I had to say about the physical properties of plastics. Understanding a plastic material’s property is a must for good productivity, ample production, low cost, and boosting profits.
I hope you like my piece. Kindly share your reviews in the comment box.
Have a wonderful day 🙂
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