Key Properties of Plastics

Plastics have been around for just over a century, but their development has been rapid due to their many unique and exceptional properties. There are many different types of plastics, and their properties vary, but here are some of the common characteristics of plastics:

1. **Excellent Stability:** Most plastics are highly resistant to corrosion and erosion in acids, alkalis, and salt solutions that are not highly concentrated or hot. Some plastics can even withstand strong acids and alkalis, and PTFE (polytetrafluoroethylene), known as the "king of plastics," can even withstand the highly corrosive "aqua regia." Plastic products are difficult to degrade naturally in nature, making them durable.

2. **Lightweight and Aesthetic:** Most plastics have a low density, about half that of aluminum and one-fifth that of steel. Some plastics, such as PE and PP, are lighter than water, making their products naturally lightweight. Additionally, most plastics have an attractive appearance, such as being glossy and transparent. Plastics are also easy to color, allowing products to come in a wide range of vibrant colors, making them popular with consumers.

3. **Good Electrical Insulation:** Most plastics have excellent electrical insulation properties because their molecular structure lacks free ions, making them non-conductive. However, the addition of additives can affect the electrical insulation properties of plastics. Most plastics have good insulation at low frequencies and voltages, and some plastics maintain good insulation even at high frequencies and voltages. Therefore, plastics are widely used in electronics, electrical, communications, and instrumentation fields.

4. **Good Mechanical Properties:** The mechanical properties of plastics are inferior to those of metals, but plastics are much lighter than metals. Therefore, when calculating strength per unit mass (also known as specific strength), plastics approach or exceed traditional metal materials. Some plastics, such as fiberglass, have a specific strength much higher than steel. Therefore, plastics can be used to make many structural components.

5. **Good Barrier Properties:** Plastics have excellent barrier properties against gases and water vapor. Therefore, plastics can be used to make various containers, products, and films that provide good waterproofing and moisture resistance.

6. **Good Processability:** Various Plastic Products are molded from molten plastic using molding machines. Since the melting point of the resin is relatively low and easy to melt, the molten material can be injected into the mold, and complex shapes, stable dimensions, and high-quality Plastic Products can be formed in a very short time.

7. **Good Friction and Wear Resistance:** Most plastics have excellent friction reduction, wear resistance, and self-lubricating properties. They can operate normally in water and corrosive media and can also work effectively under boundary friction and dry friction conditions, which is much better than most metals. Typically, the coefficient of friction of plastics is much lower than that of metals, only a fraction or a tenth of that of metals. Therefore, plastics can be used to make many friction reduction and wear-resistant products.

8. **Good Vibration Damping:** Many plastics are viscoelastic. When subjected to mechanical vibration, the plastic will produce viscoelastic internal loss, converting mechanical energy into heat energy, thereby reducing vibration. Therefore, plastics can be used to make vibration and noise reduction products, especially in high-speed machinery and office automation equipment.

In addition, plastics also have properties such as thermal insulation, electroplating, and weldability. Some plastics also have good light transmittance, such as PS and acrylic plastics, which have a light transmittance of 92% to 93%, exceeding the transmittance of inorganic glass. It is essential for plastic manufacturers engaged in the production of Plastic Products to fully understand and master the various properties of plastics.