What is the Disadvantages and Advantages of Plastic?

What is plastic?

According to the national standard (GB/T 2035-2008), the definition of plastic is: Plastic refers to a polymer artificial material composed of organic synthetic resin as the main component, with or without adding other materials (additives).

It can usually be molded into a product with a certain shape under heating and pressure, and the shape remains unchanged at room temperature, this is one of the advantages of plastic.

Some resins can be used directly as plastics, such as polyethylene, polystyrene, nylon, etc., but most resins must be added with some additives before they can be used as plastics, such as phenolic resins, amino resins, polyvinyl chloride, etc.

Plastics are widely used and the products are diversified. There are many kinds of plastics, and different plastics have different properties. Plastics can exist in three states: glassy, highly elastic, and viscous. Plastics are generally molded, and molding methods include injection molding, extrusion molding, blow molding, and compression molding.

What are the Advantages of Plastic?

1. Advantages of Plastic: Easy to process, easy to shape, suitable for automatic mass production, and low cost.

Even if the geometric shape of plastic products is quite complex, they can be molded, and their production efficiency is far better than that of metal processing, especially injection molding plastic products, which can produce very complex plastic products in just one process.

Because plastic is easy to process, it can be mass-produced, and the cost of equipment is relatively low, so the cost of the product is low.

2. Advantages of Plastic: It can be colored at will according to needs or made into transparent plastic products.

Plastics can be used to make colorful, transparent, and beautiful plastic products. Through the blending of plastics, plastic products with jewel-like effects can also be made, which greatly increases the added value of its products and gives people a fresh and bright feeling.

3. Advantages of Plastic: Lightweight and high specific strength.

The density of most plastics is comparable to that of water, around 1.0g/cm, and compared with metal and ceramic plastic products, it is light in weight. Although the mechanical strength of plastic is not as good as that of metal and ceramics, its specific strength (ratio of strength to density) is relatively high, so it can be made into lightweight and high-strength plastic products. If the glass fiber is filled in the plastic, its strength and wear resistance can be greatly improved.

4. Advantages of Plastic: No rust, not easy to corrode.

Plastic will not rust or be corroded by chemicals as easily as metal, so you don’t have to worry about the erosion of acid, alkali, salt, oil, medicine, moisture, and mold when you use it.

5. Advantages of Plastic: Not easy to transfer heat, good thermal insulation performance.

Due to the large specific heat capacity and low thermal conductivity of plastic, it is not easy to transfer heat, so its heat preservation and heat insulation effects are good.

6. Advantages of Plastic: It can make both conductive parts and insulating products.

The plastic itself is a very good insulating substance. At present, it can be said that there is no electrical component that does not use plastic. And filling metal powder or chips in plastic for molding can also be made into a product with good electrical conductivity.

7. Advantages of Plastic: Excellent shock absorption and noise reduction performance, good light transmission.

I understand that plastics have excellent shock absorption and noise reduction properties, transparent plastics (such as PMMA, PS, PC, etc.) can be made into transparent plastics. Design products such as lenses, signs, covers, etc.

What are the Disadvantages of Plastic?

• Poor heat resistance and easy to burn. This is the biggest disadvantage of plastics. Compared with metals and ceramics, their heat resistance is far inferior. If the temperature is slightly higher, they will be deformed and easy to burn. Most plastics can produce a lot of heat, smoke, and toxic gases when burned. Even thermosetting resins will smoke and peel off at temperatures exceeding 200°C.

• As the temperature changes, the properties will change. Needless to say, at high temperatures, even when encountering low temperatures, various properties will change.

• Low mechanical strength. Compared with the same volume of metal, the mechanical strength is much lower, especially for thin-walled plastic products, and this difference is particularly obvious.

• Susceptible to corrosion by special solvents and chemicals. Generally speaking, plastics are not easily corroded by chemicals, but some plastics are easily corroded by special solvents and chemicals, such as PC, ABS, PS, etc, which have particularly poor properties in this respect. It is better, not easy to corrode.

• Poor weather resistance and easy aging. Whether it is strength, surface gloss, or transparency, it is not durable, and it will creep under load. In addition, all plastics are afraid of ultraviolet rays and sunlight and are prone to age under the action of light, oxygen, heat, water, and atmospheric environments.

• Vulnerable to damage, and easily contaminated with dust and dirt. The surface hardness of plastic is relatively low, and it is easy to be damaged. In addition, because it is an insulator, it is charged with static electricity, so it is easy to be contaminated with dust.

• Poor dimensional stability. Compared with metal, plastic has a high shrinkage rate and is easily affected by injection molding process parameters, with large fluctuations and difficult control, so the dimensional accuracy of molded plastic products is relatively low. In addition, when plastic products are exposed to moisture, moisture absorption, or temperature changes during use, the dimensions are prone to change over time.