Rubber products should be natural or synthetic?
Rubber products can be seen everywhere in life, such as car tires, gloves, seals, etc. These products are divided into natural rubber and synthetic rubber. Although there is only a difference of two words, the performance is very different. Let's analyze them in detail.
From the "origin" to see the structure
Natural rubber is like a carefully designed work of nature. It comes from the sap of rubber trees. The main component is a substance called cis-1,4-polyisoprene. The molecular structure of this component is very regular, like neatly arranged small chains, and the connection between each other is not loose or tight, which is also the basis of its many excellent properties.
Synthetic rubber is the crystallization of human wisdom. Its raw materials are petroleum and other chemical products. Scientists have made different types of synthetic rubber by adjusting the arrangement of molecules. For example, some add "small bumps" like benzene rings to the chain, and some change the cis and anti-directions of the chain, just like building blocks, to build different structures, giving them different abilities.
Is elasticity good
Speaking of elasticity, natural rubber performs very well at room temperature. In the temperature range of 25-80℃, its rebound rate can reach more than 80%, just like the ball we play with, which bounces back quickly after being thrown out. But it is a bit "afraid of cold and heat". When the temperature drops below -60℃, it will become hard and lose its elasticity; when the temperature is too high, it will become soft and lose its strength.
Synthetic rubber has its own advantages in elasticity. For example, silicone rubber is a "high and low temperature expert". Even at an ultra-low temperature of -100℃, it can maintain its elasticity and work in a high temperature environment of more than 200℃, which is something natural rubber cannot do. Butadiene rubber has better elasticity than natural rubber, and tires made of it run lighter.
Is it wear-resistant and durable? Natural rubber is quite strong and can withstand 120,000 repeated bends. It also has good tear resistance and is not easy to be torn. But if it is rubbed frequently, it will wear faster than some synthetic rubbers.
Synthetic rubber has many "experts" in terms of wear resistance. Butadiene rubber is very wear-resistant, 30% higher than natural rubber. Using it as a tire tread can make the tire last longer. Styrene-butadiene rubber can withstand repeated bending and can withstand more than 200,000 flexions. It is much more durable than natural rubber, so it is often used to make rubber parts that need to be moved repeatedly.
Is it durable and afraid of corrosion? Natural rubber is a bit "delicate". It is afraid of ozone and sunlight. It will age over time, become hard and brittle, and easily crack. If it encounters organic solvents such as gasoline and motor oil, it will swell like a sponge soaked in water, and the swelling rate can reach 300%, which makes it impossible to use normally.
Synthetic rubber is much more powerful in terms of corrosion resistance. Nitrile rubber is an "oil-resistant expert". Even if it is soaked in motor oil, the volume change is very small, and the swelling rate can be controlled within 5%. It is particularly suitable for sealing rings that come into contact with oil. Neoprene is not afraid of ozone and sunlight, and it is not easy to age in the wind and sun outdoors. It can be used as a cable sheath for many years.
Is it easy to process?
Natural rubber is easy to process. It has a moderate viscosity. Just like kneading dough, it is easy to mix with additives such as carbon black and sulfur, and it consumes less energy during processing. This is also one of the reasons why many products that need to come into contact with the human body, such as medical gloves, use natural rubber, because the processing process is simple and the finished product is softer and more comfortable.
Synthetic rubber is difficult and easy to process. For example, butyl rubber is more "stubborn" and requires high temperature and high pressure conditions to process it well; but some synthetic rubbers can become better through special processes, such as nitrile rubber. After dynamic vulcanization treatment, the tensile strength can reach 20MPa, which is almost catching up with natural rubber.
How to use it in real life?
In actual applications, natural rubber and synthetic rubber often "cooperate". For example, car tires often mix natural rubber with other synthetic rubbers. Natural rubber can make tires more tear-resistant and ensure driving safety.
Synthetic rubber plays a unique role in different scenarios. Butadiene rubber can reduce the resistance of tires when rolling, making cars more fuel-efficient; silicone rubber is often used as sealing rings in car engines because it is resistant to high and low temperatures and can be firmly sealed in high temperature environments; butyl rubber inner tubes have particularly good sealing properties. If you use it as a bicycle inner tube, you can use it for half a year without inflating it.
