The spelling difference between silicon and silicone is whether the suffix has a visible letter "e". You will assume at first glance that they have similar properties. But the opposite is true. These two substances, which are often confused, simply represent different universal materials. People also often ask questions about silicon or silicone. It depends on how you define and apply it.
In this comprehensive article, we'll explore the key differences between silicon and silicone, including their manufacturing, chemical structure, properties, and applications.
What is silicon?
Silicon is an extremely common natural chemical element, second only to oxygen in the earth's crust. With its bright, ultra-pure appearance, you may be fooled into thinking that silicon is a metal. However, it is very brittle at room temperature. Because it has the properties of both a metal and a non-metal, it has another chemical name called metalloid silicon. Silicon is a tetravalent metalloid with melting and boiling points of 1414°C (2577.2°F) and 3265°C (5909°F) respectively. It rarely occurs in nature in elemental form and is more commonly known as silica or silicon dioxide. It occurs widely in quartz, quartzite, and other minerals.
The selective addition of impurities with missing or extra electrons to the silicon crystal structure changes the silicon's electrical conductivity, allowing it to act as an insulator or conductor. These properties are crucial for developing, designing, and manufacturing modern electronic products(Including microchips).
Chemical structure of silicon
Silicon atoms in the crystalline state are arranged in a tetrahedral network. Its structure is very similar to that of a diamond, with each atom connected tetrahedrally to four adjacent other atoms.
What is silicone?
Silicone is an inert man-made polymer. This large family of polymers usually consists of equal amounts of silicon and oxygen and varying amounts of carbon and hydrogen. It occasionally also contains other elements. It is commonly used in the form of oils, caulk, rubber, and resins. It is known for its excellent temperature resistance and flexibility and is used in lubricants, medical, kitchen utensils, cookware, adhesives, sealants, thermal insulation, voltage line insulators, and food storage products.
Chemical structure of silicone
Covalently bonded silicon and oxygen atoms alternate in the long polymer chain, with other elements or compounds branching out as substituents for the silicon. These substituents are mainly phenyl, vinyl, or hydrogen.
Since silicon and silicone have completely different skeleton structures, they also have different properties. Let's take a closer look at how their structure determines their performance.
How does structure of silicon determines its properties？
Unlike soft silicones, pure silicon is known for and exhibits excellent thermal conductivity due to its rigid crystal structure, allowing heat to be easily transferred through atomic vibrations, resulting in efficient heat conduction.
The presence of a single-atom layer of oxygen(SiO2) on the surface of silicon contributes to the chemical inertness of silicon, making it highly stable and resistant to decomposition. This oxide layer acts as a barrier, preventing further reactions with the surrounding environment in the first place. Therefore, silicon has excellent resistance to degradation and corrosion. Although the covalent bonds between silicon atoms are each relatively weak, there are a lot of bonds in the lattice structure that help improve silicon's heat resistance. Applying heat to silicon causes electrons to move through the crystal lattice. This effect becomes more pronounced at higher temperatures.
How does the structure of silicone determine its performance?
Because silicones have long polymer chains, they exhibit soft, rubber-like elasticity. Oxygen atoms without any substituents further enhance these properties. Having only two bonded oxygen atoms allows the siloxane bonds (Si-O-Si) to rotate relatively freely. This ability to rotate can result in silicon-based polymers with easily reduced viscosities. It's also the flexibility of silicone that makes it insulating, meaning it can effectively suppress and absorb heat energy.
The presence of non-polar groups (methyl, phenyl) on the outside of silicones makes them hydrophobic, chemically inert, and biocompatible. Therefore it does not mix easily with water and other polar substances. In addition, its very strong and stable silicon-oxygen bonds provide excellent thermal stability, allowing the silicone to withstand high temperatures before decomposing. The electrons within silicone lack free electrons due to their participation in covalent bonding, so it cannot move, conduct heat, or conduct electricity. This makes it an effective electrical insulator.
It can be seen from the above that the structural differences between silicon and silicone polymers play a crucial role in determining their respective properties.
How is Silicon Produced?
The production process of silicon is quite simple. Here are the key steps:
Step one: Extract the silicon ore from an open pit or underground mine. The most common silica mineral is quartz.
Step two: The crushed and cleaned quartz contains very few impurities. They are mixed with carbon and heated in a hot furnace to about 1800C°. At high temperatures, the quartz clock's oxygen reacts with carbon and obtains CO gas and 99% silicon. The CO gas exposed to the air reacts to CO2. The process is complex and involves multiple reaction steps. The silicon is removed from the electric arc furnace in batches.
The third step: further finely purify the crude silicon through physical vapor deposition or chemical vapor deposition technology at high temperatures.
Step four: The metallic silicon (pure silicon) with impurities removed is then cooled and solidified to obtain polysilicon. They can be used in solar cells and integrated circuit applications.
How is silicone produced?
The first two manufacturing steps of silicone are the same as the first two steps of manufacturing silicon.
Step 3: Grind or crush the cooled silicon to the desired particle size, then mix the fine powder with chlorosilanes and heat to activate the reaction between the components. The result of this reaction is the formation of methylchlorosilane. It contains dimethyldichlorosilane, the main component of silicone. This process is a crucial step in the production of silicone.
Step 4: At this stage, you need to heat the mixture to a precise temperature. The different components will evaporate and be separated based on their boiling points. This critical step is a complex distillation process.
Step 5: Next, adding water to dimethyldichlorosilane causes the hydrochloric acid and disilanol to separate. The silanol then condenses to form polydimethylsiloxane. The reaction is catalyzed by hydrochloric acid. The process of forming polydimethylsiloxane involves hydrolysis.
Step 6: At this time, the siloxane bonds in polydimethylsiloxane are the main structural components of silicone. The polymerization of silicones involves many different methods to achieve the desired properties of the finished product.
Since silicon and silicone have completely different structures and properties, they each have different applications, as follows:
Applications of Silicon
Contains between 96% and 99.99% silicon for multiple uses. Details as follows:
Gold element: Adding silicon during the production of aluminum can increase the corrosion resistance and mechanical properties of aluminum alloys.
Key raw material for silicone: Silicon can be converted into a key raw material for silicone polymers through various chemical processes.
Polysilicon: Silicon is processed to create polysilicon. Its purity is generally 99.9999% and it is mainly used in the production of electronic and solar applications.
In addition to the above uses, silicon is a key raw material and ingredient in a variety of applications and products. Silicon that easily combines with oxygen generally exists in the form of silica. You can think of silicon as silica.
Ceramic material
In its silicate form, it provides heat resistance for pottery, enamel, and ceramic applications.
Building materials
It is often the main ingredient in the manufacture of concrete, bricks, and glass. Its presence contributes to the durability and strength of these building materials.
Applications of silicone
Silicones' unique structure provides unlimited flexibility for many applications.
Adhesives and Sealants
Silicone adhesives and sealants provide flexible, water-resistant, and weather-resistant bonds for plastic automotive, construction, and aerospace applications to ensure the durability and safety of components and structures.
Electrical Insulation
Silicone is an ideal electrical insulation material and is well suited for use in power cables, high-voltage insulators, and other electrical equipment. Its excellent heat resistance, chemical stability, and weather resistance enable it to effectively isolate high-voltage parts of electrical equipment in extreme environments that may cause other materials to degrade or melt. It can maintain stable insulation performance in complex working environments, to protect sensitive parts.
Cookware and Kitchenware
Silicone provides a nonstick, heat-resistant, weather-resistant, and inert surface. These characteristics make it more suitable for ovens and microwave applications with high-temperature requirements. Its excellent tear resistance makes silicone tableware last longer than traditional similar products, thus saving you time and money in purchasing.
Softener
Silicone oil is crucial in the development and application of high-grade paper towels. Its good hydrophilicity and excellent soft feel make it particularly suitable for improving the softness of paper towels.
Lubricant
Silicone oil is a synthetic lubricant. Its excellent high temperature resistance and chemical stability allow it to withstand extreme environments that many organic lubricants cannot withstand. Its stable polymer structure makes silicone oil less likely to reorganize at high temperatures.
Medical/Dental Devices
Silicones are often found in medical devices, catheters, and dental equipment. Its excellent elasticity, biocompatibility and durability make it the material of choice for applications in these demanding fields.
Summary
Now you have learned from this article that there are big differences between silicon and silicone in structure, performance, and application. Yongrui is a top silicone products manufacturer. We manufacture silicone products that comply with LFGB or FDA approved by international agencies, especially in kitchenware, and tableware, and provide services from design, prototype, precision molds, mass production, and other services. If you have any questions about silicone rubber products or projects or need more technical support from us, please contact our team immediately.
