Silicone Polymers: Definition, Preparation, Properties and Applications

What are Silicone Polymers?

Silicones are polymeric organosilicon compounds containing (Si-O-Si) linkages and have the general formula (R₂SiO). They are typically colorless, oils, or rubber-like substances that may be linear, cyclic, or crosslinked. 

Silicone polymers have very high thermal stability and are also called high-temperature polymers. They are widely used in sealants, adhesives, lubricants, medicine, and cooking utensils.

Structure-of-a-Silicone-Polymer

Preparation of Silicone Polymer

When methyl chloride reacts with silicon in the presence of copper as a catalyst at a temperature of 570 K, various types of methyl-substituted chlorosilanes are formed.

Hydrolysis of dimethyldichlorosilane that is (CH₃)₂SiCl₂ followed by condensation polymerization forms straight-chain polymers called silicone polymers.

Preparation-of-Silicone-Polymer

Properties of Silicone polymer

1. It has low thermal conductivity, chemical reactivity, and toxicity.

2. They have low surface tensions and are capable of wetting most surfaces.

3. It does not support microbiological growth and can repel water.

4. It has high gas permeability and good electrical insulation properties.

Applications of Silicone Polymer

1. They are used in the manufacturing of sealants, surfactants, pressure-sensitive tapes, anti-foam agents, silicone rubber molds, etc.

2. They are used in medicinal and cosmetic implants due to low toxicity.

3. They are used as lubricants in both high and low temperatures.

4. They are used as grease, varnishes and these can be used even at low temperatures.

Popular Posts

Conducting Polymers: Definition, Examples, Properties and Applications

Image
What are Conducting Polymers? As the name suggests organic polymers that conduct electricity are known as conducting polymers. They are also known as intrinsically conducting polymers (ICPs) and they have alternating single and double bonds along the polymer backbone (conjugated bonds) or that are composed of aromatic rings such as Phenylene, naphthalene, anthracene, pyrrole, and thiophene which are connected through carbon-carbon single bonds. Examples: Polyacetylene, Polypyrrole, Polyaniline, etc What is the reason behind conducting nature of these polymers? Conducting polymers comes in two forms that are doped conducting polymers and non-doped conducting polymers. The conductivity of non-doped conjugated polymers is due to the existence of a conductivity band similar to a metal. In a conjugated polymer, three of the four valence electrons form strong sigma bonds through sp² hybridization where electrons are strongly localized. The remaining unpaired electron of each carbon atom re...
Read more

Crime Scene: Definition, Types and Characteristics

Image
What is a Crime Scene ? A place where the crime is committed or where the maximum physical evidence related to crime is found is known as a crime scene. A crime scene is a starting point of the investigation which provides information about the suspect and the victim. This helps to reconstruct the crime and fast resolution of the case. It is noted that the crime scene is not limited to a single place but may extend to a wider area depending upon the nature of the crime committed. For example, In a murder case where murder is done at one place and the body is disposed on another place. In this case, we have two crime scenes that give information about the crime. Types of Crime Scene Based on evidence found on the crime scene: 1. Primary Crime Scene The crime scene where the actual crime occurred or where more usable pieces of evidence were found is known as the primary crime scene. For example, A murder scene, theft, assault, etc. 2. Secondary Crime Scene The crime scene which is some...
Read more

Documentation of the Crime Scene: Step by Step

Image
What is documentation of the crime scene and Why it is done? After securing the crime scene, the next most important step is documentation of the crime scene because documentation permanently records the crime scene and its physical evidence. Documentation should be done without any wastage of time as the scene and its evidence may get altered over time. The documentation should be done innovatively and the originality of the crime scene should be maintained and documentation should not have pauses or breaks, it should remain constant till the whole crime scene is documented. There are four main tasks of documentation that is note-making, photography, videography , and sketching . It should be noted that all four tasks are necessary and none is a substitute for another. For example, notes are not substitutes for photography, video is not a substitute for sketching, etc. Following are the sequence for crime scene documentation: 1. Note making Documentation of crime scene in the f...
Read more