April 18, 2024 | UR Gate
Thermal Degradation of Polymer with Experimental Procedure
Learn about thermal degradation of polymers, its mechanisms, factors, and effects on material properties in this detailed analysis.
Introduction:
Degradation: It is the breaking of chemical bonds between atoms in the main chain of the polymer depending on the type of agent used to break the bonds (physical or chemical factors).Thermal cracking of polymers refers to the process of converting polymers into smaller compounds by thermal decomposition. This process is commonly used in recycling and disposal of plastic waste industries.
Polymers are broken down by heat into smaller units using various methods. One common method is thermal decomposition in reactors, where the polymer is heated to a high temperature in a dedicated reactor. Under the influence of heat, chemical bonds in the polymer are broken, converting it into monomers and other small compounds.
The temperature required to break down polymers varies depending on the type of polymer and its properties. For example, some thermoplastic polymers such as polyethylene terephthalate can be easily broken down at moderate temperatures, while higher temperatures are required for polyethylene.
In summary, thermal polymer cracking is an important process used in the recycling and disposal of plastic waste industries. Environmental benefits include reusing plastic materials and reducing reliance on oil, while economic benefits come from saving natural resources and reducing pollution.
Types of Cracking (Degradation):
1- Regular Cracking: (Polymer Breakdown into Monomers)
Regular cracking in the thermal cracking of polymers is a process of converting polymers into smaller and more sequentially and regularly fragmented bonds. This is done by breaking the chemical bonds in the polymer to form smaller units of monomers.
Regular cracking technology aims to obtain specific and precisely controllable monomeric compounds, which can be used in the chemical synthesis of other materials. Regular cracking requires the appropriate use of heat, time, and chemical catalysts to ensure the formation of regular small units.
The application of regular cracking can enhance the recyclability and reuse of polymers, as the monomeric compounds obtained can be used in the production of new polymers or in other industries. Depending on the nature of the polymer, breaking it down into regular small units may be necessary for use in plastic loop recycling.
2- Random Cracking: (Random Cracking Resulting in Polymer Chain Fragmentation)
It is a process of randomly breaking chemical bonds in polymers. During this process, the polymer is exposed to high temperatures, which reduce the strength of the chemical bonds and break some of them.
Procedure:
- A dry 250 ml round-bottom flask is filled with polystyrene after it has been cut into small pieces and heated on a heater with continuous stirring around the walls of the flask until the polymer starts to soften. Polystyrene is continuously added to the flask while heating until white vapors begin to rise, at which point the flask is connected to a condenser and a receiving flask to collect the styrene monomer distillate.
- We continue to collect the monomer until the liquid inside the flask becomes highly viscous, at which point we stop distillation.
- We collect a sufficient amount of styrene monomer (about 20 ml) and store it in a cool place for later experiments.